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Is it possible to build soil organic matter while simultaneously decomposing soil organic matter to supply nitrogen?
Sieg Snapp
Soils and Cropping System Ecologist
Dept. of Crop and Soil Sciences
Kellogg Biological Station
Michigan State University
Building soil organic matter (also referred to as soil carbon) depends on the following factors: 1) the amount of carbon added, 2) the quality of that carbon, and 3) the rate of carbon loss. Field crop farmers in the upper Midwest are experimenting with conservation tillage, particularly for soybean production as this crop is adapted to no-till. This reduces soil disturbance, which protects soil carbon from being lost. Adding carbon is achievable through optimizing organic inputs from practices such as applying manure, maximizing crop residues or growing cover crops.
Most organic farmers already strive to augment the use of organic inputs on all their fields. Here we present information on how the quality of organic inputs influences soil organic matter and the value of maintaining continuous living cover on all fields through integrating cover crops whenever the soil would otherwise be bare. Even if the cover crop is quite small, in cases where there is insufficient time or space to allow the cover crop to grow higher than six inches (ideally covers should be allowed to grow to at least 10 inches, which provides about 2,500 lbs. of organic materials in residues), still the ‘out of sight’ but critical inputs from roots are providing habit (homes) and food for a healthy soil community of diverse organisms.
Questions arise regarding which quality and quantify of organic amendments are worth the most, and for which purpose: building the soil, feeding the crop, or both? The costs can be high for compost or manure application, and not all manure quality is the same. This highlights the need for more information about organic amendment quality and predicted impact on soil quality. The concept of quality depends on the goals of the farmer. If the main goal in applying compost is to provide nutrients, then the nutrient content needs to be analyzed. If the main goal is to build soil organic matter, then the ideal would be to know how much carbon is being applied and if that carbon is ‘recalcitrant’ or not rapidly available to microbes to decompose. If no information is available on the amount of carbon in the manure, then the type of animal that produced it and the type of bedding used provides a guide to expected quality (amount of carbon and nitrogen applied in the compost or manure).
Compost
Compost varies in quality, as shown in Table 1 below. From poultry compost there are often short-term benefits, as illustrated in Figure 1, which shows snap bean yield response in a long-term trial from Central Michigan.
It is also important to consider the long-term effects of compost or manure, which often are highest if a mixed quality compost is applied (e.g. the compost is made with different sources of carbon, such as straw and leaves, or the compost is applied in combination with a cover crop [see below for more on this practice]). There are tradeoffs, and compost that provides immediate benefits from high levels of nitrogen and phosphorus may have lower long-term benefits. Table 1 provides a summary of the different types of manure commonly available in Michigan, and the quality of the manure for different purposes is presented for each manure source. Note that the feed provided the livestock, and the bedding used which ends up in the manure, are important in determining manure quality. For compost it is also important to consider what type of carbon was applied in the compost preparation process.
Table 1. Manure type from different livestock systems and the common nutrients, organic carbon and pH associated with different qualities of manure.
Manure type |
Poultry |
Swine |
Dairy |
Beef cattle |
Compost or aged manure |
Slurry or lagoon |
Depends on feed, bedding, storage |
Scrape or pit (pit = similar to swine) |
|
N content |
1-3% |
1-3% |
1-6% |
1-2% |
C content |
19-27% |
15-19% |
15-18% |
16-25% |
pH |
Neutral to alkaline |
Acidic |
Neutral |
Neutral to acidic |
Quality as a nitrogen source |
High |
Medium |
Low |
Low |
Quality—for soil organic matter |
Low |
Low to medium |
Medium to high |
High |
As shown in Table 1, if the primary goal of applying manure or compost is to provide a nitrogen source then poultry manure is a good choice. We also have evidence from our long-term research trials on potato and snap bean rotations that applying poultry manure in some cases can improve the health of the crop by suppressing some soil-borne diseases, leading to improved yields. It is important to learn more about what nutrients are being added with the manure and to reduce the amount of fertilizer applied accordingly. There is potential for long-term benefits in terms of nutrient build ups, so monitoring of soil nutrient status should be frequent if manure is applied.
If the primary goal is to improve soil organic matter status then this will be optimized if manure or compost is applied that is high in straw content, or from cattle fed on pastures and hay (Table 1). A combination of manure or compost is applied PLUS a high biomass producing cover crop, this is ideal for the mix of quality organic inputs and the inputs from living roots. For example, compost or manure that is applied in the fall with a rye cover crop is an easy way to successfully increase organic inputs. If summer cover crops are feasible then sorghum-sudan grass can be grown and incorporated with swine manure or some other medium quality manure to provide a mixture of qualities in the manure and cover crop residues. Application of manure will, from our experience with Michigan field trials, enhance growth of cover crops by 30 to 60 percent, and lead to reinforcement of benefits from the two organic sources. One source of further information is the MSU Extension Bulletin E-2893, “Managing manure in potato and vegetable systems” by Snapp et al., 2003.
Cover crops
Cover crops grown over the winter provide a unique, but hidden benefit in terms of living roots. These provide constant organic inputs from root exudates and root turnover. Roots grow, die back during cold spells and then regrow. This is a key source of food and habitat for soil microorganisms, which in turn helps build soil aggregates that protect soil carbon, and this leads to rapid soil organic matter formation. Choosing the right cover crop for your cropping systems will depend on resources and goals, but there are many sources of information to provide guidance. See, for example, the MSU Extension Bulletin E-2884 “Cover crop choices for Michigan” by Mutch and Snapp, 2003, or the website: www.covercrops.msu.edu/general/general.html
Cover crops are an efficient means to achieve multiple objectives: protect against soil erosion, build long-term soil organic matter and augment the “active” organic matter pool of ready-to-decompose materials that release nutrients and supply crops. So it is possible to achieve the impossible: building soil organic matter (long-term pool) while simultaneously building decomposable soil organic matter (short-term pool) to supply nitrogen and other nutrients. Both pools need to be fed, so a mixed quality of residues is your best bet to achieve these dual objectives. Mixed quality residues can be achieved by combining manure types shown in Table 1, or applying manure in combination with cover crops and other high quality crop residues (for example, rotating with a pasture or alfalfa stubble). If a “low quality” residue that is high in carbon and low in nitrogen (a carbon nitrogen ratio of greater than 25) is incorporated into the soil, then soil microorganisms will compete for available nitrogen to decompose these residues. This will result in nitrogen tie up, and insufficient nitrogen for nitrogen-demanding crops such as corn. It is essential in this case to provide a high quality, N-enriched residues or organic N-enriched fertilizers mixed with the low quality residues. Ensuring sufficient nitrogen is particularly a challenge if the spring is cold or wet.
There is emerging scientific evidence that it is a mixed quality of residues that is most reliable at enhancing soil and crop health, apparently by supporting a diverse soil food web. However, this is an area of research where responses are not consistent and economic gains have rarely been achieved in a reproducible manner, particularly in a field environment. It is not yet known which types of residues are the best to use, nor which are the most beneficial soil microorganisms. It is important to check for your self—and to test on an economically modest scale—any soil health promotion claims for residues or manure to see what works for your soil type and for your farming system.
To learn more, see New Ag Network articles on nitrogen management for organic production and soil organic matter building research findings from long-term field crop trials at the Kellogg Biological Station in Southwest Michigan, or contact Sieg Snapp at snapp@msu.edu. (http://www.ipm.msu.edu/cat07field/fc09-20-07.htm)
Illinois reports on six years of transitioning knowledge
Cathy Eastman (Illinois Natural History Survey), with Edmond Zaborski (Illinois Natural History Survey), Michelle Wander, Darin Eastburn, John Masiunas, Leslie Cooperband, Deborah Cavanaugh-Grant, Dan Anderson, Carmen Ugarte, Shin-Yi Lee, and Isabel Rosa, (University of Illinois), and Jonathan Lundgren (USDA Northern Grain Research Laboratory, Brookings, South Dakota)
Just six years ago this fall we plowed down conventional soybean stubble and seeded the rye cover crop that began an organic transition experiment involving scientists and Extension educators at the University of Illinois, Illinois Natural History Survey, and the University of Wisconsin. Growers working in organically managed systems try to achieve balance within soil biological processes whereby nutrients are more available during times of greater plant growth, but the loss of excess nutrients into the environment is minimized. With that goal of soil biological balance in mind, we posed two research questions:
1) For agricultural lands transitioning from conventional to organic production, are there ways to structure the transition process to facilitate reaching this balance once the land is certified?
2) How do biological systems in transitioning agricultural lands change as soil organisms become more diverse and as growers rely on ecological processes—not synthetic inputs—to build soil organic matter and reduced pests?
We are now in the assessment phase of the experiment, pondering reams of data in a way reminiscent of putting together a 1,000-piece puzzle. To continue the analogy, we have pieced together major portions of the puzzle – a large cloud in a blue sky, part of an old barn, a glimpse of the corner of a hay bale – but the connections between these elements and their function within the picture as a whole can only be guessed at this point. So what can we gather from the puzzle-pieces of data available now? Here are some highlights (unranked).
First, all three transition strategies improved soil fertility following conversion to organic management and were similar in their ability to build soils. The only difference was in soil pH, which was increased in the low-disturbance (perennial pasture) treatment compared to the vegetable (high-disturbance) and cash grain (intermediate) treatments. Fertility sub-treatments did not alter soil fertility significantly.
Second, there were some effects of type of organic amendments (sub-treatments) on some diseases during the transition growing seasons (e.g., increased rust in grasses in the pasture system and corn in the cash-grain system following manure application). In addition, there were also differences in the levels of disease in tomatoes in 2006, the first year after transition, associated with both the farming-system treatment and organic amendment sub-treatment, with the lowest levels of disease observed in tomatoes grown in the former pasture system plots that had previously received manure amendment. In related experiments with soil taken from the research plots during the course of the transition experiment, there were no obvious benefits in using one farming-system treatment over another in terms of enhancing the disease suppressiveness levels of soybean with the pathogens responsible for causing damping-off and sudden death syndrome.
Third, the perennial pasture treatment had the fewest weeds. While the number of weeds per plot decreased between the first and fourth growing season, weed species diversity and weed seed bank diversity increased.
Fourth, in the first year after transition (2006), tomato yields were significantly higher in former perennial pasture treatment compared to the other treatments for the Classica and Bellstar varieties, but only marginally higher for the Roma variety. For soybeans in the second year following transition (2007), yields were 42 percent higher in the former perennial pasture treatment.
These bits of information are significant but cannot be taken out of context until more pieces of the puzzle are available and more linkages become evident. We will be adding to this field activity notes (e.g., weeding and other field-plot activities) and weather data to refine our interpretation of events. We have but scratched the surface.
As we look to gain a better understanding of what is involved biologically in the transition from conventional to organic systems, I for one have a sense of awe at the sheer complexity and beauty of the biological systems we are trying to observe. That, and an even greater appreciation of those who call themselves organic farmers, is the gift I have received from working on this project. We greatly appreciate the help and continuing wise counsel of our organic advisors.
Acknowledgments: Funding for this project is provided primarily by grant number 2003-51106-02086 from the Organic Transitions program of the USDA’s Cooperative State Research, Education, and Extension Service.Andrew Clayton, Jerry Vigue, Tim Howe, and Joel Gruver
Western Illinois University
These studies were initiated to evaluate the impact of population density on soybean grain yield, seed quality and weed control.
First study using standard seedbed preparation
Four target populations (75,000, 150,000, 175,000 and 225,000 seeds/acre) were implemented by adjustments on the planter. Treatments were replicated three times. The highest and lowest populations were outside the range of populations commonly used in both conventional and organic production systems. Seed quality was an important aspect of this study because of the stricter quality standards required for food grade soybean markets.
Methods
The experimental plots (four-rows by 960 ft.) were planted to a food grade soybean variety (Iowa 3001) on June 26, 1998 using a Buffalo four-row planter with 30-inch row spacing. The experimental site was located at the Allison Organic Research and Demonstration Farm (Roseville, Illinois) and followed a three-year crop rotation (corn-soybean-small grain/red clover). Mechanical weed control consisted of multiple shallow tillage passes prior to planting, two rotary hoeings and three row cultivations. Assessment of weed suppression consisted of counting the number of giant foxtail heads and broadleaves that emerged above the soybean canopy. Giant foxtail and broadleaves were sampled on September 23, 1998 from two representative one row sections in each plot (80 total feet for foxtail and 360 total feet for broadleaves). The final stand count was performed on October 8, 1998. Nine representative rows five feet in length were counted for each population treatment to arrive at the average population. The field was harvested on November 17, 1998 with a Gleaner combine. Plot yields were determined using a weigh wagon and converted to yields per acre at 13 percent moisture. A representative sample of soybean seeds from each plot (20 g of seed isolated by three splits from 160 g) was visually separated into six quality categories and weights were determined for each category. Gross and net incomes per acre were calculated using 1998 yield data and February 2008 grain and seed prices (Table 3).
Results
Soybean yield increased with population (Graph 1 and Table 1) and weed populations decreased (Table 1). The highest soybean populations produced the highest percentages of unblemished seeds (Table 2), possibly these soybeans had less competition from weeds and experienced less stress and disease. Yields in this study were limited by the late planting date. Based on current seed and grain prices, the highest final population achieved in this study (166,900 plants/acre) was the most profitable (Table 3).
| Yields of various soybean populations |
 |
Table 1. Effect of soybean population on grain yield and weed counts
| Intended Soybean Population |
Final Soybean Population |
Yield (bu/a) |
Percent Yield increase relative to lowest population | Giant Foxtail weeds/ac | Percent Foxtail reduction relative to lowest population | Broadleaf weeds/ac |
Percent Broadleaf reduction relative to lowest population |
| 75,000/ac | 71,600/ac | 16.5 | N/A | 131,018 | N/A | 1,293 | N/A |
| 150,000/ac | 114,600/ac | 20.0 | 21% | 45,998 | 65% | 1,019 | 21% |
| 175,000/ac | 143,300/ac | 23.0 | 39% | 29,648 | 77% | 873 | 32% |
| 225,000/ac | 166,900/ac | 24.8 | 50% | 16,931 | 87% | 631 | 52% |
| LSD* = 2.96 | LSD* = 25,599 | LSD* = 727 |
Table 2. Effect of soybean population on seed quality
Intended Soybean |
Final |
Percent of soybean seeds Unblemished/ |
Percent of Soybean seeds with brown stain |
Percent of Soybean seeds with purple stain |
Percent of Soybean seeds with green stain |
Percent of Soybean seeds with damage |
Percent of Soybean seeds with splits |
75,000/ac |
71,600/ac |
9.6 |
62.2 |
2.9 |
0.3 |
17.8 |
4.5 |
150,000/ac |
114,600/ac |
16.9 |
62.3 |
2.2 |
0.2 |
9.2 |
4.8 |
175,000/ac |
143,300/ac |
22.2 |
54.9 |
3.6 |
0.2 |
10.7 |
2.5 |
225,000/ac |
166,900/ac |
26.0 |
52.6 |
1.4 |
0.2 |
9.5 |
3.8 |
|
|
LSD* = |
LSD* = 15.5 |
LSD* = |
LSD* = |
LSD* = 6.2 |
LSD* = 5.4 |
Table 3. Effect of soybean population on production system economics
| Intended Soybean Population |
Final Soybean Population |
Yield (bu/a) |
Gross income per acre at $23/bu* | Seed cost per acre at $28.50 per 50 lb bag** |
Net income increase per acre over lowest population*** |
| 75,000/ac | 71,600/ac | 16.5 | $380 | $17.80 | N/A |
| 150,000/ac | 114,600/ac | 20.0 | $460 | $35.60 | $62.20 |
| 175,000/ac | 143,300/ac | 23.0 | $529 | $41.60 | $125.20 |
| 225,000/ac | 166,900/ac | 24.8 | $570 | $53.40 | $154.40 |
** = Based on the average full retail price of two food grade seed beans from Great Harvest Organics and Blue River Hybrids in 2008.
*** = This assumes there are no other differences in production or post harvest expenses.
Second study using ridge-till
A similar soybean population study was performed a year later using ridge-till that produced slightly different results.
Methods
This study was also planted to Iowa 3001 soybeans, but on 36 - inch ridge-till rows. The intended plant populations were implemented by adjustments on the ridge-till planter. Planting occurred on May 25, 1999, which was about one month earlier than the previous year’s population experiment. Its methods of weed control included ridge-till planting, rotary hoeing three times and ridge-till cultivating three times. Weed populations were scored in the 1999 experiment instead of actual weed counts due to no significant differences (Table 4). Soybean quality was also evaluated.
Results
Note that the lowest yield occurred at the lowest soybean population, with yields increasing as the populations increased, with the highest population dipping slightly (Table 4). It is important to note that a significant amount of rain (5.1 inches) occurred between June 1and June 13. This led to shallow water standing in some parts of the field that may have impacted the upper limits of yields.
The amount of weeds in the 1999 experiment were significantly less than in the 1998 experiment even though it was planted a month earlier. This is a characteristic of ridge-till. Weed control is always significantly better in ridge-till than in standard cultivation. Our experience with planting organic soybeans early (prior to the second week in June) using standard cultivation is that the weeds are still very competitive with the crop. For example, note the light giant foxtail pressure in ridge-till (Table 4) versus the heavy giant foxtail populations in standard tillage (Table 1). For comparison, the weed pressure scores for giant foxtail in standard cultivation (Table 1) would have ranged from two (moderate weed pressure) at the highest soybean population, to four (very heavy weed pressure) at the lowest soybean population.
Table 4. Effect of soybean population on grain yield, weed counts, and seed quality in 1999 study| Intended Soybean Population |
Final Soybean Population |
Yield (bu/a) |
% Yield increase relative to lowest population | Giant Foxtail Score** | Broadleaf Score** |
% of Soybean seeds Unblemished/ Excellent appearance |
% of Soybean seeds with damage |
| 70,000/ac | 61,600/ac | 34 | N/A | 1.3 | 0.8 | 5.6 | 4.6 |
| 120,000/ac | 97,800/ac | 39 | 14% | 1.2 | 1.0 | 6.1 | 3.0 |
| 160,000/ac | 127,500/ac | 40 | 19% | 1.2 | 0.6 | 3.2 | 2.2 |
| 200,000/ac | 161,300/ac | 38 | 11% | 1.4 | 0.4 | 6.8 | 2.9 |
| LSD* = 4 | LSD* = 0.5 | LSD* = 0.7 | LSD* = 3.7 |
LSD* = 2.7 |
** = Visual score of weed populations in an area of approximately 12’x 20’ using the following: 0 = none or insignificant, 1 = light, 2 = moderate, 3 = heavy, 4 = very heavy
It is noteworthy that the quality of the soybeans grown in 1999 was lower than in 1998; possible due to wet growing conditions. Further, there were no significant differences in bean quality between soybean populations grown in ridge-till. Table 4 illustrates two quality examples.
Results from a third studyOne of the effects of weeds in organic farming is their competition for soil nutrients. In addition to the data presented in the two studies above, in 1998, we planted low (90,000 plants per acre) and high (180,000 plants per acre) populations of eight different soybean varieties in two fields. One field had low potassium fertility (K = 219 lbs/acre), while the second field had high potassium fertility (K = 430 lbs/acre). Weed control was mechanical, and weed pressure was heavy in both fields. In the field of low fertility, the average reduction in yields at the low planting rates for the eight varieties was 32 percent; in contrast, in the high fertility field, the average reduction in yields for these same eight varieties was much less, only 18 percent (data not shown). These results indicate that the higher level of potassium helped the soybeans planted at the lower seeding rates to perform better in weedy conditions.
Discussion and conclusions
Our results suggest that there are some advantages to planting higher populations of soybeans in organic production systems where good weed control is often difficult to obtain. Recent reports (e.g.,Whigham (1998) and Nafziger (2003)) advise that conventional producers, using herbicides, can increase profitability by planting at lower seeding rates than previously recommended. Our results do not conflict with their final stand recommendations (120,000 to 150,000 plants per acre) to obtain top yields. However, one must keep in mind that in conventional farming with herbicides, growers can plant in narrow rows, weed control is almost perfect, and there is almost no loss of soybean stand during weed control operations. In contrast, in organic systems, perfect weed control is seldom obtained, and soybean stands are reduced during rotary hoeings and row cultivations. While deciding on soybean planting rates for organic systems, growers need to adjust their planting rates to account for loss of stand during field operations, and keep in mind that mechanical weed control is more difficult at lower soybean populations.
Apparent differences in optimal soybean populations for organic and conventional production systems relate to differences in seed cost and role of competition in weed suppression. Weed suppression in organic soybean production relies heavily on rapid canopy closure, while conventional soybean production relies heavily on herbicides to eliminate weeds. Organic food grade soybean seed (2,400 seeds/lb), in the spring of 2008, cost about 22 cents per 1,000 seeds (Great Harvest Organics) whereas conventional feed grade seed (3,000 seeds/lb) with GMO traits cost about 24 cents per 1,000 seeds (Pioneer/Dupont). The cost of higher populations appeared to be justified in organic production systems (Table 3) due to accompanying benefits such as higher yields, better grain quality and better weed control.
These studies or similar ones will need to be repeated to draw stronger conclusions. Less tillage, more populations between 120,000 and 180,000 plants per acre, and an optimum planting date will be targeted if this type of study is pursued in the future.
Literature citedWhigham K. 1998. What is the best soybean seeding rate? Integrated Crop Management. Iowa State University Extension. http://www.ipm.iastate.edu/ipm/icm/1998/4-27-1998/soyseed.html
Nafziger E. 2003. Getting soybean planting right. Agronomy Day Field Tour Presentation. University of Illinois. http://agronomyday.cropsci.uiuc.edu/2003/soybean_planting/index.html
Duane Friend
Natural Resources Management Educator
University of Illinois Extension
Using a combination of compost and dried lake sediment as a soil amendment is showing some promise in improving low organic matter, sandy soils in Illinois.
A field study was initiated in 2007 to look at the potential use of these two soil amendments. Dried lake sediment was applied on an irrigated, sandy soil in Mason County, Illinois. In addition, compost derived from swine manure and yard materials was applied to the same plots with ratios of 25 percent compost and 75 percent sediment; 50 percent compost and 50 percent sediment; and 75 percent compost and 25 percent sediment. Plots were replicated and each amended plot received a total 60 dry tons/acre total of compost with sediment. Control plots did not receive compost or sediment application. Applications were duplicated in 2008. Plots were planted to popcorn, using normal practices for the crop in both years.
Soil tests taken in April 2008, before the second application of compost and sediment, showed a sizeable increase in organic matter percentage, compared to the control plots (see graph).
| Organic matter percent, spring 2008 |
 |
Moisture readings were taken from early June through late July (see graph). Plots that received compost and sediment appeared to hold more moisture than control plots. In all cases soil moisture, even with irrigation, was deficient, although it was less deficient in amended plots.
| Percent of relative water content, June and July 2008 |
 |
The plots were hand-harvested on October 1, and we are awaiting yield and quality results. Yield results in 2007 plots showed amended plots had slight improvements in yield, but there was too much variation to be statistically significant.
For more information, contact Duane Friend at friend@illinois.edu
 |
 |
| After sediment and compost application. | Study site south view mid-August. |
Richard Leep and Doo-Hong Min
Crop and Soil Sciences, Michigan State University
Because of excessive rainfall in many areas of Michigan this past week, many newly seeded alfalfa fields may show poor growth in wet or poorly drained fields which may be due to several diseases. Seedling diseases should be suspected when emergence is poor or there are stunted, discolored, or dead seedlings.
Aphanomyces root rot can cause death and stunting of seedlings as well as more subtle disease of established plants that can result in significant yield reduction. This disease is caused by a soilborne fungal-like pathogen. Other diseases that occur in wet or poorly drained soils include Phytophthora root rot and Pythium seed and root rot. Plants infected with Aphanomyces usually become stunted and chlorotic (yellow) before they wilt and die, whereas Phytophthora and Pythium tend to kill seedlings quickly before plants become severely chlorotic. Another clue to a problem with Aphanomyces is root rot of an alfalfa cultivar that is highly resistant to Phytophthora.
Although not much is known about Aphanomyces root rot in Michigan, it is known to be a serious problem in nearby states including Wisconsin, Indiana, and Iowa. We suspect this disease is also a problem in some Michigan fields. Perhaps because alfalfa disease that occurred in wet soil was attributed to Phytophthora, Aphanomyces root rot of alfalfa was not recognized as a serious problem until the early 1980s. Aphanomyces root rot is best managed by avoiding poorly drained soils and using Aphanomyces-resistant alfalfa varieties. However, this past week, even well drained fields have been water-saturated due to abnormally high rainfall in the past few days.
Alfalfa varieties rated highly resistant (HR) or resistant (R) to Aphanomyces root rot should be planted where slowly drained soils occur and where Aphanomyces may be a problem. A list of varieties and their disease resistance can be found at the Michigan State University Forage Information Systems web site at http://www.msue.msu.edu/fis/ and clicking on the Extension bar and then the Perennial Forage Legume and Grass Varieties for Michigan. Control of Aphanomyces root rot became more challenging when different races of this pathogen were discovered. Many commercial alfalfa cultivars are now available that have resistance to race 1, the first race discovered. Another race (race 2) of Aphanomyces was identified in the early 1990s that overcomes race 1 resistance. Alfalfa cultivars developed for resistance to race 1 are killed by the aggressive race 2 isolates. Race 2 isolates have been identified in a number of states including Wisconsin, Iowa, and Kentucky. Race 2 has not yet been confirmed in Michigan. Alfalfa varieties with resistance only to race 1 may be genetically vulnerable to Aphanomyces root rot in many regions due to the presence of race 2. Several commercial alfalfa varieties are now available that have resistance to both races of Aphanomyces. If resistance to race 2 is not specified for an Aphanomyces-resistant alfalfa cultivar, then you can assume it is resistant only to race 1.
The overall distribution and impact of races 1 and 2 of Aphanomyces are uncertain, but
Aphanomyces root rot should be considered as a potential problem in many parts of
Michigan. If you have an alfalfa seeding that has failed this fall due to the excessive rainfall this past week, it should be safe to replant with alfalfa again next spring since compounds which cause autotoxicity do not accumulate in seedlings. Phytophthora- and Aphanomyces-resistant varieties are recommended for replanting failed seedings. Spring alfalfa re-seeding should be done as early as possible in the spring.
For a photo of Aphanomyces symptoms on alfalfa, please look at this issue online at:
- http://www.ipm.msu.edu/cat08field/fc09-18-08.htm
- http://www.ent.iastate.edu/imagegal/plantpath/alfalfa/aphanomyces/0093.7aphansymp.
html
Doo-Hong Min and Richard Leep
Crop and Soil Sciences, Michigan State University
Among the four seasons, fall is one of the most important seasons in terms of preparing for winter survival and spring regrowth by storing carbohydrate and protein reserves in the crowns and roots. Fall is also the season for regeneration and the formation of the shoots or growing points. Since plants become dormant in the fall as air temperature is getting lower and day length is shorter, nutrient uptake becomes accordingly slower. The following are things to consider for fall forage management for hay and pasture:
1) Soil fertility and liming: Since the price of fertilizer is so high these days, it’s important to use phosphorus (P) and potassium (K) efficiently. One of the best ways to save fertilizer costs is to test soil phosphorus and potassium on the hay fields and pasture. In particular, potassium is directly related to winter survival rate and it’s more susceptible to winter kill when soil potassium level is lower than the optimum level.
Fall is also a good time for liming. Having optimum soil pH is a key to having a healthy forage stand. Grasses generally perform well at a pH of 6.0 or above while most legumes require a pH of 6.5 or more. With low soil pH, plant growth can be very poor caused by poor nutrient uptake, which results in poorer winter survival and more weed problems. This can also result in poor animal performance from low forage yield and nutritive value. Since increasing soil pH is a long-term process, it’s important to apply lime materials at least six to 12 months before the results can be shown, depending on the fineness of lime materials (the higher mesh numbers, the quicker response). It’s good to have fine lime materials, particles that pass a 100-mesh sieve react 100 percent with the soil in six months or less, to increase the soil pH in a short time period. In summary, it’s very critical to soil before putting any phosphorus, potassium or liming materials to the forage fields.
2) Fall harvest management of alfalfa: In the late summer and early fall, alfalfa must either be cut early enough so it can regrow and then replenish root carbohydrates and proteins, or so late that the alfalfa does not regrow more than eight inches and use root carbohydrates. This has resulted in the recommendation in Michigan of a “no-cut” window beginning in September and lasting until the killing frost. However, recent research in Quebec, Canada has helped to redefine this window by assuming that if 500 growing degree days accumulate after the last cutting, there will still be enough regrowth of alfalfa for good carbohydrate accumulation before a killing frost and good winter survival and yield the following year. So a producer can cut in September without hurting the stand as long as there is enough warm weather remaining in the growing season (accumulation of 500 growing degree days) before a killing frost. These growing degree days are calculated as the average of the daily minimum and maximum above 41°F until a killing frost of 25°F. The Quebec research also showed that cutting later in the fall was acceptable as long as less than 200 growing degree days accumulated after cutting. When less than 200 growing degree days accumulated, there would be little regrowth to use up valuable stored carbohydrates and proteins in the alfalfa roots. This would result in good winter survival of the alfalfa plants. For additional information including probability graphs of late summer growing degree days for your area in Michigan, check out the following web site: http://www.ipm.msu.edu/cat08field/pdf/9-18LateSummer.pdf
3) Fall pasture management: Most producers want to extend the grazing season as late as possible before entering winter since the weather condition in the fall is suitable to some degree for forage growth. This can sometimes result in overgrazing the pasture, which is not desirable for stand longevity. Therefore, it’s important to leave six inches of stubble before entering winter, which will be helpful to catch snow and regrow in early spring. Like fall harvest management of alfalfa, testing soil phosphorus, potassium and pH will be important to maintain good quality pasture and follow the soil testing recommendations. In particular, if you have a new late summer seeding, leaving the new seeding without grazing will be important. Grazing newly planted pasture can be damaged by trampling and close grazing. Fall is also a good timing to check the status of your pasture to see if your pasture needs to be frost-seeded next spring using red clover. To do this, pastures should be closely grazed or mechanically mowed in the late fall or winter to open stands and expose soil. A chain drag or light disking can also be an option to help open the stand to increase the opportunity for better seed to soil contact.
Editor’s note: This article was first printed in MSU’s Field Crop Advisory Team Alert newsletter.Mike Staton
Extension Agricultural Educator and Soybean 2010 Coordinator
Michigan State University
Reducing harvest losses is a simple and effective way to increase soybean yields and profitability. Losses of 10 percent are typical and can reach 15 percent. With careful maintenance and operation, harvest losses can be maintained at three percent. Reducing harvest losses from 10 to three percent in a 45 bushel per acre soybean crop will increase the marketable yield by 3.1 bushels per acre. With organic market prices projected to be around $20 per bushel, this translates into more than $62 per acre of additional income.
Harvest timing
Properly timing your harvest operations is critical to reducing harvest losses. Harvest operations can begin any time after the beans have initially dried to 14 to 15 percent moisture. Depending on weather conditions, this is usually about five to 10 days after 95 percent of the pods have reached their mature color. Try to harvest as much of your crop as possible before the moisture level falls below 12 percent to reduce splits and cracked seed coats. Shatter losses have been shown to increase significantly when seed moisture falls below 11 percent and when mature beans undergo multiple wetting and drying cycles. Shatter losses can be reduced by harvesting in the morning or the evening when relative humidity is higher.
Equipment maintenance
Before harvest operations begin, inspect and repair the cutting parts on the header. Make sure that all knife sections are sharp and tight. Check the hold-down clips to ensure that they hold the knife within 1/32 of an inch of the guards. Adjust the wear plates to the point that they lightly touch the back of the knife. Consider switching to quick cut knives if the existing knife sections need replacing or if shatter losses have been high.
Equipment adjustment
Information from the University of Arkansas shows that a skilled combine operator can add more than $150 per hour in additional profits over an inexperienced operator or one that is trying to hurry or cut corners. Despite this, statewide surveys indicate that only 10 percent of combine operators check their combine adjustments regularly and match forward speed to field conditions. Combine operators should understand how losses occur and how to make the proper adjustments.
Nearly 80 percent of harvest losses occur while cutting and gathering the plants into the combine. Most of these are due to shattering. The following recommendations will reduce gathering losses:
- Maintain ground speed at three mph or less. Slower speeds will be required if the crop is lodged or if the stubble is high and ragged. Higher speeds are possible when using quick cut knives.
- Set the speed of the reel to run 25 percent faster than the groundspeed. If the beans are lodged, increase the reel speed up to 50 percent faster than the ground speed. Setting the reel speed too fast will cause the beans to be beat out of the pods before reaching the combine. Setting the reel speed too slow will cause cut plants to fall forward and out of the combine.
- Position the reel axle six to 12 inches ahead of the cutter bar. Ideally, the reel should leave the beans just as they are being cut. Set the height of the reel just low enough to control the beans. Positioning the reel too far forward will increase shatter losses due to excessive flailing action. In lodged conditions, operate the reel as low as necessary to pick up plants. Setting the reel too deep in the canopy will also increase shattering and cause plants to ride over the reel.
Darryl Warncke
Crop and Soil Sciences, Michigan State University
With harvest operations comes trafficking over the fields by combines, tractors, wagons, grain carts, trucks etc. With trafficking comes soil compaction. The degree of compaction that occurs depends on soil moisture. Excessively wet soils will compact more than dry soils. The heavier the load the deeper the compaction occurs. Wider tires tend to spread the weight over a larger area so compaction occurs at a shallower depth. Compaction is most evident during harvest, but compaction may also have occurred during seedbed preparation. Chiseling or subsoiling can be done to help alleviate the effects of compaction, but prior to doing this find out at what depth the compact layer occurs. Studies have shown that chiseling two inches below the compaction zone or depth is very effective in breaking up the compaction layer. Chiseling deeper than this depth provides no additional benefit, and uses a lot more fuel. The presence of a compaction layer and its depth can be determined with a tile rod or even a soil probe when there is good soil moisture. An increase in resistance to pushing the rod in the ground is an indication of compaction. Some consultants may have a penetrometer to use that measures the actual resistance the rod encounters as it is being pushed into the ground. Probe the soil in several different spots in a field to determine whether not compaction is a concern or the depth of compaction. Also, check the soil moisture at the depth of subsoiling. The soil should break apart when handled and not stick together in a clump when squeezed. If the soil is too wet, subsoiling will not be of benefit. The shanks should shatter the soil and not create a smeared channel.
Editor’s note: This article was first printed in MSU’s Field Crop Advisory Team Alert newsletter.
Darryl Warncke
Crop & Soil Sciences
Planting time fertilization of wheat is very important for phosphorus (P) and potassium (K) nutrition of the crop. Having adequate P and K available for fall growth is important for root system development, winter survival and tillering of the plants in the spring. A 100 bushel per acre wheat crop removes 63 lbs P2O5 and 37 lbs K2O in the grain. And each ton of straw contains 13 lbs P2O5 and 23 lbs K2O. Therefore, a 100 bu/a wheat crop with 2 tons straw per acre removed will remove 76 lbs P2O5 and 60 lbs K2O per acre. Soil test to determine the available level of P and K in the soil. Generally, no yield benefit occurs from applying phosphorus when the soil test value is above 25 ppm. Below this value wheat yield may be improved by applying the recommended about of phosphate. The critical K soil test ranges from 85 ppm in sandy soils to 125 ppm in clay loam soils. Above these values yield benefit does not usually occur from K application. Below the critical value applying recommended amounts of potash may improve crop wheat. Even when soil levels of P and K are adequate, applying 25 lbs each of P2O5 and K2O per acre along with 25 lbs N/a will insure good fall root establishment and plant vigor. Studies in Ontario have indicated that application of P and K in bands near the seed at the time of seeding the wheat increased the potential for producing top yields as compared to broadcasting. When soil P and K levels are within 15 to 20 ppm above the critical level, it is good to apply maintenance amounts (equal to crop removal) of P and K if financial resources permit.
In an MSU study, 2007-2008 growing period, various combinations of P, K, and S broadcast just prior to seeding did not improve wheat grain yield over applying only N even though the soil K level was below the critical value. Including copper, manganese and zinc had no effect on yield.
Most of the nitrogen (N) is usually applied for wheat in the spring prior to green up. Slow release N fertilizers now in the market place make possible applying more of the N in the fall prior to seeding with minimal concern for loss. In N studies conducted 2005 through 2007 (harvest year) wheat yields with broadcast-incorporation of N as polymer coated urea (ESN) in the fall resulted in grain yields equal to those produced with urea or UAN applied at the same rates just prior to green up in the spring. However, applying the ESN prior to green up resulted in the best yields, 6 – 8 bushels more than fall applied ESN or spring applied urea or UAN. Slow release N materials provide another option for N management in wheat.
Editor’s note: This article was first printed in MSU’s Field Crop Advisory Team Alert newsletter.Editor’s note:This article was originally published on August 28, 2008 by Sharon Durham on the USDA web site.
Grain storage bins are routinely monitored for temperature to control insect and mold problems. Now an Agricultural Research Service (ARS) scientist and his colleagues at Kansas State University (KSU) have preliminary research findings showing that monitoring carbon dioxide, along with humidity and temperature, also may help detect problems more effectively.
Grain moisture content and temperature are the primary factors affecting grain deterioration in storage. If these factors are not properly monitored and controlled, grain quality can deteriorate quickly due to mold growth and insect infestation.
ARS engineer Paul Armstrong at the agency's Grain and Marketing and Production Research Center in Manhattan, Kansas, and Haidee Gonzales and Ronaldo Maghirang at KSU monitored a simulated grain storage bin during aeration to determine if high-moisture grain, or adverse storage conditions, in the bin top could be detected using sensors to measure relative humidity, temperature and carbon dioxide levels.
Relative humidity and temperature can be used to estimate grain moisture, while carbon dioxide levels indicate the amount of respiration due, primarily, to molds. Current technology allows relative humidity and temperature sensors to be placed at multiple points within the grain mass. Carbon dioxide sensing is more feasible at an aeration duct.
In the study, sensors were placed at different depths in the bin. High-moisture grain, comprising about 11 percent of the volume, was placed at the top of the bin and produced high amounts of carbon dioxide, which in most cases was easily detectable during aeration.
Lowering grain temperature with aeration diminished the amount of carbon dioxide produced, making it more difficult to detect unless the carbon dioxide sensor was located very close to the wet grain.
Relative humidity and temperature sensing gave good estimates of grain moisture for all conditions, but under some grain conditions, high carbon dioxide levels persisted for grain considered to be at safe moisture and temperature conditions. Combining relative humidity, temperature and carbon dioxide measurements gave reasonably accurate measurements of grain moisture content as well as overall storage conditions. ARS is the Unites States Department of Agriculture's scientific research agency.Vicki Morrone, Outreach Specialist
Michigan State University
C.S. Mott Group for Sustainable Food Systems
| An equipment demonstration field day for vegetable farmers was held at the Southwest Michigan Research and Extension Center in Benton Harbor, Michigan on October 2. The field day was co-sponsored by Michigan State University and USDA Farming Services Agency (FSA). This event provided information and hands-on opportunities for farmers seeking information and ideas of how to expand or start a vegetable farm operation. Twenty farmers participated in activities throughout the day. Events included equipment demonstrations; farmers talking with vendors; new farmers meeting experienced farmers; and presentations about custom transplants, market opportunities in Michigan, farm loans and programs of the USDA Farming Services Agency (FSA). The equipment demonstrated included items essential to efficiently and profitably producing and marketing vegetables for expanding vegetable farms. Many operations can be done manually on smaller farms, but require skilled and reliable laborers. With workers in short supply and the cry for locally-produced and organic vegetables growing, these tools will allow a farm to expand to meet today’s demand for fresh vegetables. |  |
The entire day was packed with learning opportunities:
- Presentations from Green Stone Farm Credit Services by Tyson Lemon and FSA by Lloyd Beebe and Paul Wagner discussed the process for a farmer to apply for a loan and the various programs available including loans for beginning farmers, those purchasing a new farm and youth seeking to get into an agricultural business.
- Another session explained how the 2008 Farm Bill will require crop insurance and how it can be obtained through FSA.
- Mark Elzinga, from Elzinga and Hoeksema greenhouses, showed how they produce high-quality, custom organic transplants, reducing a step for the farmer by providing healthy plants from the farmers’ purchased seed.
- Superior Sales, Inc., a Michigan-based produce distributor, emphasized that there are not enough organic vegetables produced in Michigan to meet Superior Sales’ current needs, never mind the growing demand. Superior’s Mitch Gasche said “Yes, the quality must be there, but we are very interested in working with farmers and helping them.” Even small volume growers can be involved. Superior is very interested in talking with organic vegetable farmers about possible supply.
- Field equipment demonstrations showcased a wide variety of equipment to save backs and increase efficiency, ranging from vegetable bed preparation and plastic mulch laying to weeding, transplanting, spraying and producing compost tea. Each piece was field demonstrated on the MSU Extension and Research fields and several attendees even gave the equipment a try.
- Dreams and schemes flowed as farmers discussed among themselves and with the presenters how the equipment works, how versatile it is and, of course, how much it costs. To follow up on the dreams, several farmers indicated they were meeting with some of the presenters to discuss possibilities.
- Vicki Morrone discussed the possibilities offered by cover crops and provided some techniques to select appropriate cover crops to meet specific soil and cropping needs.
- In addition to enthusiastic sessions, a tasty lunch was offered that was prepared by Cravings Catering, based in Stevensville, Michigan. They made wonderful sandwiches and salsa-potato salad, all from vegetables grown by local farmers.
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The day was packed, but from the evaluations and participants’ comments, valuable information was gained and will be used back on the farm. Similar future events will help farmers expand their agricultural businesses to produce vegetables for local distribution and sale. Photos from the day can be seen on the MSU Organic web site at www.MichiganOrganic.msu.edu. The day’s program was conceived and organized by Vicki Morrone. Dr. Ron Goldy, MSU Southwest Region vegetable extension educator, deserves special thanks for getting the field site prepared and demonstrating some vegetable production equipment and irrigation systems. To be contacted about similar events in the future, please contact Vicki Morrone at 517-353-3542 or sorrone@msu.edu. |
The Organic Trade Association (OTA) would like to invite you to the upcoming conference “Growing U.S. Organic Agriculture: Accessing the 2008 Farm Bill.”
The November 12 event will be held at Indiana University-Purdue University in Indianapolis, Indiana and presented by OTA and the Organic Agriculture and Products Education Institute in partnership with NCAT (home of the ATTRA project), Organic Farming Research Foundation (OFRF) and the Midwest Organic and Sustainable Education Service (MOSES).
The conference is a one-day event designed to help farmers, farmer organizations, extension service agents, state departments of agriculture, organic certifiers and others learn how to access and use the funding allocated for organic agriculture in the 2008 Farm Bill.
Registration discounts for members of OTA and affiliates of OFRF, MOSES, and ATTRA are available. Scholarship assistance is available for small farmers. Receive a complimentary conference recording if you register before September 30. For details and registration, go to:
http://www.ota.com/events/upcoming/FarmBillConference.html
Buying local is an increasingly popular and important consumer trend. On November 21-23, the annual Family Farmed Expo will be held at the Chicago Cultural Center for those interested in local foods. Learn more about production, marketing, distribution and consumption. The expo provides a wide variety of learning opportunities such as workshops, panel discussions, celebrity chef demonstrations, food tasting, industry programming and many more. For more information about the expo, visit: http://www.familyfarmedexpo.com.
Minnesota
Western Minnesota, Lac qui Parle County - Carmen Fernholz
Last night we had our first frost of the season here in Western Minnesota. It’s quite unusual for us as we are usually ready anytime after September 15. Most of the soybeans are harvested and farmers are slowly getting the corn harvest underway. Yields of soybeans have been quite disappointing. Very few, if any, numbers over 40. For all producers the hot, dry and windy August, especially around Labor Day appear to have impacted the yields. For organic producers, an additional impact from aphids affected yields. There have not been any substantial reports on corn yields, but locally we anticipate lower yields because of the wind storm of July 31. Across Minnesota, however, I think we should see some good yields, both organic and conventional.
It has been wet and warm here since early October so everything still looks like late August. I have all of the winter wheat and winter barley planted and it is coming along nicely. I interseeded some clover and alfalfa with some of the winter barley to see if planting it by September 1 will give it adequate opportunity to survive the winter and thus eliminate the need for frost seeding in February. Most producers I am talking to tell me that red clover survives better than alfalfa either seeded late in the season or frost seeded. I plan to try some frost seeding of clover in February and March once more to see what results I can achieve.
I have made two passes through my alfalfa field with the chisel plow. The first pass with straight points and the second pass with chisel points under-seated with what are called heel sweeps. They serve to sever the alfalfa roots about five inches below the surface. I must say the sweeps work great. They pull much easier than the straight sweeps that I have used in the past and I think I will get longer wear out of them as well as avoid bending the tips from hitting large rocks. And in the end I still have a significant amount of crop residue on the surface for winter cover.
That about wraps things up for another season. Now it is the time to start closing the financial books for the year, begin looking at notes from this growing season and planning for 2009. And, of course, the winter season of workshops and conferences is just around the corner.
MichiganSouth Central Michigan, Calhoun County - Anthony Cinzoni
We had frost on October 4 and October 5, so all of our summer crops are done. The past week’s temperatures have been in the 70s. We are still harvesting cabbage, greens, radish, beets and potatoes. We are finishing winter squash and cleaning up fields. In the next two weeks, we will mow weeds, pick up all irrigation and begin pulling black plastic mulch.
Illinois
Northern Illinois, Kane County – David Campbell of Lily Lake Organic Farm
We received between 13 and 14 inches of rain during September, which delayed wheat planting and kept me from plowing a couple of smaller hayfields that I had intended to sow to soft red winter wheat, because these fields are either under water or are still too wet. This year, all of my winter wheat was sown on either oats/clover or hay ground. Typically, all of my wheat is sown on soybean ground. Wheat planting took place October 4-7. We received a nice rain on my wheat the day I finished drilling, coupled with recent very warm weather should get the wheat off to a good start.
We are currently ready to harvest soybeans, but the moisture on these beans is still in the low 16 percent range. Some of the top pods are still not quite ready for harvest. It looks like beans will yield in the 25-30 bushel range this year, which is 10-15 bushels below average. These beans weren’t planted until the last week or so of June, due to the wet weather this spring. Given this late planting date, I’m very pleased with this year’s estimated yield. Last year, there was quite a bit of wheat sown after corn, which is extremely rare, given our location (40 miles south of the Illinois/Wisconsin state line.) This year, there will be no wheat sown after corn harvest, and only a small amount of wheat drilled after soybeans. Fortunately, my rotation was different this year, allowing for no wheat to be sown after soybeans, probably for this year only.
After I combine beans, hopefully sometime later this week, I will leave bean ground undisturbed for around two weeks before I chisel plow this ground, so as to capture more nitrogen from the soybean root residue to provide for next year’s corn crop. I have noticed only around 20 acres of corn that have been harvested in my area so far. Plants are still showing some green color. It will be at least another week or two before corn harvest gets going in earnest. My corn is still probably another two to three weeks away from starting harvest. Yields are estimated to be possibly the best I’ve seen on my farm. Ears are filled to the tip, and girthy as well, with deep kernel set. More than a few plants have two fair-sized ears. I’m estimating 170 bushel average yield this year. I also have the last of my third cutting hay on the ground; I hope to bale later this week.
West Central Illinois, Fulton County - Anne Patterson of Living Earth FarmAfter the tremendous amount of rain, 10-plus inches in ten days in early September, things have dried out and there has been adequate time to clear beds, prepare soil with amendments where needed per soil analysis, and plant cover crops. We have not had any frost.
I ended my e-customer season the first week of October due to poor conditions from rain and out-of-control weeds and loss of crops such as winter squash, pumpkins and some sweet potatoes and potatoes. I still have some beds with greens, lettuce, spinach, arugula, carrots, beets and sun chokes, however, these will go to a new restaurant sourcing local foods.
Currently, I am still clearing beds on areas that have not been planted to cover crops of either oats, hairy vetch and winter rye, or Peaceful Valley Farm Supply's cold "Soil Builder Mix" (oats, lana vetch, purple vetch, bio master peas, and bell beans). The permanent raised beds that I planted to the cold weather soil builder in late August look great now. I am sorting garlic to store and plant. Also I’m currently pulling stakes and clearing plastic on one field.
In the next two weeks I plan to plant garlic, order and put new plastic on the hoop house, apply lime and leaf mulch to remaining cleared beds, dig sun chokes, and develop a new business strategy for Living Earth Farm.
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