A comprehensive assessment of long-term fertilizer experiments based on soil health, crop productivity and profitability of particular cropping system is important to evaluate their sustainability. With this objective, soil indicators and yield data recorded from long-term fertilizer experiments (LTFEs) started in 1995–96 with soybean-wheat system. The experiment comprised a total of seven treatments, where six were applied to the wheat crop including control (CK), organic manure (M), inorganic fertilizers (NPK), integrated (MNPK), only nitrogen (N), nitrogen with organic manure (MN), while the seventh treatment involved the use of mineral fertilizers (NPK+NPK) in both the crops. Among different indexing method principal component analysis (PCA) based nonlinear scoring function (NLSF) showed higher sensitivity (1.76) and correlation with yield (0.77) than unscreened transformation (1.44 and 0.71, respectively). The use of organic manure alone or along with chemical fertilizer improved soil physical, chemical and biological property and provided a significantly higher PCA-based soil quality index (SQI) (0.721–0.644) than control (0.482) and NPK alone (0.536). Long-term use of N alone (urea) reduced system yield and provided a negative yield trend (−0.394 q ha−1 year−1) while its conjoint use with 10 tonnes organic manure (M) improved soil quality and ensured productivity and profitability equal to MNPK. The results suggest that organic manure application along with N or NPK sustain both long- and short-term productivity, improve soil health and provide greater profitability in soybean wheat cropping system in the north-western Himalayan region.
Parihar et al. (Fri,) studied this question.
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