Crop residue, manure and fertilizer in dryland maize under reduced tillage in northern China: II nutrient balances and soil fertility

Abstract

A long-term experiment was carried out in the dryland of northern China to assess the effects of applications of maize stover, cattle manure and NP (1:0.44) fertilizer on partial nitrogen (N), phosphorus (P) and potassium (K) balances, extractable soil N (SEN), P and K, and soil organic matter (SOM) in a spring maize cropping system, under reduced tillage conditions. The experiment was set-up according to an incomplete, optimal design, with three factors at five levels and 12 treatments, including a control with two replications. Statistical analyses using multiple regression models showed that the partial N, P and K balances were strongly influenced by annual variations in the amounts of soil water at seeding (SWS) and growing season rainfall (GSR). Most treatments had positive P but negative N and K balances. Cumulative P and K balances were reflected in extractable soil P (P-Olsen) and K (exchangeable K), but the weak relationships indicated that the sorption of P and buffering of K were strong. Cumulative balances of effective organic carbon (C) were weakly related to soil organic C (SOC) content after 12 years. Negative C balances were related to decreases in SOC, but positive C balances were not translated into increases in SOC. The analysis of nutrient balances and soil fertility indices revealed that nutrient inputs in most treatments were far from balanced. It is concluded that the concepts of 'ideal soil fertility level' and 'response nutrient management' provide practical guidelines for improving nutrient management under the variable rainfall conditions of dry land areas in northern China.

Crop residue, manure and fertilizer in dryland maize under reduced tillage in northern China: I grain yields and nutrient use efficiencies

“…This design has proven to be efficient for experiments with nutrient inputs. However, nutrient management under rainfed conditions requires rainfall to be taken into account in a dynamic approach (see also Wang et al 2007) to explain the strong interactions between GSR and the effects of NP fertilizer, stover and manure. The feasibility and adoptability by farmers of split applications of N fertilizer combined with soil and/or plant analyses should be tested in practice.…”

“…We therefore assessed the long-term effects of these applications on maize grain yield and nutrient use efficiency. A companion paper (Wang et al 2007) describes the effects of these combined applications on N, P and K balances, soil organic matter dynamics and soil fertility indices.…”

Potassium nutrition of crops under varied regimes of nitrogen supply

“…Current fertilizer N application rates of 550-600 kg N per hectare annually in Taihu region of east China and on the North China Plain could be cut by 30-60% while still maintaining crop yields and N balance in the rotation and substantially reducing N losses to the environment (Ju et al 2009). Compared to N, application of K has been neglected in many developing countries including Asian countries and this has resulted in the continual depletion of soil K (Regmi et al 2002;Panaullah et al 2006;Ladha et al 2003;Wang et al 2007b;Lal et al 2007). Frequent K deficiency has been observed in crops in these regions (Dobermann et al 1996;Panaullah et al 2006;Mussgnug et al 2006).…”

Effects of Variable Nitrogen Source and Rate on Leaf Area Index and Total Dry Matter Accumulation in Maize (Zea mays L.) Genotypes under Calcareous So

“…But at three sites (B6, B8 and C7), yield was greater with ammonium nitrate, while at two sites (B9 and C13) yield was greater with application of urea. Wang et al (2007) earlier reported that understanding concepts of ideal soil fertility level and response to nutrient management provide practical guidelines for improving nutrient management under the variable rainfall conditions. While, Okalebo et al (2006) suggested that site specific recommendations are needed for maize because of its differential response to nutrient inputs which varied widely within and across agro-ecological zones.…”