Quantifying Nitrate Leaching in Irrigated Wheat with Different Nitrogen Fertilization Strategies in an Alfisol

Abstract

Consumption of water contaminated with nitrates is associated with important health effects such as methemoglobinemia and gastric cancer. Intensive agriculture, which uses large quantities of N fertilizer, is the main source of nitrates in water systems. There are several strategies to reduce leaching and increase Nitrogen Use Efficiency (NUE). An experiment was conducted with spring wheat (Triticum aestivum L.) under sprinkler irrigation (center pivot) to determine if adjusted N applications using precision agriculture tools and plant demand resulted in a lower groundwater nitrate load. Evaluated treatments were: producer fertilization (Pr), precision agriculture (Pa), chlorophyll meter (Sm), and control without N (W/N). The ceramic capsule methodology was used to evaluate N leaching losses that were sampled after each irrigation (six) and drainage water was also estimated. Differences among treatments in terms of N loss and grain yield were not significant (p > 0.05). However, N balance showed significant differences (p < 0.01) in soil residual N among treatments. A regression between applied and residual soil N after harvest showed that N, applied as fertilizer, explained 98% of residual soil N variation, which would probably be leached in the following winter since the soil would be bare. It was concluded that NUE can be improved to result in a lower environmental load by using precision agriculture tools and considering plant N demand.

Morphophysical pedotransfer functions for groundwater pollution by nitrate leaching in Central Chile

“…However, were considerably higher than those obtained by Salazar et al (2010) in other Andisol (< 4.2 kg N ha -1 ) with 400 kg N ha -1 added as slurry and artificial fertilizers, mainly explained by gaseous losses and soil matrix retention. Claret et al (2011) in an Alfisol under 1400 mm of rainfall, reported NL values < 7.9 kg N ha -1 but without significant differences between fertilized and control soils. In central Chile, Iriarte (2007) reported risks of NL in 27% of soils (Mollisols, Inceptisols, and Alfisols) and 63% of drinking water samples analyzed showed nitrate concentrations above the threshold prescribed by the INN (1984) of 10 mg L -1 .…”

Comparing nitrate leaching in lettuce crops cultivated under agroecological, transition, and conventional agricultural management in central Chile

“…This is due to the slow release of N that sometimes does not coincide with the stages of higher N uptake by the crops, increasing leaching (Kirchmann and Bergström, 2001). Research on fertilization management to reduce leaching is very limited in Chile, and it is also focused on industrial crops (Claret et al, 2011;Salazar et al, 2019). This suggests the need for further research by extending studies to the important vegetables consumed in the country.…”

Spatial distribution prediction of agro-ecological parameter using kriging

“…One of the new directions in this area is the use of binary regression [4,5]. More studied areas include geostatistics, which allows mapping the nutrient content in the soil and other indicators for optimal farm management [6][7][8]. It should be noted that the ordinary kriging method is traditionally used from geostatistical tools to predict the spatial distribution of various agro-ecological indicators [9][10][11].…”