不同改良模式对盐碱地土壤理化性质及苜蓿产量的影响

Effect of Different Improvement Modes on Physical and Chemical Character of Saline-alkali Soil and Alfalfa Yield

为了确定盐碱地最佳的土壤改良模式,在大田试验条件下,研究了脱硫石膏、改良剂、有机肥及灌排措施等不同改良模式组合对盐碱地土壤的改良效果及苜蓿产量的影响。结果表明,总体上所有改良模式均能降低土壤含盐量和p H值,提高苜蓿抗氧化酶活性和脯氨酸含量,进而提高苜蓿耐盐能力,提高苜蓿产量,其中以脱硫石膏＋改良剂＋灌排措施＋有机肥的集成改良模式（Tr5）的效果最佳,施用脱硫石膏＋灌排措施（Tr4）处理次之。其中,Tr5处理0-20 cm、20-40 cm、40-60 cm土层土壤全盐含量和p H值分别较无改良措施处理（对照）下降25.5%、41.2%、37.0%和0.74、0.13、0.59;土壤细菌数量分别较对照增加6.2%、78.4%、1.8%,放线菌数量分别较对照增加16.0%、519.1%、175.7%,真菌数量分别较对照降低42.7%、72.4%、95.1%;苜蓿叶片净光合速率提高12.3%,CAT、SOD、POD活性和脯氨酸含量分别较对照显著增加378.4%、48.6%、70.4%和22.9%;连续3 a苜蓿产量分别较对照增加92.9%、109.8%、127.1%。

The improvement effect for saline-alkali soil and the influence for alfalfa yield of different improvement modes with desulfurized gypsum,modifying agent,organic fertilizer and irrigation were studied under field condition,so as to select the best improvement mode. The results showed that overall,all improvement modes could decrease the total salt content and p H value of soil,increase the antioxidant enzyme activity and proline content of alfalfa,so as to improve the salt-tolerance ability and alfalfa fresh grass yield. The best mode was Tr5 treatment with desulfurized gypsum + modifying agent + irrigation +organic manure,and the second was Tr4 treatment with desulfurized gypsum + irrigation. For Tr5 treatment,compared with CK without improvement mode,the soil total salt content decreased by 25. 5%,41. 2%,37. 0% respectively,and p H values decreased by 0. 74,0. 13,0. 59 respectively in 0—20 cm,20—40 cm,40—60 cm soil layer; in addition,the number of bacteria increased by 6. 2%,78. 4%,1. 8%respectively,and the number of actinomycetes increased by 16. 0%,519. 1%,175. 7,respectively,but the number of fungus decreased by 42. 7%,72. 4%,95. 1% respectively in soil layer mentioned above; thenet photosynthetic rate of alfalfa increased by 12. 3%,the activities of CAT,SOD,POD and proline content of alfalfa increased by 378. 4%,48. 6%,70. 4%,22. 9% respectively; the fresh grass yield increased by 92. 9%,109. 8%,127. 1% in three consecutive years.