The field experiments was conducted is an ongoing All India Co-ordinate Research Project on “Long term Fertilizer Experiment” during 2018-2019 with soybean-wheat cropping sequence at the Research Farm Department of Soil Science, Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur (M.P.), India. The objective of the study was the Impact of long term application of inorganic fertilizers and organic manure on soil fertility and crop productivity under soybean-wheat cropping system in a Vertisol. The experiment consists of ten treatments i.e. T1 50% NPK, T2 100% NPK, T3 150% NPK, T4 100% NPK + Hand Weeding, T5 100% NPK + Zn, T6 100% NP, T7 100% N, T8 100% NPK+ Farm Yard Manure, T9 100% NPK–S and T10 unfertilized plot (control) with four replications in a randomized block design. The findings of the present study indicated that the soil pH and EC were remaining unaltered even after continuous application of variable amounts of fertilizers either alone or in combination. A significant positive change in soil organic carbon, available N P K and S content was observed with continuous additions of balanced fertilizers and manures over the imbalanced or unfertilized treatments. The findings showed that the application of recommended dose of N, P and K (20:80:20 kg ha-1 for soybean and 120:80:40 kg ha-1 for wheat) with organic manure (FYM) @ 5 t ha-1 resulted in 185.8% and 325.9% increase over control in soybean and wheat yields, respectively. Thus, the continuous use of balanced fertilization, either alone or in combination with organic manure is necessary for sustaining soil fertility and productivity of crops.
Relative contribution of maize and external manure amendment to soil carbon sequestration in a long-term intensive maize cropping system
