Effects of crop residue incorporation and inorganic potassium fertilization on soil potassium supply power. Issue 9 (29th July 2019) - Jiang, Nan
ABSTRACT: Crop residues can be used as an effective replacement for inorganic potassium (K) fertilizers. However, the impact of the type and quantity of crop residue on soil K supply capacity in different soil types remains poorly known. To investigate the effects of crop residue incorporation rate and inorganic K fertilization on apparent K balance and soil K supply capacity in cotton-wheat cropping system, we conducted two, six-year field experiments on two soil types in Nanjing and Dafeng, China. At both sites, crop residue incorporation ameliorated the negative K balance and improved the soil water-soluble, exchangeable, and non-exchangeable K (WSK, EK, and NEK) contents. The soil WSK, EK and NEK contents were positively correlated with the net K accumulation at both sites across two soil layers. However, the correlations between net K accumulation and quantity-intensity related parameters varied with the soil types. Treatment with wheat straw (9000 kg ha −1 ) + cotton residue (7500 kg ha −1 ) at both sites performed better than the 300 kg K2 O ha −1 treatment in terms of balancing soil K depletion and keeping adequate K fertility status. Incorporation of adequate crop residues performed similarly to inorganic potash in improving the soil K supply power.