 |
Soil Management-Compost
|
 |
|
Virginia Tech researchers
study the effects of compost on experiment station vegetable
plots to improve soil quality, including water-holding capacity
and infiltration.
Photo by Greg Evanylo |
 |
Some farmers, particularly organic producers, have long applied
manure and compost to meet their fertility needs. However, most
non-organic vegetable producers rely on the quicker fix of annual
applications of commercial fertilizer. SARE-funded researchers in
Virginia tested compost on non-organic vegetable farms to demonstrate
its ability to enhance soil quality, including water-holding capacity,
bulk density, infiltration, organic matter and plant-available nutrients.
“Water stress is the most critical environmental factor
limiting crop production in the southeastern United States,”
said Greg Evanylo, professor of crops and soil environmental sciences
at Virginia Tech. “After a few drought years, farmers tend
to better understand the importance of soil quality.”
Evanylo determined that applying compost (made from three parts
yard waste to one part poultry litter) at rates designed to meet
vegetable nitrogen needs reduced soil bulk density and compaction,
and increased water infiltration.
Compost is relatively expensive. Yet, rising commercial fertilizer
costs and nutrient management regulations that prevent confined
livestock operators from land-spreading manure on high-phosphorus
soils might prompt more producers to begin composting, Evanylo said.
On a previous study, Evanylo found that compost applications at
high rates improved yields and water-holding capacity in sandy soils.
“When you add cover crops or lots of organic matter, it maintains
the structure at the soil surface, preventing the beating-down effect
of raindrops that break up the soil,” he said. “It allows
water to infiltrate and increases storage.”
You don’t have to use compost, however. Consider applying
uncomposted organic material directly to the soil and also using
cover crops. Bob Muth, who grows vegetables and hay on 52 acres
in Williamstown, N.J., augments his soil organic matter by using
cover crops and spreading the leaves collected by local municipalities
on some of his fields each autumn. Over the years, he has vastly
improved the soil’s infiltration, a must on his gravelly sandy
loam that includes 15 percent clay and a tendency to crust.
Typically, Muth covers the ground with up to six inches of leaves,
or 20 tons per acre. The following spring, he works in the decomposing
leaves. He also plants a variety of cover crops, including sudangrass,
a quick-growing high-mass summer cover that breaks up compacted
soil. His fields test as high as 5 percent organic matter, unheard
of for the mineral soils of southern New Jersey.
Caution: Apply Phosphorus With Care
Managing soil phosphorus is a growing concern
for both farmers and environmental regulators because over-applying
P in composted or uncomposted animal waste may contribute
to surface water pollution. Although phosphorus is an essential
element for plant nutrition, excessive amounts can wash
or leach into waterways.
Experts suggest analyzing the phosphorus and
nitrogen contents of compost and considering it as part
of your nutrient management planning. Routine testing is
both recommended and widely available. Test your soil –
as well as your organic amendments such as compost –
for nitrogen and phosphorus levels, and test your compost
for moisture content. Find your state’s soil testing
lab, typically at your Land Grant University, and ask whether
they also have a P index, a newly developed tool to measure
phosphorus concentration.
|
Conservation
Tillage | Cover Crops | N.Y.
Farmer Profile
 Top
|
