Nitrogen Fertilizers Used Off-Season Help Crops Planted Later

Tag : fertilizers

Cover crops are an important tool in this cycle, and while it isknown that using nitrogen fertilizers can increase these cropsbiomass, the resulting levels of nitrogen for the following cashcrops have been unknown.
Researchers found that areas that did have fertilizer applied totheir cover crops had less biomass output for soil protection,while plots that did use fertilizer had greater biomass along withan increased amount of nitrogen available for the cash crop.
“Use of high-residue cover crops is imperative to preventsoil erosion, to bank leftover nutrients during the winter forsummer cash crops, and to improve soil quality,” said MarkReiter, lead author of the study. “From this data we see thatwe can increase cover crop biomass by using nitrogen fertilizer andthat the nitrogen will later be available to our cash crop. It is awin-win situation.”
The study was conducted by USDA-ARS scientists with theConservation Systems Research Team in Auburn, AL and the J. PhilCampbell Senior Natural Resource Conservation Center inWatkinsville, GA, in cooperation with Auburn University. Scientistsinvestigated the effects of using nitrogen fertilization on ryecover crops, as well as the subsequent fertilizer availability tocotton.
The focus of the study was on plots in the Tennessee Valley Regionof northern Alabama, which is a highly productive region in thenation’s Cotton Belt. To study the effects of fertilizer, ryecover crops were varied in the amount of nitrogen used.
After the rye had dried up, cotton was planted in the same soilsand fertilized with different amounts of nitrogen. Researcherscollected the plant and soil samples and determined how muchnitrogen had been integrated into the plant and soil systems. Anitrogen isotope was used to trace the nitrogen used in thefertilizer, as opposed to nitrogen that is native to those soils.
While the results of the study are positive to understandingconservation tillage, further research is still needed beforeestablishing new fertility management guidelines in all crops usinghigh-residue cereal cover crops. In applying this research, it isexpected that soil quality, along with management of the nutrientsin the soil, will improve the success of American agriculturalproducers.
Journal reference : Reiter et al. Cotton Nitrogen Management in a High-Residue Conservation System:Cover Crop Fertilization . Soil Science Society of America Journal , 2008; 72 (5): 1321 DOI: 10.2136/sssaj2007.0313