estimation of optimum fertilizer rates is needed because of growing economic and environmental concerns. optimum fertilizer rates can be determined by fitting statistical models to yield data collected from n fertilizer experiments. the main goal of this research was to compare and evaluate quadratic, square root, mitscherlich, rectangular hyperbola, linear plus plateau and quadratic plus plate...

Growing fruit trees on the slopes of rolling hills in South China was causing serious environmental problems because of heavy application of chemical fertilizers and soil erosion. Suitable sources of fertilizers and proper rates of applications were of key importance to both crop yields and environmental protection. In this article, the impact of four fertilizers, i.e., inorganic compound ferti...

Use of dairy manure to supply crop nutrients is gaining broader acceptance as the cost of fertilizer rises. However, there are concerns regarding manure's effect on water quality. In 2003 and 2004, we measured sediment, NO3-N, NH4-N, K, dissolved reactive P (DRP), and total P (TP) concentrations in runoff from furrow irrigated field plots (6-7 irrigations yr(-1)) cropped to corn (Zea mays L.) i...

to evaluate the effects of fertilizing and deficit irrigation regimes on some chemical properties of soil and plant, an experiment was conducted during 2007 and 2008 growing seasons. experimental design was a split plot based on a randomized complete block design with four replications. the treatments consisted of three deficit irrigation regimes (main plots) and six soil fertilizing systems (s...

the objective of this study was to investigate the effects of addition of pulses in crop sequences, crop residue management, and application of fertilizer n on soil nitrogen content, soil organic carbon, nutrient uptake, and its consequences for wheat yields. the field experiments were carried out from 2009 to 2012 in the sub-humid and sub-tropical zone of northern india. the treatments were (i...

Nutrient management is central in water footprint analyses as it exerts strong control over crop yield and potentially contributes to pollution of freshwater, the so-called grey water footprint. In the frame of grey water footprint accounting, two methods are suggested, the constant leaching fraction approach (10% of applied fertilizer N) and the N surplus approach. We compared both approaches ...

To explore soil organic carbon (SOC) accumulation mechanisms, the dynamics of C functional groups and macroaggregation were studied synchronously through aggregate fractionation and (13)C NMR spectroscopy in sandy loam soil following an 18-year application of compost and fertilizer in China. Compared with no fertilizer control, both compost and fertilizer improved SOC content, while the applica...

the effect of different fertilizing systems and drought stress during grain development on grain minerals of barley (hordeum vulgare l.) was studied in field experiments on a clay-loamy soil during 2007 and 2008 growing seasons. the treatments consisted of three irrigation regimes (main plots) of: non-stressed (ns, normal irrigation continued until the end of plant physiological maturity), ...

The integrated soil fertility management paradigm, currently advocated in Sub-Saharan Africa for rehabilitating its soils, recognizes the possible interactive benefits of combining organic residues with mineral fertilizer inputs on agroecosystem functioning. Residue quality may be a controlling factor for any beneficial interactions. The objectives of this study were to determine the effect of ...

The low average grain yield (0.7 ton ha(-1)) of tef in Ethiopia is mainly attributed to low soil fertility, and inappropriate tillage and weeds control practices. Despite this, limited scientific information has been documented so far on their interaction effects on tef crop productivity in northern Ethiopia. The objective of this study was to assess the separate and interaction effects of till...