共查询到20条相似文献,搜索用时 46 毫秒
1.
罗成 《中国农村水利水电》1996,(1):10-12
经多年试验观测,膜上灌可节水20% ̄30%,增产4% ̄5%,投资少,方法简单易行,是干旱绿洲灌溉农业区地膜栽培作物节水灌溉的有效途径。文章分析了膜上灌的节水原理、节水效果及对作物根系分布的影响,并提出了其技术规范。 相似文献
2.
膜上灌是目前农村经济条件下高耗水经济作物节水灌溉的有效途径。文章介绍了大蒜膜上灌栽培基本技术,定量分析了经济效益,并对节不机理及有关值得注意的问题进行了初步探讨。 相似文献
3.
膜上灌节水技术 总被引:18,自引:0,他引:18
1膜上灌技术在新疆推广应用现状新疆是我国最干旱地区,农业生态的特点是"荒漠绿洲,灌溉农业。"合理开发和节约使用水资源对农业生产发展有着重大的意义。膜上灌是新疆广大农民和团场职工在地膜栽培基础上创造和发展起来的一种行之有效的新的节水灌溉技术。膜上灌自1986年在新疆进行生产性节水灌溉试验开始,当年就收到显著的节水效果,比原灌溉节水56.8%。这一技术很快引起了兵团和原自治区党委农工部重视,并列项、拨专款进行研究、完善,迅速在全疆推广,使这一技术的灌溉面积迅速扩大,1987年膜上灌133hm2,1988年919.4hm2,1989年l… 相似文献
4.
蒋黎明 《中国农村水利水电》1995,(5)
我国现有的膜上灌技术无法避免出膜流量,这对于入膜水量较小的井灌区来说是不允许的。分段膜上灌是一种类似滴灌的解决此问题的较新节水灌溉技术。文章介绍了该技术的要点和实验成果,并进行了较详细的分析。 相似文献
5.
宁夏干旱地区管灌与膜上灌相结合的灌水技术试验研究 总被引:5,自引:0,他引:5
该文针对管灌只解决了传输节水而未解决田间生育节水的问题,提出并实施了管灌,输水沟地膜(或微膜)防渗与田间膜上灌相结合的渠沟田全防渗灌灌溉法,并围绕该法对有关问题进行了试验研究,取得了成功。 相似文献
6.
宁夏干旱地区管灌与膜上灌相结合的灌水技术试验研究 总被引:1,自引:0,他引:1
该文针对管灌只解决了传输节水而未解决田间生育节水的问题,提出并实施了管灌、输水沟地膜(或微膜)防渗与田间膜上灌相结合的渠沟田全防渗灌溉法,并围绕该法对有关问题进行了试验研究,取得了成功。 相似文献
7.
棉花膜下滴灌节水、增产的机理与效益分析 总被引:11,自引:1,他引:11
膜下滴灌作为一种高效节水灌溉技术,近年来在南疆的小区试验、大田的推广中具有较高的节水、增产效果,发展前景极为广阔。根据实测及调查资料对膜下滴灌的节水、增产机理和效益进行了分析,结果表明:与常规灌溉对比,节水35%~63%,平均增产籽棉1200~1500kg/hm^2,增产18.5%~44.0%,水产比由常规灌的0.50~0.75提高到0.88~1.64。 相似文献
8.
为探明扶埂开沟膜下灌对番茄的影响,以温室番茄为研究对象,采用完全随机试验设计方法,通过扶埂开沟膜下灌与常规沟灌以及在各个生育期的调亏灌溉对比,研究不同沟灌对温室番茄的生长、产量及水分利用效率的影响。结果表明:扶埂开沟膜下灌较传统沟灌节水效果显著,每生产1 kg番茄省水0.005 88 m3,水分利用效率达到31.679 kg/m3,较沟灌显著提高19.64%;扶埂开沟膜下灌灌溉方式下,番茄苗期亏水灌溉时灌溉水利用效率达峰值,与适宜水分灌溉相比灌溉水利用效率显著提高26.69%,番茄节水灌溉的有效时期是苗期;综合分析发现,最佳沟灌灌溉制度为:扶埂开沟膜下灌+苗期调亏,及在扶埂开沟膜下灌模式下苗期灌水1次+开花坐果期4次+结果后期5次,每次灌水定额为40 mm。 相似文献
9.
10.
11.
12.
13.
14.
15.
《Journal of Agricultural Engineering Research》1998,69(3):249-254
A model to represent the discolouration of dried powder of carrots as a function of temperature was developed. Two types of carrots, Asian and European, containing large amount of lycopene and β-carotene, respectively, were tested. The dried powder was stored under an atmosphere with O2and at three different temperatures, 5,20 and 35°C. The surface colour of the powder was monitored during storage by a Hunter colour ratioa/b. In the proposed model, the rate of oxidation was assumed to be represented by the product of the fraction of concentration of oxidized pigment at arbitrary time and a specific rate of oxidation of pigment. The rate parameters in the proposed model were calculated by fitting the experimental data with smooth curves by trial and error at the end of the induction period but before discolouration took place. The frequency constant and activation energy, expressing the temperature dependence of the rate parameters, were expressed by the Arrhenius relation. The simulation results of a Hunter colour ratioa/bof dried powder at 25°C showed good agreement with the experimental data, suggesting that the proposed model was effective for the prediction of discolouration of dried powder of both types of carrot. The use of the induction period in the manner described may enable the shelf life of dried powder to be predicted. 相似文献
16.
感官检验棉花的品级,这是农村常见的一种检测手段.它的一个主要特点就是存在不确定性.这是由于检验员的品级检验水平存在一定的差异,其中有很多因素制约着检验的结果.文章对影响感官检验结果的因素进行了系统的分析. 相似文献
17.
18.
从灾害经济学的角度探讨了城镇供水优化调度的必要性和可能性,认为在缺水不可避免的情况下,对供水进行优化调度可以减小缺水带来的损失,产生较好的减灾效益,特别是可以大大减小严重干旱的灾害效应。并根据水资源的特性,提出了缺水损失的计算模式以及优化调度的原则和方法。 相似文献
19.
20.
The fractional outflow rate of water from the rumen, measured as the rate of disappearance of the chromium complex of ethylenediamine tetra-acetic acid, was related to a number of dietary factors. A multiple regression equation was derived which expressed fractional outflow rate as a function of the intakes of dry matter, ash, acid-detergent fibre and crude protein.The data analysed consisted of 243 observations for sheep on 59 diets, including forage, concentrate and mixed diets. The ranges covered by the data were: fractional outflow rate 0.7–3.6 day?1; dry matter intake 560–1400g/day; ash 4–30%, acid-detergent fibre 7–41%, crude protein 5–26 % of dry matter; there were no observations for sheep of less than 34 kg liveweight.The equation accounted for 56·3 % of the total variance. Between-sheep variance could not be calculated for the whole of the data but was undoubtedly substantial since, for a sixth of the data, it was known to account for 38 % of the total variance. 相似文献