Effects Of Biochar Amendment On Soil Fertility, Crop Growth And Nutrient Uptake

Currently, with carbon dioxide in the atmosphere increasing in the global, biochar can sequester C in the soil and reduce GHG emission as an effective tool. Biochar applied to the soil not only increase soil organic carbon and decrease greenhouse gas, but also promote plant nutrient uptake and enhance crop yield. Micro zone trial was conducted to study the effects of biochar produced from wheat straw at low pyrolysis on crop growth, nutrient uptake and soil chemical properties.(1) Biochar at 400℃pyrolysis were put into rice soil at different rates (0 t·hm-2,2.4 t·hm-2,12t·hm-2,48 t·hm-2). Through elements analysis of corn plant in seeding age and soil, the author found:Biochar (48 t·hm-2) significantly decreased corn height from 13 to 33 days after sowing, but the inhibition effects of biochar gradually disappeared after 39 days. Biochar did not significantly affect the corn dry weight, nitrogen uptake (g·pof-1) and phosphorus uptake (g·pot-1) in seeding stage. Biochar (12 t·hm-2,48 t·hm-2) significantly increased soil organic carbon and total nitrogen, but did not significantly affect total phosphorus, available phosphorus and pH. Soil total N, soil organic carbon and biochar amendment rates (0 t·hm-2,2.4 t·hm-2,12 t·hm-2,48 t·hm-2) had significantly positive correlation (n=12, p<0.01).(2) Biochar at 400℃pyrolysis were added to red soil and rice soil at different rates (0 t·hm-2,2.4 t·hm-2,12t·hm-2,48 t·hm-2). Through elements analysis of wheat plant and soil, the author found:Soil organic carbon and biochar amendment rates (0 t·hm-2,2.4 t(hm-2,12 t·hm-2,48 t·hm-2) had significantly positive correlation (n=12, p<0.01). Biochar (12 t·hm-2,48 t·hm-2) added to red soil significantly increased soil organic carbon. Biochar (48 t·hm-2) applied to rice soil significantly increased soil organic carbon. Total N of red soil and biochar amendment rates had significantly positive correlation (n=12, p<0.01). Biochar (48 t·hm-2) significantly improved total N of red soil, but biochar did not significantly affect total N of rice soil. C/N of red soil and biochar amendment rates had significantly positive correlation (n=12, p<0.01) while C/N of rice soil and biochar amendment rates had significantly positive correlation (n=12, p<0.05). Biochar (12 t·tm-2,48 t·hm-2) put into red soil significantly increased C/N while biochar (48 t·hm-2) significantly increased C/N of rice soil. pH of red soil and biochar amendment rates (0 t·tm-2,2.4 t·hm-2,12 t·hm-2,48 t·hm-2) had significantly positive correlation (n=12, p<0.01). Biochar (12 t·hm-2,48 t·hm-2) applied to red soil significantly increased pH while biochar did not significantly affect pH of rice soil. Biochar (48 t·hm-2) significantly improved total P of red soil. Biochar did not significantly affect total P of red soil and available P of 2 soils. Available K and biochar amendment rates (0 t·hm-2,2.4 t·hm-2,12 t·hm-2,48 t·hm-2) had significantly positive correlation (n=12, p<0.01). Biochar significantly improved available K of red soil while biochar (12 t·hm-2,48 t·hm-2) significantly increased available K of rice soil.Biochar did not significantly affect N content and P content of wheat plant on red soil while biochar (48 t·hm-2) significantly improved K content of wheat plant on red soil. K content of wheat plant on red soil and biochar amendment rates (0 t·hm-2,2.4 t·hm-2,12 t·hm-2,48 t·hm-2) had significantly positive correlation (n=12, p<0.05). Biochar (12 t·hm-2) significantly decreased N content of wheat plant on rice soil. Biochar (48 t·hm-2) put into rice soil significantly improved P content and K content of wheat plant. P content of wheat plant on rice soil and biochar amendment rates (0 t·tm-2, 2.4 t·hm-2,12 t·hm-2,48 t·hm-2) had significantly positive correlation (n=12, p<0.05) while K content of wheat plant on rice soil and biochar amendment rates (0 t·hm-2,2.4 t·hm-2,12 t·hm-2,48 t·hm-2) had significantly positive correlation (n=12, p<0.01).Biochar did not significantly affect N uptake and P uptake of wheat plant on red soil. Biochar (48 t·hm-2) added to red soil significantly improved K uptake of wheat plant. Biochar (2.4 t·hm-2,12 t·hm-2) significantly decreased N uptake, P uptake and K uptake of wheat plant on rice soil while biochar (48 t·hm-2) significantly improved P uptake and K uptake of wheat plant on rice soil.Biochar did not significantly affect wheat dry weight on red soil. Biochar (2.4 t·hm-2,12 t·hm-2) put into rice soil significantly decreased wheat dry weight while biochar (48 t·hm-2) significantly enhanced wheat dry weight on rice soil.(3) Biochar at different pyrolysis temperatures (300℃.400℃and 500℃) were put into red soil and rice soil at the same rate (12t·hm-2). Through elements analysis of wheat plant and soil, the author found:Biochar (300℃400℃and 500℃) can increase soil organic carbon. Biochar (300℃,400℃and 500℃) can enhance soil available K content, and the effect of biochar at 400℃and 500℃better than 300℃biochar. Biochar had not positive effects on dry matter weight and nutrients (N, P and K) uptake of wheat, but decreased dry matter weight and nutrients (N, P and K) uptake of wheat on rice soil.