AICRP on Long-Term Fertilizer Experiments : Salient Achievements and Future Directions

摘要

The long-term fertilizer experiments at fixed sites in different agro-ecological zones(AEZ)in India covering important soil types and predominant cropping systems were initiated during early 1970s to monitor the changes in soil quality/health,crop productivity and sustainability under continuous application of plant nutrient inputs through fertilizers and organic sources.Results revealed that the balanced application of nutrients and also their conjoint application in an integrated manner through inorganic and organic sources sustained higher stable yields and improved the nutrient use efficiency over the years and impacted positively the soil physical,chemical and biological properties.Increase in soil organic carbon content with balanced fertilization and integrated nutrient management caused improvement in sustainable yield index(SYI).Continuous application of P to a crop resulted in an increase in available P status in soil,especially in the alluvial soils which could be reutilized by readjusting the P dose.Continuous absence of K in fertilizer schedule or application in quantities lower than that removed by crop made Vertisols responsive to K application due to slower release of K from non-exchangeable pool and reduction in available K content.Based on these results,critical level of available K(IN NH4OAc,pH 7.0 extractable K)deficiency in Vertisols was revised to 330 kg K ha~(-1)against currently used value of 280 kg ha~(-1).Incorporation of FYM was more effective than lime in sustaining the productivity of Alfisols.Nearly 50 years of LTFE results lead to a conclusion that the balanced and integrated application of nutrients sustains crop productivity,improves soil quality/health,and helps in mitigating climate change by pushing more carbon from atmosphere to soil via photosynthesis route.