Irrigation and Drainage最新文献

A 2-year field experiment was conducted on drip-irrigated olive oil orchards (Coratina var.) on a private farm in the newly reclaimed sandy soil of the West Nile Delta region, Egypt, during the 2020 and 2021 seasons to evaluate the effect of five irrigation treatments (120%, 100%, 80% and 60% reference crop evapotranspiration [ETo] and farmer practice) on applied irrigation water (AIW), water consumptive use, olive fruit and oil yields and some fruit quality parameters, water use efficiency, water productivity, electric energy consumed, farm income and benefit–cost ratio and to develop local crop coefficients (K_c) and yield response factors (K_y). The results indicated that the 2-year average AIW values were 9953 (17.9 m³/tree/year), 8484 (15.3 m³/tree/year), 6971 (12.5 m³/tree/year), 5480 (9.9 m³/tree/year) and 17,488 m³/ha (31.5 m³/tree/year) for the tested irrigation treatments. Olive fruit and oil yields and quality parameters were significantly affected by the tested treatments. The highest fruit and oil yields were recorded for the 120% ETo treatment. A seasonal K_c of 0.75 and a seasonal K_y of 0.83 were obtained. It can be concluded that producing oil from olive trees (Coratina var.) in sandy soils can be achieved by applying amounts of water equal to 80% or 60% ETo.

Soil salinity and sodicity problems are one of the major challenges to the permanence of irrigated agriculture in Ethiopia. This manuscript, therefore, concerns its spatial and temporal variation under irrigated fields and suggests possible management options. For this investigation, eight monitoring locations were selected based on the irrigation intensity that farmers practised in the area. With each location, three irrigated farmers' fields were randomly selected for sampling purposes. Likewise, six farmers' fields from the rain-fed system were also selected for comparison purposes. Sampling was performed at the beginning and end of each cropping season for three consecutive years from 2017 to 2019. The major physical and chemical properties of the soil were analysed in accordance with standard laboratory procedures. A linear model of two-way analysis of variance was used to analyse parameters across time and space. The results indicated that the majority of the soil properties studied showed significant differences (p < 0.05) over time. This implies that the change is in accordance with the seasonal soil property, possibly due to irrigation practices. Similarly, approximately 90% of the soil properties studied showed noticeable differences (p < 0.05) across locations. Almost all salinity indicators showed an increasing trend in irrigated fields compared to their situation in rain-fed fields. For instance, the electrical conductivity (EC) and exchangeable sodium percentage (ESP) values across the fields ranged from 0.54 to 0.82 dS m⁻¹ and 8–1%, respectively, with maximum values observed in irrigated fields. This implies that irrigation practices influence soil properties in the area. In addition, the ESP values approaching the maximum permissible limit suggest that sodicity may cause more problems than salinity in the area. Therefore, agronomic practices (e.g. residue management, deep tillage, salt-tolerant crops and periodic fallowing), irrigation and drainage management practices, and amendments may help farmers mitigate salinity and sodicity problems in the area.

To improve the hydraulic performance of leaf vein drip irrigation emitters, a combination of a genetic algorithm and numerical simulation was used to investigate the hydraulic characteristics of the model. The minimal flow index is used as the optimization objective to obtain the best design parameters for the flow channel structure. The results show that the leaf vein drip irrigation emitter has a flow index of 0.53, and the structural loss coefficient of the leaf vein drip irrigation emitter is 64.5–70.9 under 50 kPa working pressure, with a good energy dissipation effect. Among the design variables, the flow index (denoted as x) was influenced in the following order: the width of the unit structure f had the largest impact, followed by the vertical distance from the front baffle c, the inlet width a and the length of the unit structure h. The flow index x exhibited a positive correlation with the inlet width a, the vertical distance from the front baffle c and the length of the unit structure h, while it displayed a negative correlation with the width of the unit structure f. The correlation coefficient between the simulated and measured results was 0.994, with an average error of 2%, and the accuracy of the simulation results was high. Notably, the absence of noticeable low-velocity vortices at the corners and confluence of the leaf vein flow channel indicated excellent resistance to blockage.

In semi-arid Central Namibia, poor sandy soils limit sustainable crop production. We assessed cabbage performance in two split-plot field experiments. In Experiment 1, treatments comprised two irrigation levels: full irrigation (watered 3 days a week) and reduced irrigation (watered 2 days a week) as the main plot factor and six soil amendments (biochar; compost; zeolite; nitrogen, phosphorus potassium [NPK]; Be-Grow boost [L] hydrogel; and hoof and horn + bone [HHB] meal) as subplot factors in three replications. Full irrigation produced a significantly higher yield (21.1 t ha⁻¹), head weight (0.958 kg) and larger head girths (42.1 cm). Biochar produced the highest marketable heads (24,884 heads ha⁻¹), water use efficiency (76.0 kg ha⁻¹ mm⁻¹) and the largest head girths (42.7 cm). In Experiment 2, water was applied 5 and 4 days a week for full and reduced irrigation; the application rates of compost, HHB meal, Be-Grow boost (L) hydrogel and NPK were modified. The interaction of Be-Grow boost (L) hydrogel, NPK and biochar with full irrigation and HHB meal with reduced irrigation produced more marketable heads (28,935, 28,009, 27,546 and 28,703 heads ha⁻¹, respectively). Therefore, full irrigation with these amendments could be used for resilient cabbage production in Central Namibia.

Deficit irrigation (DI) could be an important strategy to achieve the goal of reducing irrigation water consumption. This review aims to identify the impact of different DI strategies on grain yield, water use efficiency (WUE) and oil and protein content in soybean seeds. A total of 25 articles were considered and then divided into DI throughout the whole cycle (standard deficit irrigation, StDI) and DI only at certain stages of the cycle (regulated deficit irrigation, RDI). In StDI, yield reductions were approximately 20% when the replacement of the crop water requirement was between 70% and 90%. For RDI, yield reductions ranging from 9% to 30% were observed depending on the phenological stage at which the crop evapotranspiration (ET_c) deficit was imposed. StDI always increased WUE compared to full irrigation, whereas for RDI, the response in terms of WUE changed considering the stressed phenological stage. Few studies have reported the effects on oil and protein content, showing high variability and contrasting results. In general, the application of a reduced amount of water led to a decrease in yield and an increase in WUE, with a magnitude significantly influenced by the stage at which the stress was imposed.

Groundwater is an essential nonrenewable resource for agricultural activities. In this study, groundwater samples were collected from the Shouguang area, and the level of groundwater contamination was investigated by measuring the NO₃⁻, SO₄²⁻, F⁻, Cl⁻, Ca²⁺, Mg²⁺, total dissolved solids (TDS) and chemical oxygen demand (COD). Exploratory data analysis was employed initially to study the hydrochemical characteristics and the sources of pollutants. Finally, the groundwater quality was measured using principal component analysis, entropy weight and complex correlation coefficient methods. As a common observation, the groundwater in the Shouguang area is slightly alkaline, so Ca²⁺, Mg²⁺ and NO₃⁻ acted as predominant pollutants. These contaminants originated from the excessive use of chemical fertilizers and large-scale sewage irrigation. Second, perennial overexploitation of groundwater in Shouguang led to the generation of funnels and led to seawater intrusion. As a result, Cl⁻ and TDS in the water samples collected from the north Shouguang area exceeded the regulatory guideline value, which indicates the risk of land salinization. However, the measured concentrations of SO₄²⁻, F⁻ and COD were within the normal range. This confirms the minimal contribution of industries to groundwater pollution. East of the Ni River the groundwater is severely polluted, and the detected concentrations of pollutants are far beyond the standard limit and pose a potential risk to human health. Therefore, protection and treatment are urgently needed.

The primary source of water for irrigation and other agricultural activities is rainfall. It has an immediate effect on crop growth and productivity. Forecasting this rainfall in advance allows farmers to effectively plan their cropping pattern. In recent years, forecasting rainfall has become very popular due to the availability of the latest computation techniques. Artificial neural networks (ANNs) are one such technique widely used for rainfall prediction by a number of researchers. These models are more reliable as they make better predictions because of their nonlinear data learning method. In the present study, an ANN model was developed to predict the annual, monsoon and postmonsoon season rainfall. The model was developed using 34 years of data from 1985 to 2018 in the command area of the Loktak Lift Irrigation Project in Manipur, India. The ANN model was trained using the rectified linear unit (ReLU) activation function. The 3-year input model excelled in all seasons, with the best model achieving a 0.36 coefficient of determination (R²), 75.7 root mean square error, 0.60 correlation coefficient and 62.5 mean absolute error. These performance indicators were comparable with studies performed by other researchers. Thus, the model can be adopted for the study area.

High evapotranspiration and low precipitation are known as the main challenging factors for pistachio (Pistacia vera L.) orchards situated in arid and semi-arid regions. Therefore, it is necessary to take some measures to mitigate surface evaporation. This study was carried out to assess water productivity (WP) as well as yield and annual shoot growth of pistachios using a new method of irrigation known as the stratified vertical gravel tube subsurface drip irrigation (SVGTSD) system in a 15-year-old pistachio orchard in an arid region in Iran. In this system, each tree contained four vertical gravel columns with different lengths. A randomized complete block design with a split-plot arrangement with three replicates (five trees in each plot) for 3 years was used. Three irrigation regimes included 100% crop evapotranspiration (100% ET_c), 85% ET_c and 70% ET_c (as the main plots), and seven vertical gravel column with a depth arrangement of 40–40–40–40 cm (using a gravel column from the lateral pipe level and without a gravel tube as the control) and gravel-filled tubes with depths of 10–10–10–10 cm, 10–10–20–20 cm, 10–10–30–30 cm, 10–10–20–30 cm, 10–10–20–40 cm and 10–10–20–50 cm (all 30 cm below ground level) (as subplots) were used. The results showed that the different depths of gravel tube placement significantly affected the annual shoot growth and yield. The deeper the tube was placed, the greater the yield and annual shoot growth, resulting in 10–10–20–50 cm being the most productive. Regarding tree growth, yield and WP, the best performance was observed at full irrigation (100% ET_c) with a 10–10–20–50-cm vertical gravel tube arrangement. Furthermore, in this subsurface irrigation method, there was no concern regarding emitter clogging by roots, root accumulation around the emitters or root intrusion into the emitters. In addition, having a low additional cost (only 13.9%) in comparison with conventional subsurface drip irrigation together with a higher yield (3475 kg ha⁻¹), WP (0.9 kg m⁻³) and shoot growth (35 cm), SVGTSD is more economical and feasible compared to other irrigation methods and can be extensively applied in pistachio orchards.