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Knowledge of both irrigation-water withdrawal (IWW) and consumption (IWC, i.e. the evapotranspiration loss of applied irrigation water) is critical to sustainable water use and management. However, IWW and IWC are not well differentiated and an integrated analysis of their changes and causes is still lacking. Here we aim to close this gap and investigate the trends and drivers of IWW and IWC over mainland China using the logarithmic mean Divisia index approach and multivariate regression and fixed-effects panel regression models. We find that IWW decreased at a rate of −1.3 km 3 yr −1 (or −0.4% yr −1 ) while IWC increased at a rate of 2.9 km 3 yr −1 (or 2.4% yr −1 ) from 1999 to 2013, albeit both showed upward trends from 1982 to 1999. The reduction in IWW was due to the decreased water-withdrawal intensity (WWI) (i.e. IWW per unit area), while the increase in IWC was mainly due to the irrigated area expansion. We find opposite trends in IWW and IWC in about half of the Chinese provinces, with IWW decreasing and IWC increasing in most cases. Changes in irrigation efficiency (IE, defined as the ratio of IWC to IWW) and climatic factors explain a large proportion of the variance in WWI and water-consumption intensity (i.e. IWC per unit area). IE presents a strong negative correlation with WWI but a positive correlation with water-consumption intensity. The improved IE makes a nonnegligible contribution (∼20%) to the irrigated area expansion, especially in water-scarce regions. The strong positive linkage between IE and IWC together with the significant rise in IWC with increasing IE suggest that the paradox of IE (i.e. higher IE tends to increase water consumption) has manifested in mainland China. Our findings highlight the importance of considering both IWW and IWC changes as well as farmer’s behavior adjustments in water resource management.

Irrigation water is the main type of water consumption in the Yanqi Basin irrigation district of Xinjiang, which is an oasis-type irrigation district in the arid region of Northwest China. With the continuous expansion of cultivated areas, there is an increasing demand for irrigation water, resulting in an irrigation efficiency paradox and the phenomenon of “the more water-saving, the more water-scarce”. In this study, the water balance method and the improved IWMI (International Water Management Institute) water balance method were used with remote sensing and statistical data from 1980 to 2020 to analyze the changes in the irrigation water supply, consumption, and loss for improvement in irrigation water use efficiency (IWUE) in the Yanqi Basin. The results showed that there was an upward trend in the cultivated land area in the irrigation district of Yanqi Basin, as monitored with remote sensing from 1980 to 2020, and the values from the remote sensing data were higher than those from the yearbooks. According to the remote sensing data, the arable land area in the irrigation district increased from 1672 km2 in 1980 to 2494 km2 in 2020, thus showing a trend of expansion. The traditional water use efficiency in the irrigation district showed an increasing trend. The lowest value for the field water-use coefficient was 0.70 in 1998, and it exceeded to 0.81 from 2009 to 2020. The canal water-use coefficient was as low as 0.50 in 1998 and increased from 0.54 in 2009 to 0.82 in 2020. The irrigation water-use coefficient increased from 0.35 in 1998 to 0.68 in 2020, with a general upward trend. In this study, the water consumption ratio indicator DFg (depleted fraction), determined using the improved water balance method, increased from 0.8390 in 1980 to 0.8562 in 2020, although it showed an overall decreasing trend, and the average was 0.8436. Cultivated land’s actual irrigation water consumption per unit area reached the highest value of 8.41 × 106 m3/hm2/a in 2011 and the minimum value of 4.01 × 106 m3/hm2/a in 2020, and from 1980 to 2020 it showed a decreasing trend, while the total water diversion showed an increasing trend due to the continuous expansion of arable land. From 1980 to 2020, water diversion into the irrigation district changed from 1.214 km3 to 1.000 km3, and it reached a maximum of 1.593 km3 in 2000; water diversion into the irrigation district showed an overall upward trend. The positive impact of the post-2000 water conservation phase with the adaptation of water-saving irrigation technology was clear, as the findings showed an increase in IWUE in the Yanqi Basin irrigation district. These results provide a theoretical basis for breaking the paradox of irrigation efficiency, which can be used in the water resource management of irrigation districts.

This study investigated the responses of Panax notoginseng in a high-altitude area to regulated deficit irrigation at different growth stages (seedling stage, vegetative growth stage, flowering stage, and root weight gain stage) by observing indicators such as plant growth, soil nutrients, and morbidity. Conventional irrigation (70%-80% FC) was applied at the seedling stage and the root weight gain stage. Three regulated deficit irrigation levels (50%-60% FC, 40%-50% FC, and 30%-40% FC) were applied during the vegetative growth period, and three regulated deficit irrigation levels (70%-80% FC, 50%-60% FC, and 40%-50% FC) were used in the flowering period. Conventional irrigation was also applied throughout the growth stage as a control (CK). The results showed that the content of available phosphorus, available potassium, and nitrate-nitrogen in the soil was the lowest under the T4 treatment, and the cutting+main root length, rib length, root surface area, root volume, and main root diameter all reached their maximum values under this treatment. Under the T4 treatment, the total saponin content and total dry weight were the highest, the irrigation water use efficiency was the highest, and the P. notoginseng morbidity rate was the lowest. Morbidity was reduced by 53.42 percent in individuals who received the CK therapy, whereas total saponin content increased by 8.65 percent. The T4 therapy had the highest score of all the treatments in principal component analysis. As a result, planting P. notoginseng under the T4 treatment can effectively reduce irrigation water usage, enhance production and quality, and minimize the incidence of sickness in P. notoginseng.

In this paper, we investigate Chi’s vigorously promoted high-efficiency irrigation policies for farmland water conservation, deploying a governmentality framework. The paper explains how the modernist irrigation policies follow global discourses but seek to imbue these with new ambition and the meaning of ecological civilization. At the same time, the government aims to mold water users’ subjectivity in accordance with its development strategies. Following a local village case study, the paper further elucidates how, amidst the decline of commons’ local governce and water user responses, the state’s high-efficiency irrigation water governmentality project is adapted and negotiated. Local government bureaucracy actors and ordiry villagers challenge irrigation policies through local noncongruent institutions. Thereby, villagers’ pragmatic, non-aligned irrigation technologies and actions contradict state-assumed collective collaboration and government-aligned smooth operation.

Agriculture is the major economic sector in Asian countries and the majority of their population depends on it. In addition to the largest irrigation system in the Indus basin, Pakistan is suffering from water shortages that are affecting the overall crop production of the country. Different resource conservation technologies (RCTs) such as precision land leveling (PLL), raised bed planting (RBP), and different high-efficiency irrigation systems (HEISs) can be opted for better water productivity. In this study, the potential of these RCTs has been explored to enhance production and save irrigation water through their sustainable adoption. Based on studies by different researchers, water savings up to 47% and yield increases up to 35% have been reported under PLL, while water savings up to 50% and about 10–33% yield increases were observed under RBP. Similarly, under different HEISs, water savings up to 80% and yield increases up to 53% have been reported compared with crops sown under conventional farming. Based on the findings of the researchers regarding RCTs, these have been proved as progressive sowing techniques for better productivity under the limited available water scenario. The detailed review in this paper concludes that RCTs resulting in the improvement of gravity irrigation methods, viz., PLL and RBP, have a great potential of adoption and water productivity improvement at the regional scale in developing countries such as Pakistan, while high-cost HEISs can also be promoted at limited scale among progressive farmers for high-value agriculture.

Aims The objective of this study was to determine the effects of different levels of irrigation water depth, nitrogen fertilizer, and Conocarpus biochar on the quantitative and qualitative characteristics of Roselle plants and their irrigation water use efficiency (IWUE) and soil nutrition. Methods The experimental treatments included three levels of nitrogen fertilizer (N1: 100, N2: 150, N3: 200 t ha −1 ), three levels of irrigation water depth (I1: 50, I2: 75, I3: 100% of plant water requirement), and three levels of biochar (B1: 0, B2: 10, B3: 20 t ha −1 ). Results The research findings indicated that the effects of irrigation water depth, nitrogen fertilizer, and biochar were significant on all measured parameters at a 1% and 5% probability level. The highest yield (710.58 kg ha −1 ) was achieved under the B3N2 treatment. The highest IWUE was observed under the I2N3 treatment (0.125 kg m −3 ). Applying biochar at all levels increased the total nitrogen content, organic matter, and microbial carbon biomass while reducing nitrate leaching in the soil. The total nitrogen, organic matter, and microbial carbon biomass increased by 82.92%, 47.31%, and 61.75%, respectively. Conclusions Considering the region’s water scarcity, applying 75% of the water requirement (I3) can help conserve water. Additionally, using 75% of the nitrogen content (N2) and applying 20 t ha −1 of biochar (B3) can improve Roselle’s quality and mitigate drought stress’s negative impacts. Furthermore, using Conocarpus waste and other agricultural residues as biochar can increase organic matter levels in dry soil areas while preventing environmental pollution.

Owing to water scarcity and environmental hazards of synthetic fertilizers, reducing water and chemical N fertilizers is very urgent for sustainable agriculture. Thus, two field experiments were conducted to understand the physiological role of Azolla filiculoides Lam. extract (AE), as a promising biofertilizer, in enhancing growth, physiology, yield, N uptake efficiency (NUpE), N use efficiency (NUE) and irrigation water use efficiency (IWUE) in N-deficient maize plants under full and deficit irrigation. The experimental design was split plot with irrigation treatments as main plots and N treatments including full nitrogen (FN; 285 kg N ha−1), nitrogen deficiency (ND; 190 kg N ha−1) and ND (190 kg N ha−1) + AE (10% w/v) as subplots. At the vegetative stage, deficit irrigation was performed by withholding water from 26 to 56 days after sowing, while N-deficient plants received two-thirds of the total recommended N. N deficiency caused deleterious impacts on growth and yield of maize plants, particularly under deficit irrigation. However, results evidenced the role of Azolla extract, as an efficient biofertilizer, in combination with deficit irrigation in improving NUpE, NUE and IWUE without substantial decreases in grain and stover yields of N-deficient maize plants. Application of Azolla extract improved growth, yield attributes, irrigation water and N use efficiency via enhancing photosynthetic pigments, leaf water status, proline accumulation and N uptake with a reduction in membrane oxidative damage. Overall, the application of Azolla extract is an eco-friendly and cost-effective organic fertilizer to reduce more than 30% of urea fertilizer without affecting grain yield of maize plants.