水氮供应对滴灌施肥条件下黄瓜生长及水分利用的影响

Effects of Water and Nitrogen Supply on the Growth and Water Use Efficiency of Cucumber(Cucumis sativus L.)Under Fertigation

目的针对西北半干旱地区温室蔬菜灌水施肥不合理等问题,通过研究不同水氮供应对温室黄瓜生长、产量、产量构成因素、灌溉水利用效率及水分利用效率的影响,以期科学地对水肥进行调控,为实际生产提供参考依据。方法利用温室小区试验,以‘博耐9-1’黄瓜为试材,设置3个灌水水平:低水W1(60%ET0)、中水W2(80%ET0)和高水W3(100%ET0),全生育期灌水量分别为126、152和177 mm;4个施氮水平:无氮N0(0)、低氮N1(180 kg·hm-2)、中氮N2(360 kg·hm-2)和高氮N3(540 kg·hm-2),共12个处理。在生育期内对黄瓜的各生长指标进行观测,并统计产量及产量构成因素。结果除茎粗外,灌水量与施氮量对黄瓜株高、叶面积指数、干物质量、产量、产量构成因素、灌溉水利用效率(irrigation water use efficiency,IWUE)及水分利用效率(Water use efficiency,WUE)都有显著影响。灌水量与黄瓜株高、叶面积指数、瓜条数、单果重及产量有显著正相关作用,而施氮量对黄瓜生长及产量的影响则因施氮量的不同表现出不同变化趋势。其株高、叶面积指数随施氮量的增加表现为先增大后降低,并在N2处理中获得最大值。干物质量变化趋势略有不同,表现为在W1水平下,干物质量在N2处理中获得最大值,而在N3水平下略有下降,且N2与N3之间差异不显著,其余灌水水平下则随着施氮量的增加表现为不同程度的增加。黄瓜产量随施氮量的增加而增加,当施氮量增加到N2水平时,继续增加施氮量,其增产效果在不同灌水水平下表现为不同趋势,即在W1、W2水平下,施氮量增加至N2水平后继续增加时,产量之间无显著性差异;而在W3处理下,N3比N2水平增产8.4%,差异显著。灌水量对IWUE有显著负相关作用,在W1水平下获得最大值,为41.33 kg·m-2,而灌水量对WUE的影响则表现为先增加后减少的趋势,在W2水平下获得最大值,为55.82 kg·m-2。施氮量对IWUE表现为正相关作用,而对于WUE则因施氮量不同表现出不同的变化趋势,在W1和W2水平下,WUE随施氮量增加表现为先增加后降低的趋势,并在N2水平获得最大值,分别为52.34 kg·m-2、55.82 kg·m-2;W3水平下,WUE则随施氮量的增加显著增加。其中,在W3N3处理下获得最大产量,但其水分利用效率和灌溉水利用效率明显低于W2水平,且W2N2相比于W3N3灌水量减少16.7%,施氮量减少33%,而产量仅减少11.3%,且IWUE提高6.5%,WUE提高11.1%。通过产量与生长指标(株高、茎粗、叶面积指数、干物质量)间的通径分析可知,干物质量和叶面积指数对黄瓜产量的增加具有重要作用,可分别作为黄瓜高产的第一指标和第二指标。结论合理的减少灌水量与施氮量不仅能维持黄瓜较好的生长特性,而且能获得较大的经济效益。综合产量与节水节肥因素,W2N2处理(80%ET0,360 kg N·hm-2)可作为较适宜的水氮组合。

[Objective]In view of the questions of unreasonable irrigation and nitrogen in the vegetable greenhouse in semiarid northwest area, effects of water and nitrogen supply on the growth, yield, yield components, IWUE and WUE of cucumber under fertigation were investigated in order to regulate water and fertilizer scientifically and provide scientific reference for actual production. [Method] ‘Bonai 9-1’ was chosen as the test cultivar, the greenhouse plot experiment was subjected to three irrigation water levels [W1 （60% ET0）, W2 （80% ET0） and W3 （100% ET0）, the irrigation of the whole growth period of cucumber were 126,152 and 177 mm, respectively] in interaction with four nitrogen fertilization levels [N0 N1 （180 kg·hm-2）, N2 （360 kg·hm-2）, N3 （540 kg·hm-2）], and there were 12 treatments in total. Growth indexes were measured during the growing season and yield and yield components were counted after the final harvest. [Result] In addition to stem diameter, irrigation and nitrogen application influenced cucumber plant height, leaf area index, dry weight, yield, yield components, IWUE and WUE significantly. Irrigation had a significant positive correlation with plant height, leaf area index, fruit number, average fruit weight and yield, whereas the impact of nitrogen fertilizer on cucumber growth and yield showed different trends due to the different nitrogen levels. The impact of nitrogen fertilizer on plant height and leaf area index showed an increasing trend first and then decreasing, reached the maximum at N2 treatment. Dry weight was slightly different, which showed under W1 level, reaching the maximum in N2 treatment, decreased slightly in N3 treatment afterwards, and there were no significant difference between the N2 and N3 treatments. The remaining irrigation levels showed varying degrees of increase with the increasing nitrogen fertilizer. Cucumber yield also increased with the increasing nitrogen rate. When the nitrogen rate increased to N2 level, and continued to increase, the effect of yield showed different trends under different irrigation levels. In other words, there was no significant difference among yields when nitrogen rate increased to N2 levels and continued to increase under W1 and W2 levels, while difference was significant between N2 and N3 treatments and N3 improved yield by 8.4%than N2 under W3 level. Irrigation had a significant negative correlation effect on IWUE, and gained IWUE maximum 41.33 kg·m-2 at W1 level. The impact of irrigation on WUE showed an increasing trend and then decreasing, reached the maximum 55.82 kg·m-2 at W2 level. Nitrogen rate had a positive correlation effect on IWUE, whereas showed different trends on WUE. In W1 and W2 treatments, WUE showed an increasing trend and then decreasing with the increase of nitrogen rate, reached the maximum 52.34 kg·m-2, 55.82 kg·m-2, respectively, at N2 levels, while in W3 treatment, WUE was significantly increased with the increase of nitrogen rate. The maximum yield was obtained in W3N3 treatment, but the WUE and IWUE were significantly lower than W2 level. Compared with W3N3, the treatment of W2N2 reduced the irrigation amount by 16.7%, nitrogen rate by 33%, yield by only 11.3%, improved IWUE by 6.5%, and WUE by 11.1%. Path analysis on yield and growth index （height, stem diameter, leaf area index, dry weight） showed that dry weight and leaf area index had the important effects on cucumber yield improvement, which can be used for the first and second indexes of high yield.[Conclusion]Reasonable irrigation and nitrogen application not only maintained good growth characteristics of cucumber, but also obtained the maximum economic benefit. In comprehensive consideration of yield, water and fertilizer conservation, W2N2 treatment （80% ET0, 360 kg N·hm-2） was better appropriate combination of water and nitrogen under the experimental conditions.