不同分子量碳源对砂姜黑土磷素有效性和玉米磷吸收的影响

Effects of Carbon Sources with Different Molecular Weights on Phosphorus Availability and Phosphorus Uptake in Maize

为探究不同分子量碳源对土壤磷有效性的影响,以安徽省典型砂姜黑土为供试土壤,通过盆栽种植玉米试验,开展了不同碳源(果糖、蔗糖、纤维素)对土壤中磷形态转化和玉米磷吸收影响的研究。结果表明:土壤Olsen-P含量随时间先增加后降低。在玉米间苗7 d后果糖处理Olsen-P含量最高,15 d后纤维素处理Olsen-P含量达最大值,90 d后,相比于对照、果糖和蔗糖处理,纤维素处理土壤Olsen-P含量显著增加了79.74%、54.03%和30.03%(P<0.05)。②玉米间苗90 d后,相较于对照处理,纤维素处理显著降低了Fe-P和Ca_(10)-P含量,增加了Ca_(8)-P含量,而对照、果糖和蔗糖处理的Ca_(2)-P含量无显著差异。与对照处理相比较,纤维素处理显著提高了活性有机磷(LOP)和中等活性有机磷(MLOP)含量,减少了中稳定性有机磷(MROP)含量。③纤维素处理增加了土壤可溶性有机碳(DOC)含量和磷酸酶活性,降低了土壤pH和交换性钙含量,这是土壤磷有效性增加的重要原因;④与对照、果糖和蔗糖处理相比,纤维素处理下玉米磷吸收量显著增加了46.20%、19.05%和19.28%。可见,与低分子量碳源(果糖和蔗糖)相比较,高分子量碳源(纤维素)提高土壤磷有效性和玉米磷吸收效果长效性更好。研究结果为指导农田生态系统中利用碳源调控土壤磷的转化和有效性提供了重要信息。

A pot experiment was conducted to understand the effects of different carbon sources(fructose(GT),sucrose(ZT)and cellulose(XWS))on the transformation of phosphorus(P)form in soil and P uptake by maize with the lime concretion(Shajiang)black soils of Anhui Province.The results showed as follows:1)Soil Olsen-P content firstly increased and then decreased with time,after thinning for 7 days the content of Olsen-P under GT treatment reached the maximum,and after 15 days the content of Olsen-P under XWS treatment reached the maximum.After 90 days,compared with CK,GT and ZT,the content of Olsen-P under XWS treatment was significantly increased by 79.74%,54.03%and 30.03%(P<0.05),respectively.2)After 90 days,compared to CK,XWS treatments significantly reduced the contents of Fe-P and Ca_(10)-P,and increased the contents of Ca_(8)-P,while no significant difference was found in the contents of Ca_(2)-P among CK,GT and ZT treatments.Compared with CK,XWS treatment significantly increased the contents of active organophosphorus(LOP)and moderately active organophosphorus(MLOP),and decreased the content of moderately stable organophosphorus(MROP).3)Under XWS treatment,soil DOC content and phosphatase activity were increased,but soil pH and exchangeable calcium content were decreased,which were important factors influencing the increase of soil P availability.4)Compared with CK,GT and ZT treatments,P uptake of maize under XWS treatment was significantly increased by 46.20%,19.05%and 19.28%.The results show that compared with low molecular weight carbon sources(fructose and sucrose),high molecular weight carbon sources(cellulose)have better long-term effectiveness in improving soil P availability and P absorption in maize,which provide important information for the regulation and effectiveness of soil P conversion by using carbon sources in farmland ecosystems.