Comparison of Russet Burbank yield and quality under furrow and sprinkler irrigation

A survey of growers in the Treasure Valley of western Idaho/eastern Oregon indicated that Russet Burbank potato tends to produce better quality tubers under sprinkler irrigation than with furrow irrigation. Irrigation plot studies were carried out over 3 years on 2 sites to determine if these differences were a result of commonly-used management practices or inherent in the irrigation method. With good water management, irrigation method did not affect yields, but sprinkler irrigation produced tubers with slightly better visual quality and much lower incidence of sugar ends. The reasons for better quality with sprinkler-irrigation were projected to include: 1) less water stress since sprinklers can more uniformly apply the small, frequent irrigations that potato requires; 2) better nitrogen management since furrow applications often leach nitrogen from the root zone; and 3) lower soil temperatures due to sprinkler water evaporative cooling.     

Effects of irrigation system and green manure on yield and nicotine content of Virginia (flue-cured) Organic tobacco (Nicotiana tabaccum), under Mediterranean conditions

Organic tobacco consists of a new industrial crop product. Field experiments were conducted to determine the effects of irrigation system and fertilization on the growth (biomass and roots) of organic tobacco plants (Nicotiana tabaccum cv NC 71). The experiment was designed as a split plot design with four replicates, two main plots (drip and sprinkler irrigation) and three sub-plots (vetch as green manure, red clover as green manure and control; without fertilization). Drip irrigation was characterised by lower amount of water applied to the soil. Furthermore the tobacco yield was not affected by the reduced water application and the crops under drip irrigation were higher than those with sprinkler irrigation. Positive effect of green manure in the nicotine content of tobacco leaves was also observed, and that reported for first time under organic system. Equally the higher amount of nitrogen from green fertilization with vetch led to increase of nicotine concentration (0.91% max concentration). Agronomic water use efficiency (WUE) for drip irrigation was always higher than those for sprinkler irrigation. There were no significant differences between the drip and sprinkler irrigation concerning the root biomass. Moreover, green manures increased roots dry weight. Yield of tobacco crop was significantly increased by the green manures, with the lowest yield (1850 kg ha^?1) to be found in the control plots. Finally, green manures increased the SPAD values and number of leaves, with most significant impact the time when vetch applied to soil.     

Placement of soil moisture sensors in sprinkler irrigated potatoes

Potato (Solanum tuberosum L.) is particularly sensitive to soil water potential below ?50 to ?60 J kg^?1 during tuber development. Soil water must also be carefully monitored to irrigate efficiently and to minimize nitrate leaching associated with over-irrigation. Water distribution in and below potato hills during and following sprinkler irrigation was monitored using granular matrix sensors (Watermark Model 200, Irrometer Co., Riverside, CA) placed in 0.10 m × 0.15 m cross-sectional grids down to 0.6-m depth below the soil surface. Each grid consisted of 26 sensors. Sensor electrical resistance had been calibrated to soil water potential. During one test, soil water potential was intentionally lowered to levels drier than ideal for potato to emphasize soil wetting and drying patterns. Over the 26 locations in the grids, the soil water potential averaged ?33 J kg^?1 over a six week period, with sprinkler irrigations evenly rewetting the upper 0.2 m of the hill. On average, the driest locations were the top of the hill, directly under the hill, and below the furrow with wheel track compaction. Ideal sensor locations for monitoring soil water status and scheduling irrigations are offset 0.15 m from the center of the hill and 0.1 to 0.2 m deep. Sensors installed in silt loam soil responded within four hours to wetting and within 12 hours to drying, the shortest increments of time measured.     

Water use in rice crop through different methods of irrigation in a sodic soil

Sodic soils are characterized by high exchangeable sodium on exchange sites, soil pH greater than 8.5, relatively low electrical conductivity, low infiltration rate and dispersed clay. These characteristics restrict the capacity of soil to absorb water, resulting in poor infiltration. Evidently, these soils require application of irrigation water at shorter intervals for crop production. Thus, irrigation strategy for sodic soils differs from that of normal soils. An experiment to determine the suitable irrigation strategy along with methods of application namely: surface (farmer’s practice), sprinkler (double nozzle impact sprinkler), and low-energy water application device (LEWA) were initiated in the year 2012 for rice crop. Irrigation depths of 6 cm in case of surface method and 4 cm in case of sprinkler and LEWA methods were applied at each irrigation event. The irrigation events for rice were scheduled at 2-DAD (days after the disappearance of the ponded water), 3-DAD, and 4-DAD through surface method, and at daily, 1- and 2-day intervals (after initial ponding disappeared) by sprinkler and LEWA methods. Sprinkler and LEWA methods resulted in highest rice yield of 4.4 t ha^?1 in irrigated plots at the 2-day interval which was at par with the highest yielding surface-irrigated plot scheduled at 2-DAD. At the same time, irrigation strategy of 2-day interval through sprinkler and LEWA methods registered water saving to the extent of 30–40% over 2-DAD under surface irrigation method. Results revealed that there could be substantial saving of water and energy (electricity and diesel) through the use of sprinkling devices for irrigating rice under sodic soil environments.     

Applying herbicides in irrigation water—a review

The technology of applying herbicides in irrigation water to control weeds selectively in crops has developed since the late 1960s. A review of the literature indicates that under the right conditions many herbicides applied through irrigation systems will control weeds selectively in crops. The greatest use of this technology has been with sprinkler irrigation systems, especially centre-pivots. Certain herbicides are also effective when applied through gravity flow irrigation systems, although uneven herbicide distribution and the potential for downstream contamination has limited the use of the technology in these systems. Although there is considerable interest in applying herbicides through trickle irrigation systems, problems associated with poor uniformity of herbicide application, rapid degradation of herbicides near the orifices, and potential health hazards to workers who might drink treated water, have prevented this technology from being adopted. Research is needed to determine how such factors as amount of water applied, soil texture, soil organic matter, soil moisture before and after herbicide application, water droplet size, timing of herbicide applications, herbicide concentration, herbicide properties, climatic factors, and the use of oils and other adjuvants affect the behaviour of herbicides applied through irrigation systems.     

Variations in responses of potato germplasm to deficit irrigation as affected by soil texture

The response to irrigation of three parental potato cultivars was studied on loam and sandy soils by use of the line source sprinkler technique, which provided a continuous irrigation variable from 0 to 100% or more replacement of estimated evapotranspiration (Et). Solid-set sprinkler irrigation from planting until near full ground cover provided optimal early plant growth and a soil profile filled with water when the irrigation variable was started in July. On the loam soil this residual soil water provided most of the water needs of the three cultivars over a 10–12 week period until harvest. On this soil, irrigation levels providing replacement above 20 to 40% Et had little beneficial effect. In fact, higher irrigation levels had serious deleterious effects, especially on grade and solids of Nooksack. On the loam soil, Nooksack performed best in every regard at deficit irrigation levels below 50% Et. In contrast, on this loam soil, differing irrigation levels had very little effect on the productivity of Lemhi. The response of all cultivars on sandy soil was much different than on loam soil. On sand, total and U.S. No. 1 yield of all cultivars increased greatly as irrigation levels increased, up to 70 to 80% Et. Levels above this had minimal effect. Nooksack again performed better than the other two cultivars under deficit irrigation. The results of these and other studies show there is potential for identifying or developing potato cultivars which are more efficient users of irrigation water.     

喷灌对秦岭北麓旱地小麦产量及品质的效应

为给陕西旱地及关中灌区小麦高效灌溉提供技术支撑,在陕西秦岭北麓的蓝田县进行了小麦不同生育时期喷灌小区试验和生产示范试验,研究了喷灌对小麦产量及品质的影响。结果表明,在越冬期和拔节期喷灌可显著提高小麦产量、效益和水分利用效率,产量、收入和水分利用效率相对于无灌溉处理的增加幅度分别为22.0%~95.7%、16.5%~83.6%和9.3%~82.7%。喷灌后籽粒容重、吸水率和最大拉伸阻力分别增加1.8%~2.6%、0.5%~1.4%和0.6%~1.9%,其他品质指标降低,磨粉品质和加工品质明显变差。其中籽粒蛋白质含量和硬度分别降低5.2%~8.1%和6.0%~9.4%,最大拉伸面积、沉降值、湿面筋含量和稳定时间分别降低5.2%~7.8%、13.1%~17.3%、3.7%~7.8%和31.3%~42.4%。     

我国胡椒水肥管理方法及发展趋势

胡椒作为一种热带经济作物，对水肥管理的要求比较高。我国胡椒水肥管理包括浇灌、沟灌、喷灌和滴灌等灌溉方法，传统的施肥方法以及近几年发展起来的水肥一体化管理技术。本文针对各种水肥管理方法的优缺点，提出水肥一体化技术将成为胡椒水肥管理的主要方法。     

喷灌对玉米产量的影响

通过玉米全生育期喷灌7次、5次和3次处理,研究不同喷灌处理对玉米生育期叶面积、光合势、光合强度、子粒增长量及产量的影响,提出了吉林省西部地区玉米适宜的喷灌指标、喷灌时期及次数,确定了保证玉米高产稳产的喷灌技术措施。     

Effect of daily irrigation rate and soil texture on yield and quality of Russet Burbank potatoes

Adequate soil water is needed for satisfactory yield and quality of potato tubers. With sprinkler irrigation systems it is common practice to apply more water than the crop uses in order to maintain high soil water levels. A study was initiated to evaluate the response of Russet Burbank potatoes to a wide range of daily sprinkler irrigation rates when grown on two soilsa loam and a sand—differing in water holding capacity. The results from the two soils were very different. On the loam soil, yields generally increased with increased applications of water, up to the equivalent of 40 to 50% estimated Et. Irrigation treatment effect on percent No. 1 tubers was inconclusive. In 1978, percent No. 1 tubers increased with water applied up to about 70% estimated Et. In 1980, irrigation rates between the equivalent of about 20 and 80% estimated Et had little effect on tuber grade. Yields and percent No. 1 tubers were depressed at irrigation rates greater than about 80% estimated Et. On the sand, yields and percent No. 1 tubers increased with increased irrigation rates up to about 100% and 80% estimated Et, respectively. Tuber specific gravity was not affected to an important degree by irrigation treatment on either soil. These results indicate that a good crop of potatoes can be grown on a loam soil at daily irrigation rates considerably less than estimated Et rates, while such reductions will decrease yields and grade on a sandy soil.     

Evaluation of sprinkler application of fungicides for control of potato early blight in Colorado

Sprinkler application of four fungicides, Du-Ter 47.5% W.P. (0.70 kg/ha), Difolatan 4F (3.51 1/ha), Bravo W-75 (1.68 kg/ha) and Bravo 500 (1.17 1/ha, 1.761/ha and 2.341/ha) were evaluated in Colorado for control of potato early blight caused byAlternaria solani (Ellis & G. Martin) L.R. Jones and Grout and compared to the conventional method of airplane application. Fungicides applied through center pivot irrigation systems generally achieved disease control equal to airplane application. Application of fungicides through both center pivot sprinklers and by airplane effectively reduced early blight infection. Control of early blight by airplane or sprinkler application of fungicides significantly (P = 0.05) increased potato yields in 1978. In other years (1977, 1979 and 1980) fungicide applications which reduced disease severity generally increased tuber yields but the increases were not significant when compared to the control.     

喷灌不同施肥量对‘宝岛’香蕉生产效果影响

为给‘宝岛’香蕉生产提供适宜的施肥方式，试验采用低压微喷灌研究不同施肥量对香蕉生长发育的影响，以传统施肥(干撒肥料，CK)为对照，设置3个低压微喷灌施肥量处理，依次为传统施肥量的100%(T1)、80%(T2)和60%(T3)。试验结果表明：较CK相比，T1 和T2表现为生长势强，抽蕾期提前约30 d，产量分别提高8.80%和6.87%以上，每公顷经济效益分别提高11.84万和12.03万元。因此，T2是为生产中较好的施肥模式。     

Models of the interconnection of pumps to supply water to branched networks

The basic concepts from a hydraulic and mathematical point of view were introduced to describe the operation of a hydraulic branched network of water distribution. Moreover, each one of the elements (simples and complex) of the system was identified. Classic hydraulic equations were inputted to apply them to branched networks and obtain a standard solution. A set of linear and non-linear equations, through the Newton–Raphson method with the jacobian matrix were required to solve the branched network that interconnects two kinds of very different pumps: a volute type centrifugal pump and another one is submersible pump, both of them installed in a deep well. The system is a branched network with two nodes and five pipe lines, to adequately supply two pressure irrigation systems: a central pivot and a semi-portable sprinkler, where the pumps are located in different places and heights. The solution was obtained by solving a system of two linear equations and three non-linear, simultaneously.     

Surface energy flux measurements in a flooded and an aerobic rice field using a single eddy-covariance system

About 90 % of the global rice production takes place in Asia, while European production is quantitatively modest. Italy is the Europe’s leading producer, with over half of total production concentrated in a large, traditional paddy rice area in the north of the country. High irrigation requirement for continuous flooding encourages the adoption of water saving techniques. In 2013, an intense monitoring activity was conducted on two fields characterized by continuous flooding and intermittent irrigation regimes, with the aim of comparing their agronomical and hydrological effects, including their influence on the energy balance. An eddy covariance station was installed on the levee between the two fields, to monitor latent (LE) and sensible (H) heat fluxes as a function of wind direction. Additionally, the fields were instrumented with net radiometers, soil heat flux (G) plates, thermistors, tensiometers, and multilevel moisture probes. Three footprint models were applied to determine position and size of the footprint area at each monitoring time step, providing similar results. Two half-hourly turbulent fluxes datasets were obtained, one for each irrigation regime, each one comprising about 10 % of the daytime time steps over the agricultural season. The reliability of the monitoring performed with a single EC station was confirmed by the energy balance closure (H + LE versus R_n-G), showing an imbalance lower than 10 % for both the regimes. A detailed analysis of the effect of the storage terms on the ground heat flux estimation and a more thorough analysis of the radiation balance for the two plots were also performed.     

Analysis of water management structures of an Integrated Water User Group in the Chao Phraya Delta, Thailand

An Integrated Water User Group (IWUG) plays an important role assisting an irrigation project to control water distribution, expand the cropping area, operate and maintain irrigation facilities, and disseminate crucial information about the water situation to all farmers based on water supply from an irrigation agency. In this article, we present our analysis of the management of a newly established IWUG, based on a field survey in Thailand. We attempt to clarify the characteristics of irrigation management in the IWUG, while focusing on four functional processes: decision, operation, monitoring, and feedback. Thus, we analyze the water management structure and provide suggestions for better management of the IWUG. The main results of our analysis are as follows: (1) the current state of the IWUG 18R canal is not fully successful. There are second generation problems that need to be solved; (2) The upstream farmers dominate the use of the IWUG 18R canal because the establishment process of downstream WUGs was loosely performed because of a limited budget for on-farm irrigation development; (3) Water distribution structure and membership charging are not simple and uniform along the lateral irrigation canal because of the water availability of return flow from the downstream area. Such structure should be recognized and discussed to improve the future water distribution in relation to membership fees.     

Zone-subsoiling effects on potato yield and grade

Soil compaction and erosion are problems in many Pacific Northwestern potato fields. We wanted to determine if zone-subsoiling would reduce these problems and improve potato yields and or grade without adversely impacting other production practices. Studies were conducted in Southern Idaho at six locations over two years on different soils and with different irrigation methods to assess the effects of zone-subsoiling immediately after planting on tuber yield and grade. Reservoir-tillage comparisons were made at three locations where sprinkler water application rates were higher than soil infiltration rates. Russet Burbank was represented by eight location-years and Russet Norkotah by two. Zone-subsoiling consistently improved tuber grade or increased tuber size. The biggest improvement was under furrow irrigation. Zone-subsoiling also tended to increase total yield in eight of ten location-years. Reservoir-tillage improved yield and grade, but zone-subsoiling did not without reservoir-tillage when water application rates were high. At no location did zone-subsoiling significantly decrease tuber grade or yield. Zone-subsoiling had no appreciable effects on hill configuration or seed-piece dislocation. Surface cracking and “water piping” occurred under furrow irrigation but were not significant problems. Results were similar for both cultivars. Additional studies will be needed to successfully incorporate zone-subsoiling into commercial production practices     

Spatial-uniform application method of methane fermentation digested slurry with irrigation water in the rice paddy field

Promoting biomass utilization, the objectives of this study were to clarify the spatial distribution of nitrogen, one of the most important fertilizer components in the methane fermentation digested slurry (i.e., the digested slurry), and to establish an effective method to apply spatial-uniformly digested slurry with irrigation water in the rice paddy field. A numerical model describing the unsteady two-dimensional flow and solution transport of paddy irrigation water was introduced. The accuracy of this model was verified with a field observation. The tendencies of the TN simulated in inlet and outlet portions had good agreement with the measured data and the accuracy of the numerical model could be verified. Using the numerical model, scenario analyses were conducted to determine the method for spatial-uniform application of the digested slurry with irrigation water. The simulated results indicated that drainage of the surface water and trenches at the soil surface were effective for spatial-uniform application of the digested slurry with irrigation water in the rice paddy fields. The effect of the trenches was maximized when the surface water of the rice paddy field was drained adequately.     

三亚地区常年蔬菜大棚改造方案设计研究

根据海南省建设常年蔬菜基地的要求,结合三亚现有主要种植设施的结构特点和现状,提出三亚地区使用面积较广的2种类型设施（GPSG-422型、WSSG-6430型）的内、外遮阳及喷滴灌改造设计方案,并分析改造过程中存在的问题和改造后的实际运行效果。     

Effects of Water-Saving Irrigation and Nitrogen Fertilization on Yield and Yield Components of Rice (Oryza sativa L.)

Abstract

The 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 ET_p and 1.5 ET_p), 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.     

Quantification of the crop stem flow in the sprinkler irrigated field

In sprinkler irrigated fields, irrigation water is intercepted by crop leaves. This water can be separated into several categories depending on its movement. In this study, the categories are defined as crop stem flow water, leaf storage water, and drop water to the soil. Crop stem flow water is especially effective for crop growth because it reaches the soil surface near the root zone. The objective of this study is to develop a method for quantifying crop stem flow water. Field observation is conducted to observe the movement of irrigation water droplets and to quantify the varying amounts of crop stem flow water, leaf storage water, and drop water to the soil. The measurement of the amount of leaf storage water indicates that droplet movement on the leaf changes constantly. To quantify three components of irrigated water, considering the continuous change of droplet movement on the leaf surface, a simulation model is developed. The simulated amounts of crop stem flow water, leaf storage water, drop water to the soil successfully reproduce the observed result, and model accuracy can be verified.