نشریه مدیریت آب در کشاورزی
سال هشتم شماره 1 (پیاپی 15، بهار و تابستان 1400)

Improving vegetation cover in arid and semi-arid regions can be controlling desertification and the production of cellulosic materials by afforestation, in these circumstances, human survival and habitat, as well as wildlife, also provided too. For afforestation in arid and semi-arid regions, it is necessary to selection of appropriate species and pay attention to their ecological and eco adaptation needs. Drought resistance mechanisms include water use efficiency in many forest species for a stay of drought condition have been utilization. On the other hand, water requirements and the effects of drought stress on ecological adaptation are important for this plants. Through lysimetry experiments and determination of water requirement for many forest species including Saxual (Haloxylon aphyllum) and several species of eucalyptus (Eucalyptus camaldulensis, E. microtheca E. sarjentii, E. leucoxyloni, E, saligna and E. flocktoniea), there were considered and adaptation mechanisms for survival in dry conditions were studied for them. Among the mentioned species, Saxual had the lowest water requirement and the most resistant species to drought stress. This species had a higher water use efficiency to drought stress.

Among agricultural inputs, water and soil as the most important factors of production have a special economic importance. In this regard, managing water consumption and improving soil condition is one of the priorities of agriculture. This study was conducted to investigate the effect of different partial root zone drying treatments at two levels of 65 and 55%, full irrigation and different levels of biochar consumption (zero, 6 and 12 tons per hectare) on the growth characteristics of maize was done in the educational farm of Tehran Martyr Foundation in 2015 and 2016. Plant height, stem diameter, leaf dry weight, tassel height and biomass were calculated. The results of analysis of variance showed that the effect of irrigation treatments on plant height, stem diameter, leaf dry weight and biomass was significant. Also, the effect of year on plant height, leaf dry weight and corn biomass was significant at the level of one percent. The effect of biochar on plant height and stem diameter was significant.

In order to investigate the effect of bentonite application in different soil moisture levels, an experimental factorial study was performed on summer savory in a completely randomized design with two factors and three replications in the greenhouse of Department of Horticultural Science, Ferdowsi University of Mashhad. The first factor was the application of bentonite at 3 levels (0, 50, and 100 g/kg soil) and the second factor was the different levels of soil moisture at 3 levels (50, 75, and 100% of field capacity). The results showed that drought stress reduced plant height, relative water content and fresh and dry biomass of shoots in summer savory, while the use of bentonite improved the mentioned traits. During drought stress, fresh and dry root biomass, root length, electrolyte leakage, antioxidant activity, total phenol, and proline content were on the rise. The use of bentonite improved these traits. At the highest level of drought stress, the use of bentonite (50 g/kg soil) reduced electrolyte leakage (22.45%) and proline content (58.33%) in the plant. Also, the relative water content in bentonite application (50 and 100 g/kg soil, respectively) at the highest level of drought stress increased by 20.75% and 22.76%, respectively, compared to the control. In general, the results of this study showed that the application of 50 g of bentonite per kg of soil in drought stress conditions had a better effect on the studied traits and its use in these conditions is recommended.

Nowadays, the use of simulation models is of great importance for optimal management of the production process and yield on farm scale. Due to the fact that combination of remote sensing with a model increases the accuracy of simulation, this study was conducted to evaluate the updated SWAP model combined with Sentinel 2 satellite images and AquaCrop model to simulate Hashemi rice yield in one of the research farms at the National Rice Research Institute of Iran. The measured parameters that were compared with two models included the quantity of dry matter of plant components during growth period. Evaluation of simulated and measured values indicated that the root mean square error of paddy and rice yield simulated with SWAP model updated with Sentinel 2 satellite images in two stages of reproductive and ripening were 6.28 and 142.40 kg/ha, respectively. Also, the RMSE values obtained for AquaCrop model were 9.55 and 338.46 kg/ha, respectively. Further evaluation of obtained statistics revealed that both SWAP updated with satellite images and AquaCrop models, can predict the yield and biomass of Hashemi cultivar with reasonably high accuracy. However, the AquaCrop model with a slight difference (R2=0.96), was less accurate in simulating the quantity of paddy than the SWAP model updated with satellite images. Furtheremore, when SWAP’s inputs were updated by data obtained from satellite images, at different stages, provided a higher accuracy to simulate the yield of paddy. Thus, it can be fairly used to simulate the rice yield.

The agricultural sector is the largest consumer of water in the country, which is of particular importance due to the droughts of recent decades, food security, and proper management of water resources. Therefore, it is necessary to provide proper management methods to saving water resources and reduce damage to water resources. For this purpose, for the optimal use of this input, the policy of reducing agricultural irrigation water subsidies in the central part of Baft county was used using a positive mathematical planning model. The research data were collected using random sampling method by completing 150 questionnaires and data of Agricultural Jahad Organization of Baft county for the 2019-2018 crop year and to estimate the data (area under cultivation, water, yield, etc) of the region''s crops from GAMS software was used. The results showed that with increasing the price of irrigation water input, the area under cultivation of barley and wheat crops with a steep slope and alfalfa crop with a gentle slope decrease and the area under cultivation of millet crop increases. Also, the gross income and irrigation water consumption of the region will be reduced under the policies of reducing water subsidies. Farmers'' cropping patterns change in favor of crops that produce more revenue per unit of water consumed. Therefore, prioritizing the policy of reducing irrigation water subsidies is recommended in decision-making and policy programs as an appropriate and practical strategy to increase the region''s water resources.

Increasing demand for water for irrigation in the agricultural sector has led to increasing reuse of treated or raw municipal and industrial effluents in many countries around the world. The use of wastewater is usually associated with microbial contamination and heavy metals that affect various parts of nature and therefore human health. Heavy metals in these unconventional waters are one of the sources of water, soil, and plant pollution that the toxicity of heavy metals in plants reduces plant growth. The above problems can be solved by modifying water and soil magnetically. In this study, the effect of using treated magnetic effluent on the yield components of maize plants was investigated. For this purpose, a factorial experiment was conducted in a randomized complete block design with three replications in 2020 at Babolsar city. Treatments include irrigation with well water (W1), irrigation with mixing 25% of effluent and 75% of well water (W2), irrigation with the mixing of 50% of effluent and 50% of well water (W3), irrigation with mixing of 75% of effluent and 25% of water Well (W4), irrigation with 100% effluent (W5) under magnetic field (I1) and without magnetic field (I2) was. Irrigation water magnetization was created by passing water through a permanent magnet with a magnetic field intensity of 0.3 Tesla. The results showed that the effect of irrigation type and water and effluent mixing on fresh and dry mass weight, number of seeds per corn, 1000-seed weight, biological yield, and grain yield were significant. On average, irrigation with magnetic effluent significantly increased grain yield (9.18%) and biological yield of maize (10.09%) compared to non-magnetic effluent. Yield and yield components of maize also increased with increasing effluent use. In general, by using magnetic technology, unconventional waters can be used and the amount of plant yield can be increased.