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.     

Water-nutrient-herbicide management of potatoes with trickle irrigation

A study was designed to test the effectiveness of nitrogen and herbicide applications through soil moisture-controlled, trickle-irrigation systems, and to test the effectiveness of automatic irrigation via soil moisture control to minimize the water requirement and N-losses for high-frequency, trickle-irrigation systems. Results indicated that single or multiple applications of herbicide at recommended rates can be used effectively with trickle irrigation to control weeds in the potato row where cultivation is not possible. Nitrogen can be efficiently applied through a trickle system that features automatic soil moisture control through the use of a high-frequency irrigation schedule.     

Study on structure and function of an earthen bund irrigation system in Northeast Thailand

In Northeast Thailand, which overlaps with an erosional plain that is not suitable for irrigation because of poor water resources and terrains that prevent efficient water distribution, farmers have long supplied water to surrounding paddy fields by blocking rivers completely with earthen bunds. Although such a traditional irrigation system fits well with the characteristics of Northeast Thailand, those who are concerned with modern irrigation development projects in Northeast Thailand seem to have been paying little attention to it. The present study was performed to facilitate development of more appropriate irrigation systems in Northeast Thailand by providing information regarding traditional irrigation methods. We investigated the traditional irrigation methods with earthen bunds at three study sites, and our results indicated that styles of irrigation vary with riverbed slope. The traditional irrigation system that is used in most of Northeast Thailand is different from ordinal weir irrigation, in that paddy fields are not irrigated by gravity flow but by backwater of earthen bunds. Our results suggest that the development of more successful irrigation systems would be possible through improvement of the design ideas of traditional irrigation methods.

The Use of Saline Water in Agriculture in the Near East and North Africa Region: Present and Future

SUMMARY

Salinity is a major problem that negatively impacts agricultural activities in many regions in the world, and especially the Near East and North Africa region. Generally, salinity problems increase with increasing salt concentration in irrigation water. Crop growth reduction due to salinity is generally related to the osmotic potential of the root-zone soil solution. This will lead to certain phenological changes and substantial reduction in productivity. Salinity also affects the soil physical properties. Sewage treated wastewater is an alternative water source for irrigation. Using such wastewater will provide a new water resource to expand agricultural activities as well as reduce the environmental pollution. Each country in the region has a unique system of rules and regulations to protect the quality of water resources. Important aspects that should be taken into account when using wastewater for irrigation are discussed, including some information on the different irrigation systems used in the region, and the factors leading to success of using saline water for economic crop production. Information on the use of saline water or marginal saline soils for wheat production and improvement of irrigation systems, including old land irrigation systems, under Egyptian conditions is also presented. The regional experiences and the future prospects of using saline water for crop production that vary greatly among countries in the Near East and North Africa region are summarized. This article also presents information on special cultivation methods, such as protected agriculture and soilless culture that can help in alleviating the salinity effects. Finally, the article includes some examples on the inherited knowledge for saline agriculture that conveys the grower's experience in the Near East and North Africa region where several living examples for unique and sustainable cultivation system are still in operation. One of the most impressive cultivation techniques for bio-saline crop management in Egypt is the Edkawy production system.     

Potential of the system of rice intensification for systemic improvement in rice production and water use: the case of Andhra Pradesh, India

As opportunities to enhance the irrigation base for raising food production in the country are dwindling, India needs a more concerted effort to increase the efficiency and productivity of its irrigation systems. This study, based on an analysis of experience from the state of Andhra Pradesh, addresses the potential of the System of Rice Intensification (SRI) to contribute to systemic corrections in present paddy cultivation, both with regard to agronomic productivity and irrigation water use efficiency. This study points to the considerable increase in rice productivity and farmer incomes, which is being achieved in Andhra Pradesh with substantial reduction in irrigation water application, labor, and seed costs through utilization of SRI methods. Potential public savings on water and power costs could be drawn upon not only for promoting SRI but also to effect systemic corrections in the irrigation sector, to mutual advantage.     

移栽水稻高产高效节水灌溉技术的生理生化机理研究进展

水资源匮乏威胁水稻生产的可持续发展和粮食安全。为了应对水资源紧缺和增加粮食产量,农业科学家开发了各种节水灌溉技术和生产体系。本文综述了当前移栽水稻生产上主要应用的节水灌溉技术并从水稻生长、激素、蔗糖-淀粉代谢途径关键酶活性等方面阐述了其生理生化机制,提出水稻高产高效节水灌溉技术存在的问题与研究展望。     

Field Crop Production in Areas with Saline Soils and Shallow Saline Groundwater in the San Joaquin Valley of California

SUMMARY

Salinity in soil and water is irrevocably associated with irrigated agriculture throughout the world and as a result requires that salt management becomes an integral part of the production system. With careful water management, it is possible to sustain irrigated agriculture in areas with saline soil and saline groundwater with and without subsurface drainage. The results from two field projects conducted in an area with saline soils and saline groundwater demonstrated the type of irrigation systems and management needed to sustain production of moderately salt tolerant and tolerant crops. During the first study at Murrieta farms, yields of cotton and sugar beet were maintained using both saline and non-saline water for irrigation when pre-plant irrigation and rainfall were adequate to maintain soil salinity at a tolerable level. Wheat production was reduced in areas that used saline water for irrigation. Use of saline water containing toxic elements such as boron for irrigation poses a threat to the sustainability of the system. The second study evaluated the management of furrow and subsurface drip irrigation in the presence of shallow saline groundwater. Careful management of the furrow system during pre-plant irrigation and the first irrigation of the growing season was required to prevent waterlogging. It was possible to manage the subsurface drip system to induce significant crop water use from shallow groundwater. Rainfall and pre-plant irrigation were adequate at this site to manage soil salinity.     

Effects of tillage and irrigation on the occurrence and establishment of native wetland plant species in fallow paddy fields

Traditional weed management, such as tillage and irrigation, has led to an enhanced maintenance of wetland plant species in fallow paddy fields. Recent herbicide usage and improvements in irrigation and drainage systems however have caused habitat loss of these species, especially in fields on open lowlands. We conducted experiments in three fallow paddy fields situated on the alluvial Echigo Plain in central Japan with an aim to restore the habitat of native wetland plant species. The three experimental fields were managed under different irrigation regimes, (1) perennially flooded with water, (2) intermittent irrigation, and (3) temporary irrigation. Half the area of each experimental field was tilled before irrigation. Detrended correspondence analysis revealed obvious floristic differences between experimental and control fields with no irrigation. The proportion of wetland plant species in the experimental fields increased corresponding to the irrigation period, ranging 60–86%, and was relatively greater than that in control fields. In the experimental fields, differences in both tillage and irrigation affected the occurrence of plant species. Tillage restricted the occurrence of many non-wetland plant species, and had a positive effect on the establishment of several annual wetland plant species. In addition, a longer duration of irrigation is not necessarily suitable for the occurrence of all wetland plant species. We concluded that fallow paddy fields provide a possible habitat for the restoration of native wetland plant species through appropriate tillage and irrigation.     

A field screening technique for drought tolerance studies in potatoes

Summary A major objective of plant breeding programmes in semi-arid conditions is the selection of more drought-tolerant plant material. An irrigation system has been developed to assist in water use and drought tolerance screening studies of potato genotypes in the confined space of a rain shelter. The line-source principle was used as a departure point for the design of an irrigation boom, attached to the roof structure of a rain shelter. Five water regimes were achieved by using nozzles that differed in discharge rate and three genotypes per rain shelter were evaluated simultaneously. Crop production functions could be established for the different genotypes. The system shares some disadvantages of the typical line-source, such as the simultaneous irrigation of all plots and water treatments are not randomised. The main advantage above traditional plot systems, which would use drip or micro irrigation under rain shelters, is the ease of management.     

Evaluation of infiltration models and field-saturated hydraulic conductivity in situ infiltration tests during the dry season

Paddy and Water Environment - Field-saturated hydraulic conductivity (Kfs) is an important parameter used to estimate field water requirements in irrigation systems, although it is widely...     

Crop response to biochar under differing irrigation levels in the southeastern USA

Application of biochar to soils is hypothesized to increase crop yield. Crop productivity impacts of biochar application in southeastern cropping systems consisting of peanut (Arachis hypogaea L.), corn (Zea mays L.), and cotton (Gossypium hirsutum L.) produced under varying rates of irrigation have not been addressed. This research incorporated biochar at two different rates into a long-term irrigation and cropping systems study to compare yield and quality response of peanut, corn, and cotton. Biochar was incorporated into soil once at the beginning of the 4-year project at rates of 22.4 and 44.8 Mg ha^?1. Peanut, corn, and cotton were produced under three sprinkler irrigation levels (100%, 66%, and 33%), shallow surface drip irrigation (100%), and a nonirrigated control. Crop input management followed best management practices. Sprinkler irrigation was scheduled by Irrigator Pro for Peanuts, Corn, and Cotton at the 100% level and the 66% and 33% levels were applied at the same time as the 100% level. Significant year, irrigation, and year × irrigation effects for corn, cotton, and peanut yield resulted (p < 0.001). No differences resulted for biochar in corn (p = 0.930) or cotton (p = 0.678). Peanut yield showed a significant response to biochar comparing the 44.8 Mg ha^?1 rate to the untreated control in nonirrigated production at the p = 0.05 level and in the 33% irrigated treatment at the p = 0.10 level. No negative effects resulted from biochar opening opportunities for biochar application in southeastern U.S. cropping systems for purposes related to carbon sequestration without compromising productivity of producers and related agricultural sectors.     

High-yield irrigated maize in the Western U.S. Corn Belt: II. Irrigation management and crop water productivity

Appropriate benchmarks for water productivity (WP), defined here as the amount of grain yield produced per unit of water supply, are needed to help identify and diagnose inefficiencies in crop production and water management in irrigated systems. Such analysis is lacking for maize in the Western U.S. Corn Belt where irrigated production represents 58% of total maize output. The objective of this paper was to quantify WP and identify opportunities to increase it in irrigated maize systems of central Nebraska. In the present study, a benchmark for maize WP was (i) developed from relationships between simulated yield and seasonal water supply (stored soil water and sowing-to-maturity rainfall plus irrigation) documented in a previous study; (ii) validated against actual data from crops grown with good management over a wide range of environments and water supply regimes (n = 123); and (iii) used to evaluate WP of farmer's fields in central Nebraska using a 3-y database (2005–2007) that included field-specific values for yield and applied irrigation (n = 777). The database was also used to quantify applied irrigation, irrigation water-use efficiency (IWUE; amount of yield produced per unit of applied irrigation), and the impact of agronomic practices on both parameters. Opportunities to improve irrigation management were evaluated using a maize simulation model in combination with actual weather records and detailed data on soil properties and crop management collected from a subset of fields (n = 123). The linear function derived from the relationship between simulated grain yield and seasonal water supply, namely the mean WP function (slope = 19.3 kg ha⁻¹ mm⁻¹; x-intercept = 100 mm), proved to be a robust benchmark for maize WP when compared with actual yield and water supply data. Average farmer's WP in central Nebraska was ∼73% of the WP derived from the slope of the mean WP function. A substantial number of fields (55% of total) had water supply in excess of that required to achieve yield potential (900 mm). Pivot irrigation (instead of surface irrigation) and conservation tillage in fields under soybean–maize rotation had the greatest IWUE and yield. Applied irrigation was 41 and 20% less under pivot and conservation tillage than under surface irrigation and conventional tillage, respectively. Simulation analysis showed that up to 32% of the annual water volume allocated to irrigated maize in the region could be saved with little yield penalty, by switching current surface systems to pivot, improving irrigation schedules to be more synchronous with crop water requirements and, as a fine-tune option, adopting limited irrigation.     

Factors affecting irrigation water savings in raised beds in rice and wheat

Raised beds have been proposed for rice–wheat (RW) cropping systems in the Indo-Gangetic Plains as a means of increasing irrigation water productivity, among many other potential benefits. Field experiments were carried out in Punjab, India, during 2002–2006 to compare irrigation water use and productivity of transplanted rice and drill-sown wheat on fresh and permanent beds and conventionally tilled flats.     

Assessment of irrigation practices at the tertiary canal level in an improved system—a case study of Wasat area, the Nile Delta

Egypt faces great challenges due to its limited water resources by enforcement policies to improve the performance of the existing delivery system and its development. The improvement of irrigation systems in the Nile Delta is one of the most important attempts in Egypt to implement more effective irrigation technologies. This study was carried out to evaluate improved tertiary canal level and farmers’ practices by comparing with other unimproved systems to understand the farmers’ practices in their farms after modifying the existing irrigation system. This study area applied to the Wasat command area’s most commonly used to the cultivation of a paddy field in Egypt, which contributes 40 % of production. The overall results indicate that the water-use application at the improved system level improved. This was due to the role of water user association in the successful management and operation of the water-supply system on the private level of water distribution network. So, water users’ association has the positive effect on managing of the improved tertiary canal. Although, there are main problems of water delivery in the irrigation networks that was a water shortage in the main canal owing to its location at the tail of the feeder canal system in the Nile Delta, and other reasons include the absence of crop production planning by farmers, especially rice farmers in summer, and the greater demand of some fields than supply.     

Climate change’s impact on irrigation system and farmers’ response: a case study of the Plaichumpol Irrigation Project,Phitsanulok Province,Thailand

The Plaichumpol Irrigation Project, in Nan Basin of Thailand, is selected as a case study of impact study, where farmers depended on both surface and groundwater sources (especially in the dry year), to assess the impact on irrigation systems. The study used the MRI-GCM data to project the future climate condition and assess the impact on irrigation systems focusing on water shortage and groundwater pumping aspects in the selected consecutive dry years. The responses from farmers on the impact and adaptation were also gathered via site interviews and analyzed. Based on the bias-corrected MRI-GCM data, the annual rainfall in Nan Basin will decrease in the near future (2015–2039), compared with the past average data (1979–2006), while the rainfall will increase in the far future (2075–2099) compared with past. Water supply from dam will decrease in wet season and dry season, while water demand in both of near future and far future will increase in wet season and dry season. Less water shortage and groundwater pumping in both near-future and far-future periods are expected in the future consecutive dry years compared with the past, though the groundwater is still an important supplementary irrigation water source in the dry year. From the field interview, the farmers are ready to adapt to the changing situations and join in the water use meeting to follow up with irrigation officers about the adjustment of plant calendar and water allocation due to the climate change and to prepare adaptation measures as necessary.     

Assessment and water saving issues for Ningxia paddies,upper Yellow River Basin

In the Hetao Irrigation Districts of the Ningxia autonomous region, Upper Yellow River Basin, the continuous deep flooding irrigation method is used for the rice paddies. The field irrigation water use during the rice-growing season is two to three times higher than in other regions of North China where water-saving practices have been introduced. This paper, based on the data measured in experimental rice fields and sub-branch canal systems, presents main results concerning crop evapotranspiration, percolation and irrigation requirements for deep and shallow water irrigation. Causes for water waste relate to both the lack of regulation in supply and distribution canals and to the poor management of paddy fields. The potential for water saving is discussed using water balance data. Improved irrigation techniques and water management strategies, including the shallow water irrigation method, are suggested considering the expected impacts and benefits. Replacing the current continuous deep flooding with the shallow-ponded water irrigation method may reduce the growing season irrigation water use from 1,405 to 820 mm in average, with a likely increase in yields of 450 kg/ha. Water productivity would then increase from 0.49 to 1.03 kg/m³. Adopting improved canal management and modernization of regulation and control structures may lead to decreasing the gross irrigation demand from the present 3,100 mm to about 1,280 mm, which would highly benefit the environmental conditions in the area.     

花生喷水灌溉技术的研究

山东省花生１１００万亩，尚有７０％无灌溉条件。多数地处低山丘陵区，干旱是山东省花生生产的主要制约因素．通过研究明确，亩产２５０－４５０公斤中熟大花生需水量为４８０－８００毫米。经过需水量与亩产等方面相关分析，得出各阶段需水率和需水强度、花生各发育期土壤水分适宜范围，提出花生适宜灌溉方式以移动式喷灌磁化水为好，并提出花生喷灌工程规划设计基本参数。以及提供配套工程及技术要点。     

An institutional case study of Japanese Water Users Association: towards successful participatory irrigation management

This paper examines irrigation management conduct within the Japanese Water Users Association (WUA), namely the Land Improvement District (LID). LID is regarded as a successful case of participatory irrigation management (PIM), in which there are few conflicts over water between farmers so that it attains high social cost performance. However, the management system of LID still remains obscure. We throw light on this system assuming the existence of "the rule of fairness". Farmers operate the irrigation facilities in a self-serving way and have their own rule of fairness, such as upstream superiority, based on the long-term experiences of irrigation systems. We defined this rule of fairness as made up of two components: one is "fairness of outcome" and the other is "fairness of procedure". Finally, we discovered that the approach of LID staff is the essential factor to satisfying the farmers' criteria of fairness and maintaining peace; LID staff place importance on farmers' customary rules, taking care to remain neutral in arbitrating quarrels between farmers and trying to ensure organizational transparency to farmers. This can be also a good lesson for future PIM projects.     

On-farm irrigation development and management in lower Myanmar: factors for sustainable rice production and collective action

The case study is aimed at assessing impacts of on-farm level irrigation development and management on dry season rice production in the main irrigated rice production area of Myanmar. The study was carried out from 2003 to 2009 in the middle reaches of the Ngameoeyeik irrigation area of 28,000 ha. In addition to collecting information on water management and institutional arrangement of the study area, hydrologic and agronomic parameters were monitored during the study period. Results showed the effectiveness of on-farm level infrastructural development for increasing rice productivity owing to increased amount of water delivery, increased flexibility of water distribution, and improved drainage conditions. Besides, encouraging the involvement of farmers in design and implementation of the development led to improved farmer participation in the operation and maintenance of the irrigation system. The outcomes of this study demonstrated the importance of balancing between infrastructural and institutional development in irrigation systems of Southeast Asia. Such infrastructural development should be in close association with institutional development and capacity building, and the interactions between those two aspects should be well understood.     

Climate change’s impact on irrigation system and farmers’ response: a case study of the Plaichumpol Irrigation Project,Phitsanulok Province,Thailand

The Plaichumpol Irrigation Project, in Nan Basin of Thailand, is selected as a case study of impact study, where farmers depended on both surface and groundwater sources (especially in the dry year), to assess the impact on irrigation systems. The study used the MRI-GCM data to project the future climate condition and assess the impact on irrigation systems focusing on water shortage and groundwater pumping aspects in the selected consecutive dry years. The responses from farmers on the impact and adaptation were also gathered via site interviews and analyzed. Based on the bias-corrected MRI-GCM data, the annual rainfall in Nan Basin will decrease in the near future (2015–2039), compared with the past average data (1979–2006), while the rainfall will increase in the far future (2075–2099) compared with past. Water supply from dam will decrease in wet season and dry season, while water demand in both of near future and far future will increase in wet season and dry season. Less water shortage and groundwater pumping in both near-future and far-future periods are expected in the future consecutive dry years compared with the past, though the groundwater is still an important supplementary irrigation water source in the dry year. From the field interview, the farmers are ready to adapt to the changing situations and join in the water use meeting to follow up with irrigation officers about the adjustment of plant calendar and water allocation due to the climate change and to prepare adaptation measures as necessary.