The accumulation and migration of inorganic phosphorus fractions in soils under greenhouse cultivation | 温室栽培条件下土壤无机磷组分的累积、迁移特征

中国人. 【目的】揭示温室栽培条件下磷肥施用量大,但利用率低的原因,探明磷素养分淋溶损失的主体成分,为合理施用磷肥、提高磷肥利用率、减少环境污染提供依据。【方法】以辽宁沈阳地区具有代表性的温室为研究对象,通过对不同使用年限温室土壤剖面全磷及无机磷各组分含量的分析测定,探讨温室栽培条件下土壤无机磷的累积、迁移特点。【结果】(1)温室土壤全磷、无机磷、速效磷的含量均较露地土壤有明显增加,且耕层(0―20 cm)的累积量最高,平均含量分别为露地土壤的3.1倍、3.3倍、3.6倍,无机磷占全磷含量的92.1%,速效磷仅占全磷含量的16.6%。(2)温室土壤各无机磷组分的含量及其相对组成均较露地土壤变化明显,Ca8-P、Al-P、Ca2-P、Fe-P、O-P、Ca10-P的平均含量分别为露地土壤的10.2、5.9、5.0、3.1、2.7、1.5倍,温室土壤无机磷各组分占全磷含量的比例表现为Al-P(26.1%)＞Fe-P(18.1%)＞O-P(17.6%)＞Ca10-P(14.4%)＞Ca8-P (10.5%)＞Ca2-P(5.6%)。其中Ca2-P的有效性最高,但累积量最低;O-P、Ca10-P的有效性低,但累积量高,从而导致土壤磷素的利用率降低。(3)温室土壤中,Al-P和Fe-P是耕层土壤(0―20 cm)磷素养分的主要累积形态,两者可占无机磷总量的49.8%;O-P、Ca10-P是底层土壤磷素养分的主要累积形态,两者在20―100 cm土层的累积量可达无机磷总量的46.6%―78.2%,且该比例随土层深度的增加而有所增加。【结论】温室栽培条件下,土壤磷素养分虽有大量累积,但其迁移、转化的主要存在形态均以有效性较低的Ca10-P、O-P、Fe-P为主,如何提高这部分磷源的生物有效性,降低其环境风险,是温室土壤磷素养分管理的关键。

英语. 【Objective】 The aims of this paper were to determine the reason for high input but low utilization of phosphorus (P) fertilizer, and to provide a basis for raising the utilization rate of P and reducing environmental pollution under greenhouse cultivation. 【Method】 To investigate the management of representative greenhouse cultivation in Shenyang, Liaoning Province, samples of soil from greenhouses of different planting years and also an open field within the researched area were collected and analyzed for the accumulation of inorganic P fractions. 【Result】 In greenhouse soil, the contents of total P, inorganic P and available P all increased, with their maximum values in the topsoil (0-20 cm), and average values of 3.1, 3.3 and 3.6 times that of the open field soil, respectively. The content of inorganic P accounted for 92.1% of total P, while available P only accounted for 16.6%. In greenhouse soil, the average contents of Ca8-P, Al-P, Ca2-P, Fe-P, O-P and Ca10-P were 10.2, 5.9, 5.0, 3.1, 2.7 and 1.5 times that of the open field soils, respectively, and the contents of each component of total P were Al-P (26.1%) Fe-P (18.1%) O-P (17.6%) Ca10-P (14.4%) Ca8-P (10.5%) Ca2-P (5.6%). The nutrient availability of Ca2-P was high but its accumulation was low, while the availabilities of O-P and Ca10-P were high but their accumulations were low, which seriously decreased the utilization rate of P. In greenhouse soil, 49.3% of total inorganic P in topsoil (0C20 cm) was Al-P and Fe-P, while 46.6C78.2% of total inorganic P in deep soil was O-P and Ca10-P, which both increased with depth of soil. 【Conclusion】 Under greenhouse cultivation, the content of P increased greatly, with more than half of the total being Ca10-P, O-P and Fe-P. Improving the bioavailability of these components of inorganic P with low nutrient availability is the key to establish an environment-friendly nutrient management system compatible with greenhouse conditions.