PLANT-SOIL-MICROBE N RELATIONSHIPS IN HIGH RESIDUE MANAGEMENT SYSTEMS

Submitted by Erin Rasmussen on

Publication Type:

Conference Paper

Authors:

Dinnes, D.; Jaynes, D.; Kaspar, T.; Colvin, T. ,; Cambardella, C.A.; Karlen, D. L.

Source:

South Dakota No-Till Association, Best Western Ramkota Hotel, Aberdeen, South Dakota (Submitted)

URL:

http://www.sdnotill.com/Newsletters/Relationships.pdf

Abstract:

INTRODUCTIONThe importance of supplying nitrogen (N) to optimize crop production has been known for over 150 years. The use of legumes in crop rotations was the only practicalmethod of rebuilding soil-N supplies for row crops until the advent of industrial N fertilizer production following WWII. Much research has been conducted over the pastcentury on the topic of N fertility for agronomic crops. Many studies concentrated on rates of applied N to optimize economic yield in conventional tillage, while fewer studiesfocused on understanding of the complex cycle of N in the soil environment. Only in relatively recent times have research studies investigated N cycling within native prairieand no-till soils. Although some important relationships have been discovered in these experiments, much remains to be learned.Tilled and no-till soils can vary dramatically in carbon (C), oxygen (O2), water content and temperature because of the tillage process. Tillage breaks bonds betweensoil particles and mixes air and plant residues throughout the tilled zone. This increases soil temperature, evaporative losses, and the amount of available oxygen. The overalleffect of tillage is a soil environment that stimulates aerobic microbial activity, eventually leading to increased decomposition rates of plant residue-C and acceleratedcycling of soil-N compared with no-till and native prairie soils. We will briefly describe how plant residues and soil microbes interact and their effects on soil-N, and providesome recommendations on how to manage N for no-till crop production.