永久性及长期渍水的水稻土中铜的供给情况和铜肥的效果

COPPER STATUS OF PERMANANTLY WATERLOGGING AND LONG-TERMED WATERLOGGING PADDY SOILS AND RESPONSE OF RICE TO COPPER FERTILIZER

本试验于1982年在皖南山地丘陵区进行,结果表明:1.永久性渍水的水稻土上用0.1%的硫酸铜沾秧根或0.5公斤/亩作基肥,对水稻均有明显的增产效果,增产幅度为5.2—41.4%,平均每亩增产稻谷45公斤。2.施铜增产的永久性溃水水稻土通常Eh更低(74mV);有机质分解缓慢而含量高(3.99%);有效铁含量也很高(317ppm);有效铜含最低(1.24ppm)3.铜与铁有显著的拮抗作用,即水稻植株中铜、铁含量有较好的直线负相关(r=-0.7725^(**)),土壤中有效Fe/Cu比值与植株体内的Fe/Cu比值有极好的直线正相关(r=0.9470)。这二个Fe/Cu比值同样与施铜增产效果有极好的正相关(r=0.9308,r=0.9801),土壤Fe/Cu比值>120的8块试验田施铜均有增产效果。4.施用铜肥除了补充铜的不足外,同时还能减少水稻对铁的吸收,降低了水稻的Fe/Cu比值,减轻亚铁毒害,达到了增产的目的。

Response of paddy rice to copper fertilizer in permanantly waterlogging and long-termed waterlogging paddy soils in hilly region of southern part of Anhwei Province is discussed in this paper. 67% of the field experiments showed response to copper fertilizer, with yield increase of 5.2—41.4% (45 kg/mu on average); while 89% of the field experiments conducted in permanantly waterlogging paddy soils was responsive to copper fertilizer. The available copper of permanantly waterlogging paddy soils extracted with DTPA solution was 1.24 ppm on average; available iron extracted with the same solution was 317 ppm on average. In these soils the organic matter content averaged 3.99% and Eh 71 mV. It indicates that the available copper and Eh are lower, while available iron and organic matter are higher than those in long-termed waterlogging paddy soils and ameliorated paddy soil. Plant and soil analysis revealed the antagonism between copper and iron. Iron and copper contents of the rice plants indicated that there existed a significant negative correlation between these two elements (r=-0.7725). The ratio of available Fe/Cu of soils was highly correlated with the ratio of Fe/Cu of rice plant (r=0.9470). in the meantime, both the ratio of available Fe/Cu of paddy soils and the ratio of Fe/Cu in rice plants were highly correlated with yield increase caused by application of copper fertilizer with the correlation coeffecients of 0.9308 and 0.9801 respectively, i.e. the ratio of Fe/Cu in plant was affected by the ratio of available Fe/Cu in soil. Paddy rice was responsive to copper fertilizer in waterlogging paddy soils, as available copper was less than 1.5 ppm, or the ratio of available Fe/Cu of soil was higher than 120. Copper fertilization is proved to be beneficial to both growth and yield of paddy rice in the condition mentioned above. It can improve copper supply and iron toxicity in waterlogging paddy soils, and increase rice yield.