Residual Effects of Nitrogen Fertilization and Winter Cover Cropping on Nitrogen Availability

Abstract

Long‐term management practices affect the reserve of mineralizable soil N, and so can influence the amount of supplemental N fertilizer required in crop production. This study was conducted to (i) evaluate the residual effects of long‐term N fertilization and winter cover cropping on corn (Zea mays L.) N nutrition, and (ii) examine the ability of selected soil indices to detect management‐induced differences in soil N availability. In 1986, N fertilizer and winter cover crops were eliminated from plots which, from 1976 through 1985, had received varying tillage treatments, N fertilizer additions, and either hairy vetch (Vicia villosa Roth), rye (Secale cereale L.), or no winter cover crop. A history of N fertilization increased corn yield and N uptake (by an average of 20.4 kg N/ha). A history of winter cover cropping with hairy vetch increased corn yield and N uptake (by an average of 28.0 kg N/ha). Rye cover cropping generally had small or inconsistent effects relative to no cover crop. Tillage generally had insignificant effects on corn yield and N uptake. Soil N availability indices were determined on surface samples (0–15 cm) taken 2 wk after corn planting. The anaerobic incubation provided a poor index of N availability. Total soil C and Kjeldahl N were affected by tillage, though not by cover crop or fertilization history, and were marginally correlated with crop response. The autoclave index was only slightly superior to total soil C and Kjeldahl N as a N‐availability index. The soil NO3‐N concentration was highly correlated with corn yield, and N uptake. Though this study was conducted for 1 yr at one site, results indicate that measurement of surface soil NO3‐N made shortly after corn planting can provide a valid index of the effects of past crop and soil management practices on soil N availability to corn.

Spatial variability of barley (Hordeum vulgare) and corn (Zea mays L.) yields, yield response to fertilizer N and soil N test levels

“…Inclusion of NH 4 -N in the KCl-extractable level of soil N also did not improve the relationship between soil N level and either yield or estimated yield response (data not shown). This observation is in agreement with others studies such as McCracken et al (1989), which found little benefit to the inclusion of NH 4 -N in the soil test. Given that the current soil N test procedure used in Ontario does not include the NH 4 -N (Kachanoski and Beauchamp 1992), further discussion of soil N levels will be restricted to the NO 3 -N levels only .…”

Investigating the effect of previous treatments on wheat biomass over multiple spatial frequencies

“…Residual effects of nitrogen have been investigated by other workers (McCracken et al, 1989;Ruffo et al, 2004;Karlen et al, 1998), in studies generally focused on management of excess NO 3 -N to reduce leaching. For example McCracken et al (1989) used standard statistical analysis to show that measurements of surface soil NO 3 -N reflected the past management practices at the scale of experimental plots.…”

“…For example McCracken et al (1989) used standard statistical analysis to show that measurements of surface soil NO 3 -N reflected the past management practices at the scale of experimental plots. The interactions of water and nitrogen on crop biomass have also been studied for many crops (Vázquez et al, 2006, and references there in).…”

Culturas de cobertura, acúmulo de nitrogênio total no solo e produtividade de milho

“…Portanto, transcorridos 10 anos de instalação do experimento, ainda não houve correspondência do acúmulo de N total no solo no sistema plantio direto com o aumento da disponibilidade de N para as culturas. Resultados semelhantes foram encontrados por Rice et al (1986) e McCracken et al (1989). A menor disponibilidade de N no sistema plantio direto deve estar relacionada com a menor taxa de mineralização dos resíduos vegetais e da matéria orgânica do solo associada à maior imobilização do N pela biomassa microbiana (Freitas et al, 1996;Amado, 1997).…”