通过两年温室盆栽试验,研究了不同磷肥用量下生物碳对土壤磷素含量、棉花生长和养分吸收的影响。试验以棉花秸秆为原料制备生物碳,制成三种热解温度(450℃、600℃和750℃)的生物碳,分别以BC450、 BC600和BC750表示,同时以空白土壤为对照( CK);磷肥( P2 O5)用量设3个水平0、0.25、0.5 g/kg(分别以P0、P1、 P2表示)。研究结果表明,施用生物碳可显著提高土壤磷素含量及其有效性,随着生物碳热解温度的升高,土壤水溶性磷、速效磷及全磷含量均显著增加,且对三种磷素含量的影响表现为水溶性磷>全磷>速效磷。施用生物碳处理两年棉花的干物质重均显著高于对照,但不同热解生物碳处理对两年棉花干物质重的影响各异。施用生物碳可显著增加棉花养分吸收量,总体表现为750℃>600℃>450℃。因此,施用生物碳可显著提高土壤磷素含量,促进棉花生长和养分吸收;热解温度是影响生物碳质量的重要因素,生物碳的热解温度越高(450750℃),其促进作用越好。
Influence of biochar on soil phosphorus ( P ) , cotton growth and nutrient uptake under different phosphorus fertilizer application rates was evaluated with a pot experiment in years of 2011 and 2012.Biochar was produced from dried cotton stalks via pyrolysis in oxygen-limited conditions .Three types of biochar produced at 450℃, 600℃ and 750℃ ( BC450 , BC600 and BC750 ) were used as the soil organic amendment , and an untreated soil was set as control (CK) in this study.Each soil treatment was applied with three levels of P fertilizer (P2O5) as 0, 0.25 and 0.5 g/kg of soil weight (P0, P1 and P2).The experiment was that of 4×3 factorial design with four biochar treatments (BC450, BC600, BC750 and CK) and three P application rates (P0, P1 and P2).Cotton was planted for two consecutive growth seasons in 2011 and 2012.The results show that the soil P content and availability are significantly improved with biochar added .With the increase of pyrolysis temperature of biochar, the contents of water-soluble P, available P and total P in soil are increased significantly , and the order of influence of biochar on soil P content is water-soluble P>total P>available P.The dry matter amounts of cotton are significantly higher under the biochar treatments than those under the control ( CK) in both 2011 and 2012, but there are differences among three biochar treatments between 2011 and 2012.The P uptake of cotton is also promoted with biochar added .The order of cotton nutrients uptake under three biochar treatments is BC 750 >BC600 >BC450.These results suggest that biochar can increase soil P content , and enhance cotton growth and nutrients uptake .Thus, pyrolysis temperature is a vital factor for biochar , and the high temperature ( 750℃) biochar treatment demonstrates higher soil P , cotton dry matter weight and P uptake compared to the low temperature (450℃) biochar.