Nitrate Nitrogen in Surface Waters as Influenced by Climatic Conditions and Agricultural Practices

Abstract

Subsurface tile drainage from row-crop agricultural production systems has been identified as a major source of nitrate entering surface waters in the Mississippi River basin. Noncontrollable factors such as precipitation and mineralization of soil organic matter have a tremendous effect on drainage losses, nitrate concentrations, and nitrate loadings in subsurface drainage water. Cropping system and nutrient management inputs are controllable factors that have a varying influence on nitrate losses. Row crops leak substantially greater amounts of nitrate compared with perennial crops; however, satisfactory economic return with many perennials is an obstacle at present. Improving N management by applying the correct rate of N at the optimum time and giving proper credits to previous legume crops and animal manure applications will also lead to reduced nitrate losses. Nitrate losses have been shown to be minimally affected by tillage systems compared with N management practices. Scientists and policymakers must understand these factors as they develop educational materials and environmental guidelines for reducing nitrate losses to surface waters.

The British river of the future: How climate change and human activity might affect two contrasting river ecosystems in England

“…Predicting N changes in rivers is particularly difficult because of the many 299 biological interactions it undergoes. Higher rates of N mineralization during the warmer drier 300 summers would result in a greater build-up of nitrogen in the soils (Randall and Mulla, 2001; 301 Whitehead et al, 2002), although this might be partially compensated by higher rates of plant 302 uptake. Actually, long-term records of streamwater quality have shown that dry summers 303 result in high rates of diffuse source nitrogen delivery when the drought breaks (Whitehead et 304 during the autumn and winter periods (Bouraoui et al, 2002 and autumn under both the low and high -emission scenarios (Tables 1 and 2).…”

Assessment of nitrate leakage and N2O emission from five environmental-friendly agricultural practices using fuzzy logic method and empirical formula

“…However, previous studies have shown that the timing of fertilizer application and the amount of nitrogen applied are the main factors affecting it (Malone et al 2007). Thus, appropriate timing and optimal fertilizer rates are keys to reducing N losses from farmland (Randall and Mulla 2001).…”

Soil Inorganic N and N Uptake by Maize Following Application of Legume Biomass, Tithonia, Manure and Mineral Fertilizer in Central Kenya

“…Measures to curb downward movement of N like timely application of inputs and split fertilizer application that have been reported to reduce leaching should be encouraged (Randall and Mulla, 2001). In addition trees if well planted and integrated in the farming systems may assist in recovering some of this N that is lost to annual crops as observed by Mugendi et al (2003) who reported that treatments with tree hedges recorded a lower amount of mineral N in the 100-300 cm depth than treatments without tree hedges.…”