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Sustainable Yield Index: An Approach to Evaluate the Sustainability of Long-Term Intensive Cropping Systems in India

2004; Taylor & Francis; Volume: 24; Issue: 4 Linguagem: Inglês

10.1300/j064v24n04_05

1540-7578

R. H. Wanjari, Muneshwar Singh, Probir Kumar Ghosh,

Agricultural Science and Fertilization

ABSTRACT Several long-term fertilizer experiments conducted in different agro-ecological regions of India involving intensive cropping systems such as rice-wheat (Barrackpore), fingermillet-maize (Coimbatore and Bangalore) and soybean-wheat (Ranchi and Jabalpur) over the years (1972–2000) have demonstrated wide variations in crop productivity. Application of fertilizers over the years had showed significant impact on the status of soil organic carbon (SOC) and soil fertility, which in turn influence sustainability of cropping system. Sustainable Yield Index (SYI) was therefore, used as an approach to evaluate the minimum yield likely to be achieved in relation to changes in SOC and available N, P and K status of soil. Results showed that the SOC had significant effect on SYI in Inceptisols of Coimbatore (fingermillet-maize) and Jabalpur (soybean-wheat); and Alfisols of Ranchi (soybean-wheat) and Bangalore (fingermillet-maize). However, available soil N status did not much influence the SYI except in Inceptisols of Barrackpore under rice-wheat system. Phosphorus fertilization was important for all crops (finger-millet and maize at Coimbatore in particular) at all centers except in Alfisol of Bangalore. Soil available K status had, however, signified its role for maintaining SYI of different cropping system in Coimbatore, Jabalpur and Bangalore. The SYI was the lowest (0.17 and 0.14 for rice and wheat, respectively) when no manure and fertilizer was added in Inceptisols of BarracKpore. While Alfisols both at Ranchi and Bangalore aimlessly gave very low SYI ranging from 0 to 0.07 with N alone due to adverse effect of N fertilization alone compared to higher values (SYI 035 to 0.62) for NPK + FYM/lime treatment. The R2 values between SYI and SOC for soybean, wheat, fingermillet and maize at Ranchi, Jabalpur, Coimbatore and Bangalore, were approaching unity (ranging from 0.72∗∗ to 0.91∗∗) indicating higher dependence of SYI on SOC. On the contrary, rice and wheat at BarracKpore showed relatively high R2 (0.93∗∗ and 0.94∗∗) between SYI and only soil available N status. Similarly, the values of R2 between SYI and available soil P status were higher (08l∗∗−0.99∗∗) for all the crops except fingermillet and maize at Bangalore (0.51∗ and 0.52∗) whereas finger millet and maize in Kandiustalfs of Bangalore showed maximum R2 value (0.97∗∗ and 0.98∗∗) between SYI and available K followed by soybean (0.92∗∗) and wheat (0.89∗∗) in Chromustert of Jabalpur. Thus, the study highlighted that SOC followed by soil available P strongly influenced the SYI in majority of cropping systems/soil types. However, available N in rice-wheat in Inceptisols of Barrackpore is an important soil fertility parameter and that of available K in fingermillet-maize cropping system in Alfisols of Bangalore. The SYI with 100% N and NP were considerably lower (SYI 0.0–0.20) than SYI of 0.31–0.53 with 100% recommended NPK because of unbalanced and inadequate nutrition. Maximum SYI 037–0.62 achieved for 100% NPK + FYM treatment in almost all the locations indicating the beneficial effect of integrated use of nutrients on sustaining higher crop productivity by correcting marginal deficiencies of secondary and micronutrients.