陕西土壤磷素状况和磷肥有效施用的研究

本文对陕西省约400个耕层土壤样品和15个土壤剖面的磷素含量、组成和供给进行系统的研究，并采用根兹布勒哥一列别捷分级系统对Ca-P的组分进行了测定.结果表明，在Ca-P级中，约64-35%是磷灰石；10-24%是Ca₃-P；Ca_1·2，-P只占4-18%.研究表明，全省土壤有效磷的供给水平是低的，平均只有5.4ppm；Ca-P和AI-P与土壤有效磷呈正相关，与Fe-P呈负相关。本文还采用Olsen法连续测定土壤有效磷，本文谓之“土壤活性磷”。它因土壤的不同而变化较大，黄泥巴10ppm；黄绵土12ppm；楼土33ppm；莱园土126ppm。土壤活性磷是评价土壤供磷的重要依据，土壤含活性磷高的，供磷潜势大；反之则低.根据土壤供磷潜势低和磷肥移动有限的特点，建议集中深施在根系附近和水分供应的适当位置。

A Study on the Status of Soil Phosphorus and Available Application of Phosphorus Fertilizer in Shaanxi Province

Deficient in soil phosphorus is an important problem of soil fertility in whole area of Shaanxi province,The results obtained from the study indicated that the total content of soil phosphorus range 0.04 to 0.25%,a veraging 0.12. Study on forms of soil phosphorus indicated that the content of organic phosphorus are low,with an average 14%,however,the content of min phosphorus is very high, average 68%,the content of Ca-P in which makes up 47-8200/n of the total phosphorus and Al-P is very little, Ca-P and Al-P gradually reduce and Fe-P increases with the increasing weathering from the north to south, The fact shows that the phosphorus in the soil gradully transformed into unsoluble Fe-P,"Huang Niba" soil is another kind of soil in southern Shaanxi, in which Fe-P account to 27.3% of the total phosphorus, Ca-P 4700.The results cf study on Ca-P indicated that apatite makes up 64-85% of Ca-P, Ca₃-P 10-24%, Ca_1,2-P4-18%, Phosphorus supply in the soil is not adequate in Shaanxi, The content of available phosphorus in the soil ranges from zero to 34 PPm, with average value of 5.4 ppm,The study on labile-P in the soil is of great importance in Shaanxi province, It is an important index to evaluate phosphorus fertility in the soil, The study shows that the content of labile-P in "Huang Niba" soil is 10 ppm,12 ppm in "Piuang mian" soil, 132 ppm in vcgetzble garden soil, According to the characteristic of phosphorus supply in the soil and fertilizerstatus in the soil, the princiFle of phosphorus application should be centralized deep application with completely use of moisture under the horizon, meanwhile phosphorus fertilizer should be zpplicd with nitrogenous fertilizer and organic manureo.