Meng Jun

Soil quality improvement by consecutive biochar application and effect on tobacco growth

Better understanding of the effects of biochar application on crop quality as well as biochar tolerance in different soils can benefit a wide use of biochar. In this study, soil physical and chemical properties, yields and output values of flue-cured tobacco were measured during a 4-year consecutive biochar application at levels of 0, 15, and 30 t·hm -2 ·year -1 at two sites with different soil fertility. Chemical properties relevant to tobacco quality were measured in the fourth year. The results showed that in the fourth year, soil pH was increased by approximately 0.5-0.6 unit, while soil bulk density was significantly decreased. Soil organic carbon (SOC) content was increased by 77.7% and 46.7% in Hongta soil with low fertility and Tonghai soil with high fertility, respectively. The increase of SOC contents were attributable mainly to the aggregate-occluded particulate organic carbon (oPOM), indicated that biochar-C was intensively protected by aggregates. Soil alkali-hydrolyzable nitrogen (N), available phosphorus (P) and available potassium (K) contents were significantly increased, while apparent K loss in soil was significantly increased. Apparent N loss was decreased when the cumulative amount of biochar was less than 60 and 30 t·hm -2 in Hongta soil and Tonghai soil, respectively. However, the N loss value was increased when the cumulative amount of biochar exceeded the two thresholds. Biochar application increased the yield, output value of flue-cured tobacco, with the maximum increments of yield by 5.1%-12.9% and output value by 12.6%-19.7% at a cumulative amount of 60 t·hm -2 biochar. In addition, the quality of tobacco reached the optimal point at this cumulative amount. The low fertility soil responded to biochar more rapidly and showed a higher tolerance than the high fertility soil. In summary, the cumulative biochar amount of 60 and 30 t·hm -2 appears to be the optimal amount for tobacco production in Hongta soil and Tonghai soil, respectively. When biochar is applied at a considerable high rate, chemical K fertilizer should be reduced accordingly to avoid the risk of non-point source pollution.

Roles of biomass-derived black carbon in soil and environment ecosystem: A review

As the global warming intensifying, Climate change has become an important environmental problem which has caused great concern around the world. Reducing the effects of greenhouse gases to the climate and ecosystem and stocking more carbon sequestration are the solved critical problems which government and scientist around world must face. As a potential mean of solving the emission of greenhouse gases, biochar (biomass-derived black carbon) has gradually become one of the most important research issues. All the paper researches around world show that biochar plays a powerful function and important role in soil amendment and environmental system. Biochar can be used as a soil amendment to improve soil structure, soil quality and increase crop production etc. The biochar approach provides a potential powerful solution: it allows us to sequestrate more carbon as well as reducing more pollutions of greenhouse gases from the environment and it will change the way of C cycles in the ecological system. As a soil ameliorant, it could increase the carbon stock sequestrations in soil all over the world. It provides the important solution to deal with the climate change problems. This paper reviews the latest important research, and offers the further research prospects. It aims to illustrate the important function of biochar in the soil and ecosystem, and offer the references for the further scientific biochar research which benefits for the further requiring study.