Nitrogen and water management strategies to reduce nitrate leaching under irrigated maize

• Published in: Journal of contaminant hydrology 1995-12, Vol.20 (3), p.227-239
• Main Authors: Schepers, J.S., Varvel, G.E., Watts, D.G.
• Format: Article
• Language: English
• Subjects: ABONOS NITROGENADOS; Agronomy. Soil science and plant productions; AGUAS SUBTERRANEAS; Biological and medical sciences; CROP YIELD; EAU SOUTERRAINE; ENGRAIS AZOTE; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; GROUNDWATER; IRRIGATION; LEACHING; LESSIVAGE DU SOL; LIXIVIACION; NITRATE; NITRATES; NITRATOS; Nitrogen fertilization; NITROGEN FERTILIZERS; Nitrogen, phosphorus, potassium fertilizations; RENDEMENT DES CULTURES; RENDIMIENTO DE CULTIVOS; RIEGO; Soil and water pollution; Soil science; Soil-plant relationships. Soil fertility. Fertilization. Amendments; ZEA MAYS
• ISSN: 0169-7722; 1873-6009
• DOI: 10.1016/0169-7722(95)00070-4

Cropping systems that fail to integrate nitrogen (N) water management are frequently associated with elevated concentrations of nitrate-N in soil and groundwater. Examples of poorly integrated management practices are abundant, especially where irrigation is used to minimize the effects of drought and N fertilizer is inexpensive. Two maize fields under improved water and N management practices at the Nebraska Management Systems Evaluation Area (MSEA) project were compared with an adjacent field under conventional furrow irrigation that followed management guidelines mandated by the local Natural Resources District. Surge-flow furrow irrigation with laser grading and a runoff-water recovery system reduced water application by 45–69% compared to conventional furrow irrigation over the three years of this study. Center-pivot sprinkler irrigation reduced water application by 60–72% compared to conventional furrow irrigation. Uniformity of water application was improved with the surge-flow and sprinkler irrigation systems, which made it reasonable to consider adding fertilizer N in the water (fertigation) to meet crop needs. The spoon-feeding strategy, based on chlorophyll meter readings to schedule fertigation, saved 168 kg ha t1̄ N the first year and 105 kg ha −1 N the second year without reducing yields. Near total reliance of fertigation to meet crop N needs resulted in a 15% yield reduction the second year because spatial variability in soil N status made it difficult to collect representative chlorophyll meter data. Plot studies showed chlorophyll meter readings and yields were consistently higher for maize following soybean than where maize was grown in monoculture.