Trade-off between soil aggregate stability and carbon decomposition under 44 years long-term integrated nutrient management in rice-wheat-jute system

Soil stability, yield decline and higher carbon decomposition are the key issues in intensive agriculture. Long-term integrated nutrient management (INM) influences carbon (C) dynamics and maintains the soil aggregate stability, which driven by the type of cropping system and climatic zone. Therefore, the specific effects of rice-wheat-jute cropping system on soil aggregate distribution, C-stability, and trade-off between C-storage and decomposition rate were studied of a long-term INM trial in the sub-tropical zone. We investigated the effect of four long-term nutrient management practices that include, control, N (nitrogen (N) and no phosphorus (P), and potassium (K)), NPK (N, P and K) and INM (N, P, K + farmyard manure (FYM)). Results showed that the addition of FYM with NPK improved macro-aggregates by 71%, and associated C-pools by 30%. The INM enhanced C-storage (20%), however, the decomposition rate was also higher (28%) over control at 35 degrees C at field capacity. A trade-off exists between the soil-aggregate stabilization and C-decomposition rate. The proportion of C-storage was higher than decomposition in INM. Further, the C-sequestration varied (0.17 to 0.26 t ha(-1) y(-1)) under different treatments and were found highest in INM, indicating long-term soil stability and yield sustainability in the rice-wheat-jute system.

Automated summary

Soil stability, yield decline, and higher carbon decomposition are key issues in intensive agriculture. This study investigates the specific effects of a rice-wheat-jute cropping system on soil aggregate distribution, C-stability, and the trade-off between C-storage and decomposition rate in a long-term integrated nutrient management trial. The results showed that the addition of farmyard manure with NPK improved soil aggregates and associated C-pools, while the integrated nutrient management enhanced C-storage but also increased the decomposition rate. A trade-off exists between soil-aggregate stabilization and C-decomposition rate, with higher C-storage in the integrated nutrient management system.