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排序方式: 共有98条查询结果,搜索用时 31 毫秒
12.
《Plant Production Science》2013,16(3):337-346
AbstractThe effects of nitrogen (N) application (32, 72 and 112 kg N ha-1 in 2000, and 32, 92 and 152 kg N ha-1 in 2001) and water-saving irrigation and their interaction on grain yield and yield components of the rice cultivar Champa-Kamphiroozi, which is a local cultivar in a semi-arid area in the south of Islamic Republic (I.R.) of Iran, were investigated. The plants were cultivated under sprinkler irrigation (1.0 ETp and 1.5 ETp), intermittent flooding (1-day and 2-day intervals) and continuous flooding (control). The experiments were conducted on a clay loam-clay soil under a semi-arid environment using four replications in a split plot design with irrigation method as main plots and N levels as subplots. The results indicated that intermittent flooding irrigation at 2-day intervals was as effective as continuous flooding for grain yield, showing high water-use efficiency (WUE). The soil moisture tension in the root zone before each irrigation under this condition was –300 to –400 cm. Sprinkler irrigation and intermittent flooding increased WUE by 20 to 60%, compared with continuous flooding, and the increase in N application rate to 112-152 kg ha-1 increased grain yield under any irrigation condition. Under sprinkler irrigation, grain yield was low and percentage of unfilled grain was high, although WUE was high. However, by adopting sprinkler irrigation, the amount of nitrogen fertilizer application necessary for cultivation was reduced. Furthermore, when nitrogen application must be limited due to groundwater pollution, the amount of nitrogen fertilizer necessary for cultivation can be reduced. 相似文献
13.
ZY-2型喷头水力性能及喷头组合试验 总被引:1,自引:0,他引:1
在农大试区,对ZY-2型喷头组成的半固定式喷灌系统进行了实喷测试。结果表明:在喷头工作压力为298m,喷水量为279m3/h的条件下,组合喷灌强度为0167mm/min,距喷头165m处(最大喷水区)的打击强度为28mm,组合均匀性系数为0858,均符合喷灌技术要求,效果良好。为进一步研究喷灌强度及打击强度对不同作物种类、不同生长期的影响提供理论和实践依据,为研究喷头的组合形式和移动轨迹作先期准备工作。 相似文献
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喷灌条件下不同节水措施对玉米的影响 总被引:1,自引:0,他引:1
在宁夏中部干旱带采用起垄覆膜、无垄覆膜、起垄无膜、秸秆覆盖和对照(常规种植)进行玉米生育期、产量、叶绿素含量、光合速率、蒸腾速率、水分利用效率以及土壤水分含量等进行调查研究,结果表明:覆膜可使玉米提早成熟10 d以上,并可提高玉米的产量、保苗率,成穗率,使玉米的产量比对照提高25.7%~30.7%.影响叶绿素含量的主要是玉米各生育时期与玉米叶片的不同部位,影响最大的是叶片中部,其次是叶片基部.起垄可提高水分利用效率,起垄覆膜可促进玉米的光合速率. 相似文献
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为了降低喷灌工程投资,实现喷头仰角可调,减小风对喷头水量分布的影响,设计了2种规格的喷头仰角调节装置。喷头仰角调节装置安装在ZY喷头与竖管之间,在不关闭水泵的情况下喷头仰角在8°~27°范围内连续可调。对2种喷头仰角调节装置进行了结构设计、单喷头喷洒水量和转动均匀性试验。通过对试验数据分析计算得到:随着喷头仰角的减小,喷头末端喷洒水量增大,抗风性增强,漂移损失减小。喷头初始仰角降低10°时,其水力性能较好,喷头射程减少1~2 m,单喷头喷灌强度值增加了0.1~1.5 mm/h,喷头转动偏差在±7%以内,单喷头喷灌强度与转动性能均符合标准规定。 相似文献
18.
Field experiments were carried out to study the effects of sprinkler irrigation on the characteristics of topsoil pores. Total soil porosity, capillary porosity, air-space porosity and porosities of different pore shapes were analyzed using images analysis of thin sections of soil samples. The experimental treatments included five water application intensities (5.3, 7.7, 11.0, 15.0 and 20.7 mm/h), five drop diameters (0.76, 1.28, 1.92, 3.18, 4.19 mm) and five water application amounts (9.0, 23.6, 37.5, 49.6, 59.4 mm). The compounding sprinkler system was used in the experiments of water application intensity and single sprinkler was used in the experiments of drop size and water application amount. The total porosity, air-space porosity and porosities of elongated pores have the similar decreasing tendency and pattern when water application intensity, drop diameter or water application amount increase. Capillary porosity, porosities of round and irregular pores have no obvious changing tendency. The decreasing porosities of the elongated pores and macropores are the main reasons for the decreasing of total porosity under sprinkler irrigation. To maintain soil structure in good conditions, the reasonable parameters would be considered for water application intensity, drop diameter and water application amount. 相似文献
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20.
LI Jiu-sheng LI Bei SU Mei-shuang RAO Min-jie 《中国农业科学(英文版)》2005,4(9):693-699
Field experiments were conducted to investigate the effects of nonuniformity of sprinkler fertigation and the amount of fertilizers applied through fertigation on nitrogen uptake and crop yield during two growing seasons of winter wheat in 2002-2003 and 2003-2004 at an experimental station in Beijing. In the experiments, the seasonal averaged Christiansen irrigation uniformity coefficient (CU) varied from 72% to 84%. Except for the fertilizer applied before planting, fertilizer was applied with the sprinkler irrigation system with a seasonal averaged CU for fertigation varied from 71% to 85%. Three levels of fertilizer applied varying from 0 to 180 kg N ha^-1 were used in the experiments. The experimental results demonstrated that sprinkler fertigation uniformity had insignificant effects on nitrogen uptake and crop yield for the uniformity range tested. Also, the influence of fertilizer applied through sprinkler fertigation on crop yield was minor, while the total nitrogen content for stem and nitrogen uptake increased with increasing fertilizer applied. 相似文献