Nitrogen balance in agroecosystems provides a quantitative framework of N inputs and outputs and retention in the soil that examines the sustainability of agricultural productivity and soil and environmental quality. Nitrogen inputs include N additions from manures and fertilizers, atmospheric depositions including wet and dry depositions, irrigation water, and biological N fixation. Nitrogen o...

Nutrients are transported all over the world through fertilizer imports, exports of agricultural commodities, massive erosion in some places and gross volatilization and leaching in high-input/high-output agricultural systems. In other words, more or less balanced natural ecosystems have turned into highly unbalanced agricultural systems. Figure 20.1 shows the inputs and outputs that make up th...

Chemical fertilizers are used extensively in modern agriculture, in order to improve yield and productivity of agricultural products. However, nutrient leaching from agricultural soil into groundwater resources poses a major environmental and public health concern. The Evros region is one of the largest agricultural areas in Northern Greece, extending over 1.5 million acres of cultivated land. ...

Mining of nutrients from soil is a major problem causing soil degradation and threatening long-term food production in developing countries. In present research, an attempt was made for carrying out nutrient budgeting, which includes the calculation of nutrient balance at micro (plot / field) and meso (farm) level and evaluation of trends in nutrient mining / enrichment. A nutrient budget is an...

The use of different agricultural or industrial wastes is an important component of sustainable agriculture in order to close nutrient cycles on a global, regional and local scale. Farmyard manure or slurry are established as fertilizers in agricultural or horticultural production and substitute mineral fertilizers. Due to the lower nutrient use efficiency compared with mineral fertilizers, esp...

There is increasing concern over P leaching from sandy soils applied with water-soluble P fertilizers. Laboratory column leaching experiments were conducted to evaluate P leaching from a typical acidic sandy soil in Florida amended with DPR fertilizers developed from dolomite phosphate rock (DPR) and N-Viro soil. Ten leaching events were carried out at an interval of 7 days, with a total leachi...

Phosphate fertilizers were first implicated by Schroeder and Balassa in 1963 for increasing the Cd concentration in cultivated soils and crops. This suggestion has become a part of the accepted paradigm on soil toxicity. Consequently, stringent fertilizer control programs to monitor Cd have been launched. Attempts to link Cd toxicity and fertilizers to chronic diseases are common. A re-assessme...

Nitrogen is the most important essential nutrient that plays a major role in achieving maximum crop yield in agriculture. Therefore, nitrogen fertilizers such as ammonium sulfate and urea have been extensively used in modern agriculture. These fertilizers are generally oxidized to nitrate via nitrite by nitrifying microorganisms in the agricultural field (4, 10, 11). The serious environmental p...

The concentrations of cadmium in agricultural soils depend upon the amounts present in the parent rocks from which the soils form, the amounts added in the form of fertilizers and soil amendments, the amounts deposited onto soils from the atmosphere, and the amounts removed by harvested crops and by leaching. On average, sedimentary rocks contain greater concentrations of Cd than either igneous...