长期施肥褐土不同磷组分对磷素盈余的响应

Response of phosphorus components to phosphate surplus in cinnamon soil under long-term fertilization

【目的】研究褐土区玉米田长期不同磷源投入对土壤磷素形态和磷素累积的影响,通过对不同磷组分与磷素盈余之间进行相关性分析,研究不同施肥措施对土壤磷素形态转化的影响,为探索合理的磷肥调控措施,促进土壤中磷素向作物易于吸收的水溶态和碳酸氢钠溶解态转化,提高磷素利用效率提供依据。【方法】试验依托始于1992年位于山西省寿阳县北坪旱塬上的长期定位试验。9个施肥处理包括:无肥对照(CK)、N1P1、N2P2、N3P3、N4P4、N2P1M1、N3P2M3、N4P2M2、N0P0M6,其中N1、N2、N3、N4分别为尿素N 60、120、180、240kg/hm^2,P1、P2、P3、P4分别为过磷酸钙P 16、33、49、66 kg/hm^2,M为腐熟厩肥,M1、M2、M3、M6分别折合为施P量14、28、42和83 kg/hm^2。1992-2016年,收获后取0-20 cm耕层土壤样品,分析土壤磷素形态及盈余量,并计算不同形态磷素与磷盈余量之间的相关性。【结果】连续施肥25年后,土壤磷组分发生了不同的变化,不施肥处理除H2O-Pi、Residual-P外,各形态磷较试验初均有降低。施用无机肥各处理主要增加了土壤中HCl-P含量,以N4P4处理提高幅度最大,比试验初提高了127.7%。有机肥投入可以显著提高土壤中的活性磷含量,高量施用有机肥后,H2O-P总含量较试验初提高了8倍之多,NaHCO3-Pi年增加速率为11.50 mg/(kg·a)。不同施肥各处理土壤磷素盈余量为N0P0M6> N3P2M3> N4P4> N4P2M2> N3P3> N2P2> N2P1M1> N1P1> CK。磷素盈余是土壤磷组分变化的重要影响因素,各形态磷组分对磷素累积量响应大小为NaHCO3-Pi> NaOH-Pi> HCl-P>NaHCO3-Po> Residual-P> H2O-Po> NaOH-Po> H2O-Pi。【结论】长期施肥使土壤各组分磷素含量发生了显著变化,有机无机肥配施有利于土壤中活性磷的转化,过量施磷导致磷素在土壤中大量盈余,高量施用有机肥磷素盈余量最大。当以无机肥投入时,施用过磷酸钙P 33 kg/(hm2·a)基本可以满足作物生长发育的要求。当有机无机肥配施时,施用过磷酸钙P 16 kg/(hm2·a),配施厩肥P 14 kg/(hm2·a)时,土壤磷素盈余量最小。

【Objectives】The effects of different P source inputs on soil P composition and accumulation in maize feild of cinnamon soil under long-term fertilization were studied,and the correlation between different P components and soil P surplus was analyzed,which will provide basis for regulating the utilization efficiency of P fertilizers.【Methods】The long-term experiment,located in Beiping plateau,Shouyang County of Shanxi Province,was started since 1992.There were 9 fertilization treatments in the experiment,they were:no fertilizer control(CK),N1P1,N2P2,N3P3,N4P4,N2P1M1,N3P2M3,N4P2M2,N0P0M6.Among them,N1,N2,N3 and N4 represent urea N application rates of 60,120,180,240 kg/hm^2;P1,P2,P3,P4 represent super calcium phosphate rates of P 16,33,49,66 kg/hm^2;M was manure compost,the followed digital of M1,M2,M3,M6 represent the manure P application rates of 14,28,42 and 83 kg/hm^2.Soil samples were taken from 0−20 cm topsoil during 1992 to 2016 after harvest.The contents of different soil P fractions were analyzed,and the surplus amount of P in top soil and the correlation between it and the P fractions were calculated.【Results】After 25 years of continuous fertilization,the P composition in the soil changed differently.Except for H2O-Pi and Residual-P,P contents in different forms were lower than that at the beginning of the experiment.The application of inorganic fertilizer mainly increased the HCl-P in the soil,and N4P4 treatment increased the most,which was 127.7%higher than that of the initial experiment.The application of organic fertilizer could significantly improve the active P in soil.After applying high rate of organic fertilizer,the total content of H2O-P was 8 times higher than that at the beginning of the experiment,and the annual increase rate of NaHCO3-Pi was 11.50 mg/(kg·a).The surplus amount of soil P in different fertilization treatments was in order of N0P0M6>N3P2M3>N4P4>N4P2M2>N3P3>N2P2>N2P1M1>N1P1>CK.P surplus was an important factor influencing the change of P composition in soil,and the response order of various P component to P accumulation in the season was NaHCO3-Pi>NaOH-Pi>HCl-P>NaHCO3-Po>Residual-P>H2O-Po>NaOH-Po>H2O-Pi.【Conclusions】Long-term fertilization has significantly changed the contents of different fraction of soil P.Combined application of organic and inorganic fertilizer is conducive to the conversion of active P in soil.Excessive application of phosphorus results in a large surplus of phosphorus in the soil,and the highest surplus of phosphorus is obtained in high application rate of organic fertilizer.When inorganic fertilizer is applied,P 33 kg/(hm2·a)of superphosphate can basically meet the requirements of plants.When inorganic and organic fertilizers are applied with superphosphate P 16 kg/(hm2·a)and manure P 14 kg/(hm2·a),the surplus of phosphorus in soil is the least.