不同前茬作物和施肥水平下麦田土壤不同形态无机磷含量及其对冬小麦磷累积量的贡献

Content of different fractions of soil inorganic phosphorus and their contributions to phosphorus accumulation in winter wheat with different previous crops and at different fertilizer levels

为研究不同前茬作物下土壤无机磷形态的差异及对后茬作物冬小麦磷累积的影响,开展了二因素田间试验,测定了3种前茬作物(玉米、大豆、花生)和2个磷肥施肥水平(P_(2)O_(5)150 kg/hm^(2),常规施肥(+F);P_(2)O_(5)0 kg/hm^(2),限肥(-F))处理下播种前和收获后耕层(0~15 cm)土壤全磷、速效磷以及不同形态无机磷的质量分数,同时测定冬小麦植株磷累积量,运用通径分析法,分析了土壤中不同形态无机磷对冬小麦植株磷积累量的贡献.结果表明:与常规施肥相比,限肥显著降低土壤全磷、速效磷和不同形态无机磷的含量.在常规施肥水平下,玉米前茬处理的土壤速效磷质量分数最高且显著高于其他前茬处理,为18.61 mg/kg,总无机磷、Fe-P和Ca_(10)-P的质量分数也最高,分别为592.55 mg/kg、41.97 mg/kg和338.77 mg/kg;大豆前茬处理的土壤全磷质量分数最高且显著高于其他前茬处理,为972.80 mg/kg,Al-P和O-P的含量也在大豆前茬处理的质量分数最高,分别为43.44 mg/kg和64.37 mg/kg;花生前茬处理的土壤Ca_(2)-P和Ca_(8)-P的质量分数最高,分别为27.53 mg/kg和94.14 mg/kg,但与玉米前茬和大豆前茬的处理结果差异不显著.在限肥水平下,玉米前茬处理土壤的全磷、速效磷和O-P的质量分数最高且显著高于其他前茬处理,分别为770.47 mg/kg、13.50 mg/kg、58.99 mg/kg;大豆前茬处理土壤Ca_(10)-P的质量分数最高且显著高于其他前茬处理,为320.62 mg/kg,总无机磷、Al-P和Fe-P的质量分数与其他前茬处理差异不显著,分别为541.96 mg/kg、34.50 mg/kg和36.42 mg/kg;花生前茬处理土壤Ca_(2)-P和Ca_(8)-P的质量分数最高但与花生前茬处理的差异不显著,分别为23.04 mg/kg和78.78 mg/kg.2个磷肥水平下冬小麦植株磷累积量均在花生前茬处理下最高,分别为33.11 kg/hm^(2)和25.14 kg/hm^(2).在常规施肥水平下,花生前茬处理与玉米、大豆前茬处理的差异不显著,而在限肥水平下显著高于玉米、大豆前茬处理.经通径分析,土壤无机磷不同形态对冬小麦植株磷累积量的直接影响(直接通径系数)由大到小为Ca_(2)-P、Al-P、Fe-P、Ca_(8)-P、O-P、Ca_(10)-P.结合通径系数和相关系数表明,Ca_(2)-P是小麦磷累积的直接来源,其次是Al-P,而Fe-P和Ca_(8)-P是小麦的缓效磷源,O-P和Ca_(10)-P是小麦比较难以利用的磷源.在2种施肥水平下,前茬作物极显著影响全磷、速效磷、和无机磷的含量,进而影响冬小麦的植株磷累积量.

In order to confirm the influence of different fractions of soil inorganic phosphorus and the effect on phosphorus accumulation of winter wheat after different preceding crops,a two-factor field experiment was conducted to determine the total phosphorus,the available phosphorus and different forms of inorganic phosphorus contents in the topsoil(0-15 cm)before sowing and after harvesting,with three previous crops(maize,soybeans,and peanuts)at two fertilizer levels(P_(2)O_(5)150 kg/hm^(2)phosphate fertilizer(+F)and P_(2)O_(5)0 kg/hm^(2)phosphate fertilizer(-F)).Meanwhile,the phosphorus accumulation of winter wheat plants in mature period was measured,and the contribution of different fractions of inorganic phosphorus in soil to the accumulation of phosphorus of winter wheat plants was analyzed through path analysis.The results showed that the content of total phosphorus,available phosphorus and the different fractions of inorganic phosphorus in soil were significantly reduced in 0 kg/hm^(2)phosphate fertilizer treatment than that in 150 kg/hm^(2)phosphate fertilizer treatment.On one hand,at the conventional phosphate fertilizer level,the AP content in the preceding maize treatment was highest and significantly higher than others,being 18.61 mg/kg,and the content of the Pi,Fe-P and Ca_(10)-P in soil in the preceding maize treatment were all the highest one in the three previous crops treatments,being 592.55 mg/kg,41.97 mg/kg and 338.77 mg/kg,respectively.The content of the TP was highest and significantly higher than others,being 972.80 mg/kg,and the content of the Al-P and O-P in soil in the preceding soybean treatment were the highest in the three previous crops treatments,being 43.44 mg/kg and 64.37 mg/kg,severally.The content of Ca_(2)-P and Ca_(8)-P in soil in the preceding previous peanut treatment were the highest one in the three previous crops treatments,being 27.53 mg/kg and 94.14 mg/kg,but there was no significant difference in the treatment compared with the previous maize and soybean crops.On the other hand,In 0 kg/hm^(2)phosphate fertilizer,the content of the TP,AP and O-P in soil in the preceding maize treatment were the highest one in the three previous crops treatments and significantly higher than others,being 770.47 mg/kg,13.50 mg/kg and 58.99 mg/kg,respectively.The content of Pi,Al-P,Fe-P and Ca_(10)-P in soil in the preceding soybean treatment were 541.96 mg/kg,34.50 mg/kg,36.42 mg/kg and 320.62 mg/kg,and the Ca_(10)-P content was significantly higher than other crops treatments,respectively.The content of Ca_(2)-P and Ca_(8)-P in soil in the preceding peanut treatment were the highest one in the three previous crops treatments,being 23.04 mg/kg and 78.78 mg/kg,respectively.And the phosphorus accumulation of winter wheat plants in the preceding peanut treatment was all the highest one at the two phosphate fertilizer levels,which was 33.11 kg/hm^(2)and 25.14 kg/hm^(2).At the conventional fertilization level,there was no significant difference between the peanut previous treatment and previous treatments of maize and soybean,but under the 0 kg/hm^(2)phosphorus fertilizer level,that peanut previous treatment was significantly higher than the previous treatments of maize and soybean.In addition,the order to direct contribution(showed as the path coefficients)of different fractions of soil inorganic phosphorous on the accumulation of phosphorus of winter wheat plants form the highest to the lowest was as Ca_(2)-P,Al-P,Fe-P,Ca_(8)-P,O-P,Ca_(10)-P.And Ca_(2)-P in soil was the direct source to phosphorus accumulation of wheat plants,Al-P came second,and Fe-P and Ca_(8)-P in soil were the slow-released phosphorus sources to wheat plants,while O-P and Ca_(10)-P in soil were difficult to be utilized by wheat plants.At different fertilization levels,the previous crop significantly affected the content of TP,AP and Ca_(2)-P,thereby affecting the phosphorus accumulation in winter wheat plants.