Successive straw biochar application as a strategy to sequester carbon and improve fertility: A pot experiment with two rice/wheat rotations in paddy soil
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- Zhao, X., Wang, J., Wang, S. et al. Plant Soil (2014) 378: 279. doi:10.1007/s11104-014-2025-9
A pot study spanning four consecutive crop seasons was conducted to compare the effects of successive rice straw biochar/rice straw amendments on C sequestration and soil fertility in rice/wheat rotated paddy soil.
We adopted 4.5 t ha−1, 9.0 t ha−1 biochar and 3.75 t ha−1 straw for each crop season with an identical dose of NPK fertilizers.
We found no major losses of biochar-C over the 2-year experimental period. Obvious reductions in CH4 emission were observed from rice seasons under the biochar application, despite the fact that the biochar brought more C into the soil than the straw. N2O emissions with biochar were similar to the controls without additives over the 2-year experimental period. Biochar application had positive effects on crop growth, along with positive effects on nutrient (N, P, K, Ca and Mg) uptake by crop plants and the availability of soil P, K, Ca and Mg. High levels of biochar application over the course of the crop rotation suppressed NH3 volatilization in the rice season, but stimulated it in the wheat season.
Converting straw to biochar followed by successive application to soil is viable for soil C sequestration, CH4 mitigation, improvements of soil and crop productivity. Biochar soil amendment influences NH3 volatilization differently in the flooded rice and upland wheat seasons, respectively.