Water-saving Irrigation Techniques Research Articles

Optimized sand tube irrigation combined with nitrogen application improves jujube yield as well as water and nitrogen use efficiencies in an arid desert region of Northwest China

Efficient water-saving irrigation techniques and appropriate nitrogen (N) application are keys to solving the problems of water scarcity and irrational fertilization in jujube cultivation. In this study, first, the effects of sand tube irrigation (STI) on surface and subsurface wetted characteristics were investigated using in-situ infiltration tests in a jujube garden. Compared with surface drip irrigation (SD), STI reduced surface wetted area by 57.4% and wetted perimeter of the surface wetted circle by 37.1% and increased subsurface maximum infiltration distance of wetting front by 64.9%. At the optimal sand tube depth of 20 cm, surface wetted area of the surface wetted circle decreased by 65.4% and maximum infiltration distance of the wetting front increased by 70.9%, compared with SD. Two-year field experiments then investigated the effects of STI and SD on soil water storage, jujube leaf chlorophyll, net photosynthetic rate, actual water consumption, fruit yield, and water (WUE) and N (NUE) use efficiencies at four levels of N (pure nitrogen: N1, 0; N2, 286 kg ha–1; N3, 381 kg ha–1; N4, 476 kg ha–1) at the same irrigation amount (45 mm irrigation–1, total of 8). Compared with SD, STI increased soil water storage 18.0% (2021) and 15.6% (2022) during the entire growth period and also chlorophyll content, nitrogen balance index, and net photosynthetic rate, with both increasing and then decreasing with increasing N. Compared with SD, STI increased yields by 39.1% and 36.5% and WUE by 44.3% and 39.7% in 2021 and 2022, respectively. Nitrogen use efficiency was 2.5 (2021) and 1.6 (2022) times higher with STI than with SD. STI combined with N3 had the highest yield, WUE, NUE, and net income and is thus recommended as the optimal water–N combination. In conclusion, STI combined with appropriate N application can be an effective water-saving irrigation technology alternative to SD in jujube cultivation in arid areas.

Effects of alternate wetting and drying irrigation on yield, water-saving, and emission reduction in rice fields: A global meta-analysis

With limited natural resources and uncertain climate, increasing food production must mitigate the environmental impacts. Rice, a water-intensive grain crop, contributes significantly to greenhouse gas (GHG) emissions in agricultural systems. Alternate Wetting and Drying (AWD) Irrigation stands out as the prevailing water-saving irrigation technique in rice fields worldwide. Nonetheless, the effects of AWD on yield variation, water conservation, and emissions reduction as well as the synergies and trade-offs between the effects remain unclear. Here a global meta-analysis of 437 literature sources covering 93 % of global rice production was conducted to quantify changes in yield, water utilization, and GHG emissions following AWD implementation. Results show that, on a global scale, AWD reduces irrigation water usage by 33.88 % and enhances water use efficiency, irrigation water use efficiency, and water productivity by 20.27 %, 47.58 %, and 29.63 %, respectively. However, there is a minor decrease in yield by 1.56 %. Notably, AWD leads to a noteworthy 47.47 % reduction in methane emissions, counterbalanced by a 52.20 % rise in N2O emissions, ultimately resulting in a decrease in global warming potential (GWP) and greenhouse gas intensity (GHGI) by 39.38 % and 38.06 %, respectively. The AWD threshold is the most significant predictive factor, adopting a suitable threshold can greatly improve the accuracy of AWD implementation. Soil properties also play a pivotal role, with pH levels > 7 or soil organic carbon (SOC) < 12 g/kg correlating to more pronounced yield losses. Implementing reasonable field management measures, such as suitable rice varieties and straw incorporation can effectively increase rice productivity. Approximately 60.36 % of the data falls within the “win–win” zone, demonstrating simultaneous in yield increases, water conservation, and emissions reduction. AWD is more suitable for acidic soils with high SOC (>12 g/kg) and a light texture. This study introduces novel insights for analyzing the synergies and trade-offs within the food–water–climate nexus.

The impact of government support and farmers’ pro-environmental intention on water-saving irrigation techniques adoption: Evidence using propensity score matching

Abstract Agricultural water-saving irrigation (WSI) techniques becomes the main way to build drought resilience in rural areas. The effectiveness of government support in promoting the adoption of water-saving technologies is controversial. There is a research gap concerning farmers with different pro-environmental intentions to the adoption of water-saving behaviors under the influence of government support. This study is based on a survey in Yulin, Shaanxi, China, using 404 sample households. Pro-environmental intentions have been introduced into this paper by using the entropy weight method, and propensity score matching has been used to overcome the confounding between government support and farmers' adoption. Our findings reveal that farmers who received government support exhibit a significantly higher probability of adopting WSI techniques, ranging from 80 to 81.6%, representing a notable increase of 29.0–30.7% compared to those without government support. Furthermore, government support significantly affects farmers with weak pro-environmental intentions by 40.5%, but it does not have a significant impact on farmers with stronger pro-environmental intentions. These insights emphasize the significance of subsidies and advocate for an approach that tailors policies based on varying levels of pro-environmental intentions. This is particularly crucial considering that farmers with weaker intentions may be inclined to adopt the technology but face higher efficiency risks.

Assessment of soil mulching field management, and deficit irrigation effect on productivity of watermelon varieties, and AquaCrop model validation

Watermelon productivity in the Arba Minch irrigation scheme has been hampered by water scarcity, with only the Lady Bells watermelon variety being cultivated in the area. This challenge can be mitigated by adopting water-saving irrigation techniques and selecting water stress-resistant varieties. Hence, this study aimed to investigate the combined impact of soil mulching and deficit irrigation on the productivity of various watermelon varieties and validate the AquaCrop model. The experiment employed a randomized complete block design with two levels of water application (100 % SMD and 50 % SMD), two mulching practices (non-mulching and mulching), and four watermelon varieties: Lady Bells (V1), Green Pearl (V2), Kaolack (V3), and Koloss (V4). Soil physical properties and crop-related data were used to calibrate the AquaCrop model. Straw mulching, on average, conserved 64.50 mm and 262.75 mm of water under 100 % and 50 % water application levels, respectively. The minimum and maximum land productivity averages were 6.2 tonsha−1 (T13) and 17.6 tonsha−1 (T2), while water productivity ranged from 5.2 kgm−3 (T1) to 12.4 kgm−3 (T10). Lady Bell watermelon varieties displayed high sensitivity to water stress, with a 1.27 yield response factor under non-soil mulching treatment with 50 % water application. The mean benefit-cost ratio varied from 1.52 (T13) to 2.90 (T10). The average values of RMSE, NSE, and R2 for the AquaCrop model were 0.70, 0.65, and 0.80, respectively, indicating the model's acceptability in predicting the effects of mulching and deficit irrigation on watermelon productivity. Overall, the use of straw mulching combined with 50 % deficit irrigation, particularly for Green Pearl varieties, emerged as the most productive watermelon cultivation method in the Arba Minch region when facing limited irrigation water. Future research will focus on assessing the impact of deficit irrigation during various watermelon growth stages.

A Machine Learning Approach for the Estimation of Alfalfa Hay Crop Yield in Northern Nevada

Increasing pressure over water resources in the western U.S. is currently forcing alfalfa (Medicago sativa L.) producers to adopt water-saving irrigation techniques. Crop yield forecasting tools can be used to develop smart irrigation scheduling methods that can be used to estimate the future effects of a given irrigation amount applied during a current irrigation event on yield. In this work, a linear model and a random forest model were used to estimate the yield of irrigated alfalfa crops in northern Nevada. It was found that water (rain + irrigation), the occurrence of extreme temperatures, and wind have a greater effect on crop yield. Other variables that accounted for the photoperiod and the dormant period were also included in the model and are also important. The linear model had the best performance with an R2 of 0.854. On the other hand, the R2 value for the random forest was 0.793. The linear model showed a good response to water variability; therefore, it is a good model to consider for use as an irrigation decision support system. However, unlike the linear model, the random forest model can capture non-linear relationships occurring between the crop, water, and the atmosphere, and its results may be enhanced by including more data for its training.

The effect of alternate partial root-zone drying and deficit irrigation on the yield, quality, and physiochemical parameters of milled rice

While paddy fields produce a high yield, they also require a large amount of water and produce a significant amount of methane. Therefore, the adoption of water-saving irrigation techniques for rice cultivation is critical. Furrowed rice farming may be a viable alternative to paddy rice cultivation. The objective of the present study was to evaluate the impact of alternate partial root-zone drying irrigation on rice yield, milled rice quality, and cooking quality under furrow rice cultivation. A two-year field trial was conducted on a local rice cultivar, Tarom Hashemi, in 2015 and 2016. Seven water regimes, including three levels of regulated deficit irrigation (RDI), three levels of alternate partial root-zone drying irrigation (APRDI), and conventional flooding irrigation (CFI), were used in this study. In RDI and APRDI treatments, plots were irrigated when soil matric potential had reached −0.1 (RDI1 and APRDI1), −0.3 (RDI3 and APRDI3), and −0.6 bar (RDI6 and APRDI6). RDI1 and APRDI1 treatments produced milled rice yield similar to the CFI, while irrigation water productivity (IWP) was significantly higher by 22.9% and 45.7%, respectively. Regardless of the soil water potential, the IWP in APRDI treatments was 16% higher than that of RDI treatments. Severe water stress (RDI6 and APRDI6) caused a marked increase in amylose content and alkali spreading value of milled rice resulting in improved cooking quality. Nitrogen uptake in APRDI treatments was 2% higher than that of RDI treatments. On average, methane emission per milled grain yield declined by 77.9% and 78.7% in RDI and APRDI treatments, respectively. Our data indicate that the expensive and laborious practice of puddling can be avoided to increase water productivity and improve rice quality without sacrificing yield. The results also show that furrow rice cultivation could significantly reduce the methane emission contribution of rice production.

Controlling water deficiency as an abiotic stress factor to improve tomato nutritional and flavour quality.

Water deficit (WD) irrigation techniques to improve water use efficiency have been rapidly developed. However, the effect of WD irrigation on tomato quality has not been sufficiently studied. Here, we investigated the effects of varying water irrigation levels [T1-T4: 80%, 65%, 55%, and 45% of maximum field moisture capacity (FMC)] and full irrigation (CK: 90% of maximum FMC) on tomato fruits from the mature-green to red-ripening stages, to compare the nutritional and flavour qualities of the resulting tomatoes. The proline, aspartic, malic, citric, and ascorbic acid contents increased, phenylalanine and glutamic acid contents decreased, and the total amino and organic acid contents increased by 18.91% and 26.12%, respectively, in T2-treated fruits. Furthermore, the T2-treated fruits exhibited higher K and P contents alongside improved characteristic aromas. These findings provide novel insights for further improvements in tomato quality while also developing water-saving irrigation techniques.

Evaluation of Green Agricultural Development and Its Influencing Factors under the Framework of Sustainable Development Goals: Case Study of Lincang City, an Underdeveloped Mountainous Region of China

This study aims to assess the current status of green agricultural development and its influencing factors in Lincang City, a national innovation demonstration zone for sustainable development; it also seeks to enhance the potential and competitiveness of green agricultural development in underdeveloped border areas. To achieve this, an evaluation index system is constructed encompassing six dimensions. Using a coupled coordination and obstacle degree approach, this study explores the spatiotemporal differences in the level of green agricultural and sustainable development, as well as the power, coupled coordination degree, and factors that negatively impact green agricultural development in Lincang City from 2010 to 2019. The Liang-Kleeman information flow method is applied to uncover the key information flow factors that influence the coupled coordination degree in each county and district of Lincang City. The results reveal several insights: First, the comprehensive score of sustainable green agricultural development increased from 0.4405 to 0.5975 during the study period. Second, the coupling coordination degree of green agricultural development was relatively low, fluctuating between 0.1821 and 0.2816. Overall, the development has shifted from severe imbalance to mild imbalance. Third, the obstacle degree increased by 3.75%. From a systemic perspective, the “resource conservation” layer had the highest barrier level, with the maximum value being observed in Yun County at 25.5%. Further analysis of the indicators reveals that the use of outdated water-saving irrigation techniques has resulted in low irrigation efficiency and excessive water resource waste. This is the main cause of the high barrier levels in terms of water-saving irrigation intensity and effective irrigation area. Moreover, the excessive use of chemical pesticides to enhance vegetable production has contributed to high barrier levels for achieving yields of pollution-free vegetable production per unit area. Finally, the information flow values of the factors influencing the coordinated and harmonious development of green agriculture exhibit significant regional heterogeneity among counties and districts. The highest information flow value for the area of drought- and flood-resistant crop cultivation is in Zhengkang County at 1.86. Based on these results, local government departments and decision-makers should focus on promoting comprehensive improvements in the level of green agricultural development. It is crucial to tailor measures to the specific needs of each county to address the shortcomings in green agricultural development. Additionally, efforts should be made to strengthen the innovation-driven chain of green agricultural development, including production, processing and sales. Enhancing the green agricultural development system is essential for long-term progress.

Sub-surface drip irrigation reduced N2O emissions via inhibiting denitrification pathways in northern China

Water-saving irrigation has become an important method for alleviating water scarcity in semi-arid regions. However, the lack of knowledge about the effects of different water-saving irrigation techniques on soil nitrogen conversion limits the understanding of the underlying mechanisms involved in soil N2O emissions. To determine the effects of different irrigation methods on N2O emissions, we conducted a two-season experiment under four different irrigation methods (DI, surface drip irrigation; SDI, sub-surface drip irrigation; PRI, partial rootzone irrigation; FP, flood irrigation). Also, we studied the dynamics of nitrifier and denitrifier community structures and compositions and their associations and effects on N2O emissions. The results showed that seasonal N2O emissions were affected by irrigation practices and significantly correlated with the amount of irrigation and soil moisture. Drip irrigation significantly reduced N2O emissions, with 38–45 % (DI), 51–59 % (SDI), and 64–68 % (PRI) decreases compared to FP treatment. Under SDI, the copy numbers of ammonia-oxidizing archaea amoA significantly decreased and nirK displayed an increase compared to FP. The abundance of unclassified_Proteobacteria dominant among nirK-type denitrifiers under FP was observed to be strongly and positively correlated with N2O emissions, and the dominant bacteria shifted to Bosea under drip irrigation. Irrigation practices had a strong effect on the Shannon and ACE indexes of five key genes. PRI showed a similar effect under SDI treatment on nitrifier and denitrifier community structures. Furthermore, PRI, with only a 38 % reduction of irrigation water consumption, produced a 4.4–11.3 % lower yield than SDI. Therefore, SDI treatment can inhibit the denitrification process led by nirS-type denitrifiers and reduce the abundance of the dominant genus of nirK and promote nosZ abundance, thus decreasing N2O emissions. Our findings indicate that (i) drip irrigation increased ammonia-oxidizing bacteria amoA abundance and diversity but decreased nirS abundance, which led to N2O mitigation and (ii) SDI might be the best method for maintaining high crop yield with lower N2O emissions in intensively farmed fields.

Evaluation of soil water losses under irrigation saving techniques in a semi-arid region in Tunisia

Abstract In arid and semi-arid regions, managing agricultural water for irrigation is essential to cope with water scarcity and maximize crop yields. In this study, an experiment was conducted on a potato crop in the Manouba region (lower valley of Medjerda, Tunisia). The experimental protocol consisted of four water treatments utilizing water-saving irrigation techniques: FI (Full Irrigation 100%): irrigation with 100% of crop water requirements. DI (Irrigation 75%): deficit irrigation with the application of 75% of crop water requirements. PRDRight (Irrigation 50% on the right side): Irrigation by partial root drying. PRDLeft (Irrigation 50% on the left side): Irrigation by partial root drying. Simulation of soil water profiles was carried out by the Hydrus-1D model. The soil hydraulic properties were calibrated according to the experimental conditions using an inverse modeling technique. According to the obtained results, simulated soil water profiles were close to those measured. Indeed, the calculated NRMSE values are low, indicating the reliability of Hydrus-1D as a decision support tool to optimize water irrigation management. These results were then used to investigate the effects of a 2 °C temperature increase on soil water loss, and it was determined that the impact was insignificant.

Effects of Water-Saving Irrigation on Direct-Seeding Rice Yield and Greenhouse Gas Emissions in North China

Rice cultivation consumes more than half of the planet’s 70% freshwater supply used in agricultural production. Competing water uses and climate change globally are putting more pressure on the limited water resources. Therefore, water-saving irrigation (WSI) is recommended for rice production in water scares areas. The impact of WSI techniques on direct-seeding rice production and greenhouse gas emissions in North China is becoming increasingly important in the era of climate change. Therefore, we conducted a two-year field experiment on directly seeded rice to assess the impact of traditional flooding irrigation (CK) and three water saving irrigation (WSI) methods, including drip irrigation with an irrigation amount of 50 mm (DI1) and 35 mm (DI2) at each watering time and furrow wetting irrigation (FWI), on rice yield and greenhouse emissions. Generally, the WSI techniques decreased the number of rice panicles per m−2, spikelet per panicle, 1000-grain weight and rice yield compared to CK. Rice yield and yield components of (DI1) were significantly higher than (DI2). The adoption of either (DI1) or (FWI) showed insignificant variation in terms of rice yield and its yield components measured except for 1000-grain weight. The water productivity was 88.9, 16.4 and 11.4% higher in the FWI plot than the CK, DI1 and DI2 plots, respectively. The WSI decreased cumulative CH4 emission significantly by 73.0, 84.7 and 64.4% in DI1, DI2 and FWI, respectively, in comparison with CK. The usage of DI2 triggered 1.4 and 2.0-fold more cumulative N2O emission compared to DI1 and FWI, respectively. Area-scaled emission among the water-saving irrigation methods showed no significance. The yield-scaled emission in DI1 and DI2 and FWI were 101, 67.5 and 102%, respectively, significantly lower than CK. The adoption of FWI produced an acceptable rice yield with the lowest yield-scaled emission and highest water productivity among the irrigation practices. Our experiment demonstrates that dry direct-seeding with furrow irrigation can impact triple-wins of sustainable rice yield, high water-use efficiency and low GHG emissions in North China.

Effects of Different Irrigation Modes on the Growth, Physiology, Farmland Microclimate Characteristics, and Yield of Cotton in an Oasis

In order to determine the effects of different water-saving irrigation techniques on physiological growth, farmland microclimate, and yield of cotton (Gossypium Spp.), a two-year field experiment was carried out in an oasis area of Northwest China, and three irrigation methods were tested, including on-film irrigation (T1), under-film drip irrigation (T2), and automatic irrigation (T3). The results showed that the relative humidity, plant height, leaf area, stem thick, and photosynthetic index with the T3 treatment were significantly higher than those with T2 and T1. The air and soil temperature with T3 (except seedling stage) were considerably lower than those with T2 and T1. According to the fitting and statistical analysis of each index and yield, except for air and soil temperature, the other indices were positively correlated with yield. Based on the analysis of each index, the T3 treatment had the most significant regulatory effect on cotton’s physiological growth and farmland microclimate. Compared with T1, the irrigation amounts of T2 and T3 decreased by 16.43% and 25.90%, but the yield increased by 38.96% and 46.28%, respectively. The automatic irrigation strategy showed significant advantages in water saving and yield increase, which could provide some reference for cotton drip irrigation in similarly arid areas.

Training in tools to develop quantitative risk assessment of fresh produce using water reuse systems in Mediterranean production.

Water resources are increasingly coming under pressure specially around the Mediterranean area, leading to water scarcity and a deterioration in water quality. The use of treated wastewater represents an alternative source to enhance the demand for irrigation water. Water reuse in combination with the promotion of the use of water‐efficient technologies in industry and water‐saving irrigation techniques could lead to good qualitative and quantitative water status for surface and ground water bodies. Nevertheless, food‐borne outbreaks linked to fresh produce irrigated with partially or untreated wastewater caused by bacteria, parasites and enteropathogenic viruses have been widely reported. In the absence of solid scientific understanding of the actual risks involved, consumers are likely less receptive to buy leafy greens irrigated with treated wastewater, also known as reclaimed water. In this study, we aimed to assess the microbiological risks of leafy green vegetables irrigated with treated wastewater in Spain using Norovirus as a model organism to facilitate the development of risk management strategies. A conceptual exposure model was designed to describe the virus fate and transport from the Wastewater treatment plant (WWTP) secondary effluent to the consumers' fork. This study is an example of the use of reclaimed water for irrigation of commercial fields producing leafy greens in the south‐east of Spain and tries to assess potential microbiological risks to the consumers by establishing their safety.

Optimum Sowing Date and Nitrogen Rate Ensure Sustainable Production of Wet Direct-Seeded Rice under Water-saving Irrigation Technique

Optimum Sowing Date and Nitrogen Rate Ensure Sustainable Production of Wet Direct-Seeded Rice under Water-saving Irrigation Technique

Effect of arbuscular mycorrhizal fungi inoculation on growth and physiology performance of olive trees under regulated deficit irrigation and partial rootzone drying

Agriculture water resources are limited in several Mediterranean regions. In this context, the current study was conducted to examine the response of mychorrizal olive plants to two water-saving irrigation techniques, namely partial-root zone drying (PRD) and regulated deficit irrigation (RDI). Young olive (Olea europaea L., cv Picholine marocaine) trees were grown with (+AMF) or without (-AMF) Rhizophagus irregularis using a split-root experiment, which consists in dividing the root system of the plant in two parts placed in separate pots. The pots were exposed simultaneously to three different water regimes: Control, with both root compartments well irrigated; RDI, with both compartments irrigated (50% of the control); and PRD, with one compartment irrigated (50% of the control), while the other compartment was kept dry switching every 10 days. Stomatal conductance (gs), leaf relative water content (RWC), vegetative growth (shoot length, total leaf area and leaf number), proline and sugar contents and leaf carbon isotope discrimination (δ13C) were measured in order to evaluate the influence of arbuscular mycorrhizal (AM) symbiosis on the tolerance of the olive tree to water stress induced by RDI and PRD. The low soil moisture under this two water treatments have a negative effect on all studied parameters. However, the olive plants inoculated with the AM fungi (AMF) generally have significant great growth indices in comparison with the non-inoculated ones. Furthermore, at physiological (gs and RWC) and biochemical (proline, sugar and δ13C) level, +AMF olive plants exhibit better performance under drought than -AMF ones. These responses were mostly, earlier under PRD treatment. AM olive plants can tolerate better the water deficit stress of RDI and PRD treatments saving up to 50% of the irrigation water.

Internet of Things based Smart Irrigation Control System for Paddy Field

This study aimed to establish a water-saving irrigation technique-based Smart Field Cultivation Server (SFCS) for paddy field irrigation by employing information and communication technologies. The development of SFCS considered the requirement on rice growth, pest development, and fieldwork management. The proposed SFCS is equipped with a solar power supply system and consisted of sensors including illumination, air temperature, air humidity, water level, soil moisture content, soil electronic conductivity, and soil temperature. Narrowband Internet of Things (NB-IoT) is used for data transmission due to the data size and transmitting frequency. A smartphone-based application (APP) has been developed for users to monitor field environment by tabular, dashboard panel, and whisker chart box, provides multiple data display ways for different purposes. Moreover, a proposal for a water-saving irrigation technique named system of probiotics rice intensification (SPRI) has been integrated into the APP. With the developed APP, farmers will receive fieldwork reminders by calendar day that water-saving irrigation may be possibly implemented. The SFCS is not only shown ability on the field monitoring but also links the gap between the fieldwork application and modern technology.

The response of photosynthetic capacity and yield of cotton to various mulching practices under drip irrigation in Northwest China

Mulched drip irrigation is regarded as an effective water-saving irrigation technique that is adopted widely in dryland regions. However, due to the lack of efficient mulch film recovery, residual plastic film fragments accumulating in soil nowadays pose a risk to agricultural production sustainability. To mitigate the pollution result from polyethylene (PE) film mulching and demonstrate the relationship between soil microenvironment, photosynthetic capacity, yield, and water use efficiency of cotton (Gossypium hirsutum L.) in various mulching practices, a two-year field experiment was carried out to test five mulching practices (sprayable degradable film mulching; biodegradable transparent film with an 80-day induction period mulching; biodegradable transparent film with a 100-day induction period mulching; conventional transparent polyethylene film mulching; no film mulching) in Xinjiang, Northwest China. The results showed that mulching significantly increased soil water content and temperature by 23.83% and 15.01% (average on two years) in topsoil compared to the bare soil surface, associated with a higher plant height, leaf area index, photosynthetic rate and aboveground biomass accumulation. Soil moisture, temperature, and crop height all significantly influenced cotton leaf photosynthetic rate, and soil moisture had the most significant impact (the direct path coefficient was 0.450). The highest cotton yield and WUE were observed in PE film mulching (5480.59 kg ha−1 and 1.35 kg m−3, respectively, average on two years) and the biodegradable transparent film with a 100-day induction period was comparable with PE film in yield increased and reduction of water loss (yield and WUE was 5357.51 kg ha−1 and 1.29 kg m−3, respectively, average on two years). The sprayable biodegradable film also had good wetting and warming effects on soil, but notably, sprayable film performances were still weaker than that in solid films. Compared to solid degradable films mulching, soil moisture, soil temperature, photosynthetic rate, yield, and WUE in sprayable film mulching was decreased by 5.55%, 7.19%, 31.41%, 5.31%, and 8.58% on average, respectively. In general, biodegradable transparent film with a 100-day induction period could significantly improve soil water-heat status, enhance cotton development, reduce water evaporation, increase cotton yield and WUE, which provides a cotton-cultivation option to control residual PE fragments pollution and maintained cotton yield.

Effects of rice cultivar on the net greenhouse gas emission under continuous flooding and alternate wetting and drying irrigations in paddy field

Rice production has been challenged by increasing food demand and water scarcity. Alternate wetting and drying (AWD) irrigation is a water-saving irrigation technique for paddy fields. The aim of this research was to determine the effects of rice cultivars on the net greenhouse gas emission under continuous flooding (CF) and AWD irrigations in paddy field. This experiment used randomized complete block design with combination of the water management systems and rice cultivars. There were two water management systems, namely (1) CF and (2) AWD irrigations and three rice cultivars, namely (1) Ciherang, (2) Inpari 32, and (3) Mekongga. The results showed that the AWD irrigation decreased global warming potential by 51%, 40% and 19% when combined Ciherang, Inpari 32 and Mekongga, respectively, compared to CF. The combination of AWD irrigation and Inpari 32 rice cultivar resulted the highest net GHG balance among all treatments approximately 7.9 t ha−1 and also showed the highest profit around IDR 18.3 million ha−1. This study clearly suggested the possibility of reducing GHG emission from the paddy field through appropriate selection of water management and rice cultivars to achieve a technically and economically feasible as a mitigation option.

Experimental Study on the Performance of a Sand Filtration Method and Device by Using Natural Soils and Subsurface PVC Drainage Pipes

AbstractDrip irrigation is an efficient water-saving irrigation technique. However, the clogging of emitters is a major problem for drip irrigation systems that adversely affects the uniformity of ...

Assessing the impacts of irrigated agriculture on hydrological regimes in an oasis-desert system

Irrigated agriculture greatly affects the hydrological systems and thereby eco-environment and food security in arid and semi-arid regions. However, a comprehensive assessment of the hydrological system dynamics in response to irrigated agriculture is still scarce, especially in oasis-desert systems of arid inland regions. Thus, we investigated the impact of irrigated agriculture on hydrological regimes in an oasis-desert system of northwest China. Temporal variations in water balance and lateral groundwater flow in oasis and desert experimental fields (i.e. oasis plot and desert plot) were quantified using the water balance analysis method. Soil water variations, groundwater dynamics and surface water and groundwater interactions in the oasis-desert system were determined by combining line transect survey methods and stable isotope (18O, 2H) techniques using the USGS MODFLOW software. The results showed that water exchange fluxes and groundwater dynamics were altered by the application of water-saving irrigation techniques and the increase in total precipitation. In particular, the downward total exchanging flux above groundwater table and the outward total lateral groundwater flow reduced significantly in the oasis plot. Spatial heterogeneity and profile variability of soil moisture along the soil water content (SWC) transect significantly reduced. Simultaneously, the depth dependence of SWC in oasis cropland and the deep soil moisture at the edge of desert were improved under water-saving irrigation scenario. Temporal variations in groundwater table depths (GTDs) exhibited three different patterns (i.e. stable, metastable and fluctuating) and maintained a continuously downward trend except for the oasis-desert ecotone along the GTD transect, and an abrupt change was found to have occurred during 2006–2012, prompting changes in the seasonality of groundwater resource availability. Groundwater recharge and discharge processes changed dramatically due to large-scale land reclamation and groundwater pumping. Groundwater depletion is approaching hydrological limits although the process is largely compensated by precipitation and streamflow variability. Water-saving irrigation in conjunction with restriction of land reclamation and adaptation of water management practices is, at least for the present, the most effective way to maintain the coexistence of oasis and desert ecosystems in arid inland regions.