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对山西几种代表性土壤,布置施磷与不施磷盆栽试验进行了研究。结果如下:(1)供试土壤全磷量在0.0395～0.0697％之间,土壤磷素以无机磷为主,占全磷量77～87％,无机磷组成中,均以Ca—P为主,占无机磷69～77％,占全磷55～62％,其次是Al—P,再次是O—P,而Fe—P甚微。(2)栽培苜蓿条件下,磷肥施入不同土壤后,70％左右的磷素转化为Ca—P和Al—P,而Fe—P和O—P甚微。(3)不施磷土壤速效磷平衡水平在8ppm以下,潜在磷源Ca—P和Al—P亏损,而施磷土壤速效磷平衡水平在15ppm以上,形成Ca—P及Al—P具有动态可逆性,磷素平衡相对稳定。(4)苜蓿生长期间,磷肥保持速效态量随时间的推移按指数规律P=ae~(bt)(b=0)递减,而苜蓿吸磷增加量则按指数规律P=ae~(b/t)(b<0)递增。(5)山西石灰性缺磷土壤上首蓿施磷肥效果良好,研究表明采用土壤速效磷、速效N/P比及苜蓿相对产量和相对吸磷量几项指标,并结合土壤各形态磷动态可逆性供磷潜力综合分析判断,就能更经济合理施用磷肥。
Several typical soils in Shanxi Province were studied with P-applying and non-P-applying pot experiments. The results are as follows: (1) The total P content in soil was between 0.0395 and 0.0697%. The content of soil phosphorus was mainly inorganic phosphorus, accounting for 77-87% of the total phosphorus. Among inorganic phosphorus, Ca-P was the main component , Accounting for 69-77% of inorganic phosphorus, accounting for 55-62% of total phosphorus, followed by Al-P, again O-P, and Fe-P is very small. (2) Under the condition of cultivating alfalfa, about 70% of the phosphorus was transformed into Ca-P and Al-P, while Fe-P and O-P were very little after the phosphate fertilizer was applied to different soils. (3) The available phosphorus balance in the non-phosphorus-applied soil was below 8ppm, and the potential phosphorus sources were depleted in Ca-P and Al-P. However, the balance of available phosphorus was above 15ppm in phosphate-deficient soils and Ca-P and Al- Sex, phosphorus balance is relatively stable. (4) During the growth of alfalfa, the amount of available and available state of P fertilizer decreased gradually with the lapse of time (P = ae ~ (bt)), while the increase of phosphorus uptake by alfalfa increased exponentially (P = t) (b <0) increments. (5) The effect of top-dressing phosphate fertilizer on calcareous phosphate-deficient soils in Shanxi Province was good. The results showed that the available phosphorus, available N / P ratio, relative yield and relative P uptake of alfalfa, Potential phosphorus for comprehensive analysis and judgment, we can more economical and rational use of phosphate fertilizer.