Three years before the Maryland Department of Agriculture revised nutrient management regulations a BMP Challenge crop adviser, Don Moore (AET Agricultural Consulting) took the initiative and partnered with American Farmland Trust and Agflex Inc. to work with seven farmers to inject or incorporate manure into the soil. Manure injection or incorporation increases fertilizer efficiency, thus reducing potential nutrient loss from the field three ways. When the manure is below, rather than on top of the soil, nitrogen rich ammonia gas can’t escape to the air making more of it available to the plant by as much as 20%. Secondly, the fertilizer is now located several inches closer to the plant roots. Finally, it is far less susceptible to being washed away in heavy spring rains. The potential is for this practice to allow the farmer to reduce the total amount of total fertilizer inputs mainly the chemical type put on mid-season, thus be, saving money and improving water quality.
Since manure incorporation with vertical tillage equipment such as an Aerway or Turbotill is a relatively new practice, the BMP Challenge comparisons were setup to determine whether incorporation would affect yields. In 2012, participants applied the same number of nitrogen credits across the entire field. However, they reduced the amount of commercial fertilizer at sidedress on the manure incorporation acres. The incorporation increased the nitrogen credit to offset the commercial fertilizer reduction. By the third year, the part of the field where manure was applied to the surface at the recommended rate was compared to the rest of the field that used incorporation and a reduced application rate based less ammonia escaping to the air.
Across the three years, incorporation showed an average increase in net returns by $6.00 per acre and a nitrogen reduction of 7 pounds. Over-all the farmers saved more than 8,400 pounds of nitrogen applications. Five of seven participating farmers in the BMP Challenge demonstrations were interviewed last fall regarding their participation. Three have purchased new equipment. One is seriously considering it and the fifth has expanded use of vertical tillage to all his crop acres. According to Moore, “Throughout the entire BMP Challenge process, farmers demonstrated their willingness and eagerness to learn. They want to learn about and adopt new technologies if they make good economic sense. They are not willing to risk yield to experiment. This is where the yield guarantee was important to them. In this world of high commodity prices, and inputs that are equally as high, growers are hesitant to entertain additional risk. No one is interested in over-application of nutrients.
Maryland state law now requires farmers to inject or incorporate manure and other organic nutrient sources into the soil within 48 hours of application. The past three years of work on the Eastern Shore has provided important information to farmers and agricultural advisors as well. The BMP Challenge will be working with an expanded number of growers this year to transition from surface application to manure incorporation.