اثر مدیریتهای مختلف آبیاری یک درمیان با آب شور- غیرشور بر روی عملکرد ذرت و توزیع رطوبت و شوری در نیمرخ خاک

Field experiment was conducted in calcareous soil at Maryout Experimental Station Farm, Desert Research Center, Egypt to investigate the influence of deficit irrigation water using highly saline water on yield and water productivity of tomato (Lycopersicon esculentum, mill., cultivator 888) under drip and gated pipe irrigation systems. The tomato plants were subjected to 3 deficit irrigation depths (100, 75 and 50 % of ETc) throughout 3 growth stages (development, flowering and harvesting) using highly saline water of 9.15 dSm-1 plus control treatment. The tomato plants were irrigated by the full irrigation (100 % ETc) during the whole growth season using slightly saline water of 2.80 dSm-1.The reduction percentage in tomato fruit yield ranged between 9.9 to 41.5 % and 9.1 to 30.9 % at treatment T2100 – D (plants irrigated by the full irrigation: 100% of ETc) using highly saline water throughout the development stage then irrigated by the same water depth using slightly saline water (agricultural drainage water), throughout the other growth stages and treatment T950 – F (plants irrigated by deficit irrigation depth of 50% ETc using highly saline water, 9.15dSm-1. The flowering growth stage of tomatoes was the highest stage influenced to deficit irrigation using highly saline water especially at deficit irrigation of 50 % ETc. The tomato fruit yield under drip irrigation system was significantly higher than that obtained under gated pipe irrigation system. The highest value of crop water productivity (CWP) was obtained at control treatment and the lowest value was obtained at treatment T950-F. The highest and lowest values were 9.5 and 5.56 kg/m3 and 8.23 and 5.69 kg/m3 under drip and gated pipe irrigation systems, respectively. A significant polynomial relationship between tomato fruit yield (Y), kg/m2, and applied irrigation water (AW), m3/m2 was given with R2 0.78. The predicted maximum yields were 18.54 and 11.63 kg/m2 and the corresponding calculated the applied irrigation water were 2.57 and 2.59 m3/m2 under drip and gated pipe irrigation systems, respectively. The crop response factor (Ky) using highly saline water under drip and gated pipe irrigation systems were 1.090 and 0.743, respectively.

A two-year study was carried out in order to assess the effects of different irrigation scheduling regimes with saline water on soil salinity,<strong> </strong>yield and water productivity of pepper under actual commercial-farming conditions in the arid region of Tunisia. Pepper was grown on a sandy soil and drip-irrigated with water having an ECi of 3.6 dS/m. Irrigation treatments consisted in water replacements of accumulated ETc at levels of 100% (FI, full irrigation), 80% (DI-80), 60% (DI-60), when the readily available water in the control treatment (FI) is depleted, deficit irrigation during ripening stage (FI-MDI60) and farmer method corresponding to irrigation practices implemented by the local farmers (FM). Results on pepper yield and soil salinity are globally consistent between the two-year experiments and shows significant difference between irrigation regimes. Higher soil salinity was maintained over the two seasons, 2008 and 2009, with DI-60 and FM treatments than FI. FI-MDI60 and DI-80 treatments resulted also in low ECe values. Highest yields for both years were obtained under FI (22.3 and 24.4 t/ha) although we didn’t find significant differences with the regulated deficit irrigation treatment (FI-DI60). However, the DI-80 and DI-60 treatments caused significant reductions in pepper yields through a reduction in fruits number/m² and average fruit weight in comparison with FI treatment. The FM increased soil salinity and caused significant reductions in yield with 14 to 43%, 12 to 39% more irrigation water use than FI, FI-MDI60 and DI-80 treatments, respectively, in 2008 and 2009. Yields for all irrigation treatments were higher in the second year compared to the first year. Water productivity (WP) values reflected this difference and varied between 2.31 and 5.49 kg/m³. The WP was found to vary significantly among treatments, where the highest and the lowest values were observed for DI-60 treatment and FM, respectively. FI treatment provides significant advantage on yield and water productivity, compared to FM in pepper production under experimental conditions. For water-saving purposes, the FI irrigation scheduling is recommended for drip irrigated pepper grown under field conditions and can be used by farmers to optimize the use of saline water and to control soil salinity. In case of limited water supply, adopting deficit irrigation strategies (FI-DI60 and DI-80) could be an alternative for irrigation scheduling of pepper crop under the arid Mediterranean conditions of Tunisia. <strong>Key words:</strong> salinity, drip irrigation scheduling, deficit irrigation, pepper yield, water productivity

In a field experiment the effects of irrigation with saline drainage water (seasonal average of 4.5 dS/m) and non-saline water (0.55 dS/m) applied by two different water management strategies (cyclic or blended saline water with non-saline water in different ratios) and two different irrigation methods (drip or furrow) were studied on growth and productivity of tomato (Lycopersicon esculentum Mill cv Floradade), salinity distribution in root zone and water use efficiency. The results indicated that salinity (at 3 dS/m and above) significantly reduced leaf area, height and dry weight of plant as well as fruit weight and number and hence total yield, but increased fruit T.S.S. content. Water use efficiency (WUE) was increased by using water with low and moderate salinity levels (2 and 3 dS/m) as compared to those obtained with non-saline water (0.55 dS/m) or the highest salinity level (4.5 dS/m). Salinity increased Na, Cl and Mg contents as well as dry matter percentage, but decreased N, P, K and Ca contents in leaves of plants. Drip irrigation enhanced tomato growth, yield and WUE under both saline and non-saline conditions, but showed more advantages under saline conditions as compared with furrow irrigation. Drip irrigation method did not allow salt accumulation in root zone (wetted area beneath the emitters and the plants). However, more salt accumulated in root zone (30 cm apart from irrigation source) of furrow irrigated plants. Mixing saline with non saline waters (blending) produced better results in terms of more vigorous vegetative growth and highest yield, than that produced by alternate saline with non saline water (cyclic). Using saline water up to 3 dS/m produced yield that was not significantly differ than that produced by non saline water if applied by drip irrigation and blended water management.

Successive addition of rice straw biochar enhances carbon accumulation in soil irrigated with saline or non-saline water

Introduction: Water shortage is the most important factor affecting crop production in the world. The deficit irrigation is a way to reduce water consumption in farming. The Partial Root- zone Drying (PRD) irrigation is a new improvement in deficit irrigation in which the half of the root zone is irrigated alternatively in scheduled irrigation events. In the fixed partial root zone drying (FPRD) the irrigation is fixed to one side of the root zone in the growing season. Maize is a drought sensitive crop. In maize, secondary traits related to drought resistance are considered in producing tolerate cultivars. Materials and Methods: An experiment was conducted in order to investigate the effects of regulated deficit irrigation, variable partial root zone drying (PRD) and fixed partial root zone drying (FPRD) on the yield, physiological and photosynthetic parameters of forage maize (KSC 704) during the growing seasons of 2014 in Mashhad region. A factorial experiment based on randomized complete block design with four replications was carried out. The treatments included the full irrigation (FI) and the deficit irrigations (regulated deficit irrigation (DI) and the replacements of 80 % (DI80) and 60 % (DI60) of total water requirement, fixed PRD (FPRD) at 100% (FPRD100), 80% (FPRD80) and 60%(FPRD60) of water requirement, and variable PRD at 100% (PRD100), 80% (PRD80) and 60% (PRD60) of water requirement). Drip irrigation tapes were placed between plant rows. In the full irrigation and regulated deficit irrigation treatments, the plants were irrigated from two sides for every irrigation. In the PRD, one of two neighboring tapes was alternatively used for irrigation. In FPRD, a drip tape was used for two plant rows and irrigation was fixed to one side of the root. The irrigation interval was 3 days for all treatments. Dry and fresh forage yield, leaf area index (LAI), stomatal conductance, leaf relative water content (RWC) and chlorophyll content were measured. Results and Discussions: All the measured traits were affected by the deficit irrigation. The highest fresh forage yield (72099 kg/ha) was produced by the full irrigation treatment. The statistical comparison showed that there was no significant difference between regulated deficit irrigation and PRD method for the fresh forage yield. But the FPRD treatment reduced the fresh forage yield. There was no significant difference between the fresh forage yield of FI and PRD80 treatments. The dry forage yield was affected by the different irrigation methods, irrigation levels and the interaction effects of the treatments (p

Conjunctive use of saline and non-saline waters. III. Validation and applications of a transient model for wheat

HighlightsIrrigated grain sorghum yield and irrigation water use decreased under climate change.Increase in growing season temperature beyond 26°C resulted in a sharp decline in grain sorghum yield.Irrigating during early reproductive stages resulted in the most efficient use of limited water.Irrigating to replenish soil water to 80% of field capacity was found suitable for both current and future climates. Groundwater overdraft from the Ogallala Aquifer for irrigation use and anticipated climate change impacts pose major threats to the sustainability of agriculture in the Texas High Plains (THP) region. In this study, the DSSAT-CSM-CERES-Sorghum model was used to simulate climate change impacts on grain sorghum production under full and deficit irrigation strategies and suggest optimal deficit irrigation strategies. Two irrigation strategies were designed based on (1) crop growth stage and (2) soil water deficit. For the first strategy, seven deficit irrigation scenarios and one full irrigation scenario were simulated: three scenarios with a single 100 mm irrigation scheduled between panicle initiation and boot (T1), between boot and early grain filling (T2), and between early and late grain filling (T3) growth stages; three 200 mm irrigation treatments with combinations of T1 and T2 (T4), T1 and T3 (T5), and T2 and T3 (T6); one 300 mm irrigation scenario (T7) that was a combination of T1, T2, and T3; and a full irrigation scenario (T8) in which irrigation was applied throughout the growing season to maintain at least 50% of plant-available water in the top 30 cm soil profile. For the second strategy, the irrigation schedule obtained from auto-irrigation (T8) was mimicked to create a full irrigation scenario (I100) and six deficit irrigation scenarios. In the deficit irrigation scenarios, water was applied on the same dates as scenario I100; however, the irrigation amounts of scenario I100 were reduced by 10%, 20%, 30%, 40%, 50%, and 60% to create deficit irrigation scenarios I90, I80, I70, I60, I50, and I40, respectively. Projected climate forcings were drawn from nine global climate models (GCMs) and two representative concentration pathways (RCP 4.5 and RCP 8.5). Climate change analysis indicated that grain sorghum yield under full irrigation was expected to be reduced by 5% by mid-century (2036 to 2065) and by 15% by late-century (2066 to 2095) under RCP 8.5 compared to the baseline period (1976 to 2005). Simulated future irrigation water demand of grain sorghum was reduced due to the shorter growing season and improved dry matter- and yield-transpiration productivity, likely due to CO2 fertilization. Based on the simulated grain sorghum yield and irrigation water use efficiency, the most efficient use of limited irrigation was achieved by applying irrigation during the early reproductive stages of grain sorghum (panicle initiation through early grain filling). A 20% deficit irrigation scenario was found to be optimal for current and future conditions because it was more water use efficient than full irrigation with a minor yield reduction of &amp;lt;11%. In summary, these results indicated that strategic planning of when and how much to irrigate could help in getting the most out of limited irrigation. Keywords: CERES-Sorghum, Critical growth stages, Crop yield, Global climate model, Irrigation demand, Soil water depletion.

Irrigation and nitrogen management are crucial for sustainable potato (Solanum tuberosum L.) production. A field experiment was conducted during the 2022 and 2023 growing seasons at Farmington, New Mexico, to evaluate the performance of two chip potato varieties (Lamoka and Waneta) under three irrigation regimes (full irrigation (FI), 20% deficit irrigation (DI) and 40% DI) and seven nitrogen fertilizer rates (0, 60, 115, 170, 220, 280, and 340 kg N/ha). The treatment combinations of irrigation regimes, nitrogen rates, and varieties were arranged in a split–split plot design with three replications as main plot, sub-plot, and sub-sub plot, respectively. The two-year results showed that irrigation regimes had the most significant effect on plant growth, physiology, and tuber yield of the potato varieties. For both Lamoka and Waneta, the plant height and canopy cover were lower under 40% DI than under 20% DI and FI treatments. The SPAD meter values were higher under 40% DI, followed by 20% DI and FI treatments, whereas the stomatal conductance was higher under FI, followed by 20% DI and 40% DI during both growing seasons. Regardless of nitrogen rates and variety, a 20% water-saving irrigation strategy reduced the total tuber yield by 4.5% and 22.1% in the 2022 and 2023 growing seasons, respectively, while the 40% water-saving irrigation strategy reduced total tuber yield by 36.8% and 58.2% in the 2022 and 2023 growing seasons, respectively, as compared to full irrigation. Shifting from full irrigation to 20% DI could save 711.2 to 1036.3 m3/ha of irrigation water. For Lamoka, the highest total tuber yield was obtained with 60 kg N/ha under 20% DI and 220 kg N/ha under FI in 2022 and 2023, respectively. For Waneta, the highest total tuber yield was obtained with 115 kg N/ha under 20% DI and 170 kg N/ha under FI in 2022 and 2023, respectively. Maximum water use efficiency (WUE) was obtained at 60 kg N/ha with 20% DI for both Lamoka and Waneta in 2022, while maximum WUE was obtained at 220 kg N/ha under FI for Lamoka and at 170 kg N/ha for Waneta in the 2023 season. The maximum nitrogen use efficiency (NUE) was achieved with 60 kg N/ha under 20% DI for both varieties during both growing seasons. Thus, for sustainable irrigation and nitrogen management, the application of a 20% deficit irrigation strategy with a lower nitrogen rate (60 to 170 kg N/ha) could be the best option to improve WUE and NUE with minimal tuber yield reduction. Our study suggested that 40% deficit irrigation would not be beneficial as compared to both full irrigation and 20% water-saving irrigation.

Water supplies have been decreasing in several semi-arid regions, and it is therefore necessary to adopt irrigation strategies aimed at maximizing water use efficiency. In this paper, the effects of saline and deficit irrigation on water use efficiency and on potato crop response, based on observations of soil and plant water status, were investigated. Experiments were carried out in Central Tunisia, by monitoring potato crop growth during two seasons in four distinct treatments (T1–T4), represented by two different irrigation doses and two water qualities. For irrigation scheduling purposes, thresholds of soil matric potential, soil water content and Crop Water Stress Index (CWSI) were identified with the aim to quantify the effects of water and/or salinity stress on the achievable yield. Experiments allowed verifying that crop yield is strongly affected by the seasonal amount and quality of applied water. Despite differences of crop yield between treatments T2, T3 and T4 not being statistically significant (P &lt; 0.05), crop yield varied between 26.3 t/ha (T3 in 2015) to 16.3 t/ha (T4 in 2015). However, crop yield decline of 17.0 t/ha and 12.0 t/ha per each 100 mm decrease of applied water were observed under the application of water electrical conductivity of 1.6 dS/m and 4.1 dS/m respectively. On the other hand, an increase of 1.0 dS/m in water electrical conductivity caused a yield decline rate of about 10%. The results achieved showed that under the semi-arid climate of Tunisia, potato crop irrigation should be scheduled to avoid water deficit; however, the possibility to reduce water supply can be envisaged when water availability is limited, but with the awareness to accept the shortage of production. Finally, when saline water is the only source available to the farm, it is necessary to avoid the reduction of irrigation doses, to prevent excessive salt accumulation in the root zone with unavoidable effects on crop yield.

Modeling yield and biomass responses of maize cultivars to climate change under full and deficit irrigation

Core Ideas Limited irrigation of corn is likely to become more prevalent in the future.Drought genetics may make corn yield less subject to detrimental water stress under limited irrigation.Drought genetics had little effect on mitigating water stress in corn.Drought genetics did not consistently improve corn yield under water stress. Irrigated corn (Zea mays L.) in the Great Plains will be increasingly grown under limited irrigation management and greater water stress. Hybrids with drought genetics may decrease the impacts of water stress on yield. The objective of this experiment was to evaluate the effect of drought genetics on corn water stress, water use, grain yield, yield components, and water use efficiency under varying water availability. A 3‐yr (2009–2011) study was conducted at Akron, CO in which corn water use, yield, and yield components were measured for isolines of three corn hybrids with and without drought genetics grown under three water treatments (fully irrigated, no irrigation until just prior to tasseling followed by full irrigation, and limited irrigation throughout the growing season). There was no yield loss from the drought genetics under non‐water‐stressed conditions. There was no effect of drought genetics on water use, yield, or water use efficiency. However, there was a 7% increase in kernels per plant in 2011 and a 5% increase in 1000‐kernel weight in 2010 due to the presence of the drought gene. It does not appear that the non‐commercial, experimental drought genetics tested in this experiment produced any consistent effect on mitigating water stress in corn or on corn water use and yield under varying levels and timings of water stress. Further research is needed in which consistent levels of water stress are imposed during reproductive and grain‐filling growth stages to verify the effects of drought genetics on corn yield.

A global meta-analysis of yield and water use efficiency of crops, vegetables and fruits under full, deficit and alternate partial root-zone irrigation

Effect of irrigation systems and water management practices using saline and non-saline water on tomato production

Abstract. Salt accumulation in the root zone limits agricultural productivity and can eventually lead to land abandonment. Therefore, monitoring the spatial distribution of soil water content and solution salinity is crucial for effective land and irrigation management. However, assessing soil water content and salinity at the field scale is often challenging due to the heterogeneity of soil properties. Electromagnetic induction (EMI) offers a fast, non-invasive, in situ geophysical method to map spatial variability in soil. EMI instruments measure the apparent soil electrical conductivity (ECa), which reflects the integrated contribution of the bulk electrical conductivity (σb) of different soil layers. By inverting the measured ECa, it is possible to obtain the distribution of the σb along the soil profile, which provides indirect information on soil salinity. However, in saline soils, σb is influenced by both water content (θ) and soil solution electrical conductivity (σw) (the salinity), making it difficult to independently quantify these two variables through a single, straightforward procedure. The objective of this study is to separate the respective contributions of θ and σw to σb, as obtained from the EMI inversion. To achieve this, ECa was measured using a CMD-MiniExplorer instrument in two maize plots irrigated with saline and non-saline water, respectively, in an agricultural field in southern Italy. The dataset was then inverted in order to obtain the σb distribution. By employing a site-specific calibrated Rhoades linear model and assuming pedological homogeneity between the two plots, the spatial distribution of θ and σw in the saline plot was successfully estimated. To validate the results, independent measurements of soil water content by Time Domain Reflectometry (TDR) and direct measurement of soil solution electrical conductivity, σw, were performed. The proposed procedure enables the estimation of θ and σw with high accuracy along the soil profile, except in the soil surface, where EMI reliability is limited. These findings demonstrate that the integration of EMI with a site-specific θ–σb–σw model is a reliable and efficient in-situ approach for mapping soil salinity and water content at field scale, offering valuable insights for optimizing agricultural irrigation management in systems using saline water.

Drip irrigation in banana farms is an uncommon practice as compared with other horticultural crops. Records for East African Highland Banana (EAHB) diploid (AA subgroup) cvmc hare-Huti Green (HG) cultivated under drip irrigation remain unavailable in the study area. The objective of this study was to compare the effects of water regimes on flower emergence and cumulative leaf numbers in the research site situated at 3° 23′ 58″S and 36° 47′ 48″ E at an altitude of 1,188m above sea level in Arumeru District, Arusha Region, northern highlands of Tanzania. We investigated the performance of HG under Full irrigation (FI) and Deficit Irrigation (DI) treatments, to assess the influence of drought on banana growth parameters and flowering. The results exhibited significant differences within and between treatments of most tested variables. A good number of plants in FI flowered earlier as compared to those ina DI. The mean leaf length in FI was (2571.71 ± 43.18 plant-1) and DI (2144.11 ±72.23 plant-1) at (p&lt;0.001. Similarly, the mean leaf width FI (827.7 ± 11.95 plant-1) and DI (724.8± 18.43) at (p&lt;0.001 ) respectively. Understanding the banana growth characteristics in different water regimes is of great importance due to ongoing threats of global change. Prudential use of this information can assist in management decisions concerning irrigation, water use and productivity.