红壤长期肥料定位试验中土壤磷素肥力的演变

研究了长期施肥对土壤全磷、有效磷年份变化和剖面磷组分、土壤对磷吸附解吸性能、土壤需磷指数等方面的影响。结果表明:长期施用化学磷肥和化肥加有机肥,均可提高土壤全磷、有效磷数量。施用有机肥料(M)和有机肥料加化学肥料处理(NPKM),土壤中的磷组分变化以Ca-P和Al-P积累为主要表现形式,化学磷肥能够提高土壤的全磷含量,其无机磷组分变化以Al-P增幅为最大,在所有处理中均表现为土壤O-P相对稳定。随着施肥时间延长,土壤磷组分以有效性较高Ca-P和Al-P增加为特征。施肥对土壤的耕层磷组分影响最为显著,对深层土壤影响相对为弱,长期施用磷肥和有机肥料促使磷的下移,增加深层磷的含量。施用有机肥料(M)和有机肥料加化学肥料处理(NPKM)土壤,对外源磷的吸附强度明显小于施用化学肥料(N,NPK,NPKS)和不施用肥料处理(CK),有机肥料能够显著提高吸附磷的再利用,其中有机肥料加化学肥料处理(NPKM)中解吸磷可占吸附磷的47.72%,单施有机肥处理(M)占42.89%,而施用化学肥料(N,NPK,NPKS)和不施用肥料(CK)中解吸磷数量占吸附磷数量一般小于8%。有机肥料加化学肥料处理(NPKM)和单施有机肥处理(M)的PFI显著低于施用化学肥料(N,NPK,NPKS)和不施用肥料对照处理(CK)。

Development of P-fertility in Long-term Fertilizer Experiment on Red Soil

The effect of long-term fertilizer on total P,valid P,year-and-profile P composition,the property of P absorption and desorption of the soil,the index of P requirement of the soil,and so on,were studied,with the soil treated by CK,N,NPK,NPKM,NPKS,M in the long-term fertility-assessed experiment.The results showed that: both the long-term application of chemical phosphate and chemical fertilizer plus organic fertilizer can heighten the amount of total P,valid P.In treatments applied with organic fertilizer only and chemical fertilizer plus organic fertilizer,the accumulation of Ca-P and Al-P was the main form of P composition changing in soil,chemical phosphate can increase the content of total P in soil,the increasing-range of Al-P were the most in inorganic P composition,the O-P of soil was stable relatively in all treatments.With the time extending,the increasing of higher-validity Ca-P,Al-P became the trait of P composition changing.The effect of applying on topsoil was the most,and on deep soil relatively weaker,long-term application of phosphate and organic fertilizer can prompt P moving to substratum and increase P content in the deep soil.The strength of soil absorbing external P in treatments of NPKM,M was lower obviously than that in treatments of NPK,NPKS,CK and N,organic fertilizer can advance the reusing of P-absorbed,there was 47.72% P-desorbed in P-absorbed in the treatment NPKM,42.89% in M,and less than 8% in CK,N,NPK and NPKS.The PFI of treatments MNPK and M respectively was 2.51 and 2.69,obviously less than 4.53 and 4.37 of treatments N and NP.