陇东旱地苹果园不同地面覆盖模式的水分与养分效应

Effects of different soil surface mulching patterns on soil moisture and nutrient in dryland apple orchard in east Gansu Province

为完善和改进果园树盘起垄覆膜集雨保墒模式,提高土壤墒情,探寻更加有效的果园保墒措施,该研究以17 a生苹果园为研究对象,设置常规树盘起垄覆膜行间清耕模式(F),在F基础进行改进的树盘起垄覆膜+行间覆草模式(F+W)和树盘起垄覆膜+行间覆草+膜侧添加渗水穴模式(F+W+H)2种改进模式,以不起垄不覆盖为对照(CK),采用定点试验,连续3 a(2015年干旱、2016年秋旱和2017年常年降雨)开展苹果花前、果实膨大期及采后的水分效应,以及养分效应和树体生长发育响应研究。结果显示:3种覆盖模式可不同程度增加0~200 cm土层的含水率,以2017年最显著,2种改进模式可缓解300~500 cm土层水分消耗,降低休眠期无效蒸散,3 a三种覆盖模式果园土层总蒸散量均极显著(P<0.01)低于CK,由低到高顺序为F+W+H、F+W、F、CK。2015年和2016年采后覆盖模式0~300 cm土层硝态氮累积量均极显著(P<0.01)低于CK(比CK低34.4%~39.6%)。3种覆盖模式增加果实中氮磷钾养分吸收,以钾最突出。F+W+H、F+W和F 3 a平均产量分别较CK提高13.1%、13.0%和8.3%。综合各种效应,以2种改进覆盖保墒模式F+W+H和F+W较优。

Drought with less rainfall is one of the main factors affecting the high quality,high yield,and stability of apples on the Loess Plateau in western China.Ridging and film mulching in the tree tray with rows clearing(F)have currently been the most commonly-used mulching modes to preserve soil moisture in apple orchards.However,moisture preservation still needs to be improved.In this study,a fixed point test was carried out over three years to investigate the effects of different mulching patterns on soil moisture contents before flowering,in the fruit expansion stage and after harvest,as well as nutrient effects and tree growth response.A 17-year-old apple orchard was also selected in the main apple-producing area of the Loess Plateau in east Gansu Province,China.Specifically,the ridge mulching of tree trays(F)was combined with the straw mulching between rows to form a whole garden mulching model(F+W),whereas,the water seepage holes were added on the sides of the film in a row to form a three-dimensional moisture preservation model(F+W+H),with no ridging and no coverage as the control(CK).The results showed that the average moisture content of 0-100 cm soil layer in the three phases of three mulching patterns was higher than that of CK in 2015(drought year),of which 0-100 cm soil layer in 2016(Autumn drought year),and 0-100 cm and 100-200 cm soil layer in 2017(normal rainfall)of both F+W+H and F+W were extremely significant(P<0.01),while F significant(P<0.05)higher than CK.There was also no significant decrease in the inter-annual average moisture contents of 400-500 cm soil layer of F+W+H and 300-500 cm soil layer of F+W after harvest,but those of F and CK decreased significantly.The total evapotranspiration of 0-500 cm soil layer was ranked in order of F+W+H<F+W<F<CK from before flowering in 2015 to after harvest in 2017,where the mulching patterns were extremely significant(P<0.01)lower than that of CK.There was a stable and high cumulative amount of K_(2)O absorption,where the average K_(2)O accumulations over three years in three mulching patterns were significantly higher(P<0.01)than that of CK.The cumulative amounts of nitrate nitrogen in three mulching patterns in 0-500 cm soil layer were lower than that of CK in 2015,whereas,those of F+W+H and F+W in 300-500 cm soil layer,F in 300-400 cm soil layer were slightly higher than that of CK in 2016.Nitrate nitrogen accumulations in the 0-300 cm soil layer in 2015 and 2016 were 92%-96.2%of the entire profile.Furthermore,the average cumulative amounts of nitrate nitrogen in the F+W+H,F+W,and F in 0-300 cm soil layer were seriously lower(P<0.01)than those of CK by 36.8%,34.4%,and 39.6%,respectively.The average yield in three years of F+W+H,F+W,and F increased by 13.1%,13.0%,and 8.3%,compared with the CK,respectively.Consequently,the moisture conservation and rain collection were improved after tree ridge mulching in the orchard was perfected,where the F+W+H and F+W were better modes of mulching.But it was still necessary to reduce chemical fertilizer application,while increasing organic fertilizer for better nitrogen utilization.