Irrigation Water Use Research Articles

Quantifying the Hydrological Impacts of Irrigation on a Mediterranean Agricultural Context Through Explicit Satellite‐Derived Irrigation Estimates

AbstractWater budget over anthropized basins is profoundly altered by human interventions, among which irrigation prevails. This study investigates how such water use affects hydrological flux and state variables by comparing two SURFEX/ISBA (SURFace EXternalisée/Interaction Sol Biosphère Atmosphère) Land Surface Model simulations performed over a portion of the Ebro basin (Spain) that includes a heavily irrigated area. The first simulation is forced by atmospheric input only, while the second one is fed with atmospheric forcing plus remote sensing‐derived irrigation amounts added to the liquid precipitation. Four main hydrological output variables are compared under the two configurations: surface soil moisture (SM), total evaporative flux (i.e., the sum of components from bare soil and vegetation) (E), drainage, and runoff. Results indicate that SM and E are the variables mostly impacted during the main watering season. Considering mean daily rates per each month, a maximum increase of +30% and of +220% is found over the irrigation districts in July for SM and E, respectively. The reliability of the results is supported by comparisons with satellite evapotranspiration data from MODIS (MODerate‐resolution Imaging Spectroradiometer). The inclusion of irrigation reduces the RMSE between monthly anomalies of modeled E and of MODIS reference data by 41% during the main watering season. Further validation through wavelet coherence analysis is also proposed. This study sheds light on the potential of explicit satellite‐derived irrigation water use data that, when integrated into modeling platforms, allow us to track and quantify anthropogenic impacts on water resources.

Optimizing the Mulching Pattern and Nitrogen Application Rate to Improve Maize Photosynthetic Capacity, Yield, and Nitrogen Fertilizer Utilization Efficiency.

Residual film pollution and excessive nitrogen fertilizer have become limiting factors for agricultural development. To investigate the feasibility of replacing conventional plastic film with biodegradable plastic film in cold and arid environments under nitrogen application conditions, field experiments were conducted from 2021 to 2022 with plastic film covering (including degradable plastic film (D) and ordinary plastic film (P)) combined with nitrogen fertilizer 0 (N0), 160 (N1), 320 (N2), and 480 (N3) kg·ha-1. The results showed no significant difference (p > 0.05) in dry matter accumulation, photosynthetic gas exchange parameters, soil enzyme activity, or yield of spring maize under degradable plastic film cover compared to ordinary plastic film cover. Nitrogen fertilizer is the main factor limiting the growth of spring maize. The above-ground and root biomass showed a trend of increasing and then decreasing with the increase in nitrogen application level. Increasing nitrogen fertilizer can also improve the photosynthetic gas exchange parameters of leaves, maintain soil enzyme activity, and reduce soil pH. Under the nitrogen application level of N2, the yield of degradable plastic film and ordinary plastic film coverage increased by 3.74~42.50% and 2.05~40.02%, respectively. At the same time, it can also improve water use efficiency and irrigation water use efficiency, but it will reduce nitrogen fertilizer partial productivity and nitrogen fertilizer agronomic use efficiency. Using multiple indicators to evaluate the effect of plastic film mulching combined with nitrogen fertilizer on the comprehensive growth of spring maize, it was found that the DN2 treatment had the best complete growth of maize, which was the best model for achieving stable yield and income increase and green development of spring maize in cold and cool irrigation areas.

Farming Legumes for Food Security and Agricultural Sustainability in Somalia

This research was carried out in 2023 in a total of 5 cities (Muqdisho, Afgooye, Baydoa, Jowhar and Belet-hawa) from different regions of Somalia, in order to reveal the problems faced by legume growers and to investigate ways to solve them, thus contributing to food security and agricultural sustainability. A total of 100 farmers, 20 randomly selected from each province, participated in 30 survey questions face to face. As a result of the research conducted in the mentioned regions, it was seen that there are problems in pest and disease control, weed control, fertilizer application and irrigation techniques and water use in legume agriculture. These problems are the main factors affecting the production of legumes. In order to prevent such problems and mistakes, farmers need to pay extra attention to get better quality and higher yields from their legume production, and sustainability-based studies must be increased to solve such problems, especially for food security.

Low-cost Mobile Solar Operated Lift Irrigation System : A Case Study

Effective and judicious use of irrigation water contributes a lot for the management of crop growth and increase in productivity. In the light of increasing demand for irrigation in the state of Assam(India) and to cover the non irrigated area as well as to continue the supplies for the irrigated command area, it becomes imperative to look for a holistic and people centric Low Cost Innovative Irrigation technique. Irrigation water can be assured at every crop field provided we set our mind and put concerted efforts to address it. This paper highlights the Irrigation scenario in Assam with a case study on Low Cost Solar Operated Mobile Lift Irrigation in Assam, for its continuance and contribution towards growth in Agricultural Productivity. This innovation in Irrigation Sector can cause Social transformation by bringing in the development of Agriculture and other allied Sectors. An attempt was also made to establish the economic and operational benefits of the system by making a comparison amongst the different lift Irrigation Schemes in the State. The study advocates for utilization of the non conventional solar energy for irrigating the multiple crops by lifting the surface water sources in the State of Assam by using the Low Cost Solar Operated Mobile Surface Lift Irrigation System. The paper also presents the financial analysis and Key Performance Indicators of the System with a highlight on its diversified application for disaster preparedness and mitigation on the part of Stakeholder Departments with a primary aim to increase Irrigated agriculture productivity

Technical and scale efficiencies of the salinity-induced rice production system in the western coastal region of the Mekong delta, Vietnam

Salinity events make Mekong delta’s rice production change significantly. In the salinity-impacted regions, shrimp-rice production is a possibility besides the traditional rice models. This paper aims to assess the economic efficiency of rice-based farms in the Mekong delta in the context of salinity-induced hazards. The random sample is collected from 254 rice-based farms in 28 villages in 24 districts in the western coastal region in the Mekong delta. The method of Data Envelopment Analysis and OLS and Tobit regression estimations are used to measure the economic efficiency and identify the determinants of the technical and scale efficiencies respectively. The findings show that the average overall efficiencies for the technical efficiency and the scale efficiency are 0.642 and 0.848 respectively, implying that substantial inefficiencies occur in farming practices in the Mekong delta. It indicates that there is still potential for improving the economic efficiency of rice-based system. The findings also show that, statistically significantly, the land ownership and the area are the determinants of the economic profit; the irrigation system, saltwater drains, salinity impact, are the determinants of the economic irrigated water use; the land ownership status, the area, and type of seed are the determinants of the technical efficiency; and the gender, age, education level, irrigation system, saltwater drains, area, type of seed, and numbers of fertilizing and weeding are the determinants of the scale efficiency

Total irrigation by crop in the Continental United States from 2008 to 2020

We provide a dataset of irrigation water withdrawals by crop, county, year, and water source within the United States. We employ a framework we previously developed to establish a companion dataset to our original estimates. The main difference is that we now use the U.S. Geological Survey (USGS) variable ‘irrigation — total’ to partition PCR-GLOBWB 2 hydrology model estimates, instead of ‘irrigation — crop’ as used in previous estimates. Our findings for Surface Water Withdrawals (SWW), total Groundwater Withdrawals (GWW), and nonrenewable Groundwater Depletion (GWD) are similar to those of prior estimates but now have better spatial coverage, since several states are missing from the USGS ‘irrigation — crop’ variable that was originally used. Irrigation water use increases in this study, since more states are included and ‘irrigation — total’ includes more categories of irrigation than ‘irrigation — crop’. Notably, irrigation in the Mississippi Embayment Aquifer is now captured for rice and soy. We provide nearly 2.5 million data points with this paper (3,142 counties; 13 years; 3 water sources; and 20 crops).

Intelligent decision‐making for fertigation treatment of tomatoes cultivated in greenhouse: An experimental study

AbstractTo verify the effectiveness of the intelligent decision method for fertigation, an automatic control system for fertigation in greenhouses was designed, and three intelligent decision methods based on evapotranspiration (T1), soil moisture (T2) and accumulated temperature (T3) were tested. Intelligent decisions included monitoring meteorological information, automatically monitoring soil moisture, utilizing fertigation application systems and using automated control modules. The system was stable and accurately controlled according to the decision scheme. The results showed that the average errors of the automated control system for decision‐making and irrigation were 1.1 and 0.8%, respectively. The study findings serve as a reference for the integration of intelligent irrigation decision‐making and control systems and for further improving the efficiency of water and fertilizer utilized. Compared with those of the control, the three intelligent decision‐making methods increased the tomato yield by 8, 12 and 7%, respectively. In addition, the irrigation water and fertilizer levels decreased significantly compared with those in the control treatment. Although the accuracy of the soil water content (SWC) estimated based on ET and temperature in irrigation decision‐making is low, the general trend is consistent with practice. In addition, the irrigation water use efficiency (IWUE) and partial factor productivity of fertilizer (PFP) were significantly improved. Similarly, the IWUE in T1 was the highest (60 kg m⁻3), and the PFP in T3 was the highest (669 kg kg⁻¹).

Field and simulation studies on yield, water and nitrogen dynamics and use efficiency in rice-wheat crops in sequence

ContextThe dominant rice-wheat cropping system in the Indo-Gangetic plain faces challenges of water depletion and nitrogen pollution of groundwater as well as declining productivity caused by over irrigation and nitrogen fertilization by the farmers. To appreciate the apt use of irrigation water and nitrogen fertilizer in rice and wheat crops it is essential to explore the water and nitrogen balances as well as dynamics in these crops, involving complex interaction between weather, soil, irrigation water and nitrogen fertilizer management. ObjectiveThe objective of the study is to quantify yield, field water balance components, water use efficiency, water productivity, water footprint, and water and nitrogen dynamics of rice and wheat crops in relation to season, varieties, irrigation regimes and nitrogen levels. MethodsField experimentations were conducted in double split plot design along with calibrated and validated HYDRUS 1D model use for two years comprising of treatments in rice i.e. two varieties (PR122-V1 and PR126-V2), two irrigation regimes (2-days drainage period-I1 and soil water suction 16 kPa-I2) and two nitrogen levels (120-N1 and 90-N2 kg N ha−1); and in wheat, two varieties (Unnat PBW343-V1 and Unnat PBW550-V2), two irrigation (1.2 IW/CPE-I1 and 0.9 IW/CPE-I2) regimes and two nitrogen levels (120-N1 and 90-N2 kg N ha−1). ResultsThe highest grain yield recorded was 7.6 t ha−1 in treatment combination of V1I2N1 in rice and 5.4 t ha−1 in V1I1N1 in wheat owing to better plant growth and yield attributes (biomass production, number of effective tillers, panicle length, and 1000 grain weight). Total water footprints were lower in the treatment combination of V1I1N1 in rice and V1I2N1 in wheat. The water budget revealed a higher percent contribution of the total water input to drainage (62 %) in rice ensuing restoration of water in the soil profile; and to evapotranspiration (ET) (100 %) in wheat ensuing water depletion. Modeling water and nitrogen dynamics showed higher root water uptake in I2 treatment in rice and with I1 treatment in wheat; and leaching losses of NO3-N under rice than wheat; and under I2 treatment than I1 as well as in N1 than N2. ConclusionsThe V1I2N1 treatment in rice and V1I1N1 treatment in wheat demonstrated superior grain yield, soil water storage, and root water uptake. Conversely, V1I1N1 treatment in rice and V1I2N1 treatment in wheat showed higher water use efficiency and lower water footprint. SignificanceIt helps to evaluate the effectiveness of irrigation and nitrogen management strategies in maximizing crop productivity while minimizing environmental impacts.

Effects of lateral spacings and irrigation water quality on plant growth and yield parameters of onion in the semi‐arid region of India

AbstractField experiments were conducted to investigate an appropriate saline water management strategy to enhance the yield and irrigation water use efficiency (IWUE) of drip‐irrigated onion. The effects on soil water–salt dynamics, growth parameters, IWUE and yield were assessed under different lateral spacings and irrigation treatments. The different treatments comprised two lateral spacings (45 and 60 cm) and four irrigation treatments (canal water, C; conjunctive use of canal and saline water in a 1:1 ratio, C1S1; in a 1:2 ratio, C1S2; and saline water, S). The results show that soil moisture content decreased vertically downwards and radially outwards in all treatments, whereas soil salinity increased and decreased with increasing radial distance and soil depth, respectively, throughout the soil profile irrespective of the lateral spacing and irrigation treatments. The maximum yield and IWUE were observed at 45‐cm lateral spacing for treatment C, followed by C1S1, C1S2 and S. It was concluded that the C1S1 treatment can be employed successfully for onion cultivation in sandy loam soil without any significant reduction in yield. The present study highlights the significance of irrigation treatments and lateral spacing for maximum production, which may be used as a baseline/guideline to increase the income of onion growers/farmers in semi‐arid regions.

Water and carbon footprints in irrigated vineyards: an on-farm assessment

AbstractThis research aims to contribute to improving water and carbon efficiency in irrigated grapevine production in the dry Mediterranean climate of southern Europe. In regions with water scarcity, irrigation has become a relevant input in viticulture, essential to increase productivity and achieve profits. The joint estimation of the water footprint (WF) and the carbon footprint (CF) can help to comprehensively assess the environmental implications and sustainability associated with water-intensive grapevine cultivation. In this study, the WF and CF, of the farming stage of grapes production, were calculated for three years, in three vineyards located in southern Portugal. Data used for the calculation included meteorological data, irrigation requirements, energy use, fertilizers, and pesticide inputs. The total WF mean value for the study period was 223 m3 ton−1, lower than values found for similar conditions, but the blue component, related to irrigation, was predominant, with a higher proportion (75%) occurring during the driest year. The mean total CF was 98 kg CO2e ton−1; the major contributors were fuel use, fertilizer greenhouse gas emissions, and energy for irrigation. The factor analysis revealed relationships between footprint components, yielding latent variables participated by irrigation water and energy use, pollution loads and agrichemicals use. The examination of trade-offs and/or advantageous relations between footprints and yields showed that seasonal climate conditions play an important role via their effect on the farming practices and the inputs most influential on these indicators, namely: crop water requirement; irrigation volumes; energy for irrigation; fuel consumption; nitrogen and phosphorus fertilization rates.

IoT-based solar-powered smart irrigation system with solar tracker for rice fields

Water management in irrigated agricultural fields is a critical issue in Bangladesh due to a lack of improved irrigation facilities for efficient use of irrigation water, and the cost of crop production is high with low agricultural productivity in agriculture. Therefore, this research aimed to design and implement an internet of things (IoT)-based solar-powered smart irrigation system by sensing the soil moisture levels and periodically controlling the pump operations when the soil moisture is below the required level. A sun-tracking solar system was developed to generate more electricity by tracking the orientation of the sun. A comparison was made between the energy of a fixed-panel solar system with a 24.95° tilt angle and a solar tracking system with no tilt angle. The solar tracker device utilizes a Light Dependent Resistor (LDR) sensor to track the sun, aligning the 150 W solar panel perpendicular to maximize energy capture. This energy is converted into electrical energy and stored in a 12V battery for powering the operation of the submersible pump (DC 12V, 150 W). A wireless sensor network was employed to monitor pumping status and energy comparison in a rice field. A sub-station transferred water level data wirelessly to a main station, where a microcontroller processed the data. The relay module automatically triggered pumping, and the data was stored in the cloud. The solar tracking system outperformed the fixed-panel system with a fixed tilt angle of 24.95° in terms of output power by a remarkable 26.72%. There is a huge potential for solar irrigation systems in Bangladesh, and they can provide sustainable solutions with low irrigation costs. Therefore, this IoT-based solar-powered smart irrigation system could play a vital role in improving irrigation management systems with increased water use efficiency.

Effect of plastic film mulch and irrigation water regimes on soil temperature pattern, plant growth and water productivity of maize

In arid and semi-arid climate, combining different plastic film mulches and irrigation water regimes may be lead to enhance of grain yield and water use efficiency (WUE) with water saving. For the optimum grain yield of maize crop, soil water content and temperature, and irrigation water use efficiency are still not well understood in the climate of Sindh, Pakistan. Therefore, the aim of this study was to examine the soil moisture pattern, soil temperature, yield and WUE under interaction of mulching and soil water status. This field experiment was conducted at the station of department of Irrigation and Drainage during cropping seasons 2021–22. In field trial involved three mulching modes (black and white film, without film) and two irrigation water regimes (sufficiently and severely water stress). The results showed that across the irrigation water regimes treatments, without mulched treatment plants depressed both moisture status and temperature of the soil, nonetheless, the decrease soil water status was more pronounced compared with the reduction in soil temperature. Plant dry biomass was improved when mulching with black plastic film as exemplified by the increased plant height, indicating the increased plant biomass. However, across the mulching treatments, by improving the plant micro-climate condition by black colored plastic film mulching increased significantly grain yield by 17–47% and WUE by 16–46% because less soil water depletion as compared with white plastic mulch and without mulch treatments, respectively, causing the serious waste of water resources. Across the water regimes, sufficiently water stressed condition (80% of soil water holding capacity, SWHC) could significantly enhance grain yield by 17.4% and WUE by 8% as compared to moderately water stressed condition (50% of SWHC). Mulching with black colored plastic film is suggested for maize in terms of high grain yield and water use efficiency with a minor dry biomass reduction.

Enhancing Agrobiodiversity: Designing an In Vitro Screening Protocol for Solanum lycopersicum L. and Solanum pimpinellifolium L. to Explore Responses to Salinity Stress

The foremost cause behind worldwide crop losses is attributed to abiotic stresses. Among them, salinity is a major concern for agriculture and is expected to play an increasingly important role as rising food demands and climate changes will inevitably lead to the greater use of marginal lands and poor-quality irrigation water. Tomato is a moderately salinity-sensitive crop which is widely used in the presence of poor-quality irrigation water without manifesting yield reduction. However, the excessive accumulation of salts can reduce photosynthetic efficiency, unbalance nutrient assimilation, reduce growth, and reduce product quality. This study was undertaken to explore the response of some varieties of Solanum lycopersicum that could be used as model systems to evaluate the performance of wild tomato ecotypes in future studies to identify genetic resources that respond adequately to climate change in the Mediterranean area. Tomato seedlings were raised in vitro on plates with sucrose-free agarized medium containing increasing concentrations of sea salt. The autotrophic conditions enabled a response resembling the plant’s behavior in vivo. The obtained results identified an interesting variety that can be used as a model for modern cultivars and concentrations, from which the behavior of some Solanum spp. can be further investigated.

Impacts of cobalt and zinc on improving peanuts nutrient uptake, yield and irrigation water use efficiency under different irrigation levels

The knowledge of proper fertigation across various irrigation levels is necessary for maximizing peanut yield and irrigation use efficiency in arid areas, and it also can effectively alleviate the risk of nutrient deficiency induced by water stress. This study evaluated the effectiveness of cobalt combined with two zinc application methods on peanut nutrient uptake, yield, and irrigation water use efficiency across varying irrigation levels. A split-split plot experiment was carried out in 2021 and 2022. Three peanut gross water requirement (GWR) levels (100%, 80%, and 60%) were designated for main plots. Subplots featured plants treated with either 0 or 7.5 mg L−1 of cobalt. The sub-sub plots assessed chelated zinc effects at rates of 0 and 2 g L−1 via foliar and soil applications. In comparison to the control (100% GWR), nutrient uptake decreased, with sodium being the exception, and there was an increase in soil pH at 60% GWR. The results showed also significant reductions in yield and water use by approximately 60.3% and 38.1%, respectively. At this irrigation level, applying zinc via soil, either alone or combined with cobalt, led to significant yield increases of 89.7% and 191.3% relative to the control. Also, it’s crucial to note that cobalt application negatively affected iron and copper at 60% GWR, but this impact was lessened with soil-applied zinc. Hence, under a similar circumstance, treating stressed peanut plants with additional foliar applications of iron + copper and applying zinc via soil, could enhance nutrient uptake and improve yield. On the other hand, at 80% GWR, a combination of foliar-applied zinc and cobalt, had a tremendous impact on the absorption of (nitrogen, phosphorus, magnesium, and zinc), resulting in enhanced agronomic traits and decreased water losses. Additionally, at this irrigation level, foliar zinc application alone yielded a 32.4% increase compared to the 80% GWR control. When combined with cobalt, there was a 70.0% surge in water use. Based on this knowledge, the study suggests using 80% GWR and treating peanut plants with a combination of foliar-applied zinc and cobalt. This strategy aids plants in countering the adverse effects of water stress, ultimately leading to enhanced yield and irrigation water use efficiency.

Validation of farmers’ on-farm irrigation scheduling for optimal water utilization in Tigray Region, Ethiopia

Unwise use of irrigation water in water-scarce areas exacerbates water scarcity, diminishes crop yield, and leads to resource wastage. In the Tigray region of Ethiopia, where water is scarce and a determinant resource, no regional-level validation of on-farm irrigation scheduling had been conducted until now. The objectives of this study were to (i) validate farmers’ irrigation scheduling practices and (ii) optimize water consumption for increased irrigated area and number of farmers. Eight different irrigation schemes were purposively selected from the Tigray region. Primary data, acquired through field measurements, observations, and discussions, were supplemented with secondary data. Farmers' irrigation scheduling practices were predominantly of the "Fixed" type, characterized by constant irrigation intervals and amounts. Unfortunately, these practices were non-optimal, with 55% over-irrigation and 45% under-irrigation. Over-irrigation instances ranged from 1350 m3in a garlic plot within the Mesima scheme to a maximum of 1,327,067 m3in a maize plot within the Serenta scheme. The excess water could potentially be utilized to irrigate an additional area of 2 to 148 hectares, thereby benefiting 7 to 296 more farmers, respectively. Conversely, instances of under-irrigation in the Fre Lekatit scheme resulted in yield reductions of 10,445 kg for potatoes and 138,499 kg for maize. In the Tigray region, most of the schemes are semi-arid, emphasizing the imperative need for water conservation. Renovating regional-level irrigation scheduling by integrating performance assessment and enhancing water productivity at the field level, and establishing a remote-sensing-based 'Real-Time Irrigation Scheduling System' is deemed necessary to sustain dryland irrigated agriculture.

Sustainable Adaptation Plan in Response to Climate Change and Population Growth in the Iraqi Part of Tigris River Basin

Climate change and population growth play crucial roles in the planning of future water resources management strategies. In this paper, a balancing between projected water resources and water demands in the Iraqi Part of the Tigris River Basin (TRB) was evaluated till the year 2080 based on RCPs 2.6, 4.5 and 8.5 and population growth. This paper examined a sustainable adaptation plan of water resources in the TRB considering three scenarios; (S1) as no change in the current strategy, (S2) as improved irrigation efficiency and (S3) as improved irrigation and municipal water use efficiency. The results showed a decline in streamflow will occur in the range from 5 to 18.4% under RCP 2.6 and RCP 8.5, respectively. The minimum increase in water demand is expected for RCP 2.6 (maximum increase for RCP 8.5) by 51.8 (208.2), 9.9 (42) and 1.2 (7)% for the municipal–industrial, irrigation and environmental water demands, respectively, compared with the RP. The main finding indicated that S1 is the worst scenario, with water stress in four provinces, especially on the warmest RCP. Whereas, under S2 and S3 conditions, water stress can be eliminated. Increasing ambition towards adaptation becomes obligatory for developing sustainable water sources, supporting water food securities and increasing resilience towards climate change.

Optimizing Agroecological Measures for Climate-Resilient Olive Farming in the Mediterranean.

In order to evaluate the potential of climate change mitigation measures on soil physiochemical properties, an experiment based on the application of five agroecological practices such as the addition of composted olive-mill wastes, recycling pruning residue, cover crops, organic insect manure, and reduced soil tillage, solely or combined, was conducted over two years (2020 to 2022) in a 48-year-old olive plantation. The results showed significant increases in soil water content during the spring and summer periods for the combined treatment (compost + pruning residue + cover crops) (ALL) compared to the control (CONT) by 41.6% and 51.3%, respectively. Also, ALL expressed the highest soil organic matter (4.33%) compared to CONT (1.65%) at 0-10 cm soil depth. When comparing soil nutrient contents, ALL (37.86 mg kg-1) and cover crops (COVER) (37.21 mg kg-1) had significant increases in soil nitrate compared to CONT (22.90 mg kg-1), the lowest one. Concerning exchangeable potassium, ALL (169.7 mg kg-1) and compost (COMP) (168.7 mg kg-1) were higher than CONT (117.93 mg kg-1) at the 0-10 cm soil depth and had, respectively an increase of 100.9% and 60.7% in calcium content compared to CONT. Over the experimental period, the implementation of the five agroecological management practices resulted in enhanced soil fertility. In a long-term Mediterranean context, this study suggests that these sustainable practices would significantly benefit farmers by improving agroecosystem services, reducing reliance on synthetic fertilizers, optimizing irrigation water use, and ultimately contributing towards a circular economy.

Effects of Nutrient Solution Application Rates on Yield, Quality, and Water-Fertilizer Use Efficiency on Greenhouse Tomatoes Using Grown-in Coir.

The yield, quality, and water-fertilizer use efficiency of crops are important parameters for assessing rational water and fertilizer management. For an optimal water and fertilizer system with respect to the nutrient solution irrigation of greenhouse tomatoes using cultivation substrates, a two-year greenhouse cultivation experiment was conducted from 2022 to 2023. Three drip fertigation treatments (T1, T2, and T3) were implemented in the experiment, where nutrient solutions were supplied when the substrate's water content reached 60%, 70%, and 80%. The frequency of nutrient solution applications is based on weighing coconut coir strips in the morning and evening at 7:00 to determine the daily water consumption of plants. Nutrient solutions were supplied when the substrate's water content reached the lower limit, and the upper limit for nutrient supply was set at 100% of the substrate water content. The nutrient solution application was carried out multiple times throughout the day, avoiding the midday heat. The nutrient solution formula used was the soilless tomato cultivation formula from South China Agricultural University. The results show that plant height and the leaf area index rapidly increased in the early and middle stages, and later growth tended to stabilize; the daily transpiration of tomatoes increased with an increase in nutrient solution supply, and it was the greatest in the T3 treatment. Between the amount of nutrient solution application and the number of years, the yield increased with the increase of the amount of nutrient solution, showing T3 > T2 > T1. Although the average yield of the T2 treatment was slightly lower than that of the T3 treatment by 3.65%, the average irrigation water use efficiency, water use efficiency, and partial fertilizer productivity of the T2 treatment were significantly higher than those of the T3 treatment by 29.10%, 19.99%, and 28.89%, respectively (p < 0.05). Additionally, soluble solid, vitamin C, and soluble sugar contents and the sugar-acid ratio of tomatoes in the T2 treatment were greater than those in the other two treatments (p < 0.05). Using the TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution) method, it was concluded that the nutrient solution application rate of 70% can significantly increase water and fertilizer use efficiency and markedly improve the nutritional and flavor quality of the fruit without a significant reduction in yield. This finding provides significant guidance for the high-yield, high-quality, and efficient production of coconut coir-based cultivated tomatoes in greenhouses.

Monitoring plant responses in field-grown peanuts exposed to exogenously applied chitosan under full and limited irrigation levels

In recent decades, numerous studies have examined the effects of climate change on the responses of plants. These studies have primarily examined the effects of solitary stress on plants, neglecting the simultaneous effects of mixed stress, which are anticipated to transpire frequently as a result of the extreme climatic fluctuations. Therefore, this study investigated the impact of applied chitosan on boosting the resistance responses of peanuts to alkali and mixed drought-alkali stresses. Peanuts were grown in mid-alkaline soil and irrigated with full irrigation water requirements (100%IR), represented alkali condition (100% IR × alkali soil) and stress conditions (70% IR × alkali soil—represented mixed drought-alkali conditions). Additionally, the plants were either untreated or treated with foliar chitosan. The study evaluated various plant physio-chemical characteristics, including element contents (leaves and roots), seed yield, and irrigation water use efficiency (IWUE). Plants that experienced solitary alkali stress were found to be more vulnerable. However, chitosan applications were effective for reducing (soil pH and sodium absorption), alongside promoting examined physio-chemical measurements, yield traits, and IWUE. Importantly, when chitosan was applied under alkali conditions, the accumulations of (phosphorus, calcium, iron, manganese, zinc, and copper) in leaves and roots were maximized. Under mixed drought-alkali stresses, the results revealed a reduction in yield, reaching about 5.1 and 5.8% lower than under (100% IR × alkali), in the first and second seasons, respectively. Interestingly, treated plants under mixed drought-alkali stresses with chitosan recorded highest values of relative water content, proline, yield, IWUE, and nutrient uptake of (nitrogen, potassium, and magnesium) as well as the lowest sodium content in leaves and roots. Enhances the accumulation of (N, K, and Mg) instead of (phosphorus, calcium, iron, manganese, zinc, and copper) was the primary plant response to chitosan applications, which averted severe damage caused by mixed drought-alkali conditions, over time. These findings provide a framework of the nutrient homeostasis changes induced by chitosan under mixed stresses. Based on the findings, it is recommended under mixed drought-alkali conditions to treat plants with chitosan. This approach offers a promising perspective for achieving optimal yield with reduced water usage.

Effect of Irrigation Regime and Soil Nutrients on the Growth of the Paddy Weed Heteranthera reniformis and Rice Grain Yield

The growth of Heteranthera reniformis, an invasive alien paddy weed, can be affected by cultivation practices. The experiments were conducted using herbicide-free soil to understand the effects of irrigation regimes and nutrient treatments on the growth of H. reniformis, as well as yield parameters while competing with a pre-existing seedbank. The pot experiments were conducted in a randomized complete block design (RBCD) with three replicates and twelve treatments. The four irrigation regimes (IRs): continuous irrigation (CI), soil condition at near saturation (non-puddled) (S), alternate wetting and drying (AWD) irrigation under two conditions [rewatered when the soil water potential reached −25 kPa (25P) and −35 kPa (35P)], and three nutrient treatments (NTs) of 0–0–0 NPK (NT0), 40–25–30 NPK (NT1), 80–50–60 NPK (NT2), kg ha−1 were established. The IRs had a significant effect on the growth of H. reniformis and other paddy field weeds, and the growth of H. reniformis was suppressed in the AWD regimes. NT2 resulted in more rice panicles, higher grain yield, and increased irrigation water use efficiency (IWUE). The highest grain yield and protein content were observed in S–NT2 and 25P–NT2 treatments. The IR and NT can be maintained to prevent yield penalties and reduce the invasiveness of weeds.