Irrigation and Drainage最新文献

In irrigation systems, water–fertilizer mixing within pipelines profoundly affects the fertilization process and strategy development. Taking irrigation machine pipelines as the research object, a numerical simulation method is used to investigate the mixing and distribution patterns of water and fertilizer in pipelines under a steady oscillatory flow fertilization mode with different injection positions, angles, flow rates (Q) and fertilization ratios (δ). Increasing the flow rate initially increased the fertilizer concentration in the lateral pipes, but further increasing the mainline central injection flow rate significantly reduced the concentration in the lateral pipes. For δ = 2%, elevating Q from 6 to 8 m³/h increased the average fertilizer concentration in the lateral pipes by 0.4%. However, a subsequent increase to Q = 10 m³/h led to a 1% decrease. In left-side injection, lateral pipes on the same side as the injection pipe had considerably higher concentrations than those on the opposite side. In central injection, larger inclination angles increase the lateral pipe fertilizer concentration, while in left-side injection, 60°-downward injection results in the best lateral pipe fertilizer concentration. The above-mentioned results can provide valuable insights for the design of injection ports on lateral-move sprinkler irrigation systems.

Climate change poses a significant threat to global food security, and a comprehensive understanding of its impact on agricultural production is needed. We analysed the Scopus data set between 1993 and 2023. China occupies the leading position in terms of climate change production, and the United States occupies the comprehensive strength position with the largest citation strength output. Notably, a substantial 29% annual publication increase between 2000 and 2015 was noted. Despite prevailing research on specific facets, a pronounced gap exists in global-scale studies focusing on the direct impact of climate change on agricultural production and yield, with a predominant concentration in regional analyses. Collaboration in this area continues to occur within developed nations, but the rate of growth at the international level is relatively low. In addition, the frequency of co-occurrence analysis of keywords revealed that climate change and sustainability are the focal keywords, but yield, food security, irrigation and rice production have yet to be identified. The results of this research will help in designing a policy for water resource management for irrigation planning and an adaptative food security management strategy and provide a feature research guide.

In recent years, traditional sprinkler irrigation scheduling scenarios have no longer been applicable to modern agriculture because of the increase in energy prices and the rapid development of smart agriculture. This paper proposes a new irrigation scheduling scenario in which a sprinkler is used as the minimum optimization unit for sectoring design. The main challenge of the proposed approach lies in obtaining the most energy-efficient sectoring and pump operating frequencies, and the high complexity of the optimization problem requires considerable computational effort. To compare the irrigation performance before and after optimization, seven scheduling scenarios are established to analyse the performance of the unified control method, branch scheduling method and sprinkler scheduling method. Through numerical calculations and experimental verification, it was found that sprinkler scheduling can not only meet the pressure requirements of sprinklers without using pressure-regulating valves but also minimize energy consumption. Compared with optimal branch pipe scheduling, optimal sprinkler scheduling can reduce the sprinkler pressure variance from 792 to 180 kPa² and reduce the irrigation cost by approximately 18%. In addition, by analysing the uniformity coefficient and distribution uniformity under different scenarios, it was found that sprinkler scheduling optimization does not substantially improve irrigation uniformity.

As a new type of underground water-saving irrigation method, moistube irrigation has great potential for promotion and development. However, the multi-factor interaction influence and water infiltration prediction model of soil water infiltration under moistube irrigation need to be improved. This paper aims to obtain soil water infiltration data for different bulk densities (1.2, 1.3 and 1.4 g/cm³) and textures (loam, sandy loam and clay loam) under different pressure heads (1, 1.5 and 2 m) through an indoor moistube irrigation soil water infiltration test. By analysing multiple factors affecting soil water infiltration under moistube irrigation, the calculation method was determined with the initial soil moisture content, pressure head, bulk density and texture as the input variables and the Kostiakov model parameters as the output variables. Finally, the method of optimizing the back propagation (BP) neural network by a genetic algorithm (GA) was used to establish the Kostiakov prediction model of soil moisture in moistube irrigation, and the model was verified with analytics. The results showed that the Kostiakov prediction model based on GA-BP had high accuracy and good consistency. The research results provide more practical proofs and perfect theoretical supplements for the study of soil water infiltration under moistube irrigation.

It is necessary to use different planning models, including decision support systems (DSSs), to allocate water resources. For this purpose, in this study, an irrigation decision support system (IDSS) was developed to improve irrigation management in the farming fields of Mahabad Plain located to the south-east of Lake Urmia. Next, the compatibility of the IDSS with the conditions of the Mahabad irrigation and drainage network, water and soil resources, meteorological data and soil moisture (SM) were investigated. The statistical indices of coefficient of determination (R²), root mean square error (RMSE), normalized root mean square error (NRMSE), Nash–Sutcliffe efficiency (EF) and Wilmot agreement (d) were used to evaluate the adaptability of the IDSS. The results showed that the IDSS has reasonable compatibility with soil and water resources, crop yield and meteorological data. Irrigation scheduling provided by the IDSS led to a 13.9% reduction in water consumption and a 6.7% increase in crop yield. The IDSS estimated minimum and maximum temperature and sunshine hours to a satisfactory degree and relative humidity with an acceptable degree (NRMSE = 0.72–0.77) compared to regional synoptic station data. The performance of the IDSS in simulating SM is ranked from good to well (NRMSE = 0.75–0.83). The results indicate that the IDSS has a sufficient performance in estimating meteorological and soil moisture data with R² = 0.90, RMSE = 4.65, NRMSE = 0.78, EF = 0.76 and d = 0.80. In addition, the IDSS provides the optimal irrigation schedule by considering the ability to deliver water from the irrigation and drainage network to the third-grade canal and agricultural fields as the upstream condition.

Straw mulch has been widely used to inhibit soil evaporation in semi-arid regions, but little attention has been given to exploring optimal straw mulch thicknesses for suppressing soil evaporation under different meteorological conditions in seasonally frozen soil regions. By combining field observations and numerical modelling, the optimal straw mulch thickness for inhibiting soil evaporation under different meteorological conditions was determined. Field experiments indicated that the cumulative soil evaporation associated with straw mulch thicknesses of 1–3 cm was 40%, 53% and 65% lower than that of bare land during freeze–thaw cycles. Compared with that of bare fields, the cumulative soil evaporation simulated by SHAW (simultaneous heat and water) decreased from 9% to 82% and from 36% to 88% during the 2017–2018 and 2018–2019 periods, respectively, when the straw mulch thickness ranged from 1 to 20 cm. The cumulative soil evaporation tended to stabilize until the straw mulch thickness reached 14.3 cm under weather conditions with low humidity, high wind speed and sunshine and 14.5 cm under weather conditions with high or moderate humidity, low or moderate wind speed and sunshine from 1987 to 2017. The results have implications for reducing nonproductive soil evaporation and improving agricultural water management in seasonally frozen regions.

I.R. Iran, with 8.8 million ha of irrigated area, is fifth in the world with respect to irrigated land. Scarcity of water resources and great difficulty with water accessibility have brought about initiatives of technology building, as well as approaches to agricultural water management by local communities. During recent decades a huge public budget has been invested in order to improve irrigation services. Improving performance of irrigation systems needs proper diagnosis of the problems and a systematic approach towards modernization. Also having been recently developed and modernized, adjustment of the laws and regulations of the water sector has caused management frameworks of irrigation networks to be gradually improved. In general, in addition to the management framework, equipping with modern tools for measuring water flow and applying tools such as geographic information systems and databases have led to the improvement of water distribution and management. Technical, managerial and policies programmes, as well as investment in water resources and irrigation infrastructures in addition to training and education of farmers and field engineers in water saving in agriculture and enhancing water productivity, resulted in positive impacts on better management of limited fresh water in irrigation.

The suitability of a given water source for irrigation warrants the diagnosis of potential salinity, sodicity and toxicity hazards. Region-specific irrigation water quality standards and guidelines formulated worldwide are too conservative. After a comprehensive assessment of newer insights from re-analysis of the available data and examination of the associated evidence covering diversified conditions of saline water use, existing guidelines are updated to adjust for site-specific conditions. The updated versions for rating both saline and alkali waters include the chemical composition of irrigation waters, soil type (texture, clay mineralogy), salt tolerance rating of crops and rainfall for broader adaptability. As modified by soil texture and rainfall, crop salt tolerance is the decisive factor for fixing upper salinity limits in hyper-arid, arid, semi-arid and semi-humid regions. The customized recommendations include conjunctive use, leaching/rainfall management, irrigation methods, ionic ratios, fertilizers and manures. Guidelines for sodic/alkali waters are based on both crop responses and sodicity-induced water infiltration problems. The amendment requirements stand defined. In view of the increasing water scarcity, the established guidelines are expected to promote saline and alkali water irrigation in arid and semi-arid regions while safeguarding the environment.

Irrigation development has been taking place for centuries in India. Considerable areas of fertile land under irrigated agriculture have gone out of production due to waterlogging and salt-related problems. The provision of drains was deferred or postponed in several projects due to shortage of funds during the initial stages. Because of this fact, the productivity of water (t ha⁻¹ mm⁻¹) in India still remains very low. The main reason for the low yields is improper water management, especially lack of drainage in irrigated command areas. There are vast areas in the country urgently requiring drainage works and the present governmental resources are not adequate to cope with the growing demand. Promotion of the private sector in reclamation work and installation of subsurface drains at local level needs encouragement. All these issues together with the research activities inclusive of drainage materials undertaken by different organizations are critically described and discussed in this paper.