两种材质灌水器负压供水压力对菠菜水分利用效率及养分吸收的影响

Water use efficiency and nutrient absorption of spinach(Spinacia oleracea L.)under two material emitters and negative water supply pressures

【目的】进行不同材质灌水器和不同供水压力的双因素试验,以期为菠菜生长选择适宜材质的灌水器和供水水平提供技术参数。【方法】以常规浇水为对照(CK),负压灌溉灌水器采用陶瓷头(T)和PVFM(P),并分别设置了–4 k Pa(W1)、–8 k Pa(W2)、–12 k Pa(W3)3个供水压力水平,共7个处理。在遮雨网室内以盆栽的方式研究了不同处理对菠菜耗水量和土壤含水量的动态变化、菠菜的生长发育指标、干物质量、产量及其养分吸收的影响。【结果】在菠菜的整个生育期,耗水速率呈先慢后快的趋势,相同灌水器菠菜累计供水量和土壤含水量随着供水压力的减小而减小,不同负压处理土壤含水量不同且都比CK高,供水压力在设定的–12~–4 k Pa范围内,土壤含水量可以控制在18.6%~27.4%之间,变异系数范围0.039~0.052,属于弱变异,而CK变异系数为0.103,属于中等变异。在相同供水负压下,PVFM材料处理的菠菜累计耗水量均高于陶瓷头。供水压力在–8~–4 k Pa之间的负压灌溉处理土壤含水量较高,菠菜生长良好,叶片数适中,叶面积较大,比–12 k Pa和CK处理有利于菠菜生长。两种材质灌水器比较则是PVMF更有利于菠菜生长发育,–8 k Pa处理PVFM比陶瓷头的干物质量显著增加了36.2%。菠菜保持产量、生物量较高的情况下,最优水分利用效率的处理为W2P,与CK相比,该处理下菠菜产量提高了59.9%,耗水量降低了35.9%,水分利用效率提高了88.3%。随着供水压力的减小,菠菜氮磷钾吸收量先增大后减小,但均高于CK的吸收量。供水压力为–8 k Pa的氮磷钾吸收量最高,相同供水压力不同灌水器下,氮磷钾的吸收量均以PVFM的较高。所有处理菠菜吸收K2O最多,N次之,P2O5最少。【结论】本试验中,采用PVFM作为灌水器材质,控制灌溉水压在–8 k Pa(W2P处理)时较有利于菠菜的生长,也更有利于菠菜水分利用效率、产量和养分吸收量的提高。

[Objectives] The effects of water pressures and emitter materials on the growth and nutrient uptake of spinach were tested in order to provide technique parameters for the selection of negative irrigation of spinach.[Methods] Pot experiments were carried out in a rain shelter. Two emitter materials of ceramic cop （T） and PVFM （P） were used, and three irrigation pressures of -4, -8, -12 kPa and one conventional irrigation were designed with each of the emitter material, recorded as W1, W2, W3, and CK in turn. The dynamic change of water consumption, soil water content, dry matter accumulation,yield and nutrient absorption of spinach were monitored.[Results] The water consumption rate was slow at the early growth period and became fast at the late growth period. The soil water content in the negative pressure treatments was all higher than that in CK, and it could be controlled in range of 18.6%-27.4%. The coefficient of variation ranged from 0.039 to 0.052, belonging to weak variation, while that of CK was 0.103, belonging to moderate variation. Under the same water supply pressure, the cumulative water supply of PVFM was higher than that of ceramic. When the negative pressure of water supply was between -8 kPa and -4 kPa, the spinach grew well and the number of leaves was moderate （about 11-15 pieces）, soil water content was higher and leaf area was larger. Compared with the dry matter of spinach of using ceramic cop as emitter material, that of using PVFM as emitter was significantly increased by 36.2% under the -8 kPa pressure. In the case of maintaining high yield and biomass, the W2P treatment showed superiorities in that the spinach yield was increased by 59.9%, water consumption decreased by 35.9%, and water use efficiency （WUE） increased by 88.3% compared with CK. With the decrease of water supply pressure, the content of total P and total K increased, total N content decreased, all the negative water supply treatments had higher N, P and K contents than CK. With the decrease of water supply pressure, the absorption of N, P and K increased first and then decreased, but all higher than that of CK. The highest absorption of N, P and K was under the water supply pressure of -8 kPa. The N, P and K absorption of PVFM emitter was all higher than that of ceramic cop emitter at the same water supply pressure.[Conclusions] Under the experimental conditions, the best combination for spinach growth was using PVFM made emitter and the water supply pressure of -8 kPa, which could effectively improve water use efficiency, increase yield and nutrient uptake of spinach.