土壤酸度对大豆、油菜生长和产量的影响

 两个盆栽试验结果显示，施用石灰石粉和钙镁磷肥能显著促进大豆生长和根瘤形成，并能提高产量，施用石灰增加了大豆植株Ca含量，但减少其K含量；施用磷肥增加植株的P含量，但减少植株的Ca的含量，大豆的根瘤数和籽粒产量与土壤pH、交换性Ca和Al及铝饱和度之间呈显著相关。10年的石灰石粉长期定位试验结果表明，在施用钙镁磷肥的条件下，施用3750kg/hm#+2石灰石粉即可使油菜获得高产，但适当过量施用石灰并未使油菜减产。要使红壤油菜获得最佳产量，必须使土壤pH值提高到5.9以上,而交换性铝降至1.0cmol(+)/kg以下。

GROWTH AND YIELD OF SOYBEANS AND RAPESEED TO SOIL ACIDITY

The results of two-pot experiments indicated that applications of ground limestone and calcium magnesium phosphate(CMP)markedly enhanced soybean growth, nodulation, and grain yield by Al detoxifying, removing H as an inhibitor of nodulation, and supplying adequate Ca and Mg to meet the requirements of rhizobial infection and nodule intiation.Soybean nodulation had a higher demand for Ca and P than the growth of shoot and roots. Liming resulted in an increased concentration of Ca and a decreased concentration of K in the plants.Application of phosphate increased P content and decreased Ca content in the plants. Nodule number and grain yield of soybean was significantly related to soil pH, exchangeable Al and Ca, and % of Al saturation.The results of a 10-year term limestone experiment showed that under the condition of addition of CMP, liming with the half recommended rate of 3750 kg/hm2(0.5L) was suffiecient for a higher rapeseed yield and for reducing soil acidity, but the residual effect of limestone was depended on its application rates.The residual effects of limestone with 0.5L, 1.0L, 1.5L and2.0L were 2, 6, 7,and 10 years,respectively.The plots with 1.0L and 1.0H significantly increased organic matter content,total N,and available Pin the 0-15 cm soil layer.Liming increased grain yield of rapeseed by 19.7-29.6%,but overliming did not reduce the yield.To obtain a higher yield of rapeseed grown on a red soil, soil pH should be raised to higher than 5.9 and exchangeable Al should be reduced to less than 1.0 Cmol( )/kg