Optimizing Nitrogen Management in Food and Energy Production and Environmental Protection: 2nd International Nitrogen Conference 2001View this Special Issue
Research Article | Open Access
R.B. Hutmacher, R.L. Travis, R.L. Nichols, D.E. Rains, B.A. Roberts, B.L. Weir, R. M. Vargas, B. H. Marsh, S. D. Wright, D. S. Munk, D. J. Munier, M. P. Keeley, F. Fritschi, R. L. Delgado, S. Perkins, "Response of Acala Cotton to Nitrogen Rates in the San Joaquin Valley of California", The Scientific World Journal, vol. 1, Article ID 683724, 8 pages, 2001. https://doi.org/10.1100/tsw.2001.334
Response of Acala Cotton to Nitrogen Rates in the San Joaquin Valley of California
The responses of Acala cotton (Gossypium hirsutum L.) in California to a range of applied nitrogen (N) treatments were investigated in a 5-year, multisite experiment. The experiment’s goals were to identify crop growth and yield responses to applied N and provide information to better assess the utility of soil residual N estimates in improving fertilizer management. Baseline fertilizer application rates for the lowest applied N treatments were based on residual soil nitrate-N (NO3-N) levels determined on soil samples from the upper 0.6 m of the soil collected prior to spring N fertilization and within 1 week postplanting each year. Results have shown positive cotton lint yield responses to increases in applied N across the 56 to 224 kg N/ha range in only 41% (16 out of 39) of test sites. Soil NO3-N monitoring to a depth of 2.4 m in the spring (after planting) and fall (postharvest) indicate most changes in soil NO3- occur within the upper 1.2 m of soil. However, some sites (those most prone to leaching losses of soluble nutrients) also exhibited net increases in soil NO3-N in the 1.2- to 2.4-m depth zone when comparing planting time vs. postharvest data. The lack of yield responses and soil NO3-N accumulations at some sites indicate that more efforts should be put into identifying the amount of plant N requirements that can be met from residual soil N, rather than solely from fertilizer N applications.