有机培肥对旱地土壤养分有效性和酶活性的影响

为了探明有机培肥对旱地土壤肥力的影响，为建立旱地土壤改良技术体系提供依据，在渭北旱塬进行了4年有机培肥定位试验，设置3个秸秆还田量水平9 000 kg/hm2 （SH）、6 000 kg/hm2 （SM）、3 000 kg/hm2 （SL）和3个有机肥施用量水平22 500 kg/hm2（MH）、11 250 kg/hm2（MM）、5 250 kg/hm2（ML）处理，不施有机肥作为对照（CK）。结果表明，连续进行有机培肥第4年冬小麦收获后，各处理060 cm土层土壤有效养分和活性碳含量大小顺序均为:MM, SM＞SH, MH＞ML, SL＞CK，各培肥处理速效磷、速效钾、碱解氮和活性碳含量较对照提高幅度分别为13.27%～161.77%（P0.05）、7.51%～25.01%（P0.05）、10.52%～41.87%（P0.05）和64.15%～92.42%（P0.05），两种培肥措施间无显著差异；土壤脲酶、碱性磷酸酶和蔗糖酶活性均显著高于CK（P0.05），提高程度因还田量和施肥量的多少而异，以SM 和MM处理效果最显著，过氧化氢酶活性较CK变化不明显。说明旱地秸秆还田和施有机肥对提高土壤养分有效性、土壤活性有机碳和酶活性有显著效果。

Effects of organic fertilization on soil nutrient availability and enzyme activity in arid areas

A field experiment was conducted to determine the effects of organic fertilization on arid soil nutrients of winter wheat under different organic fertilizer applications,and to provide guidelines for establishing the soil amelioration technical system for the Weibei tablelands of Shaanxi.There were 3 manure application amounts(MH 22500 kg/ha,MM 11250 kg/ha and ML 5250 kg/ha),3 wheat straw returning amounts(SH 9000 kg/ha,SM 6000 kg/ha and SL 3000 kg/ha)treatments,and taking no organic fertilization as the control.The soil nutrients,soil labile organic carbon(LOC) and enzyme activities are analyzed for four years(2007-2010).After the wheat harvested in 2010,the results of the four years field experiment show that different organic fertilization amounts have different effects on the contents of soil available nutrients and LOC in 0-60 cm soil layer,the order is MM,SM>SH,MH>ML,SL>CK.Compared with the CK,the contents of soil available P,available K,alkaline hydrolytic N and LOC are increased by 13.27%-161.77%,7.51%-25.01%(P<0.05),10.52%-41.87%(P<0.05) and 39.43%-66.73%(P<0.05),and there are no significant difference between the two kinds of fertility fertilization.The activities of urease,phosphatase and invertase in 0-60 cm soil layer are significant increased(P<0.05),and the SM and MM treatments have the most significant effects,while the catalase activity is not changed significantly.This study shows that in semi-arid areas the straw returning and organic fertilizer application can play an active role in improving soil LOC,promoting soil nutrient availabilities and enzyme activities significantly.