Crop Water Use Efficiency Research Articles

Effect of Alternate Furrow Irrigation with Different Irrigation Intervals on Tomato (<i>Lycopersicon E.</i>) Yield and Water Use Efficiency

Experiment was conducted at Eastern Ethiopia of Harari Regional State of Erer Woldiya district, on farmers’ field for two years. The purpose of this study was to evaluate the effect of AFI and EFI with different irrigation intervals on growth component, yield and water use efficiency of tomato for two years 2018 and 2019. Accordingly plant height and NFPP were significantly (P<0.05) influenced by (IMs), whereas (IIs) had highly significant (P<0.01) effect on plant height and NFPP at both planting season. Total tomato yield was significantly influenced (P<0.05) by furrow IMs, but application frequency had highly significant (p<0.01). Water saved from treatment combination of AFI with 4, 6 and 8 days water IIs were 16%, 44% and 58% of total volume of irrigation water applied. Whereas water saved from EFI with 6 and 8 days of application was 33.3% and 50% respectively. AFI with 4 day water application shows little yield reduction as 4.97%, as compared with no stressed treatment; EFI with the same water application frequency). But AFI with 4 day II was saves 16% water from gross water applied for no stressed treatment EFI with 4 day. Treatment with 6 day II of AFI and, EFI were indicated that significant yield reduction as 15.74% and 14.61% respectively. But total amount of gross volume of irrigation water saved as 44 and 33.3% for AFI and EFI of the same II treatment. Crop water productivity (CWUE, IWUE and EWP) were highly significantly (P<0.01) influenced by both IMs and IIs. The result clearly confirms that, AFI had beneficial advantage over EFI on water saving and, the same consequent is happened for irrigation interval i.e. increasing interval from 4 day followed by 6 to 8 days increases water use efficiency of crop. Hence the result indicates that interaction effect of both factors (IMs and IIs) could save significant amount of irrigation water.

Response of Maize (Zea Mays L.) To Soil Moisture Stress Condition at Different Growth Stages, Central Rift Valley of Ethiopia

Water resources availability is a crucial limiting factor for crop production in arid and semi-arid area. Consuming these limited resources carefully and efficiently is unquestionable. The planning of irrigation permitting to the water stress tolerance and water use efficiency of crops remains the only way to guarantee the continuity of production in an arid area. Considering this an experiment has been conducted in Melkassa Agricultural Research Center where shortage of moisture is a problem. The experiment was laid out in RCBD with three replications having 15 experimental treatments. The treatments had four crop growing seasons or stages (Initial, Development, midseason and late season stages. Melkassa II maize variety was used for seed materials. Water stress had significant different effect on grain yield, above ground dry biomass, plant height and water productivity (P 0.05) difference in grain yield among treatments stressed only at initial stage, late stage and non-stressed. However, stressing of maize at development and mid-season crop growth stage led to significant reduction of grain yield, above ground dry biomass and plant height. Therefore, stressing maize at combination of development stages and mid stages was more sensitive with significant yield penalty.

Improving water use efficiency and productivity in rice crops by applying alternate wetting and drying with pregerminated broadcasting in farmers’ fields

Improving water use efficiency and productivity in rice crops by applying alternate wetting and drying with pregerminated broadcasting in farmers’ fields

Enhancing water use efficiency in vegetable crops

Drip irrigation technique is very useful for the row planted crops like vegetables and irrigating the crops of hill sides and rolling grounds. In vegetables, drip irrigation is known to save 25–70% of water depending on soil, climate, crop and variety. The irrigation efficiency of drip system is very high (85–90%). Experiments conducted at ICAR- IIVR, Varanasi indicated that surface drip irrigation can save about 55–62%, 34%, 31% and 38% water, respectively in tomato, cucumber, okra and broccoli. Drip irrigation, if combined with plastic mulch, can further save 15–35% more water with improved water use efficiency. Mulching experiments revealed that in tomato, about 11% and 15% water savings were achieved with use of black polythene and transparent polythene mulch, but when black polythene mulch was used in combination of raised bed planting or drip irrigation, 46% and 66% water savings, respectively were achieved as compared to absolute control. On the other hand, organic mulches such as straw, dry grass, plant residues, etc are also equally effective to conserve soil moisture thereby saving of water, besides improving physico-chemical properties of soil.

Manejo de irrigação via solo: efeito na produção e produtividade da água da calêndula

The management of water resources in irrigated agriculture is a basic method of guaranteeing water use efficiency in agricultural crops. The aim of this study was to evaluate production and water productivity in the marigold under different soil-water matric potentials and at different stages of development. The experiment was conducted in pots in a protected environment. The experimental design was of randomised blocks with six treatments (-10, -15, -30, -40, -50 and -60 kPa) and 4 replications, giving a total of 24 experimental units for each individual trial, which were represented by the development stage of the marigold. Tensiometers were used to monitor the matric potential of the soil, with readings taken daily. The production and dry weight of the floral capitula were evaluated together with water productivity. The data were submitted to regression analysis. It was found that the variations in irrigation depth throughout the growth cycle and during the reproductive phase of the marigold gave significant results for the variables under analysis. For the complete cycle, the production of floral capitula was seen to be greater at a matric potential of -10 kPa, a higher value than the pressure at field capacity (-30 kPa). However, the greatest water productivity was obtained at a matric potential of -32.74 kPa.

Effect of varying water applications on growth, yield and water use efficiency of okra under drip irrigation in Akure, Ondo state, Nigeria

The conservation of water is crucial to sustainable agricultural production during dry season when there is little or no rainfall to improve crop production. Thus this study is aimed to estimate the effects of different levels of water applications on the growth, yield and water use efficiency of Okra under drip irrigation system during dry season. The sixteen plots consist of four treatments (2 m x 2 m) with four replicates in a complete randomized block design to determine the water consumptive use of Okra. The growth, yield and water use efficiency of Okra under four different irrigation management i.e irrigation water applied at 100FIT (full irrigation treatment), 80FIT, 60FIT and 40FIT were measured. Results showed highest growth parameters being observed at 100FIT and the least at 40FIT. The difference in the growth parameters in all the experimental blocks were not significant (p=0.05) for all the stages of development of okra. Using standard bar errors the yield obtained at 60 and 100FIT was not significantly different but significantly different when compared to other treatment blocks and it ranges from 2.05-3.60 tons/ha. The Irrigation Water Use Efficiency (IWUE) ranges from 0.024-0.041tons/ha.mm while the Crop Water Use Efficiency (CWUE) ranges from 0.0088-0.0139 tons/ha.mm. Okra crop irrigated with drip irrigation at 60FIT recorded the highest IWUE, CWUE and about 73% more yield than the 40FIT of 0.041 tons/ha.mm, 0.0139 tons/ha.mm and 3.56 tons/ha respectively. It was concluded that Okra crop irrigated at 60FIT should be adopted in order to save 40% water to irrigate additional land. Drip irrigation is encouraged during dry season for farmers to produce okra all year round.

Ridge-furrow configuration significantly improves soil water availability, crop water use efficiency, and grain yield in dryland agroecosystems of the Loess Plateau

The ridge-furrow rainfall harvesting system (RFRHS) is an in-situ rainfall collection and utilization technique that has been widely adopted in global arid and semiarid farming areas because of its significant benefits to soil water availability and crop yield. However, the integrated effects of different ridge-furrow configurations on rainwater collection and crop performance are still lacking. Using a specialized database drawn from field experiments in the Loess Plateau, we examined the regional effects of three typical ridge-furrow configurations, namely high (>1:1), uniform (=1:1), and low (<1:1) ridge-furrow ratios, on soil water storage, crop water use efficiency (WUE), and grain yield. The high ridge-furrow ratio achieved the greatest improvements in soil water storage than the other two ratios. Compared with traditional flat planting without ridge-furrow configuration, crop yield and WUE were significantly increased by 37.65%, 27.12%, 31.70%, and 47.70%, 30.00%, and 17.80% under high, uniform, and low ridge-furrow ratios, respectively. Improvements in crop yield and WUE due to the different ridge-furrow configurations were jointly affected by climate, soil organic matter, and fertilizer application. The mean annual precipitation of 600 mm and the mean annual temperature of 12 ℃ can be used as the threshold for selecting the ratio of ridge–furrow. An increase in soil organic matter gradually declined the increase in grain yield and WUE owing to the three ridge–furrow ratios, such that the maximum effect was found for the high ridge–furrow ratio. Among the three ratios, the improvements in crop yield and WUE were most notable when the application rates of nitrogen and phosphorus fertilizer were 100–200 kg ha−1 and 101–125 kg ha−1, respectively. This study examined the scientific basis of a ridge–furrow farming practice for enhancing rainfall use and crop WUE; thus, these results offer novel insights for the optimized design of a ridge–furrow ratio in dryland agroecosystems of the Loess Plateau by taking into account site-based climatic conditions, soil fertility, and fertilization input level.

Optimizing irrigation schedule in a large agricultural region under different hydrologic scenarios

Irrigation schedule is essential for improving crop production and allocating water resources in agricultural regions that heavily rely on irrigation. This study designs a framework based on the AquaCrop model to optimize the irrigation schedule of winter wheat under dry, normal and wet hydrologic scenarios over a large region in China. The model parameters were calibrated for one cultivar using observed data from three locations in the Fenwei Plain, northern China, and were shown to slightly vary spatially across this region. Regional weather data at high spatio-temporal resolution were generated by interpolation and were combined with regional soil data on a 2 × 2 km grid to drive the model. The irrigation schedule for the study area was optimized by combining a multi-objective algorithm with the exponential efficacy coefficient method. The optimization objectives included crop yield, water use efficiency (WUE), irrigation WUE and economic irrigation benefit. The results showed that the optimized irrigation schedule performed better than the current irrigation schedule applied by the farmers under studied hydrologic scenarios, resulting in increased crop yield, WUE, irrigation WUE and irrigation economic benefit by 1.1–9.7% and decreased irrigation amount by 4.2–5.7%, depending on regions within the study area. The framework developed in this study reallocated irrigation water amounts between regions, thereby improving water allocation to achieve optimal crop yield, water use and economic benefit for the Fenwei Plain. The results can also serve as a guide for local farmers and irrigation district managers.

Cultivos de cobertura como antecesor de zapallo anco en la región semiárida pampeana

The objective was determine the effect of cover crops on the water use efficiency and total yield of the pumpkin crop. The study was carried out on a soil called petrocalcic Paleustoll, located in the south of the rugged plain of the semi­arid Pampa region. In the same lot for three consecutive seasons, Rye (C) and rye + vetch (CV) were sown and fallow was established without cover cultivation. In this way, 6 management treatments for pumpkin cultivation were established: T1: without CC predecessor, with tillage prior to pumpkin planting, and without weed control during the pumpkin cycle. T 2: without predecessor CC with tillage prior to planting the pumpkin, with weed control (tillage and herbicide), during the pumpkin cycle. C H: Rye ancestor used as CC, with growth arrest by herbicide. C R: Rye ancestor used as CC, with growth arrest by rolling. CV H: Rye + Vetch ancestor used as CC, with growth arrest by herbicide. CV R: Rye + Vetch ancestor used as CC, with growth arrest by rolling. The results showed that on average in the 3 seasons C was higher than C V, in 22, 19 and 6% with respect to the total biomass, for the first, second and third seasons, respectively. Cover crops had higher fallow efficiency with respect to treatments without prior CC (T1 and T2). The highest pumpkin yields were over the CC, these being the ones with the lowest UC and the highest EUAt

EFFECT OF IRRIGATION REGIMES ON YIELD AND WATER USE EFFICIENCY OF EXTRA-EARLY MAIZE VARIETY IN KANO RIVER IRRIGATION PROJECT

A field experiment was conducted to evaluate the effect of irrigation regimes on yield and water use efficiency of maize crop (Zea Mays L.; SAMMAZ 29) under different irrigation scheduling. Randomized Complete Block Design (RCBD) was used and the experiment consisted of three levels of irrigation water application depth of 100%, 75% and 50% replacement of Total Available Water Capacity (TAWC) and three irrigation intervals of 7, 10 and 13 days replicated three times. Irrigation water was applied into each of 0.75 m × 90 m furrow using siphon tube of 7.5 cm diameter and 200 cm length. The results showed that the highest average irrigation water use efficiency was at I10D75% with 0.71 kg/m3 while the least was at I13D50% with 0.41 kg/m3. The highest average crop water use efficiency (CWUE) was at I10D75% with 0.79 kg/m3 while the least was at I13D75% with 0.56 kg/m3. The highest average maize yield was at I7D100% with 3580 kg/ha while the least was at I13D50% with 1200 kg/ha. The study established that irrigation after every 10 days interval with 75% replacement of TAWC using furrow irrigation of 90 m lengths produced the highest crop water use efficiency, thus saving about 48.3% of irrigation water (amounting to 329 mm) with reference to control (I7D100%) which causes a yield reduction of about 19% (amounting to 680 kg/ha). This efficient water usage saved cost and also helps to address the problem of high water table of the study area.

The Impacts of Conservation Agriculture on Water Use and Crop Production on the Loess Plateau: From Know-What to Know-Why

Due to the scarce irrigation water supply in the Loess Plateau, efficient use of rainwater is critical for the improvement of sustainable crop production. Conservation agriculture (CA) has been regarded as an ideal field management strategy to profoundly benefit water use and therefore crop production. However, it remains unclear as to how crop production and water use respond to annual precipitation and how CA practices affect crop production through regulating water use. In this study, a meta-analysis based on field observations was conducted to investigate the relationship between water use and crop production. The results showed that annual precipitation of 300 mm yr−1 is a threshold to ensure relatively high crop production and water use efficiency (WUE), and 600 mm yr−1 is the most favorable rainfall level for crop production and WUE. Evapotranspiration (ET) was linearly related to annual precipitation, except that it was not the lowest when annual rainfall &lt;300 mm yr−1. Although straw mulching is more important than tillage reduction, tillage reduction is still necessary to combine with straw mulching to obtain a higher production of crop. Crop production, ET, and WUE kept increasing as experimental duration increased, indicating that extending CA term is essential to further improve water use and crop production. We further proposed mathematical equations to prove that the increase in transpiration plays a critical role in water use and crop production improvement. WUE is not necessarily related to the increase in yield, and, therefore, higher transpiration rather than increased WUE should be the target for crop production improvement. The results also suggest that evaporation and transpiration are not presented separately, which limits investigation of the effective use of water by identifying transpiration. Overall, annual precipitation is essential for the levels of crop production, ET, and WUE on the Chinese Loess Plateau. Reasonable CA practices, especially long-term application, could improve water use and crop production through increasing transpiration. However, a better future understanding of the relationship between crop production and water use needs more detailed information about the effective use of water at field scales.

Crop Productivity, Grain Quality, Water Use Efficiency, and Soil Enzyme Activity as Influenced by Silicon and Phosphorus Application in Aerobic Rice (Oryza sativa)

ABSTRACT The experiments were conducted to evaluate the effects of silicon (Si) and phosphorus (P) application on crop productivity, grain quality, water-use efficiency (WUE), and soil enzyme activity in aerobic rice (AR) at Indian Agricultural Research Institute, New Delhi, India. Four levels each of Si (0, 40, 80, and 120 kg Si ha–1) and P (0, 30, 60, and 90 kg P2O5 ha–1) were tested in a factorial randomized block design (FRBD) replicated thrice. The growth, yield and quality of AR were enhanced with increasing Si and P application rates and a similar trend was observed for WUE and soil enzyme activity. The highest grain yield of AR was recorded with 120 kg Si and 90 kg P2O5 ha–1 followed by 80 kg Si and 60 kg P2O5 ha–1 and the lowest in control. The grain, straw yield and water productivity increased by 10–40%, 5–30%, and 10.2–39%, respectively in different treatments over control. Though, all studied parameters showed increment with increasing dose of Si and P; however 60 kg P2O5 and 80 kg Si ha–1 were statistically superior to their other respective doses. In conclusion, supplementation of Si and P fertilizers substantially increased the AR productivity in Trans-Gangetic plains of India (Figure 1).

ASSESSMENT OF TOMATO FARMERS’ IRRIGATION PRACTICE IN PAMPAIDA MILLENNIUM VILLAGE, IKARA LOCAL GOVERNMENT AREA, KADUNA STATE, NIGERIA

This study was conducted in Pampaida Millennium Village (PMV), Ikara Local Government Area of Kaduna State, Nigeria; during the 2009/2010 dry season to assess Tomato farmer’s irrigation water management practice using furrow irrigation. A total of 7 tomato farmers were selected out of 45 farmers for the assessment exercise. Soil moisture content was monitored throughout the growing season using gypsum blocks. The hydraulic performance of the farmer’s plots were assessed. Similarly, the seasonal water requirement and irrigation schedule for the irrigated tomato were also determined. The results showed that the highest Application Efficiency, Distribution Uniformity and Adequacy of irrigation were obtained in plots T6 (92%), T3 (89%) and T7 (92 %) respectively. The least AE, DU and AI were obtained in plot T1 as 74%, 72% and 63% respectively. The yield obtained ranged from 11.6t/ha to 22.3t/ha. The least yield was obtained in plot T2; while the highest yield was obtained in plot T1. All the assessed farmers maintained a 4day irrigation interval throughout the growing season. The highest crop water use efficiency (CWUE) of 62.80 kg/ha-mm was obtained in plot T1, with a corresponding crop water use (CWU) of 355 mm/season. The least CWUE was obtained in plot T2 (41.6kg/ha-mm) with a corresponding CWU of 399 mm/season. Based on the results obtained it can be deduced that plot T1 gives best results among the assessed farmers’ plots in terms of crop water use efficiency and effectiveness of irrigation, which maximizes net farm profit.

Effect of drip irrigation scheduling and mulching on plant growth, physiology, yield, water use efficiency and weed growth in spring-summer okra (Abelmoschus esculents Muench)

Spring summer okra requires high and frequent applicationof water due to high evapo-transpiration demand. Deficitirrigation (supply less water than required) coupled withmulching is good agricultural practice to enhance water useefficiency in vegetable crops. In this study, three dripirrigation scheduling and two types mulches were evaluatedwith surface irrigation and without mulch. Maximum soilmoisture content of 12.2% and 13.5% was reported underorganic mulch, respectively at 20 and 30 cm depth. Plantsgrown under organic and black-silver mulch have registered52.5% and 35% higher chlorophyll content than control.Maximum stomatal conductance was reported with 100%PE + black-silver mulching (956.05 mmole/m2/sec).Significantly higher fruit yield (555.42 g/plant and 112.05 q/ha) was observed with drip irrigation at 100% PE, whereasin mulches, it was maximum under organic mulch (585.13 g/plant and 112.30 q/ha). As far as interaction of irrigation xmulch was concerned, the maximum yield of 684 g/plant and125.32 q/ha was reported with drip irrigation 100% PE +organic mulch, which was 64.8% higher in yield with 15.2%water saving than the control.

Spatial-temporal distribution of winter wheat (Triticum aestivum L.) roots and water use efficiency under ridge–furrow dual mulching

In dryland agricultural production areas, knowledge on the growth and variation of winter wheat root systems under different mulching methods is important for guiding winter wheat production. We conducted a two-year field trial to explore the effects of different mulching practices on the spatial-temporal distribution of root growth, soil water storage, and grain yield. Four cultivation practices were tested: (i) traditional flat planting (CK), (ii) flat planting with half-film mulching (M1), (iii) ridge–furrow planting with film mulching over ridges only (M2), and (iv) ridge–furrow planting with film mulching over ridges and wheat straw mulching in furrows (M3). The results showed that the root diameter (RD), root length density (RLD), and root surface area density (RSD) of wheat under the four treatments were mainly concentrated in the 0–40 cm soil layer. The mean RLD in the 0–40 cm soil layer accounted for 62.2 %, 61.0 %, 59.3 %, and 55.8 % of the total root length density under M3, M2, M1, and CK, respectively, at maturity in both years. The M3 cultivation method produced the maximum values for RD, RLD, and RSD among all cultivation practices and the highest water storage efficiency after the three precipitation events. The M3 treatment had 11.1 %, 15.4 %, and 38.4 % higher mean grain yields than M2, M1, and CK, respectively, over the two-year study. Soil water storage had positive correlations with RD, RLD, and RSD. The RD, RLD, and RSD in the 0–40 cm soil layer had strong positive correlations with yield components, yield, aboveground biomass, and water use efficiency (WUE). Based on this study, ridge–furrow planting with film mulching over ridges and wheat straw mulching in furrows is an effective, sustainable cultivation method for wheat production in rainfed regions, which can increase the spatial-temporal distribution of root systems and soil water content across the root zones to increase crop production and WUE.

Regulation of soil water threshold on tomato plant growth and fruit quality under alternate partial root-zone drip irrigation

Increasingly limited global freshwater resources coupled with low water use efficiency (WUE) increases the need for water-saving irrigation technologies in agricultural production. Numerous studies have investigated the emerging water-saving irrigation technology of alternate partial root-zone drip irrigation (APDI) on crop yield and WUE. This study investigated the effects of lower soil water thresholds for alteration of the irrigation (LTAI) to the previously dry root-zone on tomato plant growth, yield, and irrigation water use efficiency (IWUE) under APDI in year 2016 with field plot area of 6.48 m2. There were six APDI treatments coded as AS80, AS70, AS60 and AD80, AD70, AD60, indicating APDI under sufficient irrigation (S) or deficit irrigation (D) with LTAI controlled at 80 %, 70 % and 60 % field water capacity (FC) in the previously dry root-zone, respectively. In addition, conventional sufficient (CSD) and deficit (CDD) drip irrigation treatments were added as the controls. The results showed that lowering the irrigation amount significantly reduced tomato plant growth, yield and harvest index, but improved fruit quality in terms of reducing sugar, soluble sugar, vitamin C, and sugar-acid ratio. Compared with that of conventional drip irrigation, the promotion effect of APDI, especially with LTAI at 70 % FC, on root growth was observed in the 0−20 cm top soil layer where more than 90 % of the plant roots were distributed irrespective of irrigation amounts. Under sufficient irrigation, tomato shoot growth and the harvest index showed no significant difference among treatments, but tomato yield and the root to shoot ratio increased significantly in AS70, while fruit quality was improved in AS70 and AS60. Under APDI with deficit irrigation, when LTAI decreased from 80 % FC to 70 % FC in the previously drying root-zone, the yield and IWUE in AD80 and AD70 increased by 8.6 % and 17.4 %, respectively, and thus increased the harvest index compared with CDD. The AD70 treatment saved 31.2 % irrigation water without significant yield reduction, but increased IWUE by 44.9 % compared with the CSD. However, the harvest index and the yield decreased significantly when LTAI decreased from 70 % FC to 60 % FC (AD70 Vs. AD60). In addition, the yield showed no significant difference between AD60 and CDD. Fruit quality increased under APDI as compared with CDD under deficit irrigation, with the best quality appeared in the AD70 and AD60 treatments. These results indicated that the effects of APDI on tomato growth and fruit quality were modulated by LTAI and irrigation amount. APDI with LTAI controlled at 70 % FC was the optimal choice for better yield and fruit quality, especially under deficit irrigation. Unfavorable LTAI could diminish and even eliminate the beneficial effects of APDI on yield and IWUE as compared with conventional drip irrigation.

Effects of Different Fertilization Regimes on Crop Yield and Soil Water Use Efficiency of Millet and Soybean

Soil water and nutrients are major factors limiting crop productivity. In the present study, soil water use efficiency (WUE) and crop yield of millet and soybean were investigated under nine fertilization regimes (no nitrogen (N) and no phosphorus (P) (CK), 120 kg ha−1 N and no P (N1P0), 240 kg ha−1 N and no P (N2P0), 45 kg ha−1 P and no N (N0P1), 90 kg ha−1 P and no N (N0P2), 120 kg ha−1 N and 45 kg ha−1 P (N1P1), 240 kg ha−1 N and 45 kg ha−1 P (N2P1), 120 kg ha−1 N and 90 kg ha−1 P (N1P2), 240 kg ha−1 N and 90 kg ha−1 P (N2P2)) in the Loess Plateau, China. We conducted fertilization experiments in two cultivation seasons and collected soil nutrient, water use, and crop yield data. Combined N and P fertilization resulted in the greatest increase in crop yield and WUE, followed by the single P fertilizer application, and single N fertilizer application. The control treatment, which consisted of neither P nor N fertilizer application, had the least effect on crop yield. The combined N and P fertilization increased soil organic matter (SOM) and soil total N, while soil water consumption increased in all treatments. SOM and total N content increased significantly when compared to the control conditions, by 27.1–81.3%, and 301.3–669.2%, respectively, only under combined N and P application. The combined N and P application promoted the formation of a favorable soil aggregate structure and improved soil microbial activity, which accelerated fertilizer use, and enhanced the capacity of soil to maintain fertilizer supply. Crop yield increased significantly in all treatments when compared to the control conditions, with soybean and millet yields increasing by 82.5–560.1% and 55–490.8%, respectively. The combined application of N and P fertilizers increased soil water consumption, improved soil WUE, and satisfied crop growth and development requirements. In addition, soil WUE was significantly positively correlated with crop yield. Our results provide a scientific basis for rational crop fertilization in semi-arid areas on the Loess Plateau.

Strategies for Improved Water Use Efficiency (WUE) of Field-Grown Lettuce (Lactuca sativa L.) under a Semi-Arid Climate

Water use efficiency is a main research target in agriculture, which consumes 70% of global freshwater. This study aimed at identifying sustainable water management strategies for the lettuce crop in a semi-arid climate. Three independent experiments were carried out on a commercial variety of lettuce (Lactuca sativa L.) by applying different irrigation levels based on crop evapotranspiration (ETc), estimated through both the Hargreaves–Samani and Penman–Monteith equations. In the first experiment, one treatment was also guided by soil moisture sensors. In the second and third experiments, a factorial combination was used, combining the different irrigation levels with two soil mulching treatments, namely soil without mulch, and soil mulched with dried rice straw residues. The application of different irrigation levels significantly affected plant growth, yield, and physiology. Both the adoption of sensors for guiding irrigation and the application of mulching with straw promoted higher yield. As the irrigation water level was reduced, the WUE (water use efficiency) increased. WUE was also increased by covering the soil with mulch. The experiments point out that accurate management of irrigation water using a drip irrigation system associated with soil mulching increases yield and improves the WUE of lettuce crops in the Central Dry Zone, Myanmar.

Assessments of Humic Substances Application and Deficit Irrigation in Triploid Watermelon

Soil organic matter degradation and water limitation caused by intense farming activities are some of the major threats affecting agricultural production. Accordingly, the concepts of sustainable agricultural systems with optimized irrigation and improved soil quality can be adapted to address these issues. During this 2-year field study, two management factors—humic substances (HS) as organic inputs (HS vs. control) and deficit irrigation as the irrigation method (50% vs. 100% based on evapotranspiration)—were evaluated based on triploid watermelon (Citrullus lanatus cv. Fascination) yield and soil property changes. HS application increased watermelon early yield by 38.6% and total yield by 11.8% compared with the control; the early yield mainly increased under deficit irrigation. Compared with full irrigation, deficit irrigation increased water use efficiency (WUE) without significantly affecting total yield. In addition, HS application significantly increased the soil organic carbon (SOC) content, which was found to be positively correlated with crop WUE. These results indicate that soil organic inputs with HS and deficit irrigation are valuable strategies to establish sustainable systems for watermelon production, which will not only increase yield and WUE but also significantly improve soil quality and save irrigation water.

Improving Crop Water-Use Efficiency Requires Optimizing the Circadian Clock.

The slogan “more crop per drop,” which was popularized in the early 2000s, depicts the need to improve the productivity of crops for the same water inputs ([Kijne et al., 2003][1]). While the approaches by which this could be achieved have evolved and expanded, the motivation remains stronger