Agricultural Water Resources Research Articles

Monitoring Irrigation in Small Orchards with Cosmic-Ray Neutron Sensors.

Due to their unique characteristics, cosmic-ray neutron sensors (CRNSs) have potential in monitoring and informing irrigation management, and thus optimising the use of water resources in agriculture. However, practical methods to monitor small, irrigated fields with CRNSs are currently not available and the challenges of targeting areas smaller than the CRNS sensing volume are mostly unaddressed. In this study, CRNSs are used to continuously monitor soil moisture (SM) dynamics in two irrigated apple orchards (Agia, Greece) of ~1.2 ha. The CRNS-derived SM was compared to a reference SM obtained by weighting a dense sensor network. In the 2021 irrigation period, CRNSs could only capture the timing of irrigation events, and an ad hoc calibration resulted in improvements only in the hours before irrigation (RMSE between 0.020 and 0.035). In 2022, a correction based on neutron transport simulations, and on SM measurements from a non-irrigated location, was tested. In the nearby irrigated field, the proposed correction improved the CRNS-derived SM (from 0.052 to 0.031 RMSE) and, most importantly, allowed for monitoring the magnitude of SM dynamics that are due to irrigation. The results are a step forward in using CRNSs as a decision support system in irrigation management.

Matching Degree between Agricultural Water and Land Resources in the Xijiang River Basin under Changing Environment

The matching degree between agricultural water and land resources directly determines the sustainable development of regional agriculture. Based on climate data corrected by delta statistical downscaling from five global climate models (GCMs) in the Coupled Model Intercomparison Project Phase 6 (CMIP6) and a multi-model ensemble, this study simulated the runoff used by the Variable Infiltration Capacity (VIC-3L) model under four emission scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) and analyzed the land use changing trend to obtain the matching degree between agricultural water and land resources. The results demonstrate that annual climate factors exhibit an increasing trend, and the average annual runoff was 2128.08–2247.73 × 108 m3, during 2015–2100 under the four scenarios. The area of farmland changed with an increased area of 4201 km2 from 1980 to 2020. The agricultural water and land resources would be well matched under the SSP1-2.6 and SSP2-4.5 scenarios in 2021–2100. However, the risks of mismatch would occur in the 2030–2040 and 2050–2060 periods under the SSP3-7.0 scenario, and the 2030–2040 and 2080–2090 periods under the SSP5-8.5 scenario. This study can provide insight into the scientific decision support for government departments to address the challenges of mismatching risks of agricultural water and land resources.

Retracted: Integrated modeling of food–water–energy nexus for maximizing water productivity

ABSTRACT One of the needs of a sustainable decision-making system in agriculture is to determine the role of energy in the food production cycle. Wind energy turbines can be built in agricultural fields for groundwater exploitation and reduce the cost of energy supply for the pumping system. This study was conducted to evaluate the effect of wind energy and economics on sustainable planning of agricultural water resources. A multiobjective framework was developed based on the nondominated sorting principle and water cycle optimizer. Maximization of benefit per cost ratio for the total cropping pattern and minimization of energy consumption for the growing season were addressed as the objectives of the nonlinear problem. The prediction of biomass production was made by simulating a hybrid structure between the soil moisture balance in the root zone area and the development of the canopy cover of each crop. The results showed that the objectives of the problem have been met by irrigation planning using climatic constraints and drought stresses. About 35% of the total water requirement of plants with a higher harvest index (watermelon, melon, etc.) is in the maturing stage of the shade cover.

Optimal allocation of agricultural water resources in Yanghe watershed considering blue water to green water ratio.

Yanghe Watershed has low annual rainfall, uneven spatial and temporal distribution, extreme shortage of water resources in some areas. The contradiction between supply and demand of water for agricultural production is prominent and the expected production value cannot be achieved. Therefore, it is necessary to investigate the supply and demand of agricultural water resources and the impact of green water on agricultural crops in Yanghe Watershed. This article proposes a new crop economic model for increasing the green-water footprint to blue-water footprint ratio (GWF:BWF) in accordance with the regional characteristics, alleviating agricultural water shortage in irrigation areas, optimizing water resource allocation, and achieving sustainable agricultural development. The proposition is based on a study of five crops in eight districts and counties in the Yanghe River watershed. By combining the economic model F with a crop water production function, we achieved 89.3%, 88.9%, 97.1%, 81.5%, and 87.0% of the optimal water demands of the five crops, respectively, and effectively improved the underground irrigation of crops and the water resource utilization efficiency. The GWF:BWF threshold interval was subsequently selected based on the temporal changes in the BWF and GWF in the study area. This enabled significant reduction of the planting area of blue-water crops and increase in the proportion of green-water crops, while also improving the agricultural economy of the Yanghe Watershed. The proposed model promises to afford enhanced management of agricultural irrigation areas that experience rainfall shortage. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Spatiotemporal Rainfall Variability and Trend Analysis of Shimsha River Basin, India.

Karnataka state has the second highest rainfed agricultural land in India, where agricultural output relies heavily on rainfall. The Shimsha basin, a sub-basin of Cauvery in the state, comes under a semi-arid region and predominantly consists of rainfed agricultural land. Rainfall patterns have changed dramatically with time resulting in frequent floods and droughts. Understanding the spatiotemporal distribution of rainfall and its change patterns in the area would benefit sustainable agriculture planning and water resources management practices. The current study aims to determine the variability and trend in rainfall. The daily rainfall data of the Shimsha basin from 1989 to 2018 is collected, and the annual, seasonal, and monthly rainfall totals and the number of rainy days are derived. All the time series are subjected to statistical methods to examine rainfall variability and trend. The mean, standard deviation, coefficient of variation (CV), and Standardized Anomaly Index are used for the preliminary and variability analysis, while the coefficient of skewness and kurtosis are used to understand the rainfall distribution characteristics. The homogenous and serially independent series are identified by homogeneity and serial correlation tests. The trend in the homogenous and serially independent series is identified by Mann-Kendall and Spearman's rank correlation tests, while the magnitude of the trend is quantified using the Sen's slope technique, and the trend change point is evaluated using the sequential Mann-Kendall test. Based on the study, the average rainfall in the study area is 801.86mm, with CV ranging from 43.3 to 22.27%. The southwest monsoon (SWM) season brings the greatest rain to the basin, followed by the post-monsoon (PM), summer, and winter seasons. In the annual time frame, except one station, all other stations have shown significant or insignificant increasing trends. The seasonal rainfall has shown insignificant rising trends during the summer and winter seasons while insignificant increasing and decreasing trends during the PM season. The SWM season has indicated significant increasing trends, insignificant increasing and decreasing trends. Overall, the study area has noticed an increased annual and seasonal rainfall except for the post-monsoon season, during which the rainfall showed a considerable decline. The findings of the study are helpful in water resource management, agricultural planning, and socioeconomic development in the study area.

Water-Land-Food Nexus for Sustainable Agricultural Development in Main Grain-Producing Areas of North China Plain.

Stable and sustainable food production is an important guarantee for national security and social stability. The uneven distribution of cultivated land and water resources will threaten national food security. In this study, we adopt the Gini coefficient and water-land matching coefficient for exploring the water-land nexus in the main grain-producing areas of North China Plain (NCP) from 2000 to 2020. The water-land-food nexus considering grain crop production structure is further explored from spatial and temporal multi-scales. The results show the following: (1) The Gini coefficient presents an increasing trend in the NCP, indicating an increasing imbalance in the water-land matching degree among inter-regions. (2) There are significant differences in the WL nexus and WLF nexus among regions, showing a spatial pattern of "worse in the north and better in the south". (3) The cities which belonged to the low WL-low WLF and high WL-low WLF should be considered as key targets when formulating policies. (4) Adjusting the wheat-maize biannual system, optimizing the grain cultivation structure, promoting semi-dryland farming, and developing low water-consuming and high-yielding crop varieties are essential measures for these regions. The research results provide significant reference for the optimal management and sustainable agricultural development of agricultural land and water resources in NCP.

Study on water and heat transport of different types of vegetations and fields in Pengbo alpine irrigation district of Qinghai Tibet Plateau

Many water-saving projects have been initiated in the typical alpine irrigation district in Tibet, which resulted in dramatic changes to the hydrothermal conversion process. There is an urgent need to fully understand the hydrothermal transport process and to clarify the mechanism under which agricultural hydrology evolves in the alpine irrigation district of Tibet. This study selected highland barley field, oat field, wasteland (Natural herbage field without irrigation) in Pengbo irrigation district of Tibet as study objects to study soil water and heat dynamics and soil water balance. Observed water and temperature data were used to calibrate and validate simulations of the HYDRUS_1D model for 2019 and 2020, respectively. Simulations of soil water and temperature were in good agreement with the measured values, with determination coefficient of 0.69–0.91.This study proposes a set of hydrothermal parameters to fill the gap in the hydrothermal research of Tibet. The results showed that the variation of soil temperature was approximately sinusoidal, with a lag effect. The temperatures of the 0–20 cm and 30–50 cm soil layers lagged by about 1–2 h and 3–5 h, respectively. The highest rate of soil temperature increase occurred from the initial growth period to the rapid growth period during which the soil temperature of each layer increased by an average of 2 °C, however, the soil temperature in this period was not the most suitable for crop growth. Soil evaporation of highland barley field, oat field, and wasteland during the growth period accounted for 20 % – 29 %, 20 % – 29 %, 10 % – 18 % of the rainfall and irrigation, whereas transpiration accounted for 33 % – 43 %, 42 % – 50 %, and 36 % – 57 %, and percolation accounted for 42 %, 35–39 %, and 16–45 %, respectively. Implementation of water-saving projects resulted in reductions in irrigation volume and percolation rate. This study can provide a reference for clarifying the hydrothermal transport process and allocating agricultural water resources in the alpine irrigation district of Tibet.

Factors influencing the use of rainwater for agricultural irrigation: the case of greenhouse agriculture in southeast Spain

Abstract The availability and quality of water resources for agricultural irrigation are being increasingly compromised by different factors. In this context, the installation of rainwater harvesting (RWH) systems for use in agricultural holdings can contribute to mitigating this problem. However, the use of these systems by farmers continues to be very low. This paper analyses the factors that influence a farmer's decision to adopt these systems to take advantage of rainwater. Greenhouse agriculture in southeast Spain is the case studied. For this, a binary logistic regression model based on a survey administered to farmers was used. Among the variables found to be significant, the most important variables are the quantity of water in the pond, the pond capacity and environmental awareness. The variables that least affect the adoption decision are age, education level and income. These results have allowed the development of the main lines of action for policy-makers to intervene in order to promote the adoption of these systems. These measures focus on enhancing the training of farmers, providing them with financial support and boosting their environmental awareness. The results of this study lead to improved research on farmers’ behaviour and sustainable management of water resources in agriculture.

Spatio-Temporal Distribution Characteristics and Driving Factors of Main Grain Crop Water Productivity in the Yellow River Basin.

To reveal the relationship between agricultural water resource consumption and grain production in the Yellow River Basin, the irrigation water productivity (WPI), crop water productivity (WPC), total inflow water productivity (WPT), and eleven influencing factors were selected. The spatial and temporal distribution characteristics and driving factors of water productivity of the main crops in the Yellow River Basin were analyzed with the spatial autocorrelation analysis, grey correlation analysis, sensitivity analysis, and relative contribution rate. The results showed that the minimum mean values of WPI, WPC, and WPT were 0.22, 0.35, and 0.18 kg/m3 in Qinghai, respectively, the maximum mean value of WPI was 2.11 kg/m3 in Henan, and the maximum mean values of WPC and WPT were 0.71 and 0.61 kg/m3 in Shandong, respectively. The changing trends in WPI and WPT in Qinghai and in WPC in Shandong were insignificant, whereas the WPI, WPC, and WPT in other provinces showed a significant increasing trend. Water productivity displayed a certain spatial clustering feature in the Yellow River Basin in different years, such as a high-high (H-H) aggregation in Henan in 2005, and an H-H aggregation in Shanxi in 2015 for WPI. The water productivity had a significant positive correlation with the consumption of chemical fertilizer with a 100% effective component (CFCEC), effective irrigated area (EIA), plastic film used for agriculture (PFUA), and total power of agricultural machinery (AMTP), while it had a significant negative correlation with the persons engaged in rural areas (PERA). There was a large grey correlation degree between the water productivity and the average annual precipitation (AAP), CFCEC, PFUA, consumption of chemical pesticides (CFC), and AMTP in the Yellow River Basin, but their sensitivity was relatively small. The main driving factors were EIA (8.98%), agricultural water (AW, 15.55%), AMTP (12.64%), CFCEC (12.06%), and CPC (9.77%) for WPI; AMTP (16.46%), CFCEC (13.25%), average annual evaporation (AAE, 12.94%), EIA (10.49%), and PERA (10.19%) for WPC; and EIA (14.26%), AMTP (13.38%), AAP (12.30%), CFCEC (10.49%), and PFUA (9.69%) for WPT in the Yellow River Basin. The results can provide support for improving the utilization efficiency of agricultural water resources, optimizing the allocation of water resources, and implementing high-quality agricultural developments in the Yellow River Basin.

The drafting of village regulations concerning the management of agricultural water resources

The government is authorized to carry out agricultural water management in the village. This agricultural water management aims to ensure that water needs are well fulfilled and sustainable for the welfare of village communities. In this case, the Yosowilangun Lor Village Government, Yosowilangun District, Lumajang Regency, seeks to maintain sustainable agricultural water governance through the authority of the Village Government by establishing Village Regulation Number 7 of 2021 concerning Sustainable Agricultural Water Governance. However, based on the analysis of the situation, there are still problems regarding the implementation of Village Regulation 7 of 2021 concerning Sustainable Agricultural Water Governance, especially regarding the institutional structure and culture of the community in carrying out agricultural water governance in the country. Therefore, in order to strengthen the institutional structure. Moreover, the culture of the community in carrying out agricultural water governance in the village, steps are needed to strengthen the institutional management of agricultural water in the village.

Research on the optimal allocation of agricultural water and soil resources in the Heihe River Basin based on SWAT and intelligent optimization

In the context of global climate change, changes in precipitation and temperature conditions, especially the increasing frequency of extreme climate events, have a severe impact on agricultural production. Predicting climate change and adjusting planting structures over time are critical to sustainable agricultural development. In this study, the Coupled Model Intercomparison Project Phase 6 (CMIP6) and Soil and Water Assessment Tool (SWAT) models were used to simulate the future climate and runoff in the middle reaches of the Heihe River Basin (MHR). Then, the MOPSO and NSGA-II were used to plan future planting structures. The results showed that the temperature and precipitation in the MHR showed an increasing trend. By the 2070 s, the temperature was projected to increase by more than 2 °C under SSP245, while that under SSP585 was more than 4 °C. The annual mean precipitation was projected to increase, but the distribution was uneven, and the increased precipitation was mainly concentrated in spring and autumn. Under the interaction of temperature and precipitation, the runoff of the Heihe River will increase in the future, especially under SSP585, and the runoff of the Heihe River is projected to reach 2.48 billion m³/a in the 2070 s. Crop water demand was projected to increase with temperature, and crop irrigation water demand would increase by 14.4 % in the 2070 s under SSP245. Planting vegetables helps to improve agricultural economic benefits and carbon sinks, but to control soil erosion, the area of vegetables is best kept at approximately 16 %. Fertilizers and agricultural films are the primary carbon sources in agricultural production activities in MHR, accounting for more than 60 % of the total carbon. This study suggests promoting sustainable agricultural development by improving irrigation efficiency, using low-carbon fertilizers, controlling soil erosion, and gradually expanding the vegetable planting area with a considered ecological environment.

Bayesian vine copulas improve agricultural drought prediction for long lead times

Drought prediction models generally focus on shorter lead times (1–3-months) as their performance drastically declines at longer lead times (> 3 months). However, reliable agricultural drought prediction model with longer lead times is fundamental for reducing the impacts on agriculture sector, ecosystem, environment, and water resources. We propose a novel agricultural drought prediction model for long lead times by integrating vine copulas with Bayesian model averaging (hereafter, BVC model). Considering the previous meteorological drought, antecedent hot condition, and agricultural drought persistence as three predictors, the BVC model predicts agricultural drought with 1–6-month lead times. Here we focus on summer season (e.g., August) drought in China where agricultural drought impacts are more pronounced. Compared with optimal vine copula (OVC), average vine copula (AVC), and persistence-based models, the proposed BVC model performs better for 1–6-month lead times. Our findings can improve agricultural drought management, food security assessment, and early drought warning.

Evolutionary Trends, Regional Differences and Influencing Factors of the Green Efficiency of Agricultural Water Use in China Based on WF-GTWR Model.

Improving the green efficiency of agricultural water use is a key way to promote the sustainable utilization of agricultural water resources and sustainable development of economy and society. This work calculated and analyzed the evolution trend, regional differences and driving factors of the green efficiency of agricultural water use in China from the perspective of the water footprint. The results show that the green efficiency of agricultural water use in China shows a fluctuation trend of first declining and then rising from 1997 to 2020, after which the average efficiency dropped from 0.538 in 1997 to 0.406 in 2009, and then rose rapidly to 0.989 in 2020, with an average annual growth rate of about 3.6%. From a regional perspective, the green efficiency of agricultural water use in the eastern region was the highest (0.594), above the national average (0.538), followed by the western region (0.522), with the central region in last (0.491), with significant regional differences. The spatial differences in the green efficiency of available agricultural water in China shows a fluctuating downward trend. The Gini coefficient fluctuated from 0.271 in 1997 to 0.182 in 2020, with an average annual growth rate of about -1.4%. The main source of this regional difference was super-variable density, followed by the difference between the eastern and the central regions. The influence of urbanization level, water-saving level and agricultural trade on the green efficiency of agricultural water use was always positive and the influence of industrialization level was always negative; among them, the urbanization level, water-saving level and industrialization level had a greater impact on Northeast China, and agricultural trade had a greater impact on Southeast China. Therefore, this work puts forward relevant policy recommendations.

Impacts of meteorological factors and crop area changes on the variations in winter wheat water requirements in the lower reaches of the Yellow River Basin

Meteorological factors and human activities (such as changes in crop area) have exerted great impacts on the agricultural water resources. A thorough understanding of the changes in crop water requirements (CWR) and irrigation water requirements (IR) is crucial for effective agricultural water management. In the present study, the unit area and total volume of winter wheat CWR and IR were estimated based on meteorological and crop area data, and spatiotemporal variations were analyzed from 2001 to 2018 in the lower reaches of the Yellow River Basin. The impacts of meteorological factors and crop area changes on the CWR and IR variations were explored using sensitivity analysis and the logarithmic mean Divisia index method along with the identification of the main driving factors. The results revealed that both the unit area CWR and IR exhibited a decreasing trend with a multi-year average value of 540 mm and 488 mm, respectively, and increased gradually from south to northwest in the spatial distribution. The significant decrease in wind speed exerted the greatest impact on the unit area CWR and IR changes with the highest sensitivity among considered meteorological factors. The total volume of CWR and IR increased by 56.5 × 108 m3 and 32.3 × 108 m3 from 2001 to 2018, respectively. The crop area change of winter wheat was a major contributor to the variations in total volume of CWR and IR rather than meteorological factors during the study period, and evident spatial and temporal differences were observed. The results of this study provide valuable insights for developing adaptive strategies considering the impacts of meteorological factors and planted crop area changes and can therefore contribute to the sustainable utilization and management of agricultural water resources.

An alternative approach towards nitrification and bioremediation of wastewater from aquaponics using biofilm-based bioreactors: A review

Aquaponics combines the advantages of aquaculture and hydroponics as it suits the urban environment where a lack of agricultural land and water resources is observed. It is an ecologically sound system that completely reuses its system waste as plant fertilizer. It offers sustainable water savings, making it a supreme technology for food production. The two major processes that hold the system together are nitrification and denitrification. The remains of fish in form of ammonia reach the bio filters where it is converted into nitrite and further into nitrate in presence of nitrifying and denitrifying bacteria. Nitrate eventually is taken up by the plants. However, even after the uptake from the flow stream, the effluent contains remaining ammonium and nitrates, which cannot be directly released into the environment. In this review it is suggested how integrating the biofilm-based bioreactors in addition to aquaculture and hydroponics eliminates the possibility of remains of total ammonia nitrogen [TAN] contents, leading to bioremediation of effluent water from the system. Effluent water after releasing from a bioreactor can be reused in an aquaculture system, conditions provided in these bioreactors promote the growth of required bacteria and encourages the mutual development of plants and fishes and eventually leading to bioremediation of wastewater from aquaponics.

Optimization of Irrigation Water to Maximize Transplanted Aman Rice Production in Selected Areas of Bangladesh

In rainfed and irrigated agriculture, optimization of irrigation scheduling is very essential to maximize the crop production using the limited of agricultural water resources. A study was conducted to estimate requirement of irrigation and its scheduling of T. Aman (wet season) rice in the Northwest and Southeast region of Bangladesh using CROPWAT model. This paper utilized the daily rainfall and reference evapotranspiration data sets, obtained from seven weather stations for the period of 1981 to 2015. Effective rainfall and reference crop evapotranspiration (ETo) were calculated using the USDA Soil Conservation method and Penman-Monteith method, respectively. The simulation model of this explored the appropriate transplanting date to utilize maximum rainwater and to avoid supplemental irrigation. Four transplanting dates 15 July, 30 July, 15 August and 30 August were considered for transplanting T. Aman rice in the study areas. The optimization results showed that the water requirement was lower of the rice crop transplanting on 15 July in all locations due to higher effective rainfall. No supplemental irrigation was required for T. Aman cultivation transplanted on 30 July in Rangpur, Dinajpur, Bogura and Mymensingh regions since rainfall was sufficient to meet the demand of the crop. Therefore, this period was found for suitable and recommended for transplanting of T. Aman rice in these four locations. Transplanting after 30 July in these four locations needed supplemental irrigations. This study also revealed that 30 July transplanting required one supplemental irrigation in Jashore and Rajshahi regions due to insufficient rainfall. This period was also considered as the appropriate transplanting time in these two locations. However, in Pabna, one supplemental irrigation must be applied for T. Aman even transplanting on 15 July owing to in adequate rainfall. Irrigation requirement and number of irrigations were gradually increased with delaying the transplanting time. Early transplanting demanded less irrigation than late transplanting. Bangladesh Rice J. 25 (2) : 11-20, 2021

Considering spatio-temporal dynamics of soil water with evapotranspiration partitioning helps to clarify water utilization characteristics of summer maize under deficit irrigation

Continuously increasing the utilization efficiency of agricultural water resources is vital to ensuring future water and food security. Deficit irrigation (DI) could provide a solution to optimize crop water productivity. Research on the spatio-temporal dynamics of soil water coupled with evapotranspiration partitioning is important for clarifying summer maize (Zea mays L.) water utilization characteristics and crop water productivity under different DI strategies, especially in semi-arid regions. Consequently, a three-year field experiment with full irrigation (CK) and eight DI treatments (T1–T8, comprised of combinations of 100 %, 80 %, and 60 % of crop evapotranspiration) was conducted. Data from large-scale weighing lysimeters, micro-lysimeters, and TDR sensors were combined to assess daily root water absorption at different soil depths, actual evapotranspiration (ETa) partitioning into plant transpiration (T) and soil water evaporation (E), and water use efficiency (WUE). Results showed that soil water consumption mainly occurred in the 0–40 cm, 0–60 cm, and 0–80 cm soil layers during the maize growth stages of planting–V6, V6–V12, and V12–R6, respectively. Water absorption above the 60-cm soil depth accounted for more than 92 % of the total water consumption. The appropriate irrigation wetting depth for summer maize could be controlled in the top 80-cm layer to avoid deep percolation. DI affected soil water distribution and availability, and thus decreased soil water consumption rate (WCR) and root water absorption amount. Under moderate water deficit conditions, WCR was rapidly restored to the non-water-stressed irrigation treatment level, and even exceeded that level in the deeper layers after a subsequent irrigation was applied, especially in the early maize growth stages. E/ETa was 31.0–32.5 % under full irrigation. DI decreased total soil water evaporation amount, but increased the E/ETa ratio. The threshold soil water value for defining when maize was subjected to water stress was 22.0 % (72 % of FC) during V3–V12, and 18.0 % (60 % of FC) during V12–R1. Our results suggest that less water was used in T1 (moderate DI) than with the full irrigation treatment. WUE increased by 5.5 %–7.5 % as irrigation amount decreased by 12.3–14.5 % and yield decreased by 3.3 %–8.0 %. These results improve our understanding of maize water consumption characteristics with regard to soil water absorption in different soil layers and evapotranspiration partitioning, and provide implications for efficient water management in arid areas of northwest China.

Education level of farmers, market-oriented reforms, and the utilization efficiency of agricultural water resources in China

Education level of farmers, market-oriented reforms, and the utilization efficiency of agricultural water resources in China

Lake eutrophication: Control of phytoplankton overgrowth and invasive aquatic weeds

AbstractThis brief review describes the major causes of lake cultural eutrophication and assesses different strategies applied to control or reduce the negative consequences of this eutrophication. Excessive nutrient inputs, particularly from agricultural lands through non‐point source runoff, are among the main causes of cultural eutrophication on a global scale. Reducing nutrient inputs from agricultural lands through management of lake catchment areas, therefore, is an integral part of any effort to control lake eutrophication. Nutrient enrichment results in algal blooms and creates favourable condition for the invasion of a lake by alien aquatic weeds, making this invaluable freshwater resource unsuitable for many purposes, including drinking, agricultural and industrial water resources, fishing, transportation and recreational purposes. A major part of this review addresses attempts made to address the negative impacts of eutrophication by restoring water quality. Several research outputs discussing bottom‐up and top‐down control mechanisms were utilized for the present review. Much emphasis has been given in the literature regarding the use of biomanipulation as a promising and sustainable solution for controlling eutrophication. Biomanipulation tools used to control cyanobacteria and algal bloom have involved zooplanktivorous fish removal, piscivorous fish stocking, daphnia stocking, benthivorous fish removal, planktivorous fish stocking and mussel stocking. Further, some insect and fungal species have been used as biological control agents in an effort to control invasive aquatic weeds in tropical lakes. Although this review is limited in its analysis and explanation of the drawbacks associated with each described biomanipulation method, it can be deduced that biomanipulation generally exhibits considerable potential for controlling or reducing phytoplankton overgrowth and aquatic weed invasions, assuming it is also integrated with strategies to control external nutrient loadings to lakes.

Clean Energy Contributes to Poverty Alleviation in China

Poverty has long plagued humanity. The main factors affecting the gap between the rich and the poor are natural resources, human resources, information resources and science and technology. Using data from various clean energy industries and historical research methods, this paper shows that the clean energy industry is a new way to reduce poverty in developing countries. In the history of agricultural development, land and water resources are the important sources of wealth growth. In the history of industrial development, mineral resources, coal and oil energy have become the material basis for getting rich. In the 21st century with the great development of artificial intelligence, the importance of power resources is becoming more and more prominent, and clean energy such as solar energy and wind energy has become a new natural resource to create social wealth. Chinese successful practice in the development of clean energy industry shows that the clean energy industry is an effective way to get out of poverty. The results of the cooperation between China and African countries in developing clean energy industries show that the energy industry plays an increasingly important role in helping developing countries out of poverty. Although the development of clean energy industry is still restricted by market competition and monopoly organizations, the development road is still tortuous and long, it has a very bright future.