Sequestering soil carbon in the low input farming systems of the semi-arid tropics ? does litter quality matter? uri icon

abstract

  • Maintaining soil organic matter (SOM) in low input smallholder rice cropping systems worldwide is ofparamount importance to maintaining livelihoods and food security. A long term rainfed lowland riceexperiment tested the hypothesis that applying small (1.5 t/ha dry matter) annual additions of slowlydecomposable plant materials which were grown offsite and applied prior to land preparation, could result inincreased soil organic carbon, crop yield and improve the recovery of nutrients compared with plant materialsof higher quality or straw retention alone. Annual leaf litter applications over 9 seasons resulted in significantincreases in SOC of 39% (from 3.5 to 4.9 mg/g) in the leaf litter treatments compared to only 13 % in the noleaflitter control. In terms of rice grain production and nutrient use efficiency, leaf litter quality was animportant driver. Apparent nutrient recovery of nitrogen and sulfur reflected the decomposition rate of theadded residues. Sustainable farming systems will require that crop yields are stable through the maintenanceof soil fertility and the balanced use of nutrients in the system. The results of this study are therefore highlysignificant and provide evidence that low rate, long term residue management can have profound effects

publication date

  • 2017