Water-saving Irrigation Research Articles

Dynamic Assessment and Sustainability Strategies of Ecological Security in the Irtysh River Basin of Xinjiang, China.

The drylands of China are extensive, and they are home to more than one-third of the country's population. However, the watershed territories of the drylands, where the majority of human activities are concentrated have long experienced strained human-land relationships, culminating in ecological security concerns. Correspondingly, it is essential to carry out a comprehensive assessment of the ecological security of dryland watersheds and to identify the key factors influencing ecological security in order to formulate strategies that ensure the sustainability of drylands. Premised on the Driving-Pressure-State-Impact-Response (DPSIR) model, this study developed an ecological security index and applied it to the Irtysh River Basin of Xinjiang, China, from 2000 to 2020. The obstacle degree model was applied to reveal the obstacles in two dimensions: criterion level and indicator level. The findings suggested that the ecological security comprehensive index in the Irtysh River Basin has increased significantly from 2000 to 2020, irrespective of the fact that it decreased during the study period and then increased. The ecological security level changed from 'critically safe' in 2000 to 'general safety' in 2020, with the state subsystem and pressure subsystem becoming ecological security weaknesses. The primary factors influencing the ecological security of the study area were water consumption, the area of high-efficiency water-saving irrigation, the proportion of wetland area, vegetation coverage, and livestock population. The ecological security of different counties in the basin varies greatly, whereas the factors that influence ecological security showed both similarities and differences among the counties. In light of on the findings, we proposed that future strategies for ecological security enhancement should concentrate on enacting the policy of localizing spatial differentiation, optimizing industrial structure, strengthening scientific and technological support in the field of water conservation, bolstering the treatment capacity of environmental facilities, and implementing the Mountains-Rivers-Forests-Farmlands-Lakes-Grasslands System to support the sustainable development of dryland watersheds.

Exploring the Influences of Water-Saving Practices on the Spatiotemporal Evolution of Groundwater Dynamics in a Large-Scale Arid District in the Yellow River Basin

Water-saving practices (WSPs) have been recognized as an effective measure for reducing agricultural water use and alleviating regional water shortages in arid irrigation districts. However, WSPs have also reduced groundwater recharge, thereby causing the depth to groundwater table (DGT) to increase. Therefore, characterizing the impact of WSPs on the spatiotemporal variability in the DGT is of paramount importance for protecting limited groundwater resources. Based on monthly DGT observation data collected from 1990 to 2015 at 206 observation wells in the Hetao Irrigation District (HID), located in Northwest China with an arid climate, the spatiotemporal variations in DGT before and after the application of WSPs were analyzed using the empirical orthogonal function (EOF) method, and the major driving factors of the spatiotemporal DGT changes were also identified using comprehensive approaches. The EOF method revealed four major spatiotemporal DGT patterns both before and after WSPs were applied; these patterns explained 71.39% and 73.99% of the total variability in the HID before and after WSPs application, respectively. In addition, the main controlling factors affecting the DGT dynamics were different before and after WSPs were applied. In terms of the associations of the DGT with the impacting factors, the meteorological factors had the strongest impact on the DGT changes on the long-term scale of 64 months; however, irrigation played a leading role at the seasonal and semiannual scales, especially after WSPs application. The soil texture significantly impacted the spatial DGT patterns, particularly at depths above 150 cm. This study provides a scientific basis for the rational development of local groundwater resources and the scientific management of water-saving irrigation measures.

Influence of Irrigation Levels and Mulching Types on Growth and Yield of Bean in Drought Prone Area of Bugesera, Eastern Rwanda

Purpose: Water saving practices are crucial for crop production in drought prone areas. This study was conducted in Bugesera District, in the Eastern Province of Rwanda. The objective was to determine the effect of irrigation levels and mulching types on growth and yields of beans. 
 Methodology: A split plot experiment consisting of three irrigation levels as main plots and three mulching types (no mulch, grass mulch and plastic mulch) as subplots, in a Randomized Complete Block Design (RCBD), with three replications was conducted. Climbing bean, Mac 44 variety, was planted at 50 cm × 20 cm spacing. Different levels of irrigation and mulching were applied from 3 weeks after crop emergence. Irrigation water was applied using a manual watering can.
 Findings: Bean height and grain yield varied significantly due to the combined effects of irrigation × mulching. Highest value of plant height, 100 grain weight and yield value were obtained under the combination of 50% irrigation level with grass mulch. Compared to the control, yield improvement of 83%, 100 grains weight improvement of 39% and plant height increase of 20 % were observed under I1M1. Significant and positive correlations were observed between yield, plant height and yield parameters. The observed interdependence of yield parameters is illustrated by the positive and significant correlation between these parameters. Combining irrigation and mulching would improve climbing production while saving irrigation water up to 50%.
 Recommendation: Both plastic and grass mulch gave similar results, however grass mulch is recommended for climbing bean production in the study area due to its additional advantages over the plastic mulch. 

A Water Stress–Tolerant Pepper Rootstock Improves the Behavior of Pepper Plants under Deficit Irrigation through Root Biomass Distribution and Physiological Adaptation

The use of rootstocks tolerant to water stress in pepper crops is a complementary technique for saving irrigation water without affecting yields by means of particular rootstock physiological traits, which changes the scion’s perception stress. The present study aimed to analyze the morphological and physiological adaptation of the ‘Cuerno’ pepper cultivar grafted onto tolerant rootstock NIBER® subjected to capacitance sensor-based deficit irrigation. The stomatal conductance, relative water content and leaf water potential parameters were used to confirm the degree of crop stress. Leaf dry weight and root volume were higher in the grafted plants under the control irrigation and stress treatment conditions. Total fresh root biomass and root volume percentage of grafted plants under water stress were 24% and 33% higher, respectively, than the ungrafted plants. The grafted plants subjected to both water stress and control conditions had a higher marketable production than the ungrafted plants. The higher yields obtained using tolerant rootstocks were explained by the reduced blossom-end rot incidence.

ANALISIS PENGARUH METODE SRI DAN KONVENSIONAL TERHADAP LUAS LAYANAN IRIGASI PADA BENDUNGAN MENINTING

The biggest water demand is in the agricultural sector. This great need is caused by the irrigation system with continuous inundation (conventional). One of the water-saving irrigation methods is the System of Rice Intensification (SRI) method. The SRI method of giving water is done intermittently. One of the obstacles to the application of the SRI method is a continuous water source. The dam is one of the water sources whose water availability is relatively easy to manage, making it suitable for irrigation applications using the SRI method. This study aims to analyze the provision of irrigation water for SRI and conventional systems at the Meninting Dam and its effect on the area of irrigation services. In this study, an analysis of water availability was carried out using awlr data, an analysis of irrigation water requirements using the conventional method and the SRI method. Reservoir simulation analysis is used to determine the area that can be irrigated, planting intensity and reservoir reliability. The results for the conventional method of irrigated area that can be served are 1,559 ha with a planting intensity of 300% and a reservoir reliability of 95.83%. At the same intensity and reliability as the conventional method, the SRI method can irrigate 1,980 ha of irrigation area, so using the SRI method can increase the service area by 421 ha or can increase the service area by 27%.

Intelligent control System wide-reach Sprinklers circular action

The relevance of the introduction of intelligent control systems for agricultural machinery in the modern world is increasing every year due to the development of more and more global projects in the field of automation and robotics. The purpose of the research was to develop algorithmic software for an intelligent control system for wide-reach sprinkler machines for autonomous operation in the implementation of environmentally safe, high-quality irrigation. The article considers the possibility of matching the irrigation norm issued by the machine to the level of moisture reserves of the field for circular-acting machines, reducing the environmental load on the soil and preserving fertility. The use of an intelligent control system with the proposed algorithm of operation will improve the quality and environmental safety of irrigation, as well as ensure resource savings, in particular irrigation water savings.

The inhibitory effect of a water-saving irrigation regime on CH4 emission in Mollisols under straw incorporation for 5 consecutive years

The inhibitory effect of a water-saving irrigation regime on CH4 emission in Mollisols under straw incorporation for 5 consecutive years

Carbon reduction effect of agricultural green production technology: A new evidence from China

Both contemporary policy makers and scholars focus on the role of agricultural sector in better achieving carbon reduction and green transition. This paper empirically analyzes the impact and mechanism of agricultural green production technology (AGPT) on agricultural carbon emission intensity at the national level using the panel data of China's 31 provinces from 2000 to 2019 as well as the panel OLS method and spatial Durbin model. The results show that China's AGPTs adoption level have improved greatly and the agricultural carbon emission intensity has declined drastically in the period of 2000 to 2019. No-till planting and straw returning significantly inhibited agricultural carbon emission intensity, while water-saving irrigation had the opposite effect. Chemical fertilizers are substituted effect through zero-tillage planting and straw-return, thus reducing the agricultural carbon emission intensity. Water-saving irrigation serves as a supplement effect to chemical fertilizers application, inhibiting fertilizer's carbon increase effects. The role of AGPTs reduce carbon emissions is particularly dominant in main grain-producing areas. Straw-return played a significant negative spatial spillover effect on the agricultural carbon emission intensity of neighboring regions through technology dissemination across regions, and the spillover effect of zero-tillage planting and water-saving irrigation was not significant. According to local conditions, no-tillage planting and straw returning should be promoted, water-saving irrigation efficiency should be improved, and the input characteristics of high carbon elements in traditional agriculture should be gradually changed. A regional collaborative emission reduction mechanism should be established to achieve a long-term mechanism for agricultural carbon emission reduction and green development.

Can Agricultural Cooperatives Promote Chinese Farmers' Adoption of Green Technologies?

Green technologies are important for achieving green and high-quality agricultural development. The Chinese government has issued various policies to explicitly encourage the adoption of green technologies. However, incentives for Chinese farmers to adopt green technologies remain insufficient. This study examines whether participation in agricultural cooperatives can help break the barriers to Chinese farmers' adoption of green technologies. It also examines the potential mechanisms by which cooperatives can mitigate the lack of incentives for farmers to adopt agricultural green technologies. Using data from a study on farmers in four Chinese provinces, we found that cooperative participation significantly increases farmers' adoption behavior for both green technologies with effective market incentives (e.g., commercial organic fertilizer technologies) and those without such incentives (e.g., water-saving irrigation technologies).

Estimation of crop water stress index and leaf area index based on remote sensing data

Abstract Estimation of crop water stress index (CWSI) and leaf area index (LAI) over large-irrigation schemes requires the use of cutting-edge technologies. Combinations of remote sensing techniques with ground-truth data have become available for use at the catchment level. These approaches allow us to estimate actual evapotranspiration and have the capability of monitoring crop water status and saving irrigation water in water-scarce regions. This study was conducted in the eastern Mediterranean Region of Turkiye. Fully distributed CWSI maps were generated and we assessed the relationship between CWSI and LAI for some specific crops in the winter season of 2021. Landsat 7 and 8 data were used and meteorological data were acquired from two stations in the study area. ‘Mapping Evapotranspiration at high Resolution with Internalized Calibration’ methodology was applied to estimate the energy balance components. CWSI maps displayed spatiotemporal changes in tandem with crop-type variations. Consequently, results presented a high correlation (r = 0.95 and r = 0.99 for wheat and lettuce, respectively) between CWSI and LAI, a moderate correlation (r = 0.44) for potatoes in the winter season. Thus, by utilizing remotely sensed data, the CWSI values would be directly estimated without requiring any in situ measurements of the canopy and air temperature over-irrigation scheme.

Study on the In-Field Water Balance of Direct-Seeded Rice with Various Irrigation Regimes under Arid Climatic Conditions in Egypt Using the AquaCrop Model

Crop growth models are cost-effective and user-friendly tools for decision-makers to develop efficient in-field management strategies. These models are particularly important in countries such as Egypt, where the risk of water scarcity is inevitable. The present study aimed to examine the in-field water balance of direct-seeded rice (Giza 178) under various irrigation regimes and arid conditions during two growing seasons (2019 and 2020). Four irrigation regimes, namely, continuous flood irrigation with a fixed water depth of 5 cm, and 3-, 6-, and 10-day irrigation frequencies (FI, 3IF, 6IF, and 10IF, respectively), were arranged in a randomized complete block design with three replicates. Then, the feasibility of using AquaCrop in simulating direct-seeded rice development and in-field water balance was assessed. Five statistical indicators, including normalized root-mean-squared error (NRMSE), index of agreement (d), coefficient of determination (R2), Nash–Sutcliffe efficiency coefficient (EF), and percent deviation (Pd), were used to evaluate the performance of AquaCrop. The field trial results demonstrated that both the 3IF and 6IF irrigation regimes were the best for achieving the highest biomass (21.0 t·ha−1, under 3IF), yield (9.8 t·ha−1, under 3IF), and saving irrigation water (18.3–22.4%, under 6IF), making them the best to apply in Egypt. Moreover, the AquaCrop simulation results showed a good correlation between the observed and simulated rice yield (Y) in both seasons (R2 = 0.99 and 0.98 in 2019 and 2020, respectively). AquaCrop showed excellent performance in simulating canopy cover (CC) and biomass (B) during both growing seasons (5.0 ≤ NRMSE ≤ 15.0, 0.97 ≤ d ≤ 0.99, 0.92 ≤ R2 ≤ 0.99, and 0.92 ≤ EF ≤ 0.99). In addition, the model showed acceptable performance in simulating in-field water balance components. Reasonably good model efficiency was recorded in simulating crop actual evapotranspiration (ETact). Meanwhile, the average Pd for percolation (P) was between −15.3% and 5.4% during both growing seasons. Overall, AquaCrop showed adequate accuracy in simulating CC, B, Y, ETact, and P but relatively low efficiency in simulating ETact and P under severe water scarcity. Therefore, AquaCrop may serve as a valuable tool for irrigation management and crop yield prediction even in arid regions, such as Egypt.

Water-Saving Cropping Pattern as A Strategy to Combat Climate Change Effects and Sustain Groundwater Resource in The Dry, North-Western Region of Bangladesh

Increased groundwater use in the Barind area during the last few decades has caused serious groundwater level decline, decreased pump discharge and hence increased irrigation cost, and many associated hydrological problems which have become the biggest threat to sustainable agricultural production under climate change situation. The aims of this research were (i) to identify optimum/water-saving irrigation schedule of possible crops of different seasons, and (ii) yearly total yield and irrigation need assessment of different crop rotations to identify water-saving crop rotation. Field experiments were conducted for three consecutive years at four locations with four new cropping patterns, intervening non-rice crops (wheat, mustard, lentil) as well as natural rainfall matching ‘Aus rice’ crop. Irrigation water savings and economic benefits of each cropping pattern were evaluated. The results revealed that cultivation of non- rice crops instead of irrigation-intensive ‘Boro rice’ along with efficient irrigation schedule can reduce a substantial amount (48 - 58%) of irrigation demand along with higher economic benefits (both net profit and Benefit Cost Ratio). The findings of this research will help to plan management decisions to combat the declining trend of groundwater table, as well as the consequences of climate change and drought.

Influence of drought stress and foliar application of chitosan on nutrient accumulation and phenolic composition of Thymus daenensis Celak

AbstractChanges in climate have intensified the drought in semi‐arid regions. A shift toward cultivation of low‐input crops, including high‐value medicinal and herbal plants seems a more sustainable alternative strategy. A 2‐year field study was conducted to investigate the influence of drought stress and chitosan on nutrient density and phenolic compounds of thyme. Treatments consisted of a factorial combination of three irrigation and three chitosan rates. Irrigation treatments consisted of keeping experimental plots at field capacity (no stress), irrigation when plots reached 50% of field capacity (mild stress), and irrigation when plots reached 25% of field capacity (severe stress). Chitosan rates were 0, 200, and 400 μL L−1, while K+, and to some degree Ca+2, accumulation increased by drought, N, P, and all micronutrients (Mn2+, Zn2+, Cu2+, and Fe2+) decreased steadily as drought stress intensified. Drought stress reduced N and P by 23%–19% and 35%–23%, respectively, over the 2 years. Application of chitosan enhanced the accumulation of macro and micronutrients. Drought stress resulted in alterations in phenolic composition. In mature plants, almost all phenolic compounds, except thymol, increased as drought stress intensified. Cinnamic acid and rosmarinic contents, as the two major identified compounds, increased by 31% and 45%, respectively, under severe drought. Similar to drought, chitosan elicitation was more effective in elevating phenolic compounds in mature plants. The response of thyme to chitosan was independent of soil moisture availability. The results indicated that application of 400 μL−1 chitosan improved nutrient density and dry matter while significantly saved irrigation water.

Optimized border irrigation delays winter wheat flag leaf senescence and promotes grain filling.

Border irrigation is still the main irrigation method in the Huang-Huai-Hai Plain of China (HPC), and the suitable irrigation border length for water saving and high yield under traditional irrigation is still unclear. Therefore, a 2-year traditional border irrigation experiment (2017-2019) was conducted on the HPC. Four border lengths were tested: 20m (L20), 30m (L30), 40m (L40), and 50m (L50). These treatments were given supplementary irrigation at jointing and anthesis. An exclusively rainfed condition formed the control treatment. Compared with other treatments, the activities of superoxide dismutase antioxidant and sucrose phosphate synthetase, and the contents of sucrose and soluble proteins after anthesis were higher in the L40 and L50 treatments, while the content of malondialdehyde content was lower. Therefore, the L40 treatment effectively delayed the decrease in the soil plant analysis development (SPAD) value and chlorophyll fluorescence characteristics, promoted grain filling, and achieved the highest thousand-grain weight. Compared with the L40 treatment, the grain yields of the L20 and L30 treatment were significantly reduced, while the water productivity of the L50 treatment was significantly reduced. These findings suggest that 40m was the optimal border length for both high yield and water saving in this experiment. This study provides a simple and low-cost water-saving irrigation method for winter wheat in the HPC under traditional irrigation, which can help alleviate the pressure of agricultural water use.

Difference in Energy Input and Output in Agricultural Production under Surface Irrigation and Water-Saving Irrigation: A Case Study of Kiwi Fruit in Shaanxi

China’s kiwi industry has seen rising production costs and shrinking planting areas in recent years; at the same time, the lack of professional production standards leads to the input redundancy and waste of production factors in the production process of kiwifruit, which intensifies the dilemma of unsustainable agricultural production. This has brought more and more serious challenges to the sustainable development of the industry. In order to solve this problem and clarify the composition and utilization efficiency of energy in the production process of kiwifruit, this study took Chinese kiwifruit production as the research object and analyzed the energy input and output under surface irrigation and water-saving irrigation from the perspective of energy. The results show that the energy input of kiwifruit production under traditional surface irrigation was 85.4 GJ/ha, and the energy output was 59.7 GJ/ha. Among all energy input elements, mineral fertilizers accounted for the highest proportion of energy input, accounting for 48.31%. Under water-saving irrigation, the energy input and output of kiwifruit production are 72.3 GJ/ha and 62.3 GJ/ha; the highest energy input is also mineral fertilizer. The data envelopment analysis results also confirmed that there is a large redundancy in the amount of mineral fertilizer. Compared with surface irrigation, water-saving irrigation technology has effectively improved the energy ratio (from 0.70 to 0.86), energy productivity (from 0.37 kg/MJ to 0.45 kg/MJ) as well as net energy (from −25.8 GJ/ha to −9.93 GJ/ha). Thus, promoting the application of water-saving irrigation technology and increasing the proportion of fertigation during the kiwi production process are necessary measures to promote the sustainable development of China’s kiwi industry.

Impacts of small-scale irrigation water use on environmental flow of ungauged rivers in Africa

Failure in Environmental flow in quantity, timing, and quality leads to failure to support ecosystems, human livelihoods, and well-being. Irrigation water use is one of the main actors in impacting the water flow of rivers in quantity and time but was not well investigated in many ungauged catchments under smallholder irrigation systems. This study examined the impact of irrigation water use on environmental flow in Arata's small ungauged catchment. The study estimated the flow in sub-catchment using the area ratio method, the crop irrigation water requirement using F.A.O. cropwat 8.0, and the water balance in the Water Evaluation and Planning System tool and the environmental flow in Tennants, Q95, asnd local area thumb rule. The result showed that the minimum environmental flow of the Arata catchment is 290, 310, and 60 li/sec in the Tennant, Q95, and the local thumb rule. Irrigation consumes only 9% of the water resources of the catchment while 91% is contributed to downstream lake Ziway via Ketar river. January and February have unmet water demand and zero environmental flow. In December Tennant's 10% and Q95 recommended environmental flow had 19% and 24% deficit while the thumb rule environmental flow is 291% more than the minimum requirement. The rest of the months are by far more than the minimum environmental flow requirement. Given the result, meeting the environmental flow of the system throughout the year needs the installation of a water storage facility from upstream to downstream, the introduction of different water-saving irrigation technologies, farmers' capacity building in irrigation water management, and a standardized environmental flow estimation mechanism.

Extraction of 3D distribution of potato plant CWSI based on thermal infrared image and binocular stereovision system.

As the largest component of crops, water has an important impact on the growth and development of crops. Timely, rapid, continuous, and non-destructive detection of crop water stress status is crucial for crop water-saving irrigation, production, and breeding. Indices based on leaf or canopy temperature acquired by thermal imaging are widely used for crop water stress diagnosis. However, most studies fail to achieve high-throughput, continuous water stress detection and mostly focus on two-dimension measurements. This study developed a low-cost three-dimension (3D) motion robotic system, which is equipped with a designed 3D imaging system to automatically collect potato plant data, including thermal and binocular RGB data. A method is developed to obtain 3D plant fusion point cloud with depth, temperature, and RGB color information using the acquired thermal and binocular RGB data. Firstly, the developed system is used to automatically collect the data of the potato plants in the scene. Secondly, the collected data was processed, and the green canopy was extracted from the color image, which is convenient for the speeded-up robust features algorithm to detect more effective matching features. Photogrammetry combined with structural similarity index was applied to calculate the optimal homography transform matrix between thermal and color images and used for image registration. Thirdly, based on the registration of the two images, 3D reconstruction was carried out using binocular stereo vision technology to generate the original 3D point cloud with temperature information. The original 3D point cloud data were further processed through canopy extraction, denoising, and k-means based temperature clustering steps to optimize the data. Finally, the crop water stress index (CWSI) of each point and average CWSI in the canopy were calculated, and its daily variation and influencing factors were analyzed in combination with environmental parameters. The developed system and the proposed method can effectively detect the water stress status of potato plants in 3D, which can provide support for analyzing the differences in the three-dimensional distribution and spatial and temporal variation patterns of CWSI in potato.

Factors Influencing Water Use Efficiency in Agriculture: A Case Study of Shaanxi, China

Enhancing agricultural water use efficiency can support Shaanxi Province’s transition to a sustainable agricultural economy. Using the data envelopment approach (DEA), we evaluated the water use efficiency in agriculture of various cities in the Shaanxi Province of China. Moran’s I and Dagum Gini coefficients were used to reveal spatial and temporal characteristics of agricultural water use efficiency. Furthermore, the geographically and temporally weighted regression (GTWR) model was used to investigate the effects of the agricultural economy, level of water-saving irrigation, cropping structure, environmental factors, and water supply structure on agricultural water use efficiency. The findings demonstrate that the average agricultural water use efficiency from 2011 to 2020 is low (0.796) in Shaanxi Province. Spatially there is considerable variation in water use efficiency between cities, with some highly efficient and some with very low efficiency. There is a strong negative spatial correlation between cities, with high efficiency cities tending to be adjacent to low efficiency cities. Moreover, the spatial differences in agricultural water use efficiency have increased over time, with the most significant increase within the northern region and between the north and central areas. Each influencing factor has a different impact from year to year and from city to city. Overall, the level of water-saving, the level of agricultural economics, the structure of the water supply, and environmental factors primarily have a negative influence. In contrast, the planting structure primarily has a favorable function. Therefore, to support the coordinated growth of agricultural water use efficiency, Shaanxi Province should improve its city-to-city cooperation and exchange of water use technology and experience, as well as develop differentiated water use measures appropriately for the development of each city according to local conditions.

Spatiotemporal Characteristics and Hazard Assessments of Maize (Zea mays L.) Drought and Waterlogging: A Case Study in Songliao Plain of China

The Songliao Plain is the largest maize (Zea mays L.) cropland area in China and, thus, is most influenced by water stress. To mitigate the adverse impact of water stress on maize yield and quality, various agricultural irrigation strategies have been implemented. Based on land surface temperature and an enhanced vegetation index, this study constructed the temperature vegetation dryness index (TVDI) and combined the Hurst index and Sen trend to analyze the spatiotemporal characteristics of drought and waterlogging. From the correlation between TVDI and gross primary productivity, the weight coefficients of different growth cycles of maize were derived to determine the drought and waterlogging stresses on maize in Songliao Plain for 2000–2020. The drought hazard on the western side of Songliao Plain was high in the west and low in the east, whereas the waterlogging hazard was high in the east. Waterlogging likely persisted according to the spatiotemporal trends and patterns of drought and waterlogging. During the second growth cycle, maize was most severely affected by water stress. There was a spatial heterogeneity in the severity of the hazards and the stress degree of maize. For the reason that precipitation in the study area was concentrated between mid-late July and early August, maize was susceptible to drought stress during the first two growth stages. Irrigation concentrated in the early and middle stages of maize growth and development in the western part of the Songliao Plain reduced the drought stress-induced damage. Spatiotemporally-detected drought and waterlogging couplings and hazards for maize in the Songliao Plain for 2000–2020 provide actionable insights into the prevention and mitigation of such disasters and the implementation of water-saving irrigation practices at the regional scale.

Research on the Structure of an Underground Irrigation Composite Pipe-Forming Device

In order to promote the comprehensive utilization of corn straw and the development of field water-saving irrigation technologies, a kind of underground irrigation composite pipe-forming device mixed with soil extrusion molding was designed. The key extrusion-forming components affecting the forming rate of composite pipe were optimized by taking the diameter of the winch blade, the shaft diameter of the winch, and the winch pitch as variables and the forming rate and the output power of the winch shaft as test indices. The best structural parameters of the extrusion-forming components were obtained by using the weight normalization method; the diameter of the winch blade was 430 mm, the shaft diameter of the winch was 86 mm, the winch pitch was 387 mm, the forming rate was 1.37 kg/s, and the forming rate of the composite pipe was increased by 41%. Field tests were conducted to verify the simulation test results, and the relative error between the forming rate of composite pipe and the simulation test value was 5.88%, which verified the reliability of the simulation test. The average density of the extruded composite tube was 1.92 g/cm3, meeting the requirements for composite tube formation.