Effects of Irrigation Water Salinity and Leaching Fraction on Yield and Evapotranspiration in Spring Wheat

To determine the effects of irrigation water salinity and leaching fraction on crop evapotranspiration (ETc), grain yield, straw yield, shoot sodium (Na), and chloride (Cl) concentrations of spring wheat (Triticum aestivum L.) cultivar ‘Onfarom 9,’ a pot experiment was conducted using saline soil with electrical conductivity of soil paste extract (ECe) of 13.2 dS m^?1. A factorial experiment with a completely randomized design replicated seven times was used with three levels of saline irrigation water (4, 9, and 12 dS m^?1) and four leaching levels (0, 17, 29, and 37%) included as the factors. The results showed that ETc significantly decreased as a result of an increase in irrigation water salinity (ECi) and decrease in leaching level. Crop evapotranspiration deficit and decreasing irrigation and drainage water effectively resulted in grain and straw yield reduction. Increase in ECi increased accumulation of Cl and Na in crop shoot, but application of leaching decreased this accumulation.     

Salinity threshold value of Quinoa (Chenopodium Quinoa ‎Willd.) at ‎various growth stages and the appropriate ‎irrigation method by saline ‎water

Salinity is one of the major agricultural problems in arid and ?semi-arid regions. Considering the variation of plant’s ?sensitivity to salinity during growth, a greenhouse study with completely randomized design? was conducted to determine the relative salinity tolerance of Quinoa (Chenopodium quinoa Willd.) at different growth stages from seedling establishment to maturity (establishment, flowering and seed filling) by evaluating the Salinity Threshold Value (STV). Eight levels of EC_i (i.e., Non-saline, 2, 4, 8, 12, 15, 20, 25 dSm^?1) with four replications and five levels (i.e., Non-saline, 10, 15, 20, 25 dSm^?1) with three triplications were applied at first and two last growth stages, respectively. A ?comparison was performed on some growth and yield parameters of plants irrigated by considering STV (T) and ?plants irrigated permanently by mentioned salinity levels regardless of STV (P) to choose ?which method (P or T) is better at each salinity level. The STV was ?evaluated 8, 20 and 15 dSm^?1 at each growth stage, respectively. Seedling of Quinoa was more sensitive to salinity than the mature plant. Therefore, after establishment Quinoa has the ?feasibility of irrigation by high-saline waters. The (P) ?method was suitable only if the freshwater was available during all growth period of the plant; otherwise at higher salinities irrigation should be performed by considering STV (T method) to minimize the intensity of growth and yield reduction and to prevent yield loss at very high salinities. To achieve this, if high-saline water is available it’s possible to ?use plant propagation techniques or cultivating Quinoa simultaneously with seasonal rainfall.?     

INTERACTIVE EFFECTS OF SALINITY AND N ON PEPPER (CAPSICUM ANNUUM L.) YIELD,WATER USE EFFICIENCY AND ROOT ZONE AND DRAINAGE SALINITY

The aim of this study was to determine the salt tolerance of pepper (Capsicum annuum L.) under greenhouse conditions and to examine the interactive effects of salinity and nitrogen (N) fertilizer levels on yield. The present study shows the effects of optimal and suboptimal N fertilizer levels (270 kg ha^?1 and 135 kg ha^?1) in combination with five different irrigation waters of varying electrical conductivity (EC) (EC_iw = 0.25, 1.0, 1.5, 2.0, 4.0, and 6.0 dS m^?1) and three replicates per treatment. At optimal N level, yield decreased when the irrigation water salinity was above EC_iw 2 dS m^?1. At the suboptimal N level, a significant decrease in yield occurred only above EC_iw 4 dS m^?1. At high salinity levels the salinity stress was dominant with respect to yield and response was similar for both N levels. Based on the results it can also be concluded that under saline conditions (higher than threshold salinity for a given crop) there is a lesser need for N fertilization relative to the optimal levels established in the absence of other significant stresses.     

灌溉水盐度和施氮量对棉花产量和水氮利用的影响

淡水资源不足和盐渍化是干旱半干旱地区农业生产的重要限制因素,因此提高水、 肥利用效率和作物产量,减少根区盐分积累和地下水污染风险是这些地区水分养分优化管理的重要目标。通过田间试验研究了滴灌条件下灌溉水盐度和施氮量对棉花产量和水、 氮利用率的影响。试验设置灌溉水盐度和施氮量两个因素,灌溉水盐度（电导率,EC）设3个水平,为0.35（淡水）、 4.61（微咸水）和 8.04（咸水）dS/m,分别用SF、 SM和SH表示;施氮（N）量设4个水平,为0、 240、 360和480 kg/hm2,分别以N0、 N1、 N2和N3表示。研究结果表明,棉花干物质重、 氮素吸收量和氮肥利用率受灌溉水盐度、 施氮量及二者交互作用的影响显著。咸水灌溉处理（SH）棉花干物质重、 氮素吸收量、 产量和氮肥表观利用率均显著降低,而微咸水灌溉（SM）对棉花氮素吸收量和氮肥表观利用率影响不大,但干物质重和产量有所降低。施氮肥可显著促进棉花生长,增加干物质重、 氮素吸收量和产量,但随着灌溉水盐度的增加,其促进效应明显受到抑制。微咸水和咸水灌溉会导致水分渗漏增加、 蒸散量降低,增施氮肥则可显著降低水分渗漏、 增加蒸散量。微咸水灌溉水分利用率最高,其次是淡水灌溉,咸水灌溉最低;增施氮肥则可显著提高水分利用率。因此滴灌条件下,高盐度的咸水不宜用于灌溉。而短期的微咸水灌溉不会对棉花产量和水、 氮利用率产生严重的负面影响;同时,合理的配施氮肥也有助于促进棉花生长,提高棉花产量和水分利用率。     

SOYBEAN RESPONSE AND ION ACCUMULATION UNDER SPRINKLER IRRIGATION WITH SODIUM-RICH SALINE WATER

The magnitude of crop growth and yield depends on the salinity level, the toxic ions present, and the irrigation system used. In order to study the effect of saline sprinkler irrigation on soybean growth and ionic accumulation in plant tissues a pot experiment was set up. There were three irrigation water quality treatments [electrical conductivity (EC) 0, 2, and 4 dS m^?1]. Soybean aerial biomass was 25% lower than the Control when irrigation salinity was 4 dS m^?1. Clearly salinity entering via leaves affected the grain filling stage and severely reduced soybean grain production (80% reduction) when salinity in irrigation water surpassed 2 dS m^?1. Sprinkler irrigation aggravates soybean's low salinity tolerance and restricts its cropping in such conditions. For early stages two linear relationships between leaf chloride (Cl^?) concentration (Y = 14.2–2x) or potassium (K⁺)/ sodium (Na⁺) ratio (Y = 5.3x?3.4) and soybean grain yield were found. Both relationships may be used as diagnostic tools for soybean growing under saline sprinkler irrigation.     

Seed priming in nanoparticles of water treatment residual can increase the germination and growth of cucumber seedling under salinity stress

Abstract

A laboratory experiment was carried out to evaluate the impact of the nanoparticles of water treatment residuals (nWTRs) and salt stress on germination and growth parameters of cucumber seedling. The interaction between three nWTRs treatments (0, 500, and 1000 mgL^?1) nWTRs and five saline solution (fresh water: sea water) treatments had 0.70, 2, 3, 6, and 11?dSm^?1 were studied. The results revealed that increasing salinity levels significantly reduced the percentage of germination (GP) for the primed seeds treated in fresh water and nWTRs. The GP reduction was higher in seeds primed in fresh water compared to which primed in nWTRs. Salt stress negatively affected radicle length of cucumber seedling for both priming treatments. However, this impact was more pronounced for the primed seeds treated in fresh water than which treated in nWTRs at high salinity stress. Priming in nWTRs significantly decreased the root radius of cucumber seedlings, and the1000 mgL^?1 priming treatment obtained a lowest value of radicle radius. Increasing salt concentration in culture medium reduced total biomass of cucumber seedling, however for the primed seeds treated in nWTRs, the total biomass was increased in comparison with which treated in fresh water. Salt tolerance and vigor indices were significantly (p?<?0.01) affected by salinity levels, nWTRs treatments and their interaction. It can be concluded that nWTRs are ameliorating materials for plant growth under salt stress conditions.     

GROWTH,YIELD, AND ION RELATIONS OF STRAWBERRY IN RESPONSE TO IRRIGATION WITH CHLORIDE-DOMINATED WATERS

Strawberry is listed as the most salt sensitive fruit crop in comprehensive salt tolerance data bases. Recently, concerns have arisen regarding declining quality of irrigation waters available to coastal strawberry growers in southern and central California. Over time, the waters have become more saline, with increasing sodium (Na⁺) and chloride (Cl^?). Due to the apparent extreme Cl^? sensitivity of strawberry, the rising Cl^? levels in the irrigation waters are of particular importance. In order to establish the specific ion causing yield reduction in strawberry, cultivars ‘Ventana’ and ‘Camarosa’ were grown in twenty-four outdoor sand tanks at the ARS-USDA U. S. Salinity Laboratory in Riverside, CA and irrigated with waters containing a complete nutrient solution plus Cl^? salts of calcium (Ca²⁺), magnesium (Mg²⁺), Na⁺, and potassium (K⁺). Six salinity treatments were imposed with electric conductivities (EC) = 0.835, 1.05, 1.28, 1.48, 1.71, and 2.24 dS m^?1, and were replicated four times. Fresh and dry weights of ‘Camarosa’ shoots and roots were significantly higher than those of ‘Ventana’ at all salinity levels. Marketable yield of ‘Camarosa’ fruit decreased from 770 to 360 g/plant as salinity increased and was lower at all salinity levels than the yield from the less vigorous ‘Ventana’ plants. ‘Ventana’ berry yield decreased from 925 to 705 g/plant as salinity increased from 0.835 to 2.24 dS m^?1. Relative yield of ‘Camarosa’ decreased 43% for each unit increase in salinity once irrigation water salinity exceeded 0.80 dS m^?1. Relative ‘Ventana’ yield was unaffected by irrigation water salinity up to 1.71 dS m^?1, and thereafter, for each additional unit increase in salinity, yield was reduced 61%. Both cultivars appeared to possess an exclusion mechanism whereby Na⁺ was sequestered in the roots, and Na⁺ transport to blade, petiole and fruit tissues was limited. Chloride content of the plant organs increased as salinity increased to 2.24 dS m^?1 and substrate Cl increased from 0.1 to13 mmol_cL^?1. Chloride was highest in the roots, followed by the leaves, petioles and fruit. Based on plant ion relations and relative fruit yield, we determined that, over the range of salinity levels studied, specific ion toxicity exists with respect to Cl^?, rather than to Na⁺ ions, and, further, that the salt tolerance threshold is lower for ‘Camarosa’ than for ‘Ventana’.     

Salinity and drought affect yield response of bell pepper similarly

Abstract

There is a growing realization that an increasing number of countries are approaching full utilization of their conventional water resources and that the quantity of good-quality water supplies available to agriculture is diminishing. Effects of irrigation regime and irrigation water salinity on bell pepper including yield, fruit number and quality, vegetative and root growth, evapotranspiration and water use efficiency were investigated in this study by conducting two different experiments. Six different salinity levels of irrigation water and four different irrigation regimes were used as treatments. Considering the results from irrigation water salinity experiment, it can be concluded that as soil salinity increases, water consumption, water use efficiency, yield and other vegetative growth parameters of bell pepper were decreased. A polynomial relationship between soil salinity and water consumption was observed. It was found that bell pepper is moderately sensitive to salinity with a 1.2 dS m^?1 threshold and a 10.9% slope value. In the irrigation regime experiment, limited irrigation caused decreases in water consumption, yield and vegetative growth of bell pepper. Yield response factors were close in the cases of irrigation regime (1.50) and irrigation water salinity (1.40). Total soluble solids of bell pepper were increased due to both irrigation water salinity and water application rate but not dry matter ratio. Considerable water consumption decreases because of salinity were determined. Therefore, the effect of irrigation water salinity should be considered in irrigation management to prevent excess saline water application and to protect the environment.     

Combined effect of deficit irrigation and potassium fertilizer on physiological response,plant water status and yield of soybean in calcareous soil

A 2-year field experiment (2013 and 2014) was conducted in calcareous soil (CaCO₃ 19.2%), on soybean grown under three irrigation regimes 100%, 85% and 70% of crop evapotranspiration combined with three potassium (K₂O) levels (90, 120 and 150 kg ha^?1). The objective was to investigate the complementary properties of potassium fertilizer in improving soybean physiological response under water deficit. Plant water status (relative water content RWC, chlorophyll fluorescence F_v/F₀ and F_v/F_m), had been significantly affected by irrigation or/and potassium application. Potassium improved growth characteristics (i.e. shoot length, number, leaf area and dry weight of leaves) as well as physiochemical attributes (total soluble sugars, free proline and contents of N, P, K, Ca and Na). Yield and yield water use efficiency (Y-WUE) were significantly affected by irrigation and potassium treatments. Results indicated that potassium application of 150 and 120 kg ha^?1 significantly increased seed yield by 29.6% and 13.89%, respectively, compared with 90 kg ha^?1 as average for two seasons. It was concluded that application of higher levels of potassium fertilizer in arid environment improves plant water status as well as growth and yield of soybean under water stress.     

Optimization of irrigation management and environmental assessment using the water cycle algorithm

Obtaining high crop yields with limited water consumption requires optimal irrigation strategies based on comprehensive studies of the parameters of plant–environment interactions. Here, we used a structural equation modelling (SEM) to assess the relationships among input irrigation factors and moderate factors to find an optimum water use efficiency (WUE) response factor, for outdoor and greenhouse cultivation of eggplant (Solanum melongena). The input irrigation factors (including irrigation interval, water salinity and environment) and the moderate factors (evapotranspiration, soil salinity, plant parameters, fruit parameters and crop yield) were used in water cycle algorithm (WCA) and genetic algorithm (GA) methods to optimize the water use efficiency. The optimization process included finding the best combination of irrigation factors and optimized eggplant cultivation. The structural equation modelling results indicate that irrigation interval negatively affected water use efficiency with a more dominant effect on plant parameters. Water salinity negatively affected the water use efficiency with a more dominant effect on soil salinity, crop yield and fruit parameters. Low salinity water was more effective than full irrigation to optimize the water use efficiency. The water cycle algorithm revealed that for outdoor cultivation, the optimal range of irrigation interval was 2–5 days and water salinity in the range of 0.8–2.2 ds/m. These factors optimized evapotranspiration (346.23–738.19 mm), soil salinity (4.16–9.45 ds/m), fruit parameters (33.81–35.12 cm) and crop yield (1715.7–2190.8 g/plant), as well as increasing the water use efficiency (3.08–4.89 g/(plant-mm)). Both the water cycle algorithm and genetic algorithm yielded very close to optimal values. Two years of repeated experiments and the closeness of the optimal values using the algorithms confirmed that the optimal amounts are reliable.     

Effect of Deficit Irrigation and Dairy Manure on Winter Wheat Yield,Soil Physical Health,and Nitrate Leaching

ABSTRACT

The effect of deficit irrigation (DI) on wheat crop yield, soil physical parameters and on nitrate nitrogen movement in soil profile was evaluated under application of dairy manure and nitrogen fertilizer. Two levels of DI were taken as I_0.6 (60% FC) and I_0.8 (80% FC) along with two dairy manure levels (20 and 25 Mg ha^?1) and three nitrogen levels (80, 100, and 120 kg ha^?1). The grain yield was high under I_0.8 than I_0.6, whereas the irrigation level has no significant effect on soil organic carbon contents. Dairy manure, irrigation, and nitrogen indicated strong interaction with each other for all yield-related parameters during both years of study, however, results for 2nd year were highly positive. Soil nitrate nitrogen movement was significantly affected under I_0.8 with high rate of dairy manure (25 Mg ha^?1) and nitrogen fertilizer (120 kg ha^?1). Results concluded that combined application of dairy manure (25 Mg ha^?1) and nitrogen fertilizer (120 kg ha^?1) under DI level I_0.8 resulted in high grain yield. To overcome water scarce conditions, further experiments can be designed by addition of various organic matters in different combination that enhances the yield and soil health.     

Evaluation of water schemes for peanut,using CSM-CROPGRO-Peanut model

Drought stress is an important factor limiting the yield potential of peanut. In order to determine the effect of different irrigation scenarios on peanut production, field experiments were conducted in 2011 and 2012 growing seasons using factorial design with three replicates. On the other hand, the crop simulation models can be useful to predict crop yields and to investigate the impact of drought stress on plant growth and development. In this study, the Cropping System Model–Crop Growth (CSM-CROPGRO)-Peanut model was employed for the simulation of seed yield, pod yield, biomass, soil water balance components and water productivity for peanut in Astaneh-Ashrafiyeh, Iran. Results showed that the model was able to reasonably simulate seed yield, pod yield and final biomass for different irrigation scenarios (RMSEn < 20%, R² > 0.8 and d > 0.8). According to the results, irrigation depth and interval were important factors affecting yield and biomass. In general, model error increased as the amount of water applied decreased. The least amount of water applied (40 mm) resulted in yield reductions by 76%, 70% and 67% of the greatest amount of water applied (480 mm) for seed yield, pod yield and final biomass, respectively. For each irrigation interval, larger irrigation depth led to lower water productivity (WP) of irrigation (WP_I), but higher WP based on evapotranspiration (WP_ET) and transpiration (WP_T).The average amounts of WP_I, WP_ET, WP_T based on seed yield were 1.2, 0.63 and 1.01 kg m^?3, respectively.     

TREATED EFFLUENT AND SALINE WATER IRRIGATION INFLUENCES SOIL PROPERTIES,YIELD, WATER PRODUCTIVITY AND SODIUM CONTENT OF SNOW PEAS AND CELERY

To determine the effects of irrigation water quality, plants were irrigated with normal potable water [0.25 dS m^?1 electrical conductivity (EC), 25 mg L^?1 sodium (Na), 55 mg L^?1 chloride (Cl)], treated effluent (0.94 dS m^?1 EC, 122 mg L^?1 Na, 143 mg L^?1 Cl) and saline water with low salinity (1.24 dS m^?1 EC, 144 mg L^?1 Na and 358 mg L^?1 Cl) and high salinity (2.19 dS m^?1 EC, 264 mg L ^?1Na and 662 mg L^?1 Cl) for snow peas, and high salinity (3.07 dS m^?1 EC, 383 mg L^?1 Na and 965 mg L^?1 Cl) and very high salinity (5.83 dS m^?1 EC, 741 mg L^?1 Na and 1876 mg L^?1 Cl) for celery. The greater salts build up in the soil and ion toxicity (Cl and Na) with saline water irrigation contributed to significantly greater reduction in root and shoot biomass, water use, yield and water productivity (yield kg kL^?1 of water used) of snow peas and celery compared with treated effluent and potable water irrigation. There was 8%, 56% and 74% reduction in celery yield respectively with treated effluent, high salinity and very high salinity saline water irrigation compared with potable water irrigation. The Na concentration in snow peas shoots increased by 54%, 234% and 501% with treated effluent, low and high salinity saline water irrigation. Similarly, the increases in Na concentration in celery shoots were 19%, 35% and 82%. The treated effluent irrigation also resulted in a significant increase in soil EC, nitrogen (N) and phosphorus (P) content compared with potable water irrigation. The heavy metals besides salts build up appears to have contributed to yield reductions with treated effluent irrigation. The study reveals strong implications for the use of saline water and treated effluent for irrigation of snow peas and celery. The salt build up within the root zone and soil environment would be critical in the long-run with the use of saline water and treated effluent for irrigation of crops. To minimize the salinity level in rhizosphere, an alternate irrigation of potable water with treated effluent or low salinity level water may be better option.     

Production of Pearl Millet Irrigated with Different Levels of Brackish Water and Organic Matter

ABSTRACT

The objective is to determine the growth, yield and chemical characteristics of pearl millet irrigated with different levels of brackish water and organic matter in two cultivation cycles. The experimental design was randomized blocks in a 4 × 4 factorial arrangement, composed of 4 levels of brackish irrigation (25, 50, 75 and 100% evapotranspiration), 4 levels of organic matter (0, 15, 30 and 45 t ha^?1) with 3 repetitions. Along two cultivation cycles, pearl millet crop was analyzed for: plant growth variables, fresh and dry mass production, water-use efficiency, and chemical composition. There was significant interaction between applied water levels and organic matter for lignin in the 2nd cut (P < .05). The number of leaves, number of dead leaves and fresh mass production were influenced by the isolated effect of brackish water levels in cut 1 (P < .05). In turn, fresh mass production, dry mass production, plant height, leaves length, panicle length, fresh mass production, crude protein and ether extract were influenced by the isolated effect of saline water levels in the 2nd cut (P < .05). Growth, biomass production and chemical composition variables in second cut are positively influenced by different brackish irrigation levels under low rainfall conditions.     

Evaluation of Water–Nitrogen Schemes for Rice in Iran,Using ORYZA2000 Model

The model ORYZA2000 simulates the growth and development of rice under conditions of potential production and water and nitrogen (N) limitations. Crop simulation models could provide an alternative, less time-consuming, and inexpensive means of determining the optimum crop N and irrigation requirements under varied irrigation and nitrogen conditions. Water productivity (WP) is a concept of partial productivity and denotes the amount or value of product over volume or value of water used. For the evaluated ORYZA2000 model in Iran, a study was carried out in a randomized complete block design between 2005 and 2007, with three replications at the Rice Research Institute of Iran, Rasht. Irrigation management (three regimes) was the main plot and N application (four levels) was the subplot. In this study, simulation modeling was used to quantify water productivity and water balance components of water and nitrogen interactions in rice. Evaluation simulated and measured total aboveground biomass and yield, by adjusted coefficient of correlation, T test of means, and absolute and normalized root mean square errors (RMSE). Results showed that with normalized root mean square errors (RMSE_n) of 5–28%, ORYZA2000 satisfactorily simulated crop biomass and yield that strongly varied among irrigation and nitrogen fertilizer conditions. Yield was simulated with an RMSE of 237–443 kg ha^?1 and a normalized RMSE of 5–11%. Results showed that the significant (28–56%) share of evaporation into evapotranspiration, using the actual yield (measured) and simulated water balance (ORYZA2000), the calculated average WP_ET was significantly lower than the average WP_T: 37%. The average WP_I, WP_I+R, WP_ET, WP_T, and WP_ETQ were 1.4, 1.07, 1.07, 1.57, and 0.82 kg m^?3. Results also showed that irrigation with 8-day intervals and 60 kg N ha^?1, nitrogen level was the optimum irrigation regime and nitrogen level.     

Effects of Caspian Sea Water on Sugar Beet Seed Germination

The shortage of good quality water resources is becoming an important issue in arid, semi-arid, and coastal zones. Sugar beet yield declines with an increase in salinity, but its sensitivity to salts varies with the salt composition in water and the plant growth stage. The possible use of Caspian Sea water, which its salinity is well below that of open seas, is desirable for irrigation. The aim of this study was to determine effects of various Caspian Sea water regimes on sugar beet seed germination. A randomized complete block (RCB) design was used with four replications of 15 seeds per pot. Eleven different irrigation treatments of Caspian Sea water ranging from 0% to 100% were applied that each treatment indicates the percent of Caspian Sea water to the mixture with the fresh water. Seed germination percent and the mean time to germination data were obtained for 30 days. Statistical analysis revealed that seed germination was significantly affected by Caspian Sea water, particularly by the salinity levels above the electric conductivity (EC) 13 dSm^?1.     

Optimizing water,nitrogen and crop density in canola cultivation using response surface methodology and central composite design

Abstract

Optimisation of water and nitrogen use is an effective management tool to conserve resources and reduce environmental pollutions. Response surface methodology (RSM) is defined as a collection of mathematical and statistical methods that are used to develop, to improve or to optimize a product or process. In order to determine optimum levels of water, nitrogen and planting density of canola (Brassica napus L.), a 2-year experiment (2010–2011) was carried out by central composite design as RSM at the research station of Ferdowsi University of Mashhad. The treatments were designed based on low and high levels of irrigation (1500 and 4000 m³ ha^?1), nitrogen (0 and 400 kg N ha^?1) and density (50 and 150 plant m^?2) as independent variables. Furthermore, seed yield, nitrogen losses, nitrogen use efficiency (NUE) and water use efficiency (WUE) were measured as response variables in a full quadratic polynomial model. Optimum levels of irrigation, nitrogen and planting density were suggested to achieve the target range of dependent variables based on three scenarios: economic, environmental and eco-environmental. The results showed that increasing irrigation and fertilizer led to an increase in seed yield and nitrogen losses, whereas increasing canola density resulted in an increase in seed yield but a decrease in nitrogen losses. The optimum levels of water, fertilizer and density based on environmental scenario were 1802 m³ ha^?1, 11 kg N ha^?1 and 122 plant m^?2, respectively. To achieve optimum conditions under the economic scenario, it is necessary to use 3411 m³ water ha^?1, 178 kg N ha^?1 and 119 plant m^?2. Amounts of 2347 m³ water ha^?1, 92 kg N ha^?1 and 114 plant m^?2 were found to be the optimum conditions for the eco-environmental scenario. In general, it seems that resource use based on the eco-environmental scenario may be the most favorable cropping strategy for canola production.     

Salinity stress alleviation by Zn as soil and foliar applications in two rice cultivars

ABSTRACT

Salinity is one of the main problems in agricultural soils. In order to study zinc (Zn) application effects (0, 10, 20 mg Zn kg^?1 soil and foliar application) on growth and nutrient uptake under salinity stress (3, 7, 10 dSm^?1) in two rice cultivars (Tarom and Daylamani), the present work was conducted as a factorial arrangement based on a randomized complete design with three replications in greenhouse conditions. The results showed that Zn application under salinity stress promoted shoot and grain yield. The lowest and highest protein percent in every salinity and Zn levels belonged to Daylamani and Tarom cultivars, respectively. The results showed that the more Zn applied, the more Zn accumulated in the shoots and grain. Generally, based on the results Zn application in low and moderate salinity levels promotes the growth and yield of the rice and Daylamani cultivar showed more endurance to salinity than Tarom cultivar.     

Different Levels of Irrigation Water Salinity and Biochar Influence on Faba Bean Yield,Water Productivity,and Ions Uptake

Greenhouse experiment was conducted to investigate the effect of different levels of irrigation water salinity (0.5, 2.5, 5 and 7.5 dS m^?1) and wheat straw biochar (0%, 1.25%, 2.5%, and 3.75% w/w) on growth and yield of faba been using complete randomized design with three replications. Stomatal conductance (green canopy temperature) of faba bean increased (decreased) by application of biochar at each salinity level. The results showed increasing salinity to 2.5 dS m^?1 at zero biochar application increased the seed yield through osmotic adjustment, while by declining the osmotic potential, the nutritional values of biochar caused the seed yield to increase by increasing salinity to 5 dS m^?1. The root length density and root dry weight density in 0–8 cm soil layer declined under application of 3.75% w/w biochar in all salinity levels in comparison with that obtained in 2.5% w/w biochar, due to higher saline condition of the soil as result of higher biochar application. The results showed that addition of 2.5% w/w biochar can significantly mitigate salinity stress due to its high salt sorption capacity and by increasing potassium/sodium ratio in the soil. In general, since 2.5 % w/w biochar and salinity of 5 dS m^?1 increased dry seed yield and irrigation water productivity compared with that obtained in control (B₀S_0.5), these levels are recommended to improve faba bean growth and yield; however, these levels have to be evaluated under field conditions.