Effects Of Irrigation Management Research Articles

Controlling exposure to As and Cd from rice via irrigation management

Irrigation management controls biogeochemical cycles in rice production. Under flooded paddy conditions, arsenic becomes plant-available as iron-reducing conditions ensue, while oxic conditions lead to increased plant availability of Cd in acidic soils. Because Cd enters rice through Mn transporters, we hypothesized that irrigation resulting in intermediate redox could simultaneously limit both As and Cd in rice grain due to As retention in soil and Mn competition for Cd uptake. In a 2 year field study, we used 6 irrigation managements that varied in extent and frequency of inundation, and we observed strong effects of irrigation management on porewater chemistry, soil redox potentials, plant As and Cd concentrations, plant nutrient concentrations, and methane emissions. Plant As decreased with drier irrigation management, but in the grain this effect was stronger for organic As than for inorganic As. Grain organic As, but not inorganic As, was strongly and positively correlated with cumulative methane emissions. Conversely, plant Cd increased under more aerobic irrigation management and grain Cd was negatively correlated with porewater Mn. A hazard index approach showed that in the tested soil with low levels of As and Cd (5.4 and 0.072 mg/kg, respectively), irrigation management could not simultaneously decrease grain As and Cd. Many soil properties, such as reducible As, available Cd, soil pH, available S, and soil organic matter should be considered when attempting to optimize irrigation management when the goal is decreasing the risk of As and Cd in rice grain.

Irrigation expansion shows potential for increased maize yield and reduced nitrogen leaching in the Midwest US

CONTEXTYield gaps in Midwest US rainfed maize (Zea mays L.) are likely to continue to increase as the frequency of extreme weather events associated with future climate change increase (i.e., high temperatures, precipitation variability). One solution to closing this gap is the expansion of irrigation in regions that currently do not utilize this practice. While irrigation expansion has the potential to increase maize yields and crop productivity, there is also the potential to see improvement in nitrogen loss. However, it remains unclear at what point irrigation should be triggered (i.e., plant available water content (AWC) thresholds) to obtain a balance between crop productivity and environmental improvements. OBJECTIVEThe objective of this study is to assess the effects of irrigation management on maize yield, nitrogen leaching, and water use efficiency under the expansion of irrigation across the entire Midwest US and to determine the optimal plant AWC threshold to trigger irrigation for achieving a substantial increase in maize yield and reduction in nitrogen leaching while using the minimal amount of required irrigation. METHODSWe use an agroecosystem model, Agro-IBIS, to simulate both rainfed and irrigated maize production and nitrogen leaching under likely future climate conditions (i.e., wet-warm, dry-warm). To determine the optimal plant AWC threshold for irrigation, irrigation scenarios were conducted for a range of plant AWC thresholds (0.2 to 0.8) across the entire Midwest US. RESULTS AND CONCLUSIONSOur results show that Midwest US regions that do not currently utilize irrigation could experience an 11–37% increase in maize yield and a 12–32% decrease in nitrogen leaching when irrigation (39.0 to 96.8 mm yr−1) is triggered at the lower end of the plant AWC threshold (e.g., 0.3). Maize grown under dry-warm and wet-warm climate conditions will likely experience increased yields and reduced nitrogen loss with minimal irrigation. While these findings suggest that the expansion of irrigation could help close yield gaps while improving other ecosystem services, future work should focus on simulating these conditions under a wider range of precipitation extremes and fertilizer management to better understand the potential interactions under a changing climate. SIGNIFICANCEThis study outlines the optimal plant AWC threshold for irrigation to maximize maize yields in the Midwest while minimizing nitrogen loss and can provide valuable insights for making informed decisions about landscape management under future conditions.

Application of Irrigation Management and Water-Lifting Technologies to Enhance Fodder Productivity in Smallholder Farming Communities: A Case Study in Robit Bata, Ethiopia

Small-scale cultivation of irrigated fodder is emerging as a vital production system in mixed farming communities. Efficient water management plays a key role in enhancing forage production, especially in the face of changing climate. A field-scale experimental study was conducted in Robit Bata kebele, Ethiopia, with the following objectives: (1) to examine the effects of conventional farmers’ irrigation scheduling versus climate-based irrigation scheduling; and (2) to assess the influence of water-lifting technologies (manual pulley and solar Majipump) on dry matter yield (DMY), water productivity (WP), irrigation labor productivity (ILP), and water productivity in terms of crude protein and metabolizable energy (WP.CP and WP.ME) of Napier grass. The experiment used 10 farmers’ plots each with a size of 100 m2. Half of the plots were treated using farmers’ scheduling while the other half were treated using climate-based irrigation scheduling. Monitoring of irrigation water use and crop yield took place over two irrigation seasons from November 2020 to June 2021. Results showed there was an interaction effect of irrigation management (p = 0.019) and water-lifting technologies (p = 0.016) with season on DMY. The highest DMY occurred in the first irrigation season with climate-based scheduling and solar Majipump use. The interaction effect of irrigation management and season affected WP (p = 0.047). Climate-based scheduling had a higher WP in the first season, while farmers’ scheduling had a higher WP during the second season. On average, the solar Majipump outperformed the pulley, achieving 5 kg m−3 WP compared to the pulley’s 4 kg m−3 (p = 0.018). Emphasizing the seasonal impact, it is recommended to promote full irrigation (climate-based) in the first season for maximum yield and WP. Conversely, in the second season, advocating only deficit irrigation is advised due to water scarcity and sustainability concerns. Statistical parity in DMY and lower WP with full irrigation in the second season supports this recommendation, addressing the challenge of optimizing water use in the context of a changing climate and ensuring sustainable smallholder agriculture practices. Therefore, implementing appropriate irrigation management alongside efficient water-lifting technologies holds the potential to enhance fodder productivity and bolster smallholder farmers’ livelihoods. Future research should explore the comparative benefits of irrigated fodder versus other crops and the overall advantages of investing in irrigated fodder over vegetables.

Heat Stress and Water Irrigation Management Effects on the Fruit Color and Quality of ‘Hongro’ Apples

Increasing fruit crop production sustainability under climate change, particularly increasing temperatures, is a major challenge in modern agriculture. High temperatures affect apple fruit quality and decrease its color. Herein, we constructed an experimental field under temperature simulation to evaluate climate change mitigation strategies for apples. ‘Hongro’ apples were subjected to three treatments: (1) cultivation inside a vinyl house for heat treatment (heat induction), (2) cultivation under water irrigation (heat reduction), and (3) cultivation under normal atmospheric temperature (control). At harvest, the fruits of the heat treatment group exhibited poor coloration, with a lower gene expression and pigment accumulation than those of the water irrigation and control groups. Furthermore, the fruit quality of the heat treatment group decreased, with a lower soluble solid content (SSC) and titratable acidity (TA), and smaller fruits. Additionally, a higher fruit disorder (cracking and spots) ratio was observed in the heat treatment group than in the water irrigation and control groups. However, the fruits of the water irrigation group exhibited higher quality indexes (flesh firmness, SSC, and TA) and less cracking than those of the heat treatment and control groups. Heat reduction, including water irrigation, may be used for orchard management to prevent climate change-induced increasing temperatures.

Effects of Different Irrigation Management and Nitrogen Rate on Sorghum (Sorghum bicolor L.) Growth, Yield and Soil Nitrogen Accumulation with Drip Irrigation

Sorghum (Sorghum bicolor L.) has emerged as a pivotal global food crop. Consequently, it is imperative to explore sustainable and eco-friendly strategies to achieve sustainable sorghum production with a high yield. This study aimed to reveal the effects of irrigation management and nitrogen rates and their interactions on sorghum growth traits, yield and soil nitrate-N and ammonium-N accumulation to improve irrigation and nitrogen practices under drip irrigation. A 2-year (2021 and 2022) field experiment was conducted on drip-irrigated fertilized sorghum in Heilongjiang Province to investigate the effects of three lower levels of soil moisture (80% (HI), 70% (NI), and 60% (LI) of field capacity) with four nitrogen rates at 225, 150, 75 and 0 kg/ha (designated as HN, NN, LN and WN, respectively) on sorghum growth, yield and soil nitrogen accumulation. The results indicated that irrigation management and nitrogen rate interaction had a significant effect on sorghum growth (plant height, stem diameter, leaf area index (LAI), and SPAD value), yield, aboveground biomass and 0~60 cm soil nitrogen accumulation (p < 0.05). The NNHI treatment demonstrated the highest plant height (120.9 and 121.8 cm) and LAI (2.738 and 2.645) in 2021 and 2022, and there was a significant positive correlation between plant height, LAI, and yield (p < 0.01). However, the NNNI treatment exhibited the highest yield (7477.41 and 7362.27 kg/ha) in 2021 and 2022, sorghum yield increased and then decreased with an increase in irrigation management and nitrogen rate. In addition, soil nitrate-N and ammonium-N accumulation were significantly affected by the interaction of irrigation management and nitrogen rate (p < 0.05) while irrigation management had no significant effect on the accumulation of nitrate-N and ammonium-N. Soil nitrate-N and ammonium-N accumulation increased with the increasing nitrogen rate. Although yield differences between the NNNI and HNNI treatments were not significant, the NNNI treatment with a lower soil moisture limit of 70% field capacity and a nitrogen rate of 150 kg/ha accumulated 10.4% less nitrate-N in soil than the HNNI treatment, reduced risk of nitrate nitrogen leaching. The regression analysis indicated that the optimal irrigation management and nitrogen rate management practices of 71.93% of the soil moisture lower limit and 144.58 kg/ha of nitrogen rate was an optimal strategy for favorable sorghum growth, high-yielding and low soil nitrate-N accumulation of sorghum. This study provides a scientific reference for precise water and fertilizer management in sorghum.

Effect of Integrated Use of Poultry Manure with Fertilizer Urea for Sustainable Nitrogen Management in Rice (cv. BRRI Dhan 29) under Two Water Management Systems

The experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh. The experiment's objectives were to evaluate the performance of integrated management of poultry manure with chemical fertilizer urea and to seek water-saving technology that will allow rice (BRRI dhan 29) production to be maintained or increased in the face of declining water availability. The experiment comprised seven treatments viz. T1:100% N from poultry manure, T2:100% N recommended doses of prilled urea, T3:90% N from PU + 10% N from PM, T4:80% N from PU + 20% N from PM, T5: 70% N from PU + 30% N from PM, T6: 60% N from PU + 40% N from PM, T7: 50% N from PU + 50% N from PM. It was laid out in a split-plot design with three replications. The main plots were allocated for irrigation treatments (alternate wetting and dying and continuous flooding) and sub-plots for nitrogen treatments. Altogether, 42 unit plots were conducted, each measuring 2.5mx2.5m. The application of different nitrogen levels significantly influenced all the growth parameters. Irrigation levels significantly affected all the yield and yield contributing characters except plant height, number of ineffective tillers, panicle length, unfilled grain per panicle, 1000 grain weight and harvest index. The highest value of total tiller/hill (11.01), number of effective tillers per hill (9.72), filled grain per panicle (132.23), grain yield (4.80), straw yield (6.68), biological yield (11.47) was observed in the two-irrigation system while height value of non-effective tiller/hill (1.29). The effect of nitrogen treatment was found to be significant. On the other hand, the interaction effect of irrigation management and treatments significantly influenced all the yield parameters except plant height, No. of tiller/ hill, no. of non-effective tiller/hill, panicle length, unfilled grain/panicle and 1000 grain weight. The height value of all those parameters was recorded at the I1×T2 (continuous flooding ×100% N recommended doses of prilled urea). The lowest value of all these parameters was recorded at the I2×T1 (AWDI × 100% N from poultry manure) and I1×T1 (continuous flooding × 100% N from poultry manure). The integrated use of 90% N from PU + 10% N from PM appeared as the better practice because of reducing the considerable amount of prilled urea in Boro rice (cv. BRRI dhan 29) cultivation in terms of grain yield. Moreover, the best promising practice was obtained using 100% N recommended doses of prilled urea applied with continuous flooding (CF).

Effect of irrigation management and humic acid rate on water use efficiency and some qualitative traits of peanuts (Arachis hypogaea L.)

Effect of irrigation management and humic acid rate on water use efficiency and some qualitative traits of peanuts (Arachis hypogaea L.)

The effect of irrigation management on rice grain yield, irrigation water productivity and methane emissions in northern Iran

AbstractThis experiment aims to study the effect of water‐saving irrigation on rice production and methane emissions. Three irrigation methods, that is, flooding irrigation, deficit irrigation (DI) and alternate partial root‐zone drying (APRD), were employed in a 2‐year field trial. The experiment was conducted in a randomized complete block design with three replications. For the DI and APRD treatments, plots were not irrigated until the soil matric potential reached −10 (DI10 and APRD10), −30 (DI30 and APRD30) and −60 kPa (DI60 and APRD60). In the APRD treatments, two adjacent furrows of each plant row were alternately irrigated in consecutive irrigation events. The DI and APRD treatments did not affect yield components when the soil matric potential was −10 kPa. Applying APRD treatments increased irrigation water productivity by 45%, 51% and 31% for soil matric potentials of −10, −30 and −60 kPa, respectively. On average, water stress treatments reduced methane emissions by 78% compared to flooding treatment. On average, the APRD treatments decreased the water input by 10% compared with the DI treatments while achieving a 2.5% higher yield. This is the first study to outline the effect of APRD on methane emissions and rice production. These findings suggest that APRD could be a valuable strategy to mitigate methane emissions without risking rice yield reduction.

Effect of Irrigation Management and Transplanting Date on the Rice Production and Water Productivity

ABSTRACT Water supply via irrigation and other water sources during the rice-growing season is vital for obtaining reasonable yield. The present study was carried out to investigate the dual-interacted effects of different irrigation intervals and transplanting dates on the yield, yield components, and water productivity of rice (Hashemi cultivar). The study was conducted in a three replicated randomized complete block design (RCBD) with the split-plot arrangement in two growing seasons (spring and summer) of 2016 and 2017 at Rice Research Institute of Iran, Rasht. The main factor was irrigation at four levels (full flooding, 5-, 10-, and 15-day irrigation intervals), and the second factor was three transplanting dates (April 21st, May 11th, and May 31st). The productivity of irrigation water (WPI) and irrigation water + precipitation (WPI+R) was reported in terms of grain yield and biomass. The highest paddy yield was observed in flooding treatment (4271 kg per hectare) and the irrigation intervals of 5, 10, and 15 days with 3844, 3196, and 3264 kg/ha were in the next rank, respectively. According to the biomass yield, 15-day irrigation interval and flooding irrigation had the highest and lowest water irrigation productivity, respectively. In the study of different transplanting dates, the highest paddy yield (3795 and 3820 kg/ha, respectively) was observed on the May 11th, and May 31st transplanting dates, and the highest water productivity based on paddy and biomass yield was obtained in the April 21st transplanting date. Regarding grain and biomass yield of rice, water productivity, and water use, the five-day irrigation treatment resulted in the best crop grain and biomass yield on April 21st transplanting date.

Effect of Irrigation Management and Water Quality on Soil and Sorghum bicolor Payenne Yield in Cape Verde

Treated water use for agriculture will promote sustainable irrigation development and food sovereignty. The aim of this study is to assess the feasibility of subsurface drip irrigation (SDI) compared to drip irrigation (DI) and of reclaimed water (RW) versus conventional groundwater (CW), to produce forage sustainably in a warm arid region. A sorghum experiment was conducted in a field on Santiago Island (Cape Verde). A forage yield of 200 t fresh matter·ha−1·year−1, irrigated by RW, was obtained. Considering Cape Verde regulations, it is possible to irrigate sorghum using a drip system and RW without adding fertilizers. Soil fertility (OM and Ntot) increased, while risk parameters (EC, nitrate, and Na) returned to their initial values after the rainy season. The best irrigation water use efficiency was obtained by RWSDI (200 L·kg−1 DM) compared to RWDI, which needed 34% more water. According to the results, a high nitrate elimination rate in treatment plants might not be desirable if agricultural reuse is planned to irrigate high-N-demanding species. Establishing new salinity tolerance levels under reuse conditions with SDI, and irrigating in rainy months to promote the lixiviation of salts in arid regions are also necessary.

Effect of irrigation management on the relationship between stomatal conductance and stem water potential on cv. Cabernet Sauvignon

Water relations in vineyards have been largely studied; giving insides regarding the way grapevine interacts with its environment according to water availability, providing us terminologies like Isohydric and Anisohydric, which have been applied to categorize cultivars and rootstocks. Recently, the use of this terminology has been subjected to discussion regarding its use as a category to describe and separate grapevine cultivars instead of using it as a continuous, where grapevines can behave more iso or anysohidric depending on the environment where they are grown. In this study, using a deficit irrigation (RDI) trial in a commercial vineyard located in Maule Valley in Central Chile, the relationship between Midday Stem Water Potential (ψx), Stomatal Conductance (gs), Soil Water Content (WC), and Vapour Pressure Deficit (VPD) on cv. Cabernet Sauvignon was studied, a grape variety that has been classified as isohydric. The trial was carried out for 3 years from 2018 to 2020 in which four RDI treatments were employed to replenish different portions of evapotranspiration (ET) from pea-size until harvest. These irrigation treatments were conceived as 100% ET, 70% ET, 50-100% ET (50% ET before veraison and 100% ET afterwards) and 35-100% ET (35% ET before veraison and 100% ET afterwards). Findings in this study show how the relationship between ψx and gs is treatment dependent; in treatments where no water deficit was imposed a weaker relationship between the variables was observed, showing a large variation between gs at similar ψx, being gs more dependent on VPD compared to the treatments with a larger deficit on its irrigation. As the deficit irrigation increased, grapevines started to shift to a smaller variation on its gs over large variations on its ψx. This result shows that irrigation management and deficit irrigation strategies impact the way plants react to water availability and leads to different behavior on its gs/ψx relationship.

Irrigation Scheduling and Production of Wheat with Different Water Quantities in Surface and Drip Irrigation: Field Experiments and Modelling Using CROPWAT and SALTMED

Water is a key factor in global food security, which is critical to agriculture. The use of mathematical models is a strategy for managing water use in agriculture, and it is an effective way to predict the effect of irrigation management on crop yields if the accuracy of these models is demonstrated. The CROPWAT and SALTMED models were tested in this study, with water quantities applied to surface and drip irrigation (SI and DI) systems to estimate irrigation scheduling and wheat yield. For this purpose, field experiments were conducted for two consecutive years to study the effects of irrigation water levels of 80%, 100%, and 120% crop evapotranspiration (I80, I100, and I120) on the yield and water productivity (WP) of wheat in SI and DI systems. Irrigation treatments affected yield components such as plant height, number of spikes, spike length, and 1000-kernel weight, though they were not statistically different in some cases. In the I80 treatment, the biological yield was 12.8% and 8.5% lower than in the I100 and I120 treatments, respectively. I100 treatment under DI resulted in the highest grain yield of a wheat crop. When DI was applied, there was a maximum (22.78%) decrease in grain yield in the I80 treatment. The SI system was more water-consuming than the DI system was, which was reflected in the WP. When compared with the WP of the I80 and I100 treatments, the WP was significantly lower (p < 0.05) in the I120 treatment in the SI or DI system. To evaluate irrigation scheduling and estimate wheat yield response, the CROPWAT model was used. Since the CROPWAT model showed that increasing irrigation water levels under SI for water stress coefficient (Ks) values less than one increased deep percolation (DP), the I120 treatment had the highest DP value (556.15 mm on average), followed by the I100 and I80 treatments. In DI, I100 and I120 treatments had Ks values equal to one throughout the growing seasons, whereas the I80 treatment had Ks values less than one during wheat’s mid- and late-season stages. The I100 and I80 treatments with DI gave lower DP values of 93.4% and 74.3% compared with that of the I120 treatment (on average, 97.05 mm). The I120 treatment had the lowest irrigation schedule efficiency in both irrigation systems, followed by the I100 and I80 treatments. In both seasons, irrigation schedule deficiencies were highest in the I80 treatment with DI (on average, 12.35%). The I80 treatment with DI had a significant yield reduction (on average, 21.9%) in both seasons, while the irrigation level treatments with SI had nearly the same reductions. The SALTMED model is an integrated model that considers irrigation systems, soil types, crops, and water application strategies to simulate soil water content (SWC) and crop yield. The SALTMED model was calibrated and validated based on the experimental data under irrigation levels across irrigation systems. The accuracy of the model was assessed by the coefficients of correlation (R), root mean square errors (RMSE), mean absolute errors (MAE), and mean absolute relative error (MARE). When simulating SWC, the SALTMED models’ R values, on average, were 0.89 and 0.84, RMSE values were 0.018 and 0.019, MAE values were 0.015 and 0.016, and MARE values were 8.917 and 9.133%, respectively, during the calibration and validation periods. When simulating crop yield, relative errors (RE) for the SALTMED model varied between −0.11 and 24.37% for biological yield and 0.1 and 19.18% for grain yield during the calibration period, while in the validation period, RE was in the range of 3.8–29.81% and 2.02–25.41%, respectively. The SALTMED model performed well when simulating wheat yield with different water irrigation levels under SI or DI.

Effects of St. Augustinegrass genotype and irrigation frequency on turfgrass quality in a subtropical environment

AbstractGrowing urban populations have placed greater demands on municipal water supplies, especially during dry periods. Efforts are underway to develop turfgrasses with better performance using less irrigation. The objective of this research was to assess the effects of irrigation management and St. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze] genotype on turf quality (TQ). The field study conducted in Citra, FL, was a split‐plot design with the main plot (irrigation) arranged in blocks. Calendar‐based irrigation treatments were soil sensor‐based, 8X, 4X, 2X, and 1X per month (MO) and none. St. Augustinegrass genotypes included three commercial cultivars and eight experimental entries. Turfgrass quality varied with time, genotype, and irrigation. Sensor‐based and 8XMO irrigation produced the highest TQ values, ranging from 5 to 7 for all cultivars, but sensor‐based irrigation used less water overall. Turf quality declined with 2XMO and more restrictive irrigation frequencies, with TQ values ranging from 2 to 4. Several recently developed breeding lines performed better across all the irrigation treatments than current commercial cultivars. To satisfy both municipal watering restrictions and turfgrass health requirements, sensor‐based irrigation coupled with the use of improved breeding lines and cultivars such as DALSA 1618 or FSA1602 (CitraBlue®) offer the potential to maintain quality turfgrass while substantially reducing residential irrigation use.

Effects of Irrigation Management and Humic Acid on Yield and Yield Components of Peanut (Arachis hypogaea L.)

Peanut is an oilseed plant, which is rich in seed oil and protein content. The effects of different irrigation methods and humic acid dosages were explored on yield and yield components of peanuts in Astaneh-ye Ashrafiyeh County in Guilan province, Iran, in 2018 and 2019 cropping years. The experiment was laid upon a split-plot design based on a randomized complete block design with three replications in which the main plot was assigned to irrigation treatments including rainfed treatment and irrigation to meet 60%, 80%, and 100% of water requirement, and the sub-plot was assigned to humic acid (HA) at four rates of 0, 3, 6, and 9 L ha-1. The results showed that the highest biological yield (9750 kg ha-1) was obtained from the plants irrigated to meet 80% of their water requirement and applied with 9 L ha-1 HA and the lowest (2453 kg ha-1) was produced under rainfed conditions with no HA applied. Seed yield was 1863 kg ha-1 at the 80% water requirement level and 2067 kg ha-1 at the HA level of 9 L ha-1. Based on the results, it can be recommended to apply 9 L ha-1 HA and supply 80% of the plants’ water requirement as appropriate conditions for the studied region.

Effect of irrigation management and organic manuring on the growth and physiological attributes of direct sown rice (Oryza sativa L.)

Aggressive water stress and low productivity of rice are driving the exploration for location specific feasible agronomic management practices to increase water productivity and yield potential in rice farming. Field experiments were conducted to study the rice production using modified methods of irrigation and integrated nitrogen management, at Annamalai University Experimental Farm, Tamil Nadu, India during Kuruvai(June-October) and Navarai(Jan-April) rice growing seasons of 2016 and 2017. Two irrigation regimes viz., alternate wetting and slight soil drying (when soil moisture content reaches 75% level of the field capacity) and alternate wetting and acute soil drying (when soil moisture content reaches 50% level of the field capacity) and four nutrient management practices viz., RDF as control, 50% N through legume based green leaf manuring (GLM), 50% N through non-legume based GLM and 50% N through mixture of legume and non-legume based GLM (1: 1 ratio). The results reveled that irrigation management involving alternative wetting with acute soil drying along with 50 per cent of recommended dose of nitrogen (60 kg/ha) as mixture of legume and non-legume GLM (1: 1 ratio) and remaining 50 per cent of nitrogen as inorganic source registered the higher values of plant height of 101.76 and 97.11 cm, number of tillers/m2 of 438.10 and 384.64, DMP of 11.34 and 11.39 t/ha, root volume of 22.07 and 18.39 cc, LAI of 5.32 and 4.71 and CGR of 15.26 and 14.56 mg/m2/day during Kuruvai and Navarai seasons, respectively. Therefore, this treatment combination is used for wet spot-seeded rice cultivation in coastal regions of Tamil Nadu.

Impacts of Irrigation Managements on Soil CO2 Emission and Soil CH4 Uptake of Winter Wheat Field in the North China Plain

The North China Plain is an important irrigated agricultural area in China. However, the effects of irrigation management on carbon emission are not well documented in this region. Due to the uneven seasonal distribution of rainfall, irrigation is mainly concentrated in the winter wheat growing season in the North China Plain. In this study, we estimated CO2 emission and soil CH4 uptake from winter wheat fields with different irrigation methods and scheduling treatments using the static chamber-gas chromatography method from April to May 2017 and 2018. Treatments included three irrigation methods (surface drip, sprinkler, and border) and three irrigation scheduling levels that initiated as soon as the soil moisture drained to 50%, 60%, and 70% of the field capacity for a 0–100 cm soil profile were tested. The results showed that both the irrigation methods and scheduling significantly influenced (p < 0.05) the cumulative CO2 and CH4 emission, grain yield, global warming potential (GWP), GWP Intensity (GWPI), GWPI per unit irrigation applied, and water use efficiency (WUE). Compared to 60% and 70% FC, 50% FC irrigation scheduling de-creased accumulated CH4 uptake 26.8–30.3% and 17.8–25.4%, and reduced accumulated CO2 emissions 7.0–15.3% and 12.6–19.4%, respectively. Conversely, 50% FC reduced GWP 6.5–13.3% and 12.5–19.4% and lower grain yield 10.4–19.7% and 8.5–16.6% compared to 60% and 70% FC irrigation scheduling in 2017 and 2018, respectively. Compared to sprinkler irrigation and border irrigation, drip irrigation at 60% FC increased the accumulated CH4 uptake 11.3–12.1% and 1.9–5.5%, while reduced the accumulated CO2 emissions from 7.5–8.8% and 10.1–12.1% in 2017 and 2018, respectively. Moreover, drip irrigation at 60% FC increased grain yield 5.2–7.5% and 6.3–6.8%, WUE 0.9–5.4% and 5.7–7.4%, and lowered GWP 8.0–9.8% and 10.1–12.0% compared to sprinkler and border irrigation in 2017 and 2018, respectively. The interaction of irrigation scheduling and irrigation methods significantly impacted accumulated CH4 uptake, cumulative CO2 amount, and GWP in 2018 only while grain yield and WUE in the entire study. Overall, drip irrigation at 60% FC is the optimal choice in terms of higher grain yield, WUE, and mitigating GWP and GWPI from winter wheat fields in North China Plain.

The Effect of Irrigation Management and Nitrogen Fertilizer On Grain Yield and Water-use Efficiency of Rice Cultivars in Northern Iran

The Effect of Irrigation Management and Nitrogen Fertilizer On Grain Yield and Water-use Efficiency of Rice Cultivars in Northern Iran

Effects of Irrigation Management on Chipping Potato (Solanum tuberosum L.) Production in the Upper Midwest of the U.S.

Irrigation is required for profitable commercial potato (Solanum tuberosum L.) production. Excessive or deficit soil water availability during the growing season can have adverse effects on tuber yield, quality, and storability. A field study was conducted during the 2018 and 2019 field and storage seasons in Central Wisconsin, a region in the U.S. with a high volume of potato production, to evaluate the impacts of different irrigation rates on three chipping potato varieties, Hodag, Lamoka, and Snowden. The treatments were implemented during the late-tuber bulking and tuber maturation growth stages, and consisted of irrigation at 125%, 100%, 75%, and 50% of crop evapotranspiration (ET). Irrigation before the treatment period was at 100%ET for all plots. With the industry standard irrigation practice being at 100%ET, other treatments were designated as over-irrigation or deficit irrigation. The impact of these watering rates on tuber yield and quality was evaluated at harvest, and tuber storage quality was assessed by measuring chip fry color and sugar concentrations at 0, 4, and 8 months of storage. It was found that compared to the standard practice, the over-irrigation treatment at 125%ET when tubers reached late bulking resulted in no significant increase in total yield, marketable yield, tuber quality at harvest and during storage, as well as reduced irrigation efficiency (IE) and water-use efficiency (WUE). This treatment also increased nitrate leaching potential in both years. In comparison, deficit irrigation at 75%ET or even 50%ET during the late season had no impact on tuber growth, could increase IE and WUE in one of the two years, and showed reduced drainage. In both years, irrigation rate had no significant effects on hollow heart incidence, tuber specific gravity at harvest, and fry quality during the 8-month storage period. This study suggested that over-irrigation was not beneficial for potato production in Central Wisconsin of the U.S., and deficit irrigation during late tuber bulking and tuber maturation stages could potentially result in more sustainable water use while not penalizing tuber yield, quality and storability of chipping potatoes.

Irrigation Management Effects on Crop Water Productivity for Maize Production in the Texas High Plains

Corn (Zea mays L.) was grown under full and deficit irrigation in two research field locations near Bushland, TX, in 2018 to compare seasonal water use of two irrigation management approaches. Full irrigation was achieved in both fields by allowing no more than 55% depletion of plant available soil water. However, irrigation depth and frequency were different in each field. The USDA-ARS Conservation and Production Research Laboratory (CPRL) weighing lysimeter fields were generally irrigated twice weekly using irrigation depths ranging from 19 to 32 mm. The Texas A&M AgriLife Research Emeny field was irrigated only once per week, having greater application depths ranging from 35 to 42 mm. Deficit irrigation treatments of 75% of full irrigation were also performed in both research fields. Yield and crop water productivity values for the 100 and 75% lysimeter field irrigation treatments were greater than corresponding values for the Emeny field. Emeny field yields may have been slightly reduced by heat stress incurred between irrigations during early grain fill whereas more frequent irrigations on the lysimeter fields may have reduced heat stress during that period. Results from this study suggest that evaporative losses associated with the more frequent, smaller application depth irrigations on the lysimeter fields did not contribute to appreciably lower CWP values, as losses were likely mitigated by the rapid development of the corn canopy. These findings suggest that corn yield is principally dependent upon seasonal water inputs and losses from frequent, smaller depth irrigations are minimal outside of incomplete canopy conditions.

Studying the Effect of Irrigation Management and Foliar Application of Growth Stimulator on Yield and Some Qualitative Traits of Saffron

به منظور بررسی اثر زمان آبیاری و محلول پاشی برخی محرک­های رشد بر زعفران، آزمایشی در دو سال زراعی 96- 1395 و 97-1396 در شهرستان زاوه خراسان رضوی انجام و داده­های حاصل از سال دوم (97-1396) مورد تحلیل قرار گرفت. آزمایش به صورت کرت­های خرد شده بر پایه طرح بلوک­های کامل تصادفی با سه تکرار بود. عامل اصلی مدیریت آبیاری در 4 سطح I1 (آبیاری اول طبق عرف منطقه یعنی 20 مهر ماه)، I2 (آبیاری اول ده روز دیرتر از عرف منطقه (30 مهر ماه))، I3 (آبیاری طبق عرف منطقه به همراه یک آبیاری اضافی ده روز پس از آخرین آبیاری (20 مهر ماه+ 10 اردیبهشت ماه)) و I4 (آبیاری اول ده روز دیرتر از عرف منطقه به همراه یک آبیاری اضافی ده روز پس از آخرین آبیاری (30 مهر ماه+ 10 اردیبهشت ماه)) بودند. همچنین عامل فرعی شامل تیمارهای محلول پاشیG1 (شاهد بدون محلول پاشی)،G2 (محلول پاشی اسید سالسیلیک)، G3 (محلول پاشی کود کامل میکرو)، G4 (محلول پاشی نانو ذرات دی اکسید تیتانیوم) و G5 (محلول پاشی نانوذرات دی اکسید سیلیسیم) بود. در این آزمایش صفات مختلف گل و بنه و ویژگی­های کیفی کلاله تعیین شد. نتایج مقایسه میانگین­های ویژگی­های بنه نشان داد تیمارهای محلول پاشی کود کامل میکرو و دی اکسید سیلیسیم بیشترین تعداد بنه دختری (56/5) را داشتند، به طوریکه کاربرد این دو ماده حدود 25 درصد افزایش نسبت به شاهد نشان دادند. همچنین آبیاریI4 با 06/7 کیلوگرم در هکتار کمترین، و آبیاری I1 با 463/10 کیلوگرم در هکتار بیشترین مقدار وزن خشک کلاله و خامه را به خود اختصاص دادند. محلول­پاشی کود کامل میکرو با 275/10 کیلوگرم در هکتار وزن خشک کلاله و خامه برترین تیمار بود. بالاترین مقدار کروسین در بین تیمارهای محلول­پاشی مربوط به کود کامل با 5/264 و دی اکسید تیتانیوم با 8/263 میلی گرم بر گرم بود. مقدار پیکروکروسین در تیمارهای کود کامل و اسید سالیسیلیک نسبت به شاهد دارای افزایش بود. همچنین تیمار محلول پاشی اسید سالیسیلیک با مقدار 930/0 میلی گرم بر گرم بیشترین میزان کلروفیل را نشان داد. به طور کلی به منظور کسب حداکثر عملکرد، آبیاری بر اساس عرف منطقه در 20 مهر ماه و همچنین مصرف کود کامل توصیه می­شود.