Tree-Temperature Monitoring for Frost Protection of Orchards in Semi-Arid Regions Using Sprinkler Irrigation

Automated over-tree sprinkler irrigation systems were developed and tested in two orchards located in two separate locations in southern Iran （a 0.17 ha peach orchard and a 0.24 ha orange orchard） to protect peach blossoms and orange trees leaves and fruits from low temperature damage. The experiment used a system that monitored the trees and air temperatures using two thermistors. The water application rate by the irrigation system was determined by an energy balance as implemented by the software FROSTPRO, In the peach orchard, the system was tested during three frost events during the spring of 2003 and three other events during the spring of 2004. The system successfully kept peach flowers above the critical temperature, i.e., -4.0℃ in spring 2004 （control block -4.12℃, and sprinkled block ＋0.5℃） during all events. Similar results were obtained in the orange orchard during three frost events in the winter of 2004, during which the tree temperatures were at least 2.5℃ above the critical temperature. Results from field tests show that the system can effectively protect the peach blossoms from damage. Determination done after the frost events showed a 12% blossom kill in the sprinkled blocks while in the unsprinkled control block a 41.5% blossom kill. Calculations indicated that when using variable application rates, the amount of water used can be reduced by 54.3%. Spatial distribution of minimum temperatures during the three frosts was also studied in Jahrom, Iran. Results showed a significant temperature control in the experimental block, especially in the central part of the orchard, but the block margins （about 3.6% of the total area） were at the risk of low temperature due to the wind drift effects.

Experimental Investigation of Soil Evaporation and Evapotranspiration of Winter Wheat Under Sprinkler Irrigation

Sprinkler irrigation is one of the typical irrigation technologies used for the winter wheat-summer maize double cropping system in the North China Plain. To evaluate the evapotranspiration （ET） of winter wheat under sprinkler irrigation in Beijing area, field experiments were conducted in growing seasons through 2005-2008, in the experimental station located in Tongzhou County, Beijing, China, with different irrigation depths. Results indicated that a relatively large variation of soil water content occurred within 0-40 cm soil layer. The seasonal ET of winter wheat generally increased with increasing irrigation amount, while the seasonal usage of soil water had a negative relationship with irrigation amount. Soil evaporation （Es） was about 25% of winter wheat ET during the period from reviving to maturity. Es increased while Es/ET decreased with increasing irrigation amount. Sprinkler irrigation scheduling with relatively large irrigation quota and low irrigation frequency can reduce Es and promote the irrigation water use efficiency.

Application of Self-pressure Sprinkler Irrigation Technology to Grassland Vegetation Restoration in Alpine Arid Areas

To study the application of self-pressure sprinkler irrigation technology to vegetation restoration of grassland in alpine arid areas,three treatments including fenced grassland(FG),fencedirrigated grassland(FA),and free grazing grassland(CK) were compared in respect of primary productivity.The results showed that the community coverage of FA was only 35.96% higher than that of FG and 152.69% higher than that of CK;the plant height of FA was only 76.71% higher than that of FG and 155.77% higher than that of CK;the productivity of the community in FA was only 24.10% higher than that of FG and 110.00% higher than that of CK.It indicates that the self-pressure sprinkler irrigation technology has certain demonstration and promotion potential in vegetation restoration of grassland in alpine regions and can provide a new way for the sustainable development of grassland animal husbandry in Tibet.

Overview of advances in improving uniformity and water use efficiency of sprinkler irrigation

Water is the scarcest resource and the importance of the judicious use of water in the agricultural sector for sustaining agricultural growth and the retardation of environmental degradation needs no further elaboration.The successes of using sprinkler irrigation to develop new lands,point the way forward to a much greater role for the development of future land reclamation projects.Water use efficiency through a proper improvement of water management techniques and other production factors are essential to boost on-farm productivity.Various factors affecting uniformity and water use efficiency in sprinkler irrigation have been outlined in this research,highlighting possible ways to improve such essential parameters in crop production.The study emphasizes on an irrigation system that works adequately in applying water to stay within the root zone,making the water always available in sufficient quantities to meet the crop water needs.It suggests practical ways of managing irrigation systems within tolerable limits not neglecting the effects of wind which is a major contributing factor to non uniformity in sprinkler irrigation.

Effect of smart sprinkler irrigation utilization on water use efficiency for wheat crops in arid regions

The smart irrigation system(SIS)developed in this research is a valuable tool for scheduling irrigation and quantifying water required by plants.SIS was implemented and tested under sprinkler irrigation system to irrigate wheat crops(YecoraRojo).Results obtained from this system were compared with the control irrigation system(CIS),whose scheduling method was based on data from an automatic weather station.Results indicated significant savings in applied water using the SIS.In addition,the use of the SIS conserved 12%of irrigation water compared to CIS and obtained an economical yield.The water use efficiency(WUE)under SIS had generally higher values(1.64 kg/m^(3))compared to CIS(1.46 kg/m^(3)).Hence,the application of SIS technology provides significant advantages on WUE and irrigation water use efficiency(IWUE).Relatively high WUE and IWUE were found for the irrigation treatment(80%of evapotranspiration under SIS).Results showed that the irrigation requirements of wheat increased(100%of ETc under CIS)with increasing evapotranspiration(ETc)but excessive irrigation could decrease WUE and IWUE.These results indicated that extreme irrigation might not produce higher yield or optimal economic benefit,thus,suitable irrigation schedules by using SIS must be established and extendable to other agricultural crops.

Influence analysis of sprinkler irrigation effectiveness using ANFIS

In order to improve sprinkler irrigation quality and promote actual irrigation efficiency,the influence analysis of sprinkler irrigation effectiveness(SIE)using ANFIS(Adaptive Neural Fuzzy Inference System)was implemented to balance moisture infiltration and water redistribution in soil field.Firstly,using a detailed description of governing equations proposed for sprinkler irrigation flow,the theoretical foundation and mathematical model of irrigation effectiveness can be established;Secondly,based on a complete preparation of experimental irrigation conditions,a series of calibration indexes quantifying SIE for sprinkler irrigation quality and infiltration efficiency were proposed;Then thirdly,a novel ANFIS system was designed and introduced to evaluate these key effectiveness indexes in actual working operations,so that a series of detailed influence analysis and comprehensive infiltration assessment focusing on sprinkler irrigation effectiveness could be achieved afterwards,which result to the realization of better infiltration equilibrium and higher water redistribution efficiency in actual irrigation test.Therefore,the qualification of sprinkler irrigation effectiveness was achieved,and in addition,the moisture infiltration improvement and soil moisture uniformity were facilitated also in return.

Sprinkler irrigation system for tea frost protection and the application effect

A sprinkler irrigation system was designed and applied for a tea field to achieve frost protection through latent heat release when water turning into ice.Frost protection effects during night were tested at different irrigation application rates by monitoring air temperature around tea canopy(Tc).Temperature sensors were arranged at different distances from the sprinkler.The preliminary results showed that,when the sprinkler system worked continuously at the application rate of 2-4 mm/h before sunrise,tea canopy was covered with ice and Tc remained around 0℃,preventing tea plants from frost damage.But no more temperature rise was obviously observed at the application rates above 4 mm/h,which means less cost effectiveness.The system was stopped after sunrise when background air temperature rose back to 0℃and Tc increased by 2.2℃in one hour,while Tc of non-irrigated area increased by 4.8℃,which might cause thawing injuries to tea plants.The leaf surface temperature was lower than Tc,and the difference between the leaf surface temperature and Tc decreased with the increase of application rate.Therefore,the sprinkler irrigation system could achieve tea frost protection,and the recommended application rate was 2-4 mm/h for better protection effect.The system should keep running throughout frost night till half an hour after sunrise.The start and stop of the sprinkler irrigation system should be controlled based on Tc.

Overview of emerging technologies in sprinkler irrigation to optimize crop production

Water saving is an essential part of sprinkler irrigation owing to the impact of climate change and rising energy costs.This review highlights the technologies that are emerging in sprinkler irrigation to optimize crop production.While there have been notable advances in irrigation,the continued progress has occurred by the combination of current status with the postulation of new ideas such as conversion of high-pressure sprinkler to low-pressure ones,incorporation of smart controllers in sprinkler irrigation systems.To enhance the adoption of these technologies,research on the dispersion device is needed to improve the performance of impact sprinklers to efficiently operate at low-pressure conditions.It is also important to study how water savings estimates based on water use,irrigated area,longevity of saving,and level of wasteful irrigation prior to the retrofit obtained from field trials can be extrapolated to other areas with different conditions.Research in the development of optimized method for irrigation scheduling is necessary.This review emphasizes that the status of technologies should be considered a continuum,building on earlier knowledge and progress,and hopefully leading toward optimized crop production in sprinkler irrigated areas.

Improved sprinkler irrigation layouts for smallholders

Pressurized irrigation systems are economically justifiable for medium-to large-scale farms,while fewer choices are available for smallholders.The current research work provides additional options for small plots,as the only income source for low-income farmers in poorer countries,which produce a considerable portion of the agricultural products in some regions of the world.In this research,two novel layouts of a semipermanent sprinkler irrigation system,namely,clock hand(CH)and corner pivot(CP)lateral designs,were designed for a lighter irrigation system to lower the cost requirement.The new techniques were based on a quadrant/full circle movement pattern of manually pivoting laterals,with no/shorter main pipe requirements,which causes a higher system efficiency.These retrofitted layouts were examined in different farms with areas of 0.20 hm^(2),0.81 hm^(2),1.62 hm^(2),and 3.24 hm^(2) in Guangxi,China.This study introduced,analyzed,and compared the layouts with the widespread traditional split lateral method on technical planning,components,implementation,operation details,size optimization,performance evaluation,and economic advantages.In comparison with the traditional system,CH and CP were found to be more user-friendly and cost-effective but slightly complicated in design with higher required manual work.The results revealed a distribution uniformity(LQDU)of 81.0%to 84.0%via the catch can method,lower capital costs(35.0%-45.0%),and lower annual expenses(6.5%-9.8%)for CP and CH,respectively,compared to the split lateral method.The 0.81 hm^(2) and 1.62 hm^(2) farms were found to be the optimum farm sizes for implementation of the new methods for a 25-year project time horizon.The outcomes of this experimental work can encourage small farm owners with limited capital to apply pressurized systems for efficient irrigation and water resource sustainability.

Influence of sprinkler irrigation droplet diameter, application intensity and specific power on flower damage

To determine the main parameters of droplet strike damage and avoid flower injury due to the unsuitable practices during sprinkler irrigation, an indoor experiment of irrigation droplet impact on cyclamen was conducted.The influences of different parameters such as droplet diameter, application intensity, specific power on flower strike damage was analyzed using Image Pro-Plus software to compute strike damage area and define damage level by sense-analysis. The results showed that a damage area of < 1% represents a safe irrigation level, 1%–3% slight damage level, 3%–6% moderate damage level, and > 6%heavy damage level. Equations of application intensity,specific power with sprinkler irrigation time and flower injury ratio were regressed against parameters which cause impact damages. The results indicated that specific power has a significant correlation with injury, and flower damage area increased as the increasing of the value of specific power for the same irrigation time. Application intensity was also correlated with injury when the droplet diameter was larger than 1 mm. When the duration of sprinkler irrigation was 1, 5 and 10 min, the threshold of impinging damage of application intensity was 25.30, 5.01 and1.64 mm·h^(–1) and the specific power was 0.467×10^(–3),9.340×10^(–3) and 3.110×10^(–3)W·m^(–2). These results provide a reference for determining the suitable values of sprinkler properties in operation design.

Effects of different irrigation methods on micro-environments and root distribution in winter wheat fields

The irrigation method used in winter wheat fields affects micro-environment factors, such as relative humidity（RH） within canopy, soil temperature, topsoil bulk density, soil matric potential, and soil nutrients, and these changes may affect plant root growth.An experiment was carried out to explore the effects of irrigation method on micro-environments and root distribution in a winter wheat field in the 2007–2008 and 2008–2009 growing seasons.The results showed that border irrigation（BI）, sprinkler irrigation（SI）, and surface drip irrigation（SDI） had no significant effects on soil temperature.Topsoil bulk density, RH within the canopy, soil available N distribution, and soil matric potential were significantly affected by the three treatments.The change in soil matric potential was the key reason for the altered root profile distribution patterns.Additionally, more fine roots were produced in the BI treatment when soil water content was low and topsoil bulk density was high.Root growth was most stimulated in the top soil layers and inhibited in the deep layers in the SDI treatment, followed by SI and BI, which was due to the different water application frequencies.As a result, the root profile distribution differed, depending on the irrigation method used.The root distribution pattern changes could be described by the power level variation in the exponential function.A good knowledge of root distribution patterns is important when attempting to model water and nutrient movements and when studying soil-plant interactions.

Irrigation Water Demand Model as a Comparative Tool for Assessing Effects of Land Use Changes for Agricultural Crops in Fraser Valley, Canada

Available water for human needs and agriculture is a growing global concern. Agriculture uses approximately 70% of global freshwater, mainly for irrigation. The Lower Fraser Valley (LFV), British Columbia, is one of the most productive agricultural regions in Canada, supporting livestock production and a wide variety of crops. Water scarcity is a growing concern that threatens the long-term productivity, sustainability, and economic viability of the LFV’s agriculture. We used the BC Agriculture Water Demand Model as a tool to determine how crop choice, irrigation system, and land-use changes can affect predicted water requirements under these different conditions, which can aid stakeholders to formulate better management decisions. We conducted a comparative assessment of the irrigation water demand of seven major commercial crops, by distinct soil management groups, at nineteen representative sites, that use both sprinkler vs drip irrigation. Drip irrigation was consistently more water-efficient than sprinkler irrigation for all crops. Of the major commercial crops assessed, raspberries were the most efficient in irrigation water demand, while forage and pasture had the highest calculated irrigation water demand. Significant reductions in total irrigation water demand (up to 57%) can be made by switching irrigation systems and/or crops. This assessment can aid LFV growers in their land-use choices and could contribute to the selection of water management decisions and agricultural policies.

Responses of Nitrogen Uptake and Yield of Winter Wheat to Nonuniformity of Sprinkler Fertigation

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.

Collaborative operation and application influence of sprinkler drip irrigation:A systematic progress review

Considering the high-quality requirements related to agricultural crop production,the collaborative operation and application influence of sprinkler drip irrigation is an important issue in precision agriculture.The objective of this review is to give a comprehensive demonstration focusing on the subject of collaborative operation and application influence of sprinkler drip irrigation,by using a set of comparative analysis and literature bibliometric maps,therefore the sprinkler drip irrigation quality considering actual influential factors could be determined and analyzed.This review establishes on a broad spectrum of agricultural drip irrigation performance,throughout its whole procedure of collaborative monitoring,irrigation scheduling,application efficiency,and environmental influence,covering such aspects as soil physicochemical quality,irrigation scheduling,water resource redistribution,crop productivity,tillage management,climate adaptation,and environmental monitoring,etc.This review indicates that,the irrigation efficiency and drip infiltration quality of soil field can be planned precisely and allocated reasonably by sprinkler drip irrigation,which has extraordinary infiltration capability and enables much better performance,than that of other ordinary irrigation approaches in accuracy,stability,regularity,and efficiency.Thereafter,the investigation on the collaborative operation and application influence of sprinkler drip irrigation can be used to ensure the infiltration uniformity of moisture distribution,and then the high-quality requirements of practical irrigation performance can be met,too.This systematic review facilitates the productive soil-moisture-environment management for precision irrigation and agricultural production.

Grain-filling strategies of wheat of contrasting grain sizes under various planting patterns and irrigation levels

In a study comparing grain filling and yield in a large-and a small-grain-size wheat cultivar under two planting patterns and two irrigation regimes,plastic-covered ridge and furrow planting with sprinkler irrigation increased grain filling and yield in both cultivars.The largest contributors to grain yield were an extended active grain-filling period in Shuangda 1 and an increased mean grain-filling rate in XN538.

Optimization of movable irrigation system and performance assessment of distribution uniformity under varying conditions

The evaluation of the performance of distribution uniformity by linearly moved irrigation system(LMIS)should consider the impacts of non uniformity of the water on crop yield.With increasing pressures to improve water use efficiency,plant productivity and farm profitability,questions continue to be raised concerning the future direction of irrigated agriculture.This study therefore aimed at evaluating water distribution under LMIS newly designed by the National Research Centre of Fluid Machinery Engineering and Technology,Jiangsu University,China.This article reports the real distribution of irrigation water under the LMIS with respect to sprinkler height above the ground surface as well as the consequence of different operating pressures.Water distribution coefficients used in the performance assessment were Christiansen’s coefficient of uniformity(CU),distribution uniformity(DU),scheduling coefficients(Sc)and the coefficient of variation(CV).The results showed that the mean CU ranged from 82.30%to 93.17%,and mean DU ranged from 70.39%to 88.44%.Also Sc values ranged from 1.13 to 1.42 with CV values ranging from 10.3%to 22.5%.The optimum method and results in this study can provide a reference to the operations for saving water and cost in the application of LMIS.

Comparison of droplet distributions from fluidic and impact sprinklers

To adapt to the trend toward low-energy precision irrigation, the droplet distributions for two new prototype sprinklers, outside signal sprinkler(OS) and fluidic sprinkler(FS), were compared with impact sprinkler(IS). A laser precipitation monitor was used to measure the droplet distributions. Droplet size and velocity distributions were tested under four operating pressures for nozzles 1.5 m above the ground. For the operating pressures tested, the mean OS, FS and IS droplet diameters ranged from 0 to 3.4, 0 to 3.5, 0 to 4.0 mm, respectively.The mean OS and FS droplet velocities ranged from 0 to6.3 m$s–1, whereas IS ranged from 0 to 6.3 m$s–1. Being gas-liquid fluidic sprinklers, droplet distributions of the OS and FS were similar, although not identical. IS mostly produced a 0.5 mm larger droplet diameter and a 0.5 m$s–1greater velocity than OS and FS. A new empirical equation is proposed for determination of droplet size for OS and FS, which is sufficiently accurate and simple to use. Basic statistics for droplet size and velocity were performed on data obtained by the photographic methods. The mean droplet diameter(arithmetic, volumetric and median)decreased and the mean velocity increased in operating pressure for the three types of sprinkler.

Estimating water distribution of the rotating sprinkler with pulsating pressure on sloping land

Pulsating pressure plays an important role in improving the poor irrigation quality and the uneven water distribution caused by the terrain slope.Water distribution is one of the key factors in design of the sprinkler irrigation system,however,it is difficult to measure in practice.To provide appropriate technical parameters for the design of sprinkler irrigation system with pulsating pressure on sloping land,a mathematical model was established according to the water conservation principle and finite element idea,and its accuracy was experimentally verified.The model was applied to study the effects of terrain slope,sprinkler arrangement,sprinkler spacing and average pulsating pressure on water distribution on sloping land.The results showed that the water distribution was more favorable under the gentle terrain slope,when slope decreased from 25%to 5%,the uniformity increased from 74.47%to 86.22%.Sprinklers arranged in equilateral triangle and with the spacing close to R_(0)had the best water distribution uniformity,the uniformity coefficient(CU)of which was 11.43%and 8.75%higher than that in square and rectangular arrangement,respectively.The CU increased with the increase of the average pulsating pressure.However,the effect of increasing water pressure on promoting the uniformity of water distribution gradually decreases.Therefore,when using the Rainbird R5000 sprinkler on sloping land with pulsating pressure,it is suggested that the sprinkler irrigation systems should be arranged below the terrain slope of 20%,and operated at the average pulsating pressure of 300 kPa.The suitable sprinkler arrangement is the equilateral triangle,and with the spacing of 0.8R_(0)to 1.0R_(0).