This is Gwen Outen with the VOA Special English AgricultureReport.
Clay soil is a problem for soybean farmers. When the soil is dry,the clay shrinks and breaks up. This condition damages the rootsystem of the plants.
A few years ago, two United States Agriculture Departmentresearchers made a discovery. They found a simple way to grow moresoybeans in dry soil that contains a lot of heavy clay.
Soybean farmers with heavy clay soils usually till the earthabout ten to fifteen centimeters deep. The researchers found thatpreparing the soil to a depth of thirty to forty centimeters isbetter. The seeds are still planted about two to three centimetersbelow the surface.
The system of preparing the soil this way is called subsoiling.It breaks up hard areas of soil that form when the clay dries. Andit does not harm crop materials on the surface.
Subsoiling is done with a device that looks something like alarge hook to catch fish. Farmers pull it through the ground tobreak up the soil structure.
Subsoiling permits water to reach areas below the surfacequickly. More water is stored in the soil than would be withtraditional ways.
Increasing the ability of the soil to hold water produces biggercrops. It also helps the environment. Less water runs off the land.And less soil is washed away. The researchers said that subsoilingis probably not needed every year.
Richard Wesley and Lowrey Smith made their discovery at anAgricultural Research Service laboratory in the state ofMississippi. They found that farms with deep subsoiling producedalmost fifty percent more soybeans than farms with traditionalmethods.
The farms with subsoiling produced, on average, more than fourhundred seventy kilograms of soybeans per hectare. Farm withtraditional planting, but without watering systems, produced threehundred twenty kilograms per hectare.
Lowrey Smith also found improvements with cotton. Studies in thepast showed that subsoiling clay soil in the spring does not improvecotton harvests. In the spring, the soil still holds rainwater. Sothe subsoiling process is unable to change the soil structure toprepare it for cotton production.
Mister Smith did his studies in the fall, when the soil was dry.He found that subsoiling in the fall increased harvests of cotton,just as with soybeans.
This VOA Special English Agriculture Report was written by AviArditti. This is Gwen Outen.