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Guar is a typical legume cash crop native to India. Guar beans are ever-rising in the market share at present. Among them, the guar gum of its seed endosperm has been mainly used in the oil exploration industry. Water-based fracturing fluid can be formulated to increase the permeability of oil-bearing strata during oil production. In addition, guar gum is also widely used in paper making, textiles, food, spices, drugs, as well as mining and metallurgical industries. The nutrient-rich green seeds of guar beans are edible for food vegetables, due to a large amount of protein and a small amount of fat. The plant can be used as fodder and green manure. However, the low supply of guar gum on the market cannot fully meet the broad market space. Only a small number of planting areas of guar beans are suitable for the cultivation of guar beans in the food industry. Among them, Xinjiang located in the northwestern inland arid zone is very similar to the unique geographic conditions for the production and cultivation of guar beans. The temperature and heat conditions are suitable for the origin of guar, rich in the light and heat resources under the soil and water environment, with the high temperature difference between day and night, due to the scarce rainfall and high evaporation. But the relatively small region of guar bean planting still remains so far. Therefore a broad prospect can be expected to optimize the water and nitrogen management for the high crop yield and efficient use of water and nitrogen. This study aims to explore the water and nitrogen mode suitable for drip irrigation of guar beans under film in the Xinjiang area of China. Four irrigation levels were set: W1:1170 m³/hm², W2:1 530 m³/hm², W3:1 890 m³/hm², W4: 2 250 m³/hm²; Two levels of nitrogen application were: N1:30 kg/hm², N2:50 kg/hm². A systematic investigation was made to clarify the effects of water and nitrogen interaction on the growth index, yield, water, and nitrogen use efficiency, as well as the quality of guar bean during drip irrigation under film. The results showed that the coupling effect of water and nitrogen shared a significant effect on the yield, irrigation water use efficiency, and partial factor productivity of nitrogen fertilizer (W3>W4>W2>W1). There was an increase in the plant height, stem diameter, dry matter accumulation, yield, water use efficiency, galactomannan, soluble sugar, and polysaccharide content of Guar bean under the N2 level, compared with the N1 level. Only the partial productivity of nitrogen fertilizer decreased slightly. Principal component and membership function analysis showed that the optimal treatment was achieved in the irrigation amount of 1 890 m³/hm² and the nitrogen application rate of 50 kg/hm²(W3N2). The finding can also provide a theoretical basis to promote the yield, water, and nitrogen use efficiency of Guar bean under mulched drip irrigation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Agricultural Outlook (1673-3908) is the property of Institute of Agricultural Information, Chinese Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Background] The problem of agricultural drought has always restricted the sustainable development of agriculture in Yulin area of Northern Shaanxi. In the process of water resources development and utilization, the contradiction between industrial and agricultural production, life and ecology is becoming more and more obvious, and the gap between supply and demand of agricultural water resources continues to increase, which seriously affects the high and stable yield of spring maize. Yulin in northern Shaanxi is located in the central and northern part of the Loess Plateau. It is located in the arid and semi-arid climate zone with sufficient light resources. It is a eugenic and high-yield area of spring maize in China. The field irrigation of spring maize in this area is mainly drip irrigation. [Objective]In order to determine the suitable soil moisture limit of drip irrigation spring maize in Yulin of northern Shaanxi, the irrigation system of drip irrigation spring maize in this area was obtained. [Method] In this study, orthogonal test design method was used to set up four irrigation levels in five growth stages of spring maize, including seedling stage, jointing stage, tasseling stage, filling stage and maturity stage, to explore the effects of different irrigation schemes on the growth and water use efficiency of drip-irrigated spring maize. [Result] The results showed that: (1) The key growth stages of spring maize were jointing stage and tasseling stage, and the seedling stage, filling stage and maturity stage were non-critical stages. Appropriate reduction of irrigation level at jointing stage and tasseling stage is more conducive to the subsequent growth and development of spring maize. (2) Based on the effects of different irrigation schemes on plant height, stem diameter, leaf area index and yield of spring maize, the optimal field soil moisture control limit is: the suitable soil moisture limit at seedling stage is 59%-79%FC (FC represents soil field water holding capacity), 70%-90%FC at jointing stage, 68%-88%FC at tasseling stage, 56%-76%FC at filling stage, and 49%-69%FC at maturity stage. [Conclusion] The optimal irrigation system is irrigation 9 times in the whole growth period, namely 2 times in the seedling stage (m=20 mm), 3 times in the jointing stage (m1=20 mm, m2,3=30 mm), 3 times in the tasseling stage (m=30 mm), 1 time in the filling stage (m=25 mm), no irrigation in the mature stage, and the comprehensive irrigation quota is 235 mm. Under this system, the yield of spring maize was 14 664 kg/hm², and the water use efficiency was 3.01 kg/m³. Compared with the control group, the yield increased by 15.56% and WUE increased by 19.19%. The results of this study have important guiding significance for the field management of drip irrigation spring maize in Yulin, Northern Shaanxi. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Northwest A & F University - Natural Science Edition is the property of Editorial Department of Journal of Northwest A&F University (Natural Science Edition) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Methane is a powerful greenhouse gas with a global warming potential 34 times greater than carbon dioxide. The emitter flow rate, as a fundamental parameter of drip irrigation systems, controls the horizontal and vertical distribution of soil water, resulting in distinct soil wetting patterns. At the same time, the soil wetting pattern influences soil temperature, aeration, and the movement and transformation of nitrogen, all of which affect soil microbial activity and consequently methane uptake. Understanding the role of the emitter flow rate of drip irrigation in regulating the diffusion, oxidation and surface uptake of methane in the soil is crucial to increasing the potential of methane uptake in drip-irrigated croplands to mitigate global climate change. In this study, a two-year field experiment combining static chamber gas chromatography with the concentration gradient method was conducted in 2021 and 2022 in Wuwei, Gansu of China. Three drip irrigation flow rates (F1: 1.3 L/h, F2: 2.0 L/h, F3: 3.0 L/h) were set to investigate the characteristics of methane diffusion, absorption, and surface net uptake in different soil layers and their responses to soil environmental factors. The results showed that soil methane concentrations decreased with increasing soil depth. There was no significant difference in the average surface methane concentration between treatments, and the average methane concentration in the 0-60 cm soil layer showed F3 > F2 > F1. The value in the F3 treatment was significantly higher than F1 by 11.9% in the 0-20 cm soil layer. The average methane concentration of F3 treatment was significantly higher than that of F2 and F1 treatments by 8.5%, 26.8% (>20-40 cm soil layer) and 10.2%, 19.1% (>40-60 cm soil layer), respectively. Average surface methane uptake fluxes were 85.4, 80.2 and 78.5 μg g/(m−2 h) for F1, F2 and F3 treatments, respectively, and were significantly increased by 6.4% and 8.9% for F1 treatment compared to F2 and F3 treatments (P < 0.05). The average methane diffusion flux in the 0-20 cm and >20-40 cm soil layers was significantly higher in the F1 treatment than in the F2 and F3 treatments, while the average methane diffusion flux in the 40-60 cm soil layer was significantly lower in the F1 treatment than in the F2 and F3 treatments. The cumulative methane uptake in the F1 treatment increased by 5.9%-13.8% compared to the F2 and F3 treatments, respectively. Methane uptake primarily occurred in the 0-20 cm soil layer, accounting for 72.1%-82.5% of the total uptake. Emitter flow rate had significant effects on soil water-filled pore space, soil oxygen concentration and nitrogen content (P < 0.05). Among various soil environmental factors, soil water-filled pore space had the most significant influence on soil methane concentration. Cumulative surface methane uptake fluxes were significantly and positively correlated with cumulative methane diffusion fluxes (downward) in the 0-20 and >20-40 cm soil layers, and cumulative methane diffusion fluxes in the >20-40 cm soil layer were significantly positively correlated with the values in the 0-20 cm soil layer. Cumulative methane transformation fluxes in the 0-20 cm soil layer were significantly and positively correlated with cumulative methane diffusion fluxes in the 0-20 cm soil layer, and cumulative transformation fluxes in the >20-40 cm soil layer were significantly and positively correlated with cumulative diffusion fluxes in the 0-20 and >20- 40 cm soil layers. The lower values of soil water-filled pore space in the surface soil of the F1 treatment facilitated the entry of methane from the atmosphere into the soil and its diffusion into deeper layers, thereby increasing methane uptake. In addition, the potato yield and irrigation water use efficiency under F1 treatment were relatively highest. Soil methane uptake, diffusion, and transformation were influenced by soil water distribution. Therefore, it should be considered to regulate the soil wetting area through an appropriate emitter flow rate to enhance the soil methane sink capacity and potato yield in the drip irrigation management. The results can provide a valuable information for soil carbon sinks and potato yield improvement in drip irrigated soils. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Objective] Brackish groundwater can be used as a complementary irrigation resource to safeguard crop production in regions lacking freshwater resources. The purpose of this paper is to study the effect of the salinity of brackish water and soil water content on spatiotemporal variations in soil enzymatic activities, as well as growth and yield of cucumber. [Method] The experiment was conducted in an greenhouse, with the cucumber irrigated by brackish waters with salt concentrations of 5 (E1), 3.5 (E2), 2.5 (E3), 0.5 g/L (E4), respectively. We measured soil matric potential at the depth of 20 cm underneath the drip emitter, such that irrigation was resumed when the matric potential decreased to -15 kPa (L1), -25 kPa (L2) or -35 kPa (L3), respectively. In each treatment, we measured the spatiotemporal changes in activities of urease, alkaline phosphatase and sucrase in the soil, as well as growth and yield of the cucumber. [Result] The activities of all three enzymes decreased vertically with the soil depth and horizontally with the distance from the drip emitters. The three enzymes were most active in the top 0-20 cm soil layer, 0-15 cm away horizontally from the drip emitters. Irrigation with water at salt concentration of 0.5-2.5 g/L improved the alkaline phosphatase activity, with limited effect on the activities of urease and sucrase. Increasing water salinity to 3.5-5 g/L suppressed the activities of all three enzymes. With the decrease in soil matric potential used for irrigation control, the activity of sucrase increased steadily, while the activities of urease and alkaline phosphatase increased first followed by a decrease. Irrigation with water at salt concentration of 3.5-5 g/L significantly inhibited the growth and development of the cucumber, while reducing the soil matric potential used for irrigation control to -35 - -25 kPa improved the cucumber growth and yield. [Conclusion] Irrigating greenhouse cucumber using brackish water with salt concentration of 0.5-2.5 g/L and resuming irrigation whenever the soil matric potential at the depth of 20 cm underneath the drip emitters decreased to -35 - -25 kPa can improve cucumber production without resulting in noticeable soil quality deterioration. [ABSTRACT FROM AUTHOR]

To improve peanut yield under drip irrigation in Xinjiang, effect of potassium fertilizer application was investigated. Huayu 9610 (T1, a common cultivar in Xinjiang) and Heihua 5 (T2, a high yield cultivar) were used as materials at the Agricultural Meteorological Experiment Station in Wulanwusu, Xinjiang. Four potassium (K2O) fertilizer gradients were set as K0 (0 kg/hm²), K1 (150 kg/hm²), K2 (225 kg/hm²) and K3 (300 kg/hm²), and thus the potassium rates were at 15%, 40%, 30% and 15% at the seedling, pegging, podding and full fruit ripening stages respectively. Results showed that the main stem height and lateral branch length of Huayu 9610 and Heihua 5 changed parabolically with the increase of potassium application. The dry matter accumulation were the highest at K2 level, which were 84.37 g per plant and 89.37 g per plant, respectively. Compared with no potassium fertilizer, the main stem height and lateral branch length of K2 treatment increased by 17.91% and 16.56%, 7.4% and 12.31%, respectively. The number of nodules was the highest at podding stage, which was 42.0 per plant and 45.3 per plant respectively. The leaf area index increased with the increase of potassium fertilizer application, and reached the maximum at 90 days after emergence. The photosynthetic potential also changed in a parabolic shape with the increase of potassium fertilizer application rate, and reached the maximum value of 4.38 m2·d and 4.51 m2· d respectively after 75-90 days of K2 treatment. The fertilizer contribution rate and agronomic utilization rate of K2 treatment were the largest, which were 26.06% and 1.83 kg/kg (for Huayu 9610), 25.18% and 1.67 kg/kg (for Heihua 5), respectively, and the yields were 9628.38 kg/hm² and 10 368.35 kg/hm², respectively. The results showed that potassium application amount of 225 kg/hm² at K2 level could be used as reference for drip irrigation peanut in Xinjiang, China. [ABSTRACT FROM AUTHOR]

In order to study the irrigation uniformity of alfalfa under subsurface drip irrigation and propose a reasonable irrigation quota, this paper uses the method of field experiment, 3 irrigation quotas (20, 25, 30 mm) for subsurface drip irrigation, 2 drip irrigation belts for burial depth (10, 20 cm), and 2 drip irrigation belt dripper flow rates (1.38, 2.0 L/h) are used to study the research, the effects of drip irrigation belt dripper flow, burial depth of drip irrigation belt, alfalfa growth period on irrigation uniformity, and effects of different water treatments on alfalfa plant height and yield. The drip irrigation belt dripper flow has a relatively large influence on the drip irrigation uniformity. Increasing the drip irrigation dripper flow can improve the drip irrigation uniformity coefficient. Under the same drip irrigation belt dripper flow, the burial depth of drip irrigation belt of 10 cm and 20 cm has no significant effect on the uniformity coefficient of drip irrigation. The effect of alfalfa turning green period and flowering period, jointing period and branching period on the irrigation uniformity coefficient is not significant. When the water consumption is 456.69 mm, the hay yield of alfalfa is the largest, which is 12 847.78 kg/hm2. Considering the production factors such as water saving, high yield and high efficiency, it is suggested that the irrigation quota of subsurface drip irrigation of alfalfa in Ordos Otuokeqianqi Area is 25 mm, and the irrigation water is 12 to 14 times. [ABSTRACT FROM AUTHOR]

Jingdian Irrigation Area is a high-lift cross-basin irrigation area with agricultural economy as the main, drought and water shortage have become the main factors restricting the high and stable yield of crops, water-saving irrigation technology has been popularized in Jingdian Irrigation Area reasonable water-saving irrigation can save water improve unilateral water efficiency it is beneficial to promote the intensive and economical utilization of water resources and the construction of water-saving irrigation area. This paper is based on the entropy method, the evaluation system of water-saving irrigation benefit is constructed from the aspects of social economic benefit and ecological environmental benefit, the benefits of different water-saving irrigation modes for the main crops in irrigated areas are analyzed. The results show that the efficiency of efficient water-saving irrigation is generally higher than other irrigation methods drip irrigation is the best water-saving irrigation mode in this area. The evaluation results are basically consistent with the reality, it shows that this method is feasible to evaluate the benefit in irrigated areas, so it has a guiding significance to the comprehensive evaluation of irrigated areas. [ABSTRACT FROM AUTHOR]

Sediment deposition has posed a serious risk to the performance of emitter flow channels. This study aims to explore the influences of the emitter performance on sediment deposition, in order to reduce the risk of physical blockage occurrence. Different concentrations (1.8, 2.8, and 3.8 g/L) and particle sizes (0 ≤ d ＜ 0.054 mm，0.054 mm ≤ d ＜ 0.075 mm，0.075 mm ≤ d ＜ 0.1 mm) of sandy water were used in the emitter clogging test of intermittent drip irrigation. A comparison was also made on the particle size composition in the sediment output from the emitters that irrigated with the sandy water. A systematic analysis was then implemented for the sediment transport and siltation inside the emitters. A numerical simulation was also carried out to analyze the flow pattern in the emitter. The low-velocity or vortex zone was prone to clogging. An operation mode was finally recommended to improve the clogging-resistant performance of the emitters in the drip irrigation system, according to the flow pattern and the deposited sediments. The results show that: 1) There was a consistent effect of side-seam labyrinth emitters on the size of settled sediment, with a decrease in the specific gravity of clay and sand particles, and the increasing specific gravity of powder particles. The grain size composition of the input original sediment was compared with the output one. There was a decreased proportion of clay and sand particles with an increased proportion of silt particles. Since the water-following property of sand particles was weaker than that of clay particles and silt particles, there was a weak discharge from the emitter with water. Specifically, the proportions of clay particles and sand particles in the sediment decreased by 1.14-2.98 percentage points and 1.55-11.14 percentage points, respectively, whereas, the proportion of silt particles increased by 1.25-13.74 percentage points. 2) The low transport of large particle size was attributed to the small size of the labyrinth emitter flow channel. The clogging of the particle size was concentrated in the range of 0.054-0.1 mm particle size. Most sediment sizes were between 0.002 and 0.05 mm in the flow channel of the emitter, due to the agglomeration of sediment flocs. 3) Streamline in the mainstream area was moving forward in a wave-like manner. The flow velocity in the mainstream area was greater than that in the near-wall area, while the flow velocity at the central corner was large, and a vortex was generated in the upper and lower corners. The inner and outer water bodies in the centrifugal force and water pressure under the joint action of the inner water body flew to the lower wall of the lower runner unit, while the outer water body flew to the upper side wall of the upper runner unit, where the turbulence of the water flow diffusion rate was faster. A vortex area was formed in the inner and outer boundaries of the circulation in the labyrinth runner. Part of the particles was retained in the vortex area, thus causing the runner blockage. That was the main factor for the emitter clogging. After that, sand particles were very easy to settle and concentrate in the vortex center and the water surface. Some suggestions were proposed to reduce the number of right- and sharp-angled areas, in order to reduce the formation of low-velocity zones in the design optimization. The clogging of emitters can be prevented by the sand deposition. The long and narrow over-flow structures can also be avoided, according to the location of the clogging of sediments. [ABSTRACT FROM AUTHOR]

Using brackish water for irrigation in arid and semi-arid areas can alleviate the supply-demand contradiction of freshwater resources. However, the correlation between its irrigation effect and soil texture remains to be studied. This study investigated the effects of irrigation mineralization on the growth and development of drip-irrigated cotton with different soil textures and the yield and fiber quality of seed cotton. In 2022, a barrel planting experiment was conducted to study two common cotton field soil textures (sandy loam soil T1 and sandy soil T2) and four irrigation mineralization degrees (0.85 (S0), 2.00 (S1), 5.00 (S2), and 8.00 g/L (S3)) in the Manas River Basin. Under different treatments, eight experimental treatments were used to study cotton photosynthetic indicators, plant height, stem diameter, yield, and quality. The results showed that as the mineralization degree of irrigation increased, the plant height, stem diameter, net photosynthetic rate, transpiration rate, single boll weight, number of bolls per plant, yield, irrigation water use efficiency, and fracture ratio intensity of cotton seedlings in sandy soil showed a decreasing trend after the seedling stage. The transpiration rate of S3 treatment decreased by 10.61% compared to S0 during the bud stage. Under sandy loam conditions, all indicators showed an increasing and decreasing trend. The net photosynthetic rate of S1 treatment increased by 8.40% compared to S0. As irrigation's mineralization degree increases, underground cotton's maximum fluorescence in two soil types decreases, while nonphotochemical quenching shows an increasing trend. It can be concluded through regression analysis that there is a negative correlation between cotton yield and irrigation mineralization in sandy soil cotton fields. However, irrigation water less than 3.69 g/L in sandy loam cotton fields will not reduce cotton yield. Using path analysis, it can be concluded that cotton stem diameter and transpiration rate are the main factors affecting yield under sandy loam conditions. Plant height is the main factor affecting the micronaire value. Under sandy soil conditions, the nonphotochemical quenching coefficient and transpiration rate are the main factors affecting yield. In contrast, plant height and transpiration rate are the main factors affecting micronaire value. This study can provide a theoretical basis and technical support for the rational utilization of brackish water resources in cotton fields with different soil types in the Manas River Basin. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study aims to investigate the effect of rated flow rate and lateral distance on the risk of clogging in the button)type emitter during drip irrigation using high-sediment sediment-loaded water. Three rated flow rates (2, 4, and 8 L/h) of button)type emitters were subjected to the muddy water clogging tests, corresponding to the different lateral positions (lengths of branch pipe at the inlet of the lateral: w, 2w, and 3w, respectively, with lateral spacing w=204 mm; referred to the inside, the middle, and the outside, in that order). A two-factor full-scale test was then carried out with a total of nine combinations. Three combinations were tested at one time, and three tests were conducted as one round, where a total of two rounds of tests were conducted to ensure the reliability. The results show that the rated flow rate of the emitter and the lateral distance posed the great impacts on the full cross-section mean flow rate in the lateral and the branch pipe, leading to the initiation of sediment deposition in the pipe, even in the process of emitter clogging. The emitter with the rated flow rate of 4 L/h presented the slowest decrease in the average relative flow rate and the coefficient of irrigation uniformity, indicating the best anti-clogging performance, and the highest number of effective irrigation times. The average service life increased by 11.84% and 49.11%, respectively, compared with the emitters with a rated flow rate of 2 and 8 L/h, respectively. The smaller the rated flow rate of the emitter was, the more significant the impact of the lateral distance on the service life of the emitter was. The lower the rated flow rate of the emitter was, the greater the mass of sediment retained in the lateral was, the greater the proportion of large)particle sediment deposited was, and the greater the tendency for the large-particle sediment to be retained in the lateral relative to small-particle sediment was. The emitter with the rated flow rates of 8, and 2 L/h shared the highest and lowest number of particles in the initiating motion of sediment deposited in the lateral, as well as the largest and smallest upper limit of particle size, respectively. The higher the rated flow rate of the emitter and the closer to the front of the installation on a single lateral were, the larger the sediment particle size it discharged. The initiation of sediment deposits in the lateral was the main cause of faster clogging of high-flow emitters. The amount of sediment entered the emitter, due to the too too-large rated flow rate of the emitter, the large velocity of water flow in the lateral, and the strong sand holding. The sediment particles then failed to discharge from the emitter in time to be easily deposited inside the emitter or flocculation and sedimentation by collision, leading to the emitter more susceptible to clogging. The clogging was easier to be washed away, due to the rated flow rate of the emitter for the 8 L/h of the flow channel cross-section dimensions (1.60 mm×1.08 mm) and the flow velocity of the muddy water within the channel is maximum. Repeated clogging was more likely to occur in the 8 L/h emitter than in the 4 and 2 L/h ones. The finding can provide a strong reference for the selection of a rated flow rate to prevent the emitter clogging in drip irrigation. [ABSTRACT FROM AUTHOR]

China's most fabulous cotton-producing area is Xinjiang. In Xinjiang, soil salinization and water shortage are now the two key challenges limiting agricultural productivity and sustainable growth. Water wastage and secondary soil salinization in the area are still being made worse by irrational irrigation during the growth period and salt leaching during the off-growing period. A breakthrough in solving these problems is the development of sensible irrigation and salt-leaching techniques throughout the growing period to preserve water efficiently, cut expenses, and guarantee cotton crop yields. Following calibration of the model parameters and validation using field experiment data from 2020 and 2021, respectively, the optimal scheduling of cotton field irrigation and salt leaching was investigated to clarify the applicability of the Aquacrop model to the growth and production of simulated cotton fields under membrane and subsurface drip irrigation in northern Xinjiang. Then the calibrated model was used to reveal the effects of three irrigation levels (100%ETc (D1), 80%ETc (D2), and 60%ETc (D3)), three salt leaching amounts (0 (Q1), 120 mm (Q2), and 240 mm (Q3)), three irrigation frequencies (5 (F1), 7 (F2), and 10 d/time (F3)) and three types of precipitation year (rainy years(H1), normal years (H2), and dry years (H3)) on cotton yield and irrigation water productivity. The results showed that canopy cover, aboveground biomass NRMSE (Normalized root mean square error)İ20.998%, d (Index of agreement)ı0.967, and R² (Coefficient of determination)ı0.914 for all treatments in 2021, and yield RMSE, NRMSE, d, and R² were 0.389 t/hm², 6.797%, 0.836, and 0.754, respectively, and the model simulated well overall. Model simulations based on 58 years of meteorological data showed that the effects of irrigation level, salt leaching quota, and precipitation year type on cotton yield and irrigation water productivity were statistically significant, and irrigation frequency effect was not significant; in the cotton planting area with average soil salinity ranging from 12 to 18 g/kg, accounting for yield, irrigation water productivity, and actual production, the total irrigation and salt leaching quota of 80% ETc+120 mm (D2Q2) was recommended for rainy years, and the total irrigation and salt-leaching quota of 100% ETc+120 mm (D3Q2) was recommended for both normal and dry years; it was suggested that the irrigation frequency be increased to 10 d/time to reduce the frequency of irrigation and save costs. The optimal irrigation and salt leaching strategy proposed in this study was limited by model function and evaluation perspective. It was based on water conservation and optimal yield in cotton fields and did not consider the desalination conditions of membrane and subsurface drip irrigation. To develop more rigorous and convincing irrigation and salt leaching strategies, the Aquacrop model must be coupled with other water and salt transport models to improve the model's functionality and comprehensively assess soil desalination and cotton field production conditions. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Northwest A & F University - Natural Science Edition is the property of Editorial Department of Journal of Northwest A&F University (Natural Science Edition) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Inappropriate irrigation and fertilization have led to high carbon (C) emissions and degradation of ecosystem services in the saline-alkali sunflower farmland in the arid upper Yellow River basin of Northwest China. This study aims to determine the rational irrigation and fertilization strategy for the sustainable production of saline-alkali sunflower farmland in this area. A field experiment was carried out to investigate the effects of organic fertilizer application on the net ecosystem carbon budget (NECB) and ecosystem service values of saline-alkali farmland under drip irrigation in 2021 and 2022. Two factors were considered, including the lower limit of irrigation and the fertilization mode. Among them, the lower limit of irrigation (drip irrigation) was divided into two soil matric potential thresholds (SMPT) (W1: −20 kPa SMPT and W2: −30 kPa SMPT). Three fertilization modes were selected (CK: Chemical fertilizer, LBF: Lignite C-based organic fertilizer 4.5 t/hm², SMF: Sheep manure compost 5 t/hm²) under each SMPT using a completely random block design. In addition, the border irrigation combined with chemical fertilizer was set as the control treatment (MCK), corresponding to the local farmer practices. A comparison was performed on the NECB of different ecosystems and the components, as well as three ecosystem service values (supply function value of agricultural products, accumulated functional value of organic matter, and gas regulation value) among different treatments. Results indicated that the LBF and SMF treatments effectively promoted crop growth and biomass accumulation, compared with the CK. There was also an increase in the soil moisture content and soil organic matter (SOM) content under the drip irrigation. Among all treatments, better performance was achieved in drip irrigation with −20 kPa SMPT combined with 4.5 t/hm² lignite C-based organic fertilizer application treatment (W1LBF). The highest aboveground biomass and yield also increased by 32.30% and 44.13%, respectively, compared with the MCK. These soil and crop indicators depended mainly on the NECB. The net primary productivity (NPP) and grain C output were the main components of the carbon sink and carbon source in the farmland system, respectively. NPP, SOM content, grain C output, and soil C emission in the drip irrigation treatment were higher than those in the surface under the same fertilization, where the values of these indicators increased with the increase of SMPT. Moreover, the organic fertilizer application (LBF and SMF) also significantly improved NPP, SOM content, and grain C output under the same irrigation, but reduced the soil C emissions, compared with the chemical fertilizer application (CK). The W1LBF treatment obtained the highest NPP and lower soil C emissions, thus achieving the highest NECB. Compared with the W1CK and MCK treatments, the W1LBF treatment increased NECB by 26.24%−159.98% and 151.74%, respectively. In addition, the changes in NPP, SOM, and soil carbon emissions also significantly affected the ecosystem service value. W1LBF treatment increased the supply function value of agricultural products, SOM accumulation, and gas regulation by 8 004.20, 923.90, and 2 094.70 Chinese Yuan /hm², respectively, compared with the MCK. In conclusion, the drip irrigation with −20 kPa soil matric potential thresholds combined with 4.5 t/hm² lignite C-based organic fertilizer application can effectively increase the C sink and service values from the saline-alkali sunflower farmland ecosystem in the arid upper Yellow River basin of Northwest China. The research can provide the scientific basis for the saline-alkali farmland C sequestration and ecosystem service value, while greenhouse gas emission reduction in the arid and semi-arid areas. [ABSTRACT FROM AUTHOR]

The transport characteristics of water, air, and oxygen are unclear in drip irrigation systems with micro-nano bubble water, limiting its application in the field of agriculture. This study improved the method of collecting and measuring water and air flowing from an emitter on a drip irrigation system with micro-nano bubble water. The flow rate of water and air was calculated for the emitter at the beginning, middle, and end of the drip tubing. In addition, the dissolved oxygen concentration of the same emitter samples was measured. Then the transport characteristics of water, air, and dissolved oxygen along the drip tubing were analyzed. The uniformity of water, air, and dissolved oxygen for the whole pipe system was calculated. The influence of air intake rate (set by micro nano bubble machine) and system operating pressure on the transport characteristics and uniformity of water, air, and dissolved oxygen was analyzed. The results showed that the micro-nano bubbles had no significant effects on the water flow rate and uniformity (P<0.05), with the average water flow rate and uniformity remaining not less than 1.97 L/h (rated flow of 2.0 L/h) and 96.02%, respectively. The influence of air intake rate and operation pressure on the average air flow rate reached a significant level (P<0.05), as well as the interaction between other factors and operation pressure, while the influence of emitter position on the average outflow flow rate did not reach a significant level (P<0.05).Within a moderate operating pressure range (0.10-0.18 MPa), the average airflow rate and uniformity ranged from 0.13-0.23 L/h and 85.50%-92.41%, respectively, increasing and decreasing with the air intake rate increasing. At high or low operating pressures (0.22, 0.06 MPa), individual emitters in the middle of the drip pipe had abnormally high air flow rates, greatly reducing the air flow uniformity while increasing the average air flow rate of the drip irrigation system. The dissolved oxygen concentration of the drip irrigation system with the micro-nano bubble water was greatly higher than that of tap water. Its mean value increased a little bit along the drip tubing. And there was a single-peak variation trend with the increase in the air intake rate. The drip emitter position, air intake rate, operation pressure, and the interaction between the latter two had significant effects on the mean value of dissolved oxygen concentration for the whole pipe system(P<0.05). When an air intake rate of 1.5 L/min was combined with an operation pressure of 0.14 MPa, the average dissolved oxygen of the drip irrigation system reached the highest of 14.45 mg/L. Taking into account the transport effects of water flow, airflow, and dissolved oxygen, the optimal operating parameters for a drip irrigation system with micro-nano bubble water were determined to be an air intake rate of 1.5 L/min and an operation pressure of 0.14 MPa. The suitable operation pressure range was 0.10- 0.18 MPa and the air intake rate range was 1.5-2.4 L/min according to the airflow uniformity>85% and the average dissolved oxygen>12 mg/L. This study provides a theoretical basis for the scientific operation of drip irrigation systems with micro-nano bubble water. [ABSTRACT FROM AUTHOR]

For high yield peanut in Northeast Agro-pastoral Ecotone, topdressing ratios of NPK fertilizer (pure N 68.18 kg/hm², P 22.08 kg/hm², and K 174.33 kg/hm²) were used in 6 treatments for investigation of NPK effects. The field experiment was conducted under mulch drip irrigation. Nutrient and enzymatic activities of sandy soil and peanut yield were detected to clarify the optimal basal/topdressing ratio. Results showed that the content of soil organic matter and available N, the activity of urease and sucrase were both increased with the topdressing ratio, while the thicker the soil layer, the lower its content and activity were. The peanut yield was increased firstly and then decreased with the topdressing ratio, which was higher than the traditional fertilization method. The two-year peanut increasing yield range was 3.77%-41.27%. Yields reached the highest at T60, as 6427.7 kg/hm² and 6046.8 kg/hm² respectively. When all of the NK fertilizers were used as topdressing, the yield was not increased obviously, which was average 4.53% higher in two years. In summary, it had the best effect with 40% of the total fertilization amount used as the base fertilizer, and 60% used as topdressing under water and fertilizer integration measures in the area. [ABSTRACT FROM AUTHOR]

Drainage water can be recycled from subsurface pipe networks in farmland, in order to alleviate the shortage of irrigation water resources in the arid and semi-arid regions of Northwest China. The outsourcing filter material and structure of subsurface pipes play a key role in the effluent water quality. In this study, a self-developed seepage tank device was used to simulate and investigate the effects of different outsourcing filter material structures on soil water and salt transport, drainage water quality and flow rate, as well as saturated zone water quality and water level, under winter irrigation and leaching salt conditions. Adsorption materials were used instead of traditional sand filter materials. Two types of outer filter materials were tested, namely geotextile only and geotextile wrapped with 10 cm mixed filter materials. The soil water and salt dynamics were monitored from the start of irrigation to the end of drainage. The results showed that in the early stage of the leaching test, the water gradually infiltrated the soil, where the salt migrated vertically downward with the water flow, and then accumulated around the subsurface pipes in the soil layer at a depth of 60-90 cm. In the mid-stage of leaching, the water level of the saturation zone gradually rose from the bottom to the top. The subsurface pipe with geotextile only started draining, when the water level exceeded the axis of the pipe, whereas, the subsurface pipe wrapped with geotextile and 10 cm mixed filter materials started draining only, after the water level reached the top of the pipe. In terms of the desalination performance, the soil desalination rate of both outer filter materials decreased gradually with the increase of depth. The average desalination rate of the soil with geotextile only was 11.45% lower than that with mixed filter materials. The average mineralization level of the water samples from the subsurface pipe with the mixed filter materials was reduced by 1.89 and 1.21 g/L, respectively, after subsurface pipe drainage in Test 2-1 (the first round of leaching test of subsurface pipe wrapped with geotextile+10 cm mixed filter material) and Test 2-2 (the second round of leaching test of subsurface pipe wrapped with geotextile+10 cm mixed filter material), compared with the geotextile only. The drainage flow rate also increased significantly, with the maximum drainage flow rate of 6.27 mL/s for Test 2-1 and 2.46 mL/s for Test 2-2. In the late stage of leaching, the drainage stopped under the delayed effect of gravity drainage, when the water level of the saturation zone approached the bottom of the subsurface pipe. The salt in the soil was distributed mainly in a concave curve that centered around the subsurface pipe. The findings can provide a strong reference for the subsurface pipe drainage reuse in the Yinbei irrigation district of Ningxia. Nevertheless, the experimental process cannot consider evaporation, which is one of the main factors of soil salt accumulation. At the same time, the test environment of the seepage tank was greatly varied in the actual farmland drainage from the subsurface pipe project. Therefore, better performance can be expected for the adsorption filter material on the farmland soil. [ABSTRACT FROM AUTHOR]

Clay soils with subsurface drip irrigation are often characterized by hypoxia. The addition of hydrogen peroxide to water to produce hydrogen peroxide oxygenated water, which is delivered to the root zone of crops via a subsurface drip irrigation system to increase soil oxygen levels, is a promising method of alleviating oxygen deprivation in the root zone. To explore the variation of dissolved oxygen concentration, oxygen transfer coefficient, surface tension coefficient, electrical conductivity and pH value with different hydrogen peroxide oxygenated water concentrations (H0-0 mg/L; H1-600 mg/L; H2-800 mg/L; and H3-1 000 mg/L), as well as the response of cumulative infiltration, depth of the wetting front and soil water content to hydrogen peroxide oxygenated water concentrations, two trials were carried out in 2021 at the State Key Laboratory of Eco-hydraulics in Northwest Arid Region at Xi'an University of Technology, China. The results of the study showed that H2O2 significantly increased the concentration of dissolved oxygen in water and the concentration of dissolved oxygen increased with increasing concentration of H2O2 added. Dissolved oxygen concentration was significantly enhanced by 52.10%, 87.11% and 126.59% in H1 to H3 treatments, respectively, as compared to the H0 treatment. The increase in H2O2 concentration decreased the oxygen transfer coefficient and inhibited the oxygen transfer process. Oxygen transfer coefficient was significantly increased by 65.17% in the H1 treatment as compared to the H3. The surface tension coefficient decreased significantly with increasing H2O2 concentration. The surface tension coefficients in H1 to H3 treatments were significantly reduced by 17.72%, 23.57% and 31.60%, respectively, compared to the H0 treatment. Electrical conductivity showed an increasing trend with increasing concentration of H2O2 addition, but the difference between H0 and H1 treatments was not significant (P＞0.05). Electrical conductivity was significantly higher in H2 and H3 treatments by 6.60% and 10.42%, respectively, as compared to the H0. The change in pH showed an opposite trend to electrical conductivity, with pH showing a decreasing trend with increasing concentration of H2O2 added. There was a good logarithmic function relationship between dissolved oxygen concentration and surface tension coefficient, and the two could be used as a quantitative evaluation indicator of the physicochemical properties of hydrogen peroxide oxygenated water. Compared to the control, hydrogen peroxide oxygenated water facilitated the process of soil water infiltration and increased the water holding capacity of the soil. The cumulative infiltration showed a trend of increasing and then decreasing with increasing H2O2 addition concentration. Cumulative infiltration was significantly increased by 14.50%, 29.98% and 16.64% for H1 to H3 treatments, respectively, compared to the H0 treatment. For the same infiltration time, the depth of the wetting front showed a tendency of increasing and then decreasing with the increase of H2O2 addition concentration. The depth of wetted fronts was significantly increased by 7.66%, 18.84% and 13.39% in H1 to H3 treatments, respectively, compared to the H0. The soil water content was significantly increased by 8.73% and 4.23% in H2 and H3 treatments, respectively, as compared to the H0. The Philip infiltration model was able to better simulate the infiltration process of hydrogen peroxide oxygenated water, and the soil sorptivity showed a tendency of increasing and then decreasing with the increase of the added concentration of H2O2, with the maximum value also appeared in the treatment of 800 mg/L. There was a good quadratic polynomial relationship between the soil sorptivity and the dissolved oxygen concentration. Considering the results of the study together, the recommended concentration of 800 mg/L of H2O2 was the optimal concentration under the test conditions. These results could provide a scientific foundation for the practical application of hydrogen peroxide oxygenated water and a theoretical guide for the efficient regulation of soil aeration. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Y-type mesh filters have been widely used in the micro-irrigation systems. A better hydraulic performance is highly required for the stable operation during irrigation. In this study, the standard k-model was adopted to simulate the internal flow field of different filters using the computational fluid dynamics with multi-angle analysis. A series of simulation tests were carried out under three types of filter screen shapes (square, circular and diamond) and three angles of cylinder arc (0°, 15°, and 30°). Specifically, a systematic analysis was implemented on the hydraulic characteristics of the internal pressure drop coefficient, the flow distribution on the surface of the filter element, the internal flow field, and the pressure distribution. Physical tests were also conducted to verify the numerical simulation. The results show that: There was 9% average difference in the head loss coefficient between the physical test and the numerical simulation, indicating the better reliability of the numerical simulation. The head loss of the filter was concentrated on the outlet side of the screen, which was accounted for 85% of the total head loss. A stagnant zone of water flow was formed inside the plug, where the velocity was very low without the water flowing back. The smallest pressure was found in the center of the filter chamber from the center to the surrounding area. There was also an increase in the minimal pressure in a stepwise manner from the center to the periphery. Among them, the circular mesh filter shared the largest head loss coefficient, followed by the square mesh filter, and the smallest was found in the diamond mesh filter. The pressure dropped at the mesh, and the total pressure dropped to change, as the shape of the mesh changed. But there was no variation in the value and distribution of the maximum and minimum pressure in the chamber. It infers that the shape of the mesh posed a greater influence on the distribution of the overflow rate on the mesh surface of the filter. The highest proportion of medium-rate overflow area was 47.5% in the square mesh filters, followed by the circular shape, and the smallest medium-rate overflow area of diamond shape was only 26.5%. The head loss of the filter gradually decreased with the increase of the arc angle of the cartridge. The pressure drop coefficient at 35° decreased by 73.15%, compared with 0°. There was also the much more uniform distribution of the flow rate on the mesh surface with the increase of the angle, in which the area of the medium speed overflow area at 35° increased by 71.48%, compared with 0°, indicating the outstandingly improved hydraulic performance. There was the significant decrease in the internal and external pressure difference at the middle and upper section of the screen on the outlet side with the increase of the arc angle of the cartridge, particularly for the differences between 35° and 0°. The difference of the pressure drop between 35° and 0° was 2.97 times. Therefore, an optimal filter can be selected with a square cylinder arc angle of 30°in the actual micro-irrigation system, in order to improve the hydraulic performance and service life of the filter with the gentle internal flow field and uniform flow distribution on the mesh surface. [ABSTRACT FROM AUTHOR]

In order to determine the nitrogen fertilizer input threshold of rice based on yield and environmental safety under drip irrigation in the Hexi Oasis irrigation area, field tests on rice drip irrigation were conducted at the Zhangye Water-Saving Agricultural Pilot Station in 2020 and 2021. Five nitrogen application levels of 0, 135, 225, 315 kg·hm-2, and 405 kg·hm-2 were set and labeled as N0, N1, N2, N3, and N4, respectively. Then, the impacts of the nitrogen application levels on the rice yield, accumulative mineral nitrogen, and nitrogen balance in soil were studied. The results showed that nitrogen application significantly increased the rice yield and formed a significant quadratic parabolic curve together with the rice yield and the amount of nitrogen applied. The rice yield reached the value of 5 684 kg·hm-2(99.7% of the maxium yield) when 222 kg·hm-2 of nitrogen was applied. There was a significant exponential correlation between the cumulative amount of mineral nitrogen in soil and the amount of nitrogen applied. When the amount of nitrogen applied was 315 kg·hm-2, the cumulative amount of mineral nitrogen was 151 kg·hm-2, which was significantly higher than the levels of 119 kg·hm-2when the amount of nitrogen applied was 225 kg·hm-2. Additionally, when the amount of nitrogen applied reached 315 kg·hm-2, the mineral nitrogen moved from the shallow to deep layers, following a trend of aggregation. There was a significant linear correlation between the nitrogen apparent balance value and the amount of nitrogen applied. The amount of nitrogen applied was 171 kg·hm-2 when the nitrogen apparent balance value of nitrogen was 0. When the amount of nitrogen applied ranged from 171 to 222 kg·hm-2, the rice yield was 5 551 to 5 684 kg·hm-2, the cumulative amount of mineral nitrogen in soil was 104 kg·hm-2 to 118 kg·hm-2, and the nitrogen balance value was 0 kg·hm-2 to 44 kg·hm-2. By considering the relationship among the yield, accumulative amount of mineral nitrogen, soil nitrogen surplus, and the amount of nitrogen applied, the proposed rational nitrogen fertilizer input threshold for rice under drip irrigation in the Hexi Oasis irrigation area is 171 kg·hm-2 to 222 kg·hm-2. Under this nitrogen application condition, the rice yield is high, the input and output of nitrogen in soil reach equilibrium, and the cumulative amount of mineral nitrogen is low, ensuring a high and stable rice yield and reducing environmental risks. [ABSTRACT FROM AUTHOR]

Cabbage has been widely cultivated with distinctive features in each cultivation area. The high output of vegetables can be found with better taste and high quality in Ningxia Liupanshan region with the unique cool climate conditions. But it is unclear on the efficient farming of mechanized production of cabbage in this region, in order to promote efficient and standardized production in the cabbage industry. This study aims to clarify the effects of different tillage modes on cabbage growth for the efficient agro-mechanical-agricultural integration system. Three tillage factors were also selected from the perspective of tillage practices, including the starting height of monopoly, light transmission rate of mulch, and the age of cabbage transplanted seedlings. A study plot was located in the Xiji region of Ningxia in China, where drip irrigation was used to locally irrigate using integrated water and fertilizer irrigation. The various types of vegetables were previously cultivated with alkaline soils. A 3-factor and 3-level quadratic regression orthogonal experiment was conducted with 80%, 45%, and 10% mulch light transmittance, 0, 15, and 30 cm monopoly height, as well as 30, 35, and 40 d transplanted seedlings in the test plot with 'China Cabbage No. 15' as the test variety. Response surface models were established to explore the effects of different factors on the soil environment and the yield of cabbage using the Box-Behnken model in Design-Expert 8.0.6 Trial software. The results showed that a significant effect of the soil environmental index was found in the interaction between mulch light transmission rate and transplanting seedling age, while there was no significant interaction of other factors. The higher the age of the seedlings was, the higher the overall soil environmental index was. The significant effects on the yield were observed in the interaction of starting height with mulch light transmission rate, mulch light transmission rate, and transplanting seedling age. The yield of cabbage tended to increase with a lower starting height and lower mulch light transmission rate, or with a higher starting height, and higher mulch light transmission rate. Finally, the response surface analysis and multi-objective optimization were utilized to adjust the monopoly height of cabbage cultivation, ground film light transmission rate, and transplanting seedling age tillage. A better performance was achieved in the soil structure and the comprehensive capacity of the soil environment, leading to the significantly increasing yield of cabbage. The best tillage mode was optimized for cabbage production using the response surface method. The optimal combination of parameters was obtained at 30 cm of monopoly height, 80% of the ground film light transmittance and 39 d of transplanted seedling age. This treatment combination can be the best way of tillage to promote the standardization and mechanical efficiency of the cabbage industry. [ABSTRACT FROM AUTHOR]

[Objective] This study explored the effects of alternate irrigation with brackish water and alternate partial root-zone irrigation upper and lower limits on tomato photosynthetic characteristics, stress resistance, quality and yield in production, providing reference for high-quality tomato production in regions with large reserves of brackish water. [Method] Using ’TY1602’ as the material under the condition of alternate partial root-zone irrigation, fresh water and brackish water (EC= 2.5, 3.3, 4.1 mS/cm) were used for irrigation. Two maximum field water-holding capacities were set as upper and lower limits: A [ (65%-90%) on the left side and (35%-50%) on the right side] and B [ (55%-80%) on the left side and (25%-40%) on the right side]. Automatic drip irrigation was performed when the moisture was below the lower limit; drip irrigation stopped when the moisture reached the upper limit. There were nine treatments in total: CK (fresh water, (65%-90%) on the left and right sides), T1 (fresh water, A), T2 (fresh water, B), T3 (2.5 mS/cm, A), T4 (2.5 mS/cm, B), T5 (3.3 mS/cm, A), T6 (3.3 mS/cm, B), T7 (4.1 mS/cm, A), T8 (4.1 mS/cm, B) . The effects of different treatments on tomato photosynthetic characteristics, osmoregulation substances, antioxidant enzymes, hormone levels, quality and yield were analyzed. [Result] Compared with the control group, as the EC value of brackish water increased, the photosynthetic rate of plants also increased. When the EC value reached 4.1 mS/cm, a decreasing trend began. The carbon assimilation enzyme activity changes in T6 and T8 were the most significant. The stress resistance index in the leaves was significantly increased in the T7 and T8 treatments, while the contents of CTK and ABA in the fruit were significantly increased in the T5 and T8 treatments, which effectively coped with external environmental stress. The quality indicators of T7 and T8 treatments were significantly better than those of other treatments, with good taste performance and a significant increase in water use efficiency. However, the yield decreased significantly. [Conclusion] Treatment T8 had the best comprehensive evaluation. In regions with rich reserves of brackish water and scarce fresh water resources, it can be used as a water-saving strategy for producing high-quality tomatoes. [ABSTRACT FROM AUTHOR]

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Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Water resource is very deficient in the world. Agricultural water consumption is accounted for a large proportion of the total. Especially, high consumption can be found in the protected cultivation of vegetables, due to the great scale and multiple cropping index. Hence, it is urgent to develop water-saving irrigation for protected cultivation. However, simple and practical technology is still lacking in practical production. In this study, three typical soil textures (loam, clay loam, and sandy loam) were adopted for vegetable cultivation. Cucumber was selected as the experimental material, because of its wide cultivation areas. A field experiment was carried out from 2021-08-02 to 2021-12-24 in the Chinese solar greenhouse in Beijing, China. Cultivation density was set as 2.57 plants per square meter. Three irrigation treatments for each soil texture were performed from the fruiting period in the form of drip irrigation. The accumulated solar radiation reached up to the setting value (15/20/25 MJ/m²), corresponding to the onset of the irrigation system. The data logger was reset and recounted in the control system. There was consistency in the total irrigation amount under the same accumulation of solar radiation for each soil texture. A systematic investigation was made to explore the effects of different irrigation strategies on the growth and quality of autumn-winter cucumber under the above soil textures. The average air temperature varied from 11.5 to 25.6 ℃ during this experiment. There were 35 days below 12 ℃ during nighttime. The daily solar radiation on the plant canopy varied from 0.18 to 11.87 MJ/(m²·d). Meanwhile, the average water vapor deficit during the daytime varied from 0.11 to 3.75 kPa. Results showed that the irrigation strategies with different accumulated solar radiations caused the ‘ high frequency and low irrigation amount’ and ‘ low frequency and high irrigation amount’ . However, there was no influence of different irrigation strategies on the fruit yield and irrigation water use efficiency using the same total irrigation amount under the same soil texture. Greater photosynthetic rate, leaf area, plant height, and number of internodes were obtained, when the accumulated solar radiation of 25 MJ/m² was set as the irrigation starting point, together with each irrigation amount of 3.22, 3.56, and 2.77 mm for the loam, clay loam, sandy loam, respectively. The highest contents of soluble sugar and vitamin C and the lowest nitrate content were all achieved, when the accumulated solar radiation of 20 MJ/m² was set as the irrigation starting point, together with the irrigation amount of 2.59, 2.85, and 2.22 mm for the loam, clay loam, sandy loam, respectively. Meanwhile, there was no significant difference in soil textures on the contents of soluble sugar, soluble protein, and vitamin C. Therefore, controlling accumulated solar radiation can be expected to serve as the irrigation starting point for the feasible irrigation strategy in protected cultivation. Meanwhile, the discrepant parameters of accumulated solar radiation as an irrigation starting point should be considered for the different cultivation goals under various soil textures. [ABSTRACT FROM AUTHOR]

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Objectives] This study aimed to explore the physiological response mechanism of maize to different drip irrigation patterns, and seek the optimization scheme between drip irrigation method and drip irrigation quota, so as to provide a theoretical basis for water-saving and efficient production of maize in semi-arid areas. [Methods]The movable rainproof shed was used to carry out a two-year plot experiment. Taking maize variety’Fumin 985’as the experimental material, two drip irrigation methods of aboveground drip irrigation and shallow buried drip irrigation were set, and three drip irrigation quotas of 300,400 and 500 mm were set in the whole growth period of maize. There were 6 treatments: aboveground drip irrigation-300 mm (T1), aboveground drip irrigation-400 mm (T2), aboveground drip irrigation-500 mm (T3), shallow buried drip irrigation-300 mm (T4), shallow buried drip irrigation-400 mm (T5) and shallow buried drip irrigation-500 mm (T6). The effects of different drip irrigation patterns on photosynthetic characteristics, chlorophyll fluorescence characteristics, leaf nitrogen metabolism enzyme activity and root bleeding sap mass of maize were studied. [Results]Compared with T1,T2 and T4 treatments, the net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular carbon dioxide concentration (Ci), transpiration rate (Tr), water use efficiency (WUE), apparent mesophyll conductance (AMC),maximum photosynthetic efficiency of photosystem Ⅱ (Fv/Fm), actual photosynthetic efficiency of photosystem Ⅱ(ΦPSⅡ), electron transfer efficiency (ETR), photochemical quenching coefficient (qP) increased and stomatal limiting percentage (Ls) and non-photochemical quenching coefficient (NPQ) of T3,T5 and T6 treatments in maize leaves at V12,R1 and R3 stages decreased. The glutamine synthetase (GS) activity and root bleeding sap mass of T3,T5 and T6 treatments showed an increasing trend, and were significantly higher than those of T1,T2 and T4 treatments under different drip irrigation patterns, while the glutamate dehydrogenase (GDH) activity showed a decreasing trend. [Conclusions]The drip irrigation pattern of shallow burying drip irrigation-400 mm drip irrigation quota in the whole growth period (T5 treatment) was better in root bleeding sap mass, leaf nitrogen metabolism enzyme activity, photosynthetic characteristics and chlorophyll fluorescence characteristics. The dual purposes of water saving and high yield were obtained. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Most pastoral areas in China are subjected to arid and semi-arid zones, particularly with annual precipitation of less than 400 mm. Since irrigation is indispensable for the cultivated grass industry, the protection of natural grassland can focus on the water, land, forage, and livestock balance with the development of the irrigation cultivated grasslands, rather than the forage-livestock balance only. Taking the specific pastoral management units as the entry point, this study aims to propose a new evaluation for the tradeoff between the water and land for the family pasture from the perspective of the water cycle. A water-land-forage-livestock balance was constructed to consider the quality differences between forage species in the calculation of the forage-livestock balance. An example was taken as the typical family pasture in the Otog Front Banner of the Inner Mongolia Autonomous Region in China. The assessment showed that the current water, land, forage, and livestock status of the family pasture were in a mild overload state, with a water resource overload rate of 6.05%. In the condition of water, land, forage, and livestock balance, the livestock overload rates with/without considering forage quality were 5.38% and 12.98%, respectively. By contrast, the livestock overload rates with/without considering forage quality were 1.29%, and 9.05%, respectively, under current planting conditions (without considering water resource overload). An optimal combination of water-use schemes was proposed to feature the different planting structures and irrigation adjustments, according to the status quo in this family pasture. A systematic analysis was made to determine the available water supply, and the carrying capacity for the irrigation of cultivated grasslands, and livestock under multiple optimizations. It was found that the carrying capacity was determined for the irrigation of cultivated grasslands by the available water supply. More water-efficient irrigation was adopted to select the forage crops with the decreased water consumption, in order to significantly improve the support capacity of water resources in the irrigation-cultivated grasslands. Livestock carrying capacity significantly increased after considering the forage quality, indicating more consistency with the actual condition of this family pasture. Consequently, the family pasture was maintained the current areas of cultivated grassland without increasing, while adjusting the irrigation of alfalfa to underground drip irrigation. Once the irrigation form was adjusted to drip irrigation under the condition of oat planting, the number of livestock was reduced to 464 sheep units, in order to maintain the balance of water, land, forage, and livestock in the family pasture. Furthermore, the oats were adjusted to grow the corn or alfalfa in the median condition of oats. Although the number of livestock was more than the current number of livestock, some suggestions can keep the current number of livestock raised in family pastures, in order to make more room for the rest and recuperation of water resources and natural grassland. The finding can provide a new approach to calculating and managing the water, land, forage, and livestock balance in pastoral areas. [ABSTRACT FROM AUTHOR]

：In order to explore the effects of foliar spraying selenium fertilizer and applying selenium fertilizer in roots on selenium accumulation in fruits of strawberry under protected cultivation, in this study, two different fertilization methods were adopted, they were spraying fertilizer solution on strawberry leaves(P) and drip irrigation fertilizer solution around strawberry roots (G). Eight treatments were set, they were foliar selenium fertilizer nutrient solution diluted by 1 500 times(P1 500, 14.40 mg/L), 2 500 times(P2 500, 8.64 mg/L), 3 000 times(P3 000, 7.20 mg/L), control spraying with water(CKP), drip irrigation with selenium fertilizer nutrient solution diluted by 750 times (G 750, 28.80 mg/L), 1 250 times(G1 250, 17.28 mg/L), 1 500 times (G1 500, 14.40 mg/L), and control drip irrigation with water (CKG). The results showed that under the same concentration of foliar selenium fertilizer nutrient solution diluted by 1 500 times (P1 500, 14.40 mg/L), the accumulation of selenium in strawberry fruits treated with selenium applying in the roots was higher than those treated with selenium spraying on the leaves. After selenium supplementation by the two fertilization methods, the experimental data of leaf photosynthetic system, leaf chlorophyll content, root activity, and fruit quality index were lower than those of the controls, indicating that the supplementary application could not improve the physiological traits and fruit quality of strawberry. However, supplementation of selenium, especially the production of selenium -enriched fruits and vegetables, had important significance to solve the problem of selenium deficiency in human beings. Strawberries produced by spraying selenium fertilizer or drip irrigation with 14.40 mg/L selenium fertilizer met the requirements for selenium content classification of selenium-rich agricultural products, and could provide selenium supplementation to the human body. [ABSTRACT FROM AUTHOR]

This study aims to determine the influence of hydrodynamic conditions on the formation of calcium carbonate fouling and the appropriate control threshold. A systematic investigation was implemented to explore the influence of hydraulic shear on the growth mechanism of calcium carbonate attached to the fouling process, together with the effect of changes in the total amount of fouling. The control threshold of hydraulic shear was also clarified on the growth of calcium carbonate fouling. This experiment was carried out to evaluate the 12 near-wall hydraulic shear forces (0-0.70 Pa) on the dry weight, crystalline phase composition, crystal size, and apparent morphology of calcium carbonate fouling in the irrigators of drip irrigation systems using a shear simulation device, the Couette-Taylor reactor, and with the aid of scanning electron microscopy (SEM) and X-ray diffractometry (XRD). The results showed that the dry weight of calcium carbonate fouling and different shear forces were significantly (P<0.05) dominated the formation of calcium carbonate fouling. Total amount of calcium carbonate fouling showed a trend of first increasing and then decreasing with the increase of shear force. The trend of the total amount of calcium carbonate fouling with the shear force was consistent with the Gaussian growth model. The most suitable shear force was at (0.42 ± 0.02) Pa for the formation of calcium carbonate fouling. The total amount of calcium carbonate fouling was 6.2-8.5 and 1.8-3.1 times of 0 and 0.70 Pa, respectively. The surface roughness of calcium carbonate crystals gradually increased with the increase of shear force, while the number of fragmented crystals also increased in the crystal surface morphology. The crystal size of calcium carbonate first increased and then decreased with the increase of shear force, reaching the maximum at about 0.25 Pa. In terms of crystal composition, the proportion of calcite was tended to decrease and then increase with the increasing shear, while the aragonite showed the opposite pattern. The content of both types of materials showed a linear increase with the increasing shear at the low shear (0-0.30 Pa), whereas, a linear decrease with the increasing shear at the high shear (>0.50 Pa), with the maximum content of calcite and aragonite between 0.35-0.50 Pa. In the shear force on calcium carbonate fouling growth, there was the thicker boundary layer of mass transfer between the material wall and water flow at the low shear force. The dispersion rate of Ca2+ and CO32- ions was the dominant factor of calcium carbonate fouling deposition. The increase of shear force was accelerated the ion dispersion rate, leading to the faster fouling growth of calcium carbonate. However, the exfoliation effect of water flow on the calcium carbonate played a dominant role in the fouling growth of calcium carbonate at the high shear force. Furthermore, the stripping effect of water flow on calcium carbonate was occupied a dominant role in the growth of calcium carbonate attached fouling, as the shear force increased. The stronger stripping was found in the calcium carbonate crystal structure, as the mass transfer layer thinned, where more broken grains appeared. In turn, there was the decrease in the total amount of calcium carbonate attached fouling. Therefore, the hydraulic shear at the near-wall surface of the irrigator flow channel was controlled at 0-0.24 and 0.65-0.70 Pa, in order to reduce the formation of calcium carbonate fouling. The finding can provide a strong support to the application and promotion of highly clog-resistant irrigators for the better quality in the water drip irrigation. [ABSTRACT FROM AUTHOR]