石灰性潮土长期定位施肥对小麦根际无机磷组分及其有效性的影响

在长期定位施肥的基础上，采用网室盆栽试验，研究了石灰性潮土中不同施肥处理对冬小麦根际土壤与非根际土壤中无机磷组分及其有效性的影响。结果表明，不同施肥处理的供试土壤无机磷组分均以磷酸钙盐为主，平均占无机磷总量的73．9％，其它组分占26．1％。不施磷肥的各处理（CK、N、NK）中，小麦生物量和吸磷量均较低，小麦根际土壤与非根际土壤中无机磷总量变化不大，Ca2-P和Ca8—P在各处理的根际土壤中含量均很低。在施用磷肥的各处理（NP、PK、NPK）中，NP和NPK处理小麦的生物量和吸磷量均显著高于PK处理，而PK处理根际与非根际土壤中无机磷各组分的增幅明显高于NP和NPK处理。磷肥和有机肥处理，均显著提高小麦的吸磷量和生物学产量，各处理根际与非根际土壤中无机磷组分含量和总量增加的幅度以1．5（M＋NPK）处理最高。对不同施肥处理的小麦根际各无机磷形态及其与土壤速效磷间的相关分析表明，Ca2-P与土壤速效磷间的相关性达极显著水平，Ca8-P、Al-P、Fe—P达显著水平，O-P、Ca10—P不显著。

Effects of long-term fertilization on inorganic phosphorus fractions and availability in wheat rhizosphere in calcareous fluvo-aquic soil

Based on a 15-year long-term fertilization experiment in the fluvo-aquic soil,the effect of different fertilization treatments on inorganic-P forms and their availabilities in wheat rhizosphere was studied by pot experiment.The results showed that the content of Ca-P was higher than those of other forms in all the fertilized treatments,occupied 73.9% of total inorganic P,the total content of other P forms occupied 26.1%.The wheat biomass and P uptake were very low without P application(CK,N,K),and the total content of inorganic P changed very small in the rhizosphere and bulk soils,and the contents of Ca2-P and Ca8-P were very low in all treatments.The wheat biomass and P uptake of NP and NPK were significantly higher than those of PK,and PK significantly increased the content of inorganic P in the rhizosphere and bulk soils compared with N and NP.While combined application of P fertilizer and organic manure,the biomass and P uptake of wheat were significantly increased,and 1.5(M NPK) significantly increased the total and all forms of inorganic P,those of S NPK were not increased clearly.By correlation analysis between OlsenP and inorganic P forms,it was shown that Ca2-P was correlated most significantly with Olsen-P;Ca8-P,Al-P and Fe-P were significant,while O-P and Ca10-P were not significant.