滴灌条件下基肥减施后移对夏玉米养分吸收和根系生长的影响

Reducing and Postponing Base Fertilizer Supply Under Drip Irrigation:Effect on Nutrient Absorption and Root Growth of Summer Maize

为探明滴灌条件下基肥减施后移对夏玉米养分吸收和根系生长的影响,在大田条件下,以‘郑单958’为供试材料,研究基肥传统施用(CK)、基肥减施后移至拔节期(T1)及基肥减施后移至大喇叭口期(T2)对夏玉米干物质积累、根系生长、植株氮营养指数、氮素积累、土壤硝态氮含量及产量的影响。结果表明,T1和T2处理拔节期(V6)虽然植株氮营养指数低于1 (0.88),但地上部氮磷钾含量和干物质积累量与CK差异不显著,且T2处理吐丝期(R1)到成熟期(R6)植株氮素积累量高于对照(+33.39%)。处理间收获期夏玉米行间0~20 cm土层硝态氮含量差异显著,其中T2分别低于CK和T1处理41.85%和35.46%,深层80~100 cm土层硝态氮含量T1和T2处理分别低于CK 78.68%和56.02%,差异未达到显著水平。大喇叭口期(V12) 15~30 cm土层根系表面积密度为T2>T1>CK,其中T2和T1分别比CK高25.89%和36.17%,且T2处理30~45 cm土层根系表面积密度也较CK高68.59%。各处理间收获指数及产量差异不显著,但总体T2处理值最高,氮肥利用率比对照也增加12.13%。因此在滴灌水肥一体化条件下,夏玉米生产上应根据地力优化基追比,中高肥力农田玉米基肥可以适当减施后移至拔节期(V6)甚至大喇叭口期(V12),控前促后,降低土壤硝态氮残留,同时促进前期根系下扎。

The aim is to investigate the effects of reducing and postponing base fertilizer supply on nutrient absorption and root growth of summer maize under drip irrgation.‘Zhengdan 958’was used as the test material, three treatments were set up, i.e. traditional base fertilizer supply(CK), postponing base fertilizer supply to V6(T1) or V12(T2), the dry matter accumulation, root growth, plant nitrogen nutrient index, nutrient accumulation, soil nitrate nitrogen content and yield of summer maize were investigated. The results showed that although the nitrogen nutrition index of T1 and T2 was lower than 1(0.88) at jointing stage(V6), the difference in contents of N, P, K and dry matter accumulation of shoot among the treatments was not significant,and for T2, the plant nitrogen accumulation from silking stage(R1) to mature stage(R6) was higher than that of the CK(+33.39%). There was significant difference among the three treatments in nitrate nitrogen content in 0-20 cm soil layer between rows, while the value of T2 was 41.85% and 35.46% lower than those of CK and T1,respectively. The content of nitrate nitrogen in 80-100 cm soil layer of T1 and T2 treatments was lower than that of CK by 78.68% and 56.02%, respectively, the difference was not significant. The root surface area density of15-30 cm soil layer was T2 > T1 > CK in the bell-mouthing stage(V12), in which T2 and T1 was 25.89% and36.17% higher than CK, respectively, and the root surface area density of 30-45 cm soil layer in T2 treatment was 68.59% higher than CK. Overall, the harvest index and yield of T2 treatment were relatively the highest,the difference was not significant, and the nitrogen utilization rate of T2 was 12.13% higher than that of CK.Therefore, under drip irrigation, the ratio of base fertilizer and topdressing should be optimized according to the soil fertility in summer maize production. The base fertilizer in middle and high fertility farmland could be appropriately reduced and topdressed to V6 or even V12, to control the growth at early stage and keep sufficient fertilizer for later growth, reduce the residual nitrate nitrogen in the soil and promote the root growth.