Evaluating the Use and Seed Production of Forage Radishes in Field and Forage Crop Fields to Control Compaction, Concentrate Nutrients, Suppress Weeds and provide a local seed source in Limestone Soil of the Northern Shanendoah Valley

• 2009 annual report

The use of cover crops in the northern Shenandoah Valley has diminished greatly over the last ten years because of issues related to timely planting, crop residue which must be killed in a timely fashion, harboring pests such as slugs and the cost burden without a perceived benefit. The lack of cover crops has increased the potential for soil and nutrient movement both across the surface and down through the soil profile. Recent probing with a penetrometer in several crop fields by a Certified Crop Adviser found compaction to be an issue in Jefferson County. The solution for these producers was deep tillage which was expensive, buried crop residue, increased the possibility of soil erosion, destroyed natural infiltration channels and required the removal of many rocks. Yield loss is unrealized and somewhat ignored by producers in the region due to the many disincentives to reduce compaction with tillage. The negative effect of compaction on row crops and forage fields is well documented. In forages there are many trips over the field during harvest, fertilizer, lime or manure application and animal traffic on wet soils. Compaction can limit growth and yield of forages, limit uptake of nutrients and reduce stands. Soil compaction can easily reduce crop yields by 10 percent, and can lead to water and soil quality degradation due to increased runoff and soil structure destruction. Unlike annual crops, the use of tillage equipment on permanent pastures and meadows is not practical. In corn experiments at Purdue University, compacted plots resulted in stand reductions of 20 to 30 percent, plant height decreases of one-third to one-half, and yield reductions of about 19 percent compared to non compacted plots. Corn yields were 160 bushels per acre for non compacted soil compared to only 130 bushels for compacted plots. ObjectivesThe goal of this project is to evaluate the use of forage (Daikon) radishes as a cover crop and “bio-driller” to reduce compaction and increase nutrient infiltration in forage and field crops. These forage radishes may also provide competition for warm season weeds in fallow wheat fields after harvest reducing the use of herbicides the following spring. If these uses flourish, the need for a local and reliable supply of seed will grow. In research conducted by Dr.Ray Weil of the University of Maryland, row crop yields responded positively to cover crops including forage radishes. Radishes can capture nitrogen which reduces leaching with a quick spring release of nitrogen. These plants also bring other nutrients from deep in the soil profile to the surface. They leave 4000 pounds of dry matter per acre with little residue in the spring as the plant dies after a few nights in the 20’s. Even so it does provide weed suppression in the fall and early spring, possibly eliminating a herbicide application. Soils also warm up quicker in the spring allowing corn planting to begin as much as seven days sooner resulting in a quicker canopy closer which preserves moisture and shades the ground which can result in less weed germination. These same radishes reduced compaction. Research has shown that radishes have a greater number of roots to a greater depth than other cover crops allowing corn roots to move deeper and reach subsoil moisture. Using the forage radish has shown a significant increase in yield of the following crop over no or other cover crops. This project will evaluate the ability to produce seed in this region which can then be used in further plantings and for retail sale. Grower Steve Groff from Lancaster County, Pennsylvania has been a major local source for forage radish seed, but has had issues producing clean seed to sell. This project will evaluate the ability to grow clean seed in the Northern Shenandoah Valley which will diversify the source for seed and grow it closer than in the west. Grower Cam Tabb feels very confident that with our dryer summers and the correct adjustment to combining equipment, a clean seed can be achieved. Dr. Weil feels there is a local market for seed.