Timing Nitrogen Applications for Corn in a Winter Legume Conservation‐Tillage System

Abstract

Fertilizer N efficiency of com (Zea mays L.) in conservation-tillage systems witb winter legumes such as crimson clover (Trifolium inctJr. lllllum L.) can possibly he improved by better synchronization of leg· ume-N release, fertilizer·N application time, and crop demand for N. The objective of this 3-yr (1986)(1987)(1988) field experiment was to deter· mine the effect of N application time on dry matter accumulation, N uptake, and grain yield of com grown in a winter legume conservation-tillage system. Com was planted witb unit planters into crimson clover residue following In-row subsoiling. The clover was killed at midbloom every year. Treatments were a factorial arrangement of fertilizer N rates and application time. Nitrogen as NH.N0 3 was broadcast at rates of 34, 67, and 134 kg ba-•. Zero-N checks were also Included in botb clover and rye (Seca/e cereol L.) plots. AppUcation times were at planting, or 3, 6, or 9 wk later. 1n addition, split applications (1/3 at planting and tbe remainder 6 wk later) of tbe 67 and 134 kg N ba-• rates were included. 1n 2 of 3 yr, dry matter accumulation was not affected by N application time. 1n 1987, how· ever, dry matter production was greater when N was applled at planting compared to split applications or appllcations later than 3 wk after planting. Application time affected N uptake patterns during the growing season, but generally did not affect total N uptake at the end of the season. With the exception of the first year, split N applications re-

Nitrogen Benefits of Winter Cover Crop and Fall‐Applied Poultry Litter to Corn

“…This suggests a cumulative effect on organic N and supply of plant available N from the legume residues in this low disturbance system (McSwiney et al, 2010). These results are consistent with previous work on FNEQ of other legume CC, which also show increasing trends (Reeves et al, 1993;Torbert et al, 1996). The effects of Rye and RyePL on grain yield also increased slightly across years, but the FNEQ was either slightly negative (2013) or positive (2014 and 2015).…”

Nitrogen supply from fertilizer and legume cover crop in the transition to no-tillage for irrigated row crops

“…As suggested by others (Touchton et al 1982(Touchton et al , 1984Hargrove 1986;Blevins and Frye 1993;Reeves et al 1993;Abdul-Baki et al 1997;Sainju et al 2002), for reduced tillage systems that include winter legume cover crops, the crop fertilizer requirement can diminish with successive seasons, and fertilizer rates can often be appreciably reduced. This may be due directly to the release of cover crop N, as well as indirectly through build up of organic matter and improved recycling of N inputs.…”

Suitability of peanut residue as a nitrogen source for a rye cover crop

“…In the southeastern USA, legume crop residues have been evaluated in conservation tillage systems to improve crop production and enhance soil physical characteristics (Mitchell & Teel, 1977;Touchton et al, 1984;Oyer & Touchton, 1990;Reeves et al, 1993;Torbert & Reeves, 1996). Typically, legumes are planted after harvest in the fall, terminated in the spring, and a summer crop is planted into that residue.…”