紫色土旱坡地减磷配施有机肥的磷肥效应及磷素迁移特征

Phosphorus Effect of Purple Soil Sloping Field in Condition of Reduced Phosphorus Fertilizer Combining Organic Fertilizers and Phosphorus Migration Characteristics

【目的】本文探索了长江上游紫色土旱坡地麦玉轮作系统减少农田磷素流失和有效提高磷肥利用率的最佳施肥模式,以期降低磷对水体富营养化的影响。【方法】2011-2015年,以紫色土旱坡地典型农作冬小麦和夏玉米为材料,在西南大学试验农场进行田间定点试验。试验采用随机区组设计,共设置7个田间小区试验,依次为不施用磷肥(P0)、优化施肥(P)、倍量施磷肥(2P)、优化施肥+秸秆还田(SP)、优化施肥+猪粪有机肥(MP)、优化施肥量磷肥减量20%+猪粪有机肥(MDP)、优化施肥量磷肥减量20%+秸秆还田(SDP)。测定了各处理土壤基础性质,以及0~20、20~40、40~60 cm土层土壤全磷和有效磷含量,调查不同生育期冬小麦和夏玉米各主要生长指标和产量。【结果】冬小麦季和夏玉米季都以2P处理作物磷吸收量为最高,但是磷素表观利用率却不高。小麦季SDP和MDP处理分别比P处理磷肥表观利用率高5.9%和4.2%。玉米季有机无机肥配施处理磷肥表观利用率也显著高于单施化肥处理(P<0.05)。坡上除了P0和P处理全磷含量有所减少外,其他各处理全磷含量都呈增加趋势;坡中、坡下的增长幅度要大于坡上。除了P0处理土壤有效磷含量降低外,其他处理坡上、坡中、坡下土壤中有效磷含量都呈增加趋势。【结论】紫色土旱坡地冬小麦和夏玉米适当减磷配施有机肥可以显著提高作物对磷肥的吸收利用,提高磷肥的利用率,秸秆和猪粪有机肥还田对土壤磷素有活化效果,可以促进磷素在土壤中的迁移,猪粪有机肥促进作用较强。

【Objective】The paper aimed to explore the optimum fertilization model for the reducing the loss of phosphorus in purple soil sloping field and improve the utilization ratio of phosphate fertilizer in the Yangtze River Basin to reduce the threat to the water quality of the Yangtze River. 【Method】Seven plot experiments were conducted consecutively in five years. The tests were designed with the amount of applied fertilizer（ 2 P）,optimum fertilization（ P）,optimization fertilization ＋ pig manure organic fertilizer（ MP）,optimization fertilizer ＋straw（ SP）,optimum amount of fertilizer phosphorus minus 20 % pig manure organic fertilizer（ MDP）,optimization of fertilizer phosphorus reduced 20 % straw（ SDP） and No application of phosphate fertilizer（ P0）. Soil basic properties and the total phosphorus and available phosphorus contents at 0-20,20-40,40-60 cm soil layers were measured,and the yield and components of winter wheat and summer maize at critical growth stages were investigated.【Result】During winter wheat season and summer maize season,the absorption of the plants with the amount of phosphorus fertilizer（ 2 P） were the highest,but the phosphorus element on utilization rate was not high. Winter wheat optimal phosphorus fertilizer ＋ straw（ SDP） and optimum amount of fertilizer phosphorus reduction 20 % ＋ pig manure organic fertilizer（ MDP）,the utilization rate of which respectively was 4. 2 % and 5. 9 % higher than that with the conventional optimal fertilizer（ P） treatment of phosphate fertilizer. The apparent utilization rate of fertilizer application in maize season was also significantly higher than that of single fertilizer application（ P 〈0. 05）. The content of total phosphorus increased on the top slope except for the treatment of P0 and P; Besides,the growth rate in the middle slope and the bottom slope was greater than that in top slope. Except for the decrease of available phosphorus in soil treated with P0,the available phosphorus contents in all the slope soils increased.【Conclusion】Purple soil sloping field in condition of reduced phosphorus fertilizer combining organic fertilizers could remarkably increase the absorption of phosphorus from soil,suppress the decreasing of P fixation and enhance P mobility and P use efficiency,and the pig manure promoting effect was bigger than the rice straw.