磷肥深施对谷子根系分布、养分利用及产量的影响

Effects of Deep Application of Phosphate Fertilizer on Root Distribution,Nutrient Utilization and Yield of Foxtail Millet

为探明磷肥运筹获得谷子高产高效的合理途径,本研究采用大田试验法,设置低、中、高3个磷肥水平(P2O550、100、150 kg/hm^(2))和深、浅2个施磷肥深度(15、5 cm),研究磷肥深施对谷子根系分布、水肥利用以及产量的影响。结果表明,不同磷肥水平下,磷肥深施(15 cm)均可降低谷子抽穗期0~10 cm土层内的根长和根干质量,而显著提高10~20、20~40 cm土层中的根长和根干质量;磷肥深施降低抽穗期和成熟期10~20、20~40 cm土层的土壤含水量,促进根系对深层土壤水分的利用;磷肥深施也降低成熟期10~20、20~40 cm土层的土壤有效氮含量,促进植株对深层土壤氮素的利用;磷肥深施不同程度地提高单穗重、单穗粒重、出谷率、千粒重和收获指数,最终籽粒产量提高6.20%~8.35%。肥料偏生产力分析显示,磷肥深施有效提高氮、磷和钾肥的偏生产力,尤其是低磷条件下的。相关性分析表明,产量及其构成因素与深层土壤的含水量、有效氮含量存在明显的负相关关系,其中,与10~20 cm土层土壤含水量和有效氮含量呈极显著负相关。综上,磷肥深施15 cm促进了深层土壤中谷子根系的生长、提高了谷子对深层土壤中水肥资源的利用,进而提高谷子产量,具有高产高效、节肥增产的效果。

In order to find out the rational way of phosphate fertilizer management to obtain high yield and high efficiency of foxtail millet,the field experiment was conducted with three phosphate fertilizer levels(50,100,150 kg/hm^(2) P2O5)and two application depths(15,5 cm)to study their effects on root distribu-tion,water and nutrient utilization,and yield.The results showed that at each phosphate fertilizer level,deep application(15 cm)decreased the root length and dry weight in 0~10-cm soil layer at heading stage,but significantly increased them in 10~20-cm and 20~40-cm soil layers.Deep application of phosphate fertilizer reduced the water content in 10~20-cm and 20~40-cm soil layer at heading and maturation stages,and promoted the utilization of water in deep soil layer.Deep application of phosphate fertilizer also reduced the available nitrogen content in 10~20-cm and 20~40-cm soil layers at maturation stage,and promoted the utilization of nitrogen in deep soil layer.Deep application of phosphate fertilizer increased the single panicle weight,grain weight per panicle,grain rate,1000-grain weight and harvest index in varying degrees,and consequently increased the grain yield by 6.20%~8.34%.Deep application of phosphate fertilizer effectively increased the partial productivity of nitrogen,phosphorus and potassium,especially under the condition of low phosphorus.Correlation analysis showed that yield and its components had obvious negative correlation with water content and available nitrogen content in deep soil layer,especially in 10~20-cm soil layer,which reached very significant level.In summary,15-cm deep application of phosphate fertilizer could promote the root growth in deep soil layer,improve the utilization of water and nutrient resources in deep soil layer,and then increase the yield of foxtail millet,which had obvious effects in increasing yield and saving fertilizer.