| In order to explore the effects of biochar on the growth of crops and nutrient loss and further utilization and development of biochar, simulation experiment indoor of soil column was conducted in this experiment, and adding0%(0t·hm-2),0.5%(5t·hm-2),2%(20t·hm"2),4%(40t·hm-2),6%(60t·hm-2),8%(80t·hm-2) biochar (the biochar was prepared by pyrolyzing corn straw at500-550℃under oxygen limited condition) into red dryland land of Southern China under urea application condition (300kg·hm-2), and using static chamber/gas chromatograph techniques to collect and determine the CH4, CO2, N2O fluxes and the effects of biochar on dynamic change of nitrogen and phosphorus. A field plot experiment was conducted to study the effects of different fertilization models on nitrogen runoff, yield, quality, fertilizer nitrogen utilization of summer maize in the dryland. Results showed that:Compared with urea application treatment, the total nitrogen and NH4+contents of leachate were significantly decreased when biochar addition ratio was above2%(including2%), and the NO3-contents of leachate was obviously decreased when the ratio reached4%. The content of soil total nitrogen was significantly increased when biochar addition was above2%(including2%); With the increasing addition of biochar, total phosphorus content gradually increased. The leaching amount of soil phosphorus was closely related to content of Olsen-P in deep soil, and the deeper the soil layer went, the better the correlation became; When biochar addition ratio was above2%(including2%), the comprehensive greenhouse effective of CH4and N2O were significantly decreased, and the decreased range was bigger when the ratio reached4%. As a conclusion, recommended applying amount of biochar is2%in agricultural production, which has a better effect both on carbon fixation and reduction;Compared with chemical fertilization, the following fertilization modes, combined application of chemical fertilizer and biochar, combined application of chemical fertilizer and organic manure, combined application of chemical and organic manure and biochar, all kinds of nitrogen runoff and all kinds of phosphorus runoff are remarkably decreased in dryland; Compared with chemical fertilization, combined application of chemical and organic manure and biochar can significantly increase the yield and quality of maize and Chinese cabbage and fertilizer utilization ratio. Therefore, this kind of fertilization mode, which is combined application of chemical and organic manure and biochar, is worth of being popularized on dryland production in the future. |
