开花期补充水肥对花生田土壤水分、氮磷养分时空变化特征的影响

Effect of Irrigation with Fertilizer on Spatial-Temporal Variation of Soil Moisture,Nitrogen and Phosphorus Contents at Flowering Stage in Peanut Field

田间条件下,以花育22号和花育25号为试材,采用膜下滴灌方法,设置花生初花后20d灌水(WN0)、灌水施N 20kg/hm^2(WN1)和灌水施N 30kg/hm^2(WN2)处理,以田间自然降雨条件为对照,研究开花期补充水肥对0—100cm剖面土壤水分、水解性氮、速效磷(Olsen-P)和NO-3-N含量变化及迁移特征的影响。结果表明:(1)开花期灌水施肥使0—100cm土壤剖面土壤含水量均随土层深度增加而升高,利于0—60cm土层土壤含水量保持稳定;施用氮肥可使0—60cm土层土壤含水量升高滞后于不施肥处理10d左右,高量施氮处理使水分下渗速度减缓且20—40cm土层含水量变异性增大。(2)开花期灌水施氮肥提高了0—60cm土层NO-3-N含量,灌水施肥10~20d后是NO-3-N淋失迁移的风险期,其淋溶迁移时间与土壤水分同步。高量施氮肥使土壤硝态氮淋溶风险提前10d。(3)花后补充水分并施氮肥均可提高0—100cm剖面土壤水解性氮含量,不施氮肥处理使开花后60d时0—40cm土层水解氮含量降至57.4~89.6mg/kg,高量施氮使土壤水解性氮素养分向下淋溶风险增强。(4)开花后补充水分和氮肥处理均明显增加0—40cm土壤Olsen-P含量,施氮肥使磷素供应强度高峰后移20~40d。花生开花期灌水补充氮肥可使0—60cm土层土壤含水量、NO-3-N含量、水解氮含量和0—40cm土壤Olsen-P含量升高且水氮下渗速度减缓,促进水肥利用效率提高,但施氮量不应超过30kg/hm^2,以降低氮素养分淋失迁移风险。

To study the effect of irrigation with fertilization at flowering stage on soil moisture,hydrolysable nitrogen,Olsen-P and NO-3-N content in 0—100 cm soil profile,the peanut Huayu 22 and Huayu 25 were planted under filed condition.Three treatments were set 20 days after flowering.The treatments are：（1）Only irrigation,（2）Irrigation with 20 kg/hm^2 nitrogen,and（3）Irrigation with 30 kg/hm^2 nitrogen using the method of drip irrigation beneath film.The results showed that：（1）the soil moisture content in 0—100 cm soil profile increased with increase of soil depth,which could keep the soil moisture content stable.Nitrogen fertilizer could make increase of soil moisture content lag for 10 days in 0—60 cm layer compared with nofertilizer treatment,and high nitrogen treatment could make water infiltration slow,and variability of water content in 20—40 cm soil layer increased;（2）NO-3-N content in 0—60 cm soil layer increased under irrigation with nitrogen treatment,irrigation was the risk of NO-3-N leaching migration after 10-20 days,its leaching time synchronized with soil moisture;high amount of nitrogen fertilizer make the risk of nitrate leaching peak 10 days in advance;（3）the soil hydrolysable nitrogen content in 0—100 cm soil profile increased under irrigation with fertilization,while the soil hydrolysable nitrogen content in 0—40 cm soil layer decreased to 57.4-89.6 mg/kg under nofertilization 60 days after flowering;the high amount of applied nitrogen could enhance soil hydrolysable nitrogen leaching risk;（4）the soil Olsen-P content in 0—40 cm soil layer increased significantly under irrigation and fertilization treatments;and the peak of phosphorus supply intensity delayed 20-40 days by application of nitrogen fertilizer;applying nitrogen fertilizer and complementary irrigation at peanut blooming stage can enhance the soil water,NO-3-N and hydrolyzed nitrogen content in 0—60 cm soil layer and Olsen-P content in 0—40 cm soil layer,and can decrease the hydrolyzed nitrogen infiltration rate;in this way,water and fertilizer use efficiency can be promoted;the amount of applied nitrogen should not exceed 30 kg/hm^2 in order to reduce the risk of nitrogen nutrient leaching.