土层置换对马铃薯根际土壤酶活性及晚疫病病情指数的影响

以常规施肥不置换土层为对照,研究了0~20 cm和20~40 cm土层置换、置换后增施15%磷肥、置换后增施有机肥及25%多菌灵可湿性粉剂土壤灭菌等不同处理对马铃薯根际土壤不同土层土壤酶活性及晚疫病病情指数影响,结果表明:土层置换处理及置换后增施磷肥或有机肥和土壤灭菌处理,对马铃薯田间根际不同深度土壤脲酶活性、蔗糖酶活性和磷酸酶活性均有影响。马铃薯播种后35 d时,土层置换及土壤灭菌处理降低了0~10cm土层土壤脲酶活性;土层置换并增施有机肥显著提高了各土层土壤蔗糖酶活性;土层置换并增施磷肥或有机肥可有效保持马铃薯根际土壤中磷酸酶的活性,其中以增施磷肥效果更为明显。土层置换后增施磷肥或对表土灭菌处理可减少马铃薯晚疫病的发病率;在播种后77 d时,置换后增施有机肥的病情指数分别比不置换土壤、土层置换、置换后增施15%磷肥和土壤灭菌处理分别提高17.5%、47.1%、60.8%和66.6%,在土壤置换后施用有机肥不利于降低马铃薯的晚疫病发病。

Effects of soil layer exchange on rhizosphere soil enzyme activities and late blight disease index in potato

Compared with the conventional fertilization without soil layer exchange,the effects of different treatments,including 0 ～ 20 cm and 20 ～ 40 cm soil exchange,soil exchange with 15％ phosphate or organic fertilizer application,and soil sterilization by 25 ％ carbendazim wet powder,on the soil enzyme activity and the disease index of potato late blight in different soil layers(O ～ 10 cm,10 ～ 20 cm,20 ～ 30 cm,30 ～ 40 cm) were studied in this paper.Results showed that the activity of soil urease,invertase and phosphatase in rhizosphere was affected by the soil layer exchange,soil exchange with 15％ phosphate or organic fertilizer,and soil sterilization.At 35 days after sowing,the soil layer exchange and sterilization treatment decreased the urease activity in 0 ～ 10 cm soil layer.The soil invertase activity in each soil layer was significantly increased by soil layer exchange with 15％ organic fertilizer.Soil exchange with phosphate or organic fertilizer application could maintain the phosphatase activity in the rhizosphere,and the effect of applying phos phorus fertilizer was more obvious.Moreover,soil exchange with phosphate application and soil sterilization reduced the incidence of potato late blight.At 77 days after sowing,the disease index for soil exchange with organic fertilizer was increased by 17.5％,47.1％,60.8％,and 66.6％,compared with CK,soil exchange,soil exchange with 15％ phosphate,and soil sterilization,respectively,suggesting that application of organic fertilizer after soil exchange was not helpful to reduce the incidence of potato late blight.