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为了研究石灰物质对红壤磷肥肥效的影响及其本质,分别进行了盆栽和化学试验。盆栽试验以荞麦和蚕豆为指示作物,试验表明石灰对红壤磷肥肥效有显著影响,但这种影响的方向(即良好的影响和不良的影响)和强度,则视石灰用量、磷肥水平以及石灰物质的性质等而异。红壤施用石灰后显著地增加供试植物的吸磷总量。在本试验的条件下,石灰影响红壤磷肥肥效的主要原因可能是由于对磷肥固定量的影响所致。因施用石灰而促进了植物利用磷肥的能力,也可能是重要原因之一。当pH 5.0左右以下时,CaO 对磷有效性的影响是由于改变了土壤的pH,因而加速了磷酸铁铝的水解所致。超过pH 5.0,则因磷酸钙盐沉淀(包括磷灰土型盐类)的逐渐形成,而使磷的肥效降低。对于MgCO_3和NaOH 来说,则因不能与磷盐形成难溶性化合物,故不致显著影响磷的溶解度,而且随着这些物质用量的增加,由于pH 的升高,还可以提高已被固定的磷酸铁、铝盐类的水解。
In order to study the effect of lime material on the fertilizer efficiency of red soil and its essence, pot and chemical tests were carried out. Pot experiments showed that buckwheat and broad bean were the indicated crops. The results showed that lime had a significant effect on the fertilizer efficiency of red soil. However, the direction (ie, good influence and bad effect) and the intensity of the effect were affected by lime dosage, phosphate fertilizer level, The nature of the difference. Red soil application of lime significantly increased the total phosphorus uptake of the test plant. Under the conditions of this experiment, the main reason that lime affected the fertilizer efficiency of red soil may be due to the effect on the fixed amount of phosphate fertilizer. The ability of plants to use P fertilizers due to lime application can also be one of the important reasons. When pH is below pH 5.0, the effect of CaO on phosphorus availability is due to changes in the pH of the soil, thus accelerating the hydrolysis of aluminum phosphate. Above pH 5.0, phosphorus is reduced in fertilizer efficiency due to the gradual formation of calcium phosphate precipitates, including the apatite salts. For MgCO 3 and NaOH, the solubility of phosphorus is not significantly affected by the inability to form poorly soluble compounds with phosphorus salts, and as the amount of these materials increases, the pH of the fixed iron phosphate , Hydrolysis of aluminum salts.