Nitrogen Fertilization I: Impact on Crop, Soil, and Environment

Abstract

Nitrogen (N) is a major limiting nutrient to sustain crop yields and quality. As a result, N fertilizer is usually applied in large quantity to increase crop production throughout the world. Application of N fertilizers has increased crop yields and resulted in achievement of self-sufficiency in food production in many developing countries. Excessive application of N fertilizers beyond crops' demand, however, has resulted in undesirable consequences of degradation in soil, water, and air quality. These include soil acidification, N leaching in groundwater, and emissions of nitrous oxide (N 2 O), a potent greenhouse gas that contributes to global warming. Long-term application of ammonia-based N fertilizers, such as urea, has increased soil acidity which rendered to soil infertility where crops fail to respond with further application of N fertilizers. Another problem is the groundwater contamination of nitrate-N (NO 3-N) which can be a health hazard to human and livestock if its concentration goes above 10 mg L À1 in drinking water. The third problem is emissions of N 2 O gas which is 300 times more powerful than carbon dioxide in terms of global warming potential. This chapter examines the effect of N fertilization on soil and environmental quality and crop yields.

Divergent Accumulation of Microbial Residues and Amino Sugars in Loess Soil after Six Years of Different Inorganic Nitrogen Enrichment Scenarios

“…The nitrate concentration in the soil was higher than that of ammonium throughout the experimental period, as nitrate is the main form of available N in soils [46,64]. High-N treatment had the highest nitrate (NO 3 − -N) concentration, partly due to its high rate exceeding the N requirement of the plants, which is consistent with previous studies [46,65,66]. However, the linear accumulation of residual soil NO 3 − -N content by the high-N treatment could pollute underground water, and thereby affect human health [66][67][68].…”

“…Lu et al [69] pointed out that N enrichment increases the leaching of basic cations such as Ca 2+ and Mg 2+ in the charge balance of the soil solution, thereby decreasing soil pH. An increase in N rate decreased soil pH, which agrees with previous studies [47,49,52,66,70]. The slight decrease in soil pH in the control occurred probably as a result of the depletion of basic cations by plants and the decomposition of organic matter [70].…”

Silicon Amendment Enhances Agronomic Efficiency of Nitrogen Fertilization in Maize and Wheat Crops under Tropical Conditions

“…Nitrogen is considered one of the most limiting nutrients for crop growth and yield [ 29 ]. However, excessive N supply could directly contribute to soil acidification, ammonia (NH 3 ) and nitrogen oxide (N 2 O, NO 2 and NO) emissions, and N leaching with extended consequences on global warming [ 30 ]. The application of N to maize and wheat using a side-dressing approach in the Brazilian Savannah has led to an increase of about 15% in the farmer’s total operational profit [ 31 , 32 ].…”

Worldwide Regulations and Guidelines for Agricultural Water Reuse: A Critical Review

“…Nutrients and Micronutrients Important nutrients and micronutrients for crop growth include Nitrogen (N), Phosphorus (P), Potassium (K), Zinc (Zn), and Sulfur (S). Although Nitrogen is the most important nutrient for crop growth, high concentrations of this nutrient may result in over stimulation of plant growth, lodging, poor crop quality, maturity postponement, and excessive foliar growth [67,157,158]. Additionally, as a long-term consequence of Nitrogen high concentration, stalks, stems, and branches of crops go weak which make the crop incapable to support the weight of vegetation in the case of winds and rain [4].…”