WP30—6固定式系列微喷头的研制

ＷＰ３０－６属于折射式微喷头，由铜合金或铝合金制成。喷嘴直径１．４－５．０ｍｍ共分八档，流量０．１７－１．３２ｍ~３／ｈ射程２．３５－６．５４ｍ，工作压力１５０－３００ｋＰａ，喷灌强度＝９．６４ｍｍ／ｈ。     

Farmers’ scheduling patterns in on-demand pressurized irrigation

Irrigation scheduling results from the irrigator's integration of meteorological, environmental and crop information. In this paper, the irrigation scheduling patterns of a group of irrigators in the Candasnos Water Users Association (WUA), located in north-eastern Spain, were analysed. Scheduling sprinkler and drip irrigation in this WUA shows additional complications due to the sharing of a collective pressurized irrigation network and to the need to file water orders two days in advance of its foreseen use. The database created by a remote surveillance and control system was mined to obtain the time evolution of hydrant operation time during the 2004–2008 irrigation seasons. Records were selected for clearly identified crops and irrigation systems, and for verified water allocations. Hydrant operation showed a relationship with meteorology (precipitation, wind speed, relative humidity and air temperature), although this relationship was often not evident when hydrants were individually analysed. Statistical analyses were run to classify irrigator's scheduling practices, leading to the establishment of ten different groups. The adopted classification criteria included the average number of weekly irrigations, the SD of the number of weekly irrigations and the modal range of the irrigation starting time. The irrigation pattern was determined by the irrigator (56%), the irrigation system (33%), and the crop (11%). Only in a fraction of the cases (22%) the time change in the scheduling pattern responded to a clear time trend; in 39% of the cases, changes in time appeared random. Further, 45% of the irrigators used the same irrigation pattern in at least half of their hydrant-years, independently of the crop. Only 14% of the irrigators applied different irrigation scheduling patterns to different crops. Our results suggest that irrigators do not find value or do not have the capacity to develop irrigation patterns more consistent and adapted to the local environment, the crops and the irrigation systems.     

Supplemental irrigation effect on canola yield components under semiarid climatic conditions

With the availability of irrigation water, supplemental irrigation in winter-grown crops, such as lentil, wheat, and barley, has been intensely practiced to prevent crop yield losses due to the incidence of intermittent drought stress. In the crop growing seasons of 2006-2007 and 2008-2009, a study was conducted to determine the effect of supplemental irrigations on Canola (Brassica napus L. cv. Elvis F1) under the semiarid climatic conditions of the Harran plain, Sanliurfa, Turkey. A sprinkler irrigation system was used to irrigate the study plots. The irrigation treatments included 0.0, 0.25, 0.50, 0.75, and 1.0 (full irrigation) of Class-A pan evaporation amounts. The full irrigation treatment during both years consisted of 250 and 225 mm, respectively. In turn, crop water use values during the same years and treatments were 462 and 449 mm. In general, plant height and 1000 seed weight ranged from 140 to 165 cm and from 2.5 to 3.3 g, respectively, and these variables significantly differed among irrigation treatments (p < 0.05). Crop yield and above ground biomass measurements were affected by irrigation treatments and varied from 1094 to 3943 kg ha⁻¹ and from 6746 to 18,311 kg ha⁻¹, respectively (p < 0.05). Similarly, harvest index values were affected (p < 0.05) and ranged from 0.16 to 0.23 on average. The water use efficiency obtained in the different treatments indicated a strong positive relationship between crop yield and irrigation. Overall, our results indicate that supplemental irrigation substantially increased canola yield; however, for an optimum yield, full irrigation is suggested.     

Uniformity testing of variable-rate center pivot irrigation control systems

As water supplies become limited, agricultural water use needs to become more efficient to maintain current productivity levels. The efficiency of center pivot and linear move irrigation systems can be increased by matching the amount and rate of water application to specific soil conditions that vary in the field. Such site-specific application can be achieved by variable-rate control systems. Although such systems are being developed, their effects on center pivot and linear move uniformity have not been documented. The uniformity along the length of a center pivot and a linear move irrigation system was measured at two system movement speeds and three variable-rate settings. One variable-rate system is commercially available using pneumatically actuated solenoid valves to turn groups of sprinklers ON and OFF at fractions of a minute corresponding to the cycle rate, for example a 50% cycle rate is 30 s ON and 30 s OFF. The other variable-rate system used commonly available electric solenoid valves to accomplish the same task. Overall, the coefficient of uniformity and low quarter distribution uniformity averaged 93% and 0.90, respectively for the center pivot irrigation system; 84% and 0.74 for the linear move system. The results were not significantly (P > 0.05) affected by wind speed, cycling rate, or system movement speed. The type of nozzle did influence the uniformity because of the distinctly different application characteristics of rotator, fixed plate, and wobbling low pressure sprinklers. Thus, the variable-rate technologies tested under the conditions presented in this paper had at least as good uniformity as the center pivot and linear move systems when functioning in non-variable-rate mode.Mention of a trade name, proprietary product, or specific equipment does not constitute a guarantee or warranty by the University of Florida or the University of Georgia and does not imply approval of a product or exclusion of others that may be suitable.     

Poinsettia growth,tissue nutrient concentration,and nutrient uptake as influenced by nitrogen form and stage of growth

Growth, development, and uptake of essential nutrients as influenced by nitrogen (N) form and growth stage was evaluated for ‘Freedom’ poinsettias (Euphorbia pulcherrima Willd. Ex Klotz.). Treatments consisted of five nitrate (NH₄ ⁺):ammonium (NO₃ ^‐) ratios (% NH₄ ⁺:% NO₃ ^‐) of 100:0, 75:25, 50:50, 25:75, and 0:100 with a total N concentration of 150 mg L^‐1. Plants were grown in solution culture for ten weeks under greenhouse conditions. Nutrient uptake data was combined into three physiological growth stages. Growth stage I (GSI) included early vegetative growth (long days). Growth stage II (GSII) began at floral induction and leaf and bract expansion (short days). Growth stage III (GSIII) was from visible bud through anthesis and harvest. Dry weights for all plant parts and height increased as the ratio of NO₃ ^‐ increased. Leaf area and bract area were maximized with 25:75 and 50:50 N treatments, respectively. Nitrogen treatments significantly affected foliar nutrient concentrations with calcium (Ca⁺⁺) and magnesium (Mg⁺⁺) being highest when NO₃ ^‐ was the predominant N form. Uptake of each macronutrient was averaged across all treatments and divided into physiological growth stages (GS) to identify peak demand periods during the growth cycle. The greatest uptake of NH₄ ⁺ and NO₃ ^‐ was from the early vegetative stage to floral induction (GSI). Phosphorus (P), potassium (K⁺), and Mg⁺⁺ uptake were greatest from floral induction to visible bud (GSII) and Ca⁺⁺ uptake remained relatively unchanged through GSI and GSII. Uptake was lowest for all nutrients from visible bud to anthesis (GSIII). Results from this study clearly indicate that peak demand periods for macronutrient uptake existed during the growth cycle of poinsettia.     

国内外喷灌系统研究简史与发展趋势

在回顾国内外喷灌系统研究简史和评述现有典型文献的基础上,分析了喷灌系统研究今后的若干趋势。     

旋转式喷头射程的理论计算模型

基于空气动力学原理,研究了喷头水滴在空气中的运动模型,分析了喷灌水滴阻力特性参数及最大水滴直径与喷嘴直径、工作压力的关系,推导了考虑风速条件下的旋转式喷头射程的解析计算公式,并以无风条件下的试验值和文献中多种喷头射程实测值对模型进行了验证.结果表明所建模型物理背景清晰,模型中的参数与喷头的型号无关,适应性强,计算值与实测值的平均相对误差仅为8%,适用于其他类型喷头的射程计算.     

调节阀在喷灌系统中的应用研究

调节阀是最终控制元件最广泛的使用型式。调节阀用于调节介质的流量、压力和液位。根据调节部位信号,自动控制阀门的开度,从而达到介质流量、压力和液位的调节。在固定式喷灌系统中,采用空气调节阀结构,使用空气流通调节输水管道内气体及真空现象,管道在启运和关闭时,不易产生气、水锤现象,该系统在喷灌管道设计施工中省略了繁杂的气、水锤设计施工,简化了结构设计。     

Comparison of different irrigation methods based on the parametric evaluation approach in Dosalegh plain: Iran

Declining water resources and limited clean water reservoirs call for more efficient water use for food production in the future. The objective of this research was to compare different irrigation methods based on a parametric evaluation system in an area of 60,000 ha in the Dosalegh plain of the Khuzestan province, in the southwest of Iran. After the soil properties were analyzed and evaluated, suitability maps were generated for surface, sprinkler and drip irrigation methods, using Remote Sensing (RS) techniques and Geographic Information System (GIS). The results demonstrated that by applying sprinkler and drip irrigation instead of surface irrigation method, the land suitability of 23,790 and 33,261 ha (39.89%) in the Dosalegh plain will improve, respectively. The comparison of the different types of irrigation techniques revealed that the drip and sprinkler irrigations methods were more effective and efficient than that of surface irrigation for improved land productivity. However, the main limiting factor in using either surface or/and sprinkler irrigation methods in this area were soil texture, salinity, and slope, and the main limiting factor in using drip irrigation methods were the calcium carbonate content, soil texture and salinity.     

新型条带喷灌机设计思路及总体设计研究

针对原有圆形喷灌系统受风影响大、喷洒不均匀、成本高和使用不方便且一直得不到推广的问题,进行了条带喷灌机总体构思思路和设计思路的深入研究,并且进行了总体设计。新型条带喷灌机总体思路是利用农户现有的机械,如农用车动力、喷农药柱塞泵和输水软管,设计一套采用叶轮条带旋洒的新型喷头,沿着植物行间实施田间隔行喷洒的、可移动的新型条带喷灌机。它造价低、使用方便、性能可靠,容易在缺水山区和丘陵区等广大干旱半干旱地区的小农户中推广使用,为新农村建设提供一项重要的技术支持。