Upland red soil is characterised by its primary barriers of being acidic, barren, harden, corrosive, etc, during the process of soil-formation. On top of that, the radical change in the management mode of soil nutrient (prevalent use of chemical fertilizer instead of organic fertilizer) gives rise to the secondary barriers of the upland red soil: decline of soil fertility, acidification, attenuation of soil biodiversity, etc, which severely impact the utilization and sustainable development of upland red soils. Consequently, removing the barriers to improve the soil fertility and crop yields has become a matter of primary importance. The research, based on the field experiment of upland red soils, is aimed at resolving the problems of hardening of the heavy clay and low fertility in upland red soils, with its focus on how low doses of biochar will affect fertility and production of upland red soils. Three treatments with different doses of biochar, CK, BC1 and BC2, were set in the experiment. The doses of biochar in CK, BC1 and BC2 are 0, 758, 1515 kg.hm-2.a-1, respectively.
Results/Conclusions
Compared with CK, the findings indicated that the bulk density of soil with BC1, BC2 decreased by 0.57%-2.05% and 0.87%-4.88%, soil pH increased by 2.51%-13.66% and 8%-12%, and soil cation exchange capacity increased by 3.73%-6.45% and 4.91%-7.13% in 0-60 cm upland red soils layer added low doses of biochar; the bulk density of upland red soils shows a trend of decrease, soil pH and cation exchange capacity present an upward trend with increasing doses of biochar. The study indicates application of low doses of biochar is beneficial to increasing content of organic carbon and N, P, K in upland red soils, and organic carbon, total potassium and soil available potassium increased with increasing doses of biochar. The crop yield of BC1, BC2 increased by 19.08%, 23.68% in 2013, and 18.01%、22.98% in 2014. It follows that application of low doses of biochar in upland red soils improves its physical and chemical properties and nutrient utilization efficiency. And this study also provides preliminary practical and theoretical guidance for the implementation of the circular agriculture in upland red soil.