نشریه مدیریت آب در کشاورزی
سال دهم شماره 1 (پیاپی 19، بهار و تابستان 1402)

Due to the quantitative and qualitative reduction of water resources and also to maintain existing agriculture, the only solution is to increase yield per unit area by changing the cultivation pattern, correct use of inputs, optimal irrigation management and ultimately increase irrigation water productivity. In this regard, a study was conducted in a pistachio garden of Ahmad Aghaei cultivar in Sarvestan city during the 2018-2019 crop year with the aim of comparing the volume of applied water, irrigation water productivity and machine efficiency in different water distribution substrates in surface irrigation method. The experimental design was performed in the form of randomized complete blocks with 4 treatments of irrigation management in three replications. The treatments were: conventional flooding method with a strip width of 6 meters (Control treatment), the creek created on both sides of the tree row (Ditcher), reducing the strip width through the border created in the middle of the row of trees (Border) and the bed of Sine-Morghi created on both sides of the rows of trees (Kadval). The amount of irrigation water according to the inflow to each treatment and the time of cut off based on the management applied by the gardener in control, border, kadoul and ditcher treatments was 8400, 4648, 4200 and 3080 cubic meters per hectare, respectively. The results showed that in all treatments, irrigation water productivity increased compared to the control treatment. So that the rate of increase in ditcher, kadoul and border treatments compared to the control treatment was 120, 91 and 62%, respectively. Finally, ditcher and Kadval treatments with reduction of irrigation water by 63 and 50%, respectively, and no significant yield compared to the control treatment were suggested as the best irrigation treatments for pistachio trees in the tested garden.

Potato is one of the most important crops, which is very sensitive to the amount of irrigation water. This leads to a lot of research to determine its yield and water productivity in different irrigation conditions. Doing the researches waste time and cost. For this reason, researchers have suggested that crop growth models such as AquaCrop be sensitively analyzed and evaluated to simulate the crop under different conditions. Due to this issue, the present study was conducted using three irrigation treatments including T1: 100% supply; T2: 75% supply and T3: 50% supply of potato water requirement. To analyze the sensitivity step, Beven method was used. To evaluate AquaCrop, statistics criteria root mean square error (RMSE), normalized root mean square error (NRMSE), mean bias error (MBE), efficiency factor (EF) and agreement index (d) were used. The results showed that AquaCrop model was very sensitive to changes in water productivity parameters. The sensitivity of this model to changes in evapotranspiration coefficient and crop growth coefficient was moderate and to changes in initial crop canopy and crop decay coefficient was low. According to MBE values, AquaCrop model suffered a low estimation error in determining yield and water productivity. The error of this crop model was acceptable for determining yield (RMSE=1.5) and water productivity (RMSE=0.23). Its accuracy was also excellent for simulating yield (NRMSE=0.06) and water productivity (NRMSE=0.06). Based on the values of EF and d, AquaCrop was more efficient than water productivity in determining yield. Therefore, it is suggested that this crop model be used to simulate potatoes under similar conditions.

From the economic and medicinal point of view, Aloe vera is a herbaceous and perennial plant that has attracted the attention of many farmers Iran. Climatic conditions throughout the year and the quantity and quality of irrigation water affect Aloe vera yield. For this reason, the research was conducted with the aim of investigating the effect of aforementioned factors on the Aloe vera yield and yield components. To achieve this goal, a strip-block design was carried with two factors, include: amount of irrigation water at three levels (I1: 50, I2: 75 and I3: 100% of irrigation water requirement) and irrigation water salinity at two levels (S1: 5 and S2: 10 dS.m-1) with three replications, in a research farm in Omidiye with longitude 30°37° and latitude 49°49°. The first harvest was done in the fall of 2019 and the second harvest in the spring of 2020. The results showed that in the first harvest, irrigation had a significant effects on leaf width, leaf fresh weight (P-value≤0.05), gel weight, the ratio of gel weight to leaf weight, the number of leaves and the water use efficiency (P- value≤0.01). Salinity had a significant effects on leaf thickness (P-value≤0.05), leaf width, leaf fresh weight, gel weight, the ratio of gel weight to leaf weight and water use efficiency (P-value≤ 0.01). In the second harvest, irrigation had a significant effects on the ratio of gel weight to leaf weight, number of leaves and water use efficiency and salinity had a significant effects on leaf width, leaf thickness, leaf fresh weight, gel weight , the ratio of gel weight to leaf weight and water use efficiency . In both the first and second harvests, the interaction effect of irrigation water and salinity only showed a significant effect on the water use efficiency (P-value ≤ 0.05).

The purpose of this study is to measure the impact of agricultural land-use change on the process of reducing the water level of Urmia Lake and accelerate its land process. The data used in this research include Landsat satellite images in the period 2000 to 2020 and statistics and information of water sources entering the lake of Urmia Lake Rehabilitation Headquarters, which are classified by SVM, Kappa Coefficient algorithms in ENVI5.3 software and Validated and then using Arc-GIS software to determine the extent of user changes. Finally, after determining the number of changes in each land use, the amount of water required for each type of cultivation was calculated based on the climatic type and soil characteristics of the city by the NETWAT model. The satellite images show that in the period, the research aimed to change the cultivation pattern from irrigated agriculture to cropland, from an area of 395 km3 in 2000 to 688 km3 in 2020. The outputs of the NETWAT model also show that due to the change in the land-use area of agricultural lands and the change in the cultivation pattern, the amount of water consumption required in the agricultural sector has almost doubled in the growth period, from 1600 million cubic meters in 2000. It reached 2900 million cubic meters in 2020. This increase in consumption needs has eliminated the surface flow of rivers and lowered the groundwater level of the basin, which is the main reason for reducing the volume of water entering Urmia Lake.

In order to evaluate of grain yield and fatty acids composition in peanut (Arachis hypogaea L.) oil as affected by supplementary irrigation and Salicylic acid, this experiment was performed as split plat based on randomized complete block design with three replications in experimental field of Agicutural and Natural Resources Research and Education Center of Guilan Province, Astara (Kanroud research station), Iran, during 2018 and 2019 cropping seasons. Four level of irrigation regimes including no irrigation (as control), irrigation at initial flowering stage, irrigation at pod formation stage and irrigation at initial flowering + pod formation stages and three levels of Salicylic acid such as 100, 200 and 300 µmol/l comprised experimental treatments, as main and sub plot, respectively. Drought stress dercreased grain yield, grain oil content, oil yield, protein yield, linolenic, stearic and bihenic fatty acids percent in peanut oil. But, grain protein percent, oleic, palmitic and arashidic fatty acids percent enhanced in response to drought stress. Foliar application of salicylic acid at the rate of 300 µmol/l improved all measured characteristics except stearic and bihenic fatty acids under both drought stress and supplementary irrigation conditions. The greatest grain yield (3450 kg/ha) of peanut was obtained in response to supplementary irrigation at initial flowering + pod formation stages along with Salicylic acid application at the rate of 300 µmol/l. Also, Salicylic acid application at the rate of300 µmol/l. showed the highest rate of oleic acid in peanut oil (60.98 %) under no irrigation (rainfed) condition. Hence, supplementary irrigation and foliar application of Salicylic acid could be recommendable in direction to enhance quantity and quality of grain and oil yield of peanut under similar climatic condition.

About three quarters of the country's sweet lime orchards are located in Fars province. Having sufficient information on the amount of irrigation water and water productivity of these gardens can lead to better management of water resources and increase water productivity. In this research, the water productivity and the amount of water given in 60 sweet lime orchards in six regions of Fars province were measured during 2021. Among the selected orchards, due to differences in irrigation management, soil salinity and other factors, the volume of irrigation water varied from about 10000 to 24000 m3/ha per year. The average total volume of irrigation water was 14712 m3/ha. In terms of the regional average, the lowest and highest amount of irrigation water was related to Ghir-Karzin and Darab regions with 13023 and 17079 m3/ha per year, respectively. The productivity of irrigation water in selected gardens was between 0.71 and 2.23 kg/m3 and on average 1.40 kg/m3. Comparing the volume of irrigation water with the gross water requirement showed that in the year of conducting the research, these differences were statistically significant in Lar and Darab regions. In general, the average difference between the volume of irrigation water and the annual gross water requirement in the province was 569 m3/ha, which was not statistically significant. But on average, the volume of irrigation water was 2288 m3/ha more than the long-term gross water requirement, which was a significant difference. Therefore, it is necessary to apply irrigation scheduling and accurately determine the required water to increase the productivity of sweet lime orchards in Fars province.

In order to investigation of influence drought stress and salinity stress on photosynthetic pigments and concentration of elements of Mentha piperita L and influence foliar spraying of selenium, an experiment of split in time and with three replications was performed in research greenhouse in Torbat-e Jam region, Iran and in during 2020, including three levels of Salinity (S1=0, S2=50 and S3=100 mmol NaCl), three levels of irrigation (I1=100, I2=75 and I3=50 percent of water requirements) and two levels of selenium (0 and 5 mgrperlit Na2SeO4). results showed that with increasing level of drought and salinity stresses, chlorophyll a, b and total and carotenoids decreased. Also, foliar spraying of selenium (5 mgr/lit Na2SeO4), respectively, 5/53, 6/10, 7/59 and 8/10 percentage was added to chlorophyll a, b and total and carotenoids in Mentha piperita L plant. Investigating effect of drought and salinity stresses on the concentration of elements in Mentha piperita L plant showed that with increasing level of drought stress from I1 to I2 and I3 , concentration of iron respectively, 6/61 and 68/59, concentration of zinc respectively, 9/09 and 181/8, concentration of sodium respectively, 26/39 and 62/93 and concentration of potassium respectively, 11/91 and 12/77 were added and with the increasing of salinity stress from S1 to S2 and S3, from concentration of iron, respectively, 19/94 and 27/81, and from concentration of zinc respectively, 87/10 and 83/57 percentage decreased and concentration of sodium from 8/45 to 21/87 and 123/67 mg/gr increased respectively. Also, with increasing level of salinity stress from S1 to S2 and S3, concentration of potassium respectively, 2/17 percentage increased and 21/55 percentage decreased. results showed that selenium is effective in reducing the effects of salinity and drought stresses and on photosynthetic pigments and concentration of elements in Mentha piperita L plant.

Considering the consequences of climate change and the existence of drought, the current conditions should be managed in such a way that the spread of the negative effects of these changes, including the reduction of water resources in open water transfer systems through evaporation, is limited and controlled. Evaporation from the surface of open channels, especially in arid and semi-arid areas like Iran, needs more detailed studies; Therefore, in the present study, the factors affecting evaporation were first investigated based on the data received by the Meteorological Organization, and then the potential amount of solar radiation was estimated in the area of the water supply channel on the right bank of the Noruzlu Diversion Dam, and the amount of coverage of the channel surface was investigated. . For this purpose, the required data were extracted through the meteorology software and using the RCP 2.6, RCP 4.5 and RCP 8.5 scenarios. Based on the research findings, the decrease in the radiation potential and the gradual increase in temperature and as a result the global warming revealed.In the continuation of this process, by entering the extracted data into the PVC system software, different angles of the radiation effect and simulating the shading scenarios of the panels at different distances were carried out in order to choose the optimal angle with the maximum amount of energy received. As a result, the slope angle is 37 degrees with the water supply channel coverage of about 67% in the covered area of about 24,763 of the 36,960 square meters of the canal, 7,377 megawatt hours of electricity energy annually at a cost of about 82 billion tomans and annual income of 6.5 billion tomans with return on investment 12.4 years was selected.

Due to the rising climate change, chilling and frost have affected agricultural production in many areas. At the same time, frost also causes freezing in irrigation systems. In the last decade, frost usually occurred yearly in farming regions and affected the economy of farmers. A bibliometric analysis of these researches may provide the importance of this topic and future research trends. Bibliometric is a statistical method to analyze bibliometric publications data such as peer-reviewed journal articles, books, conference proceedings, periodicals, reviews, reports, and related documents. It has been widely used to present the relations of research domains with quantitative methods. “Frost” and “chilling” were used as the keywords to reach the relevant publications. In this article, we used VOSviewer software for bibliometric analysis. We found 344 documents about the late spring frost. More than 79% of the publications were in the form of scientific journals and conference and review articles. The publication of articles showed a steep increase after 2014. The most publication was in 2021. The United States was the largest producer of scientific papers in the world. The highest-ranking journal was Acta Horticulturae, with 45 publications on frost and chilling. “Climate change,” with a total link strength of 56, appeared as the most frequent .

Reduction of water resources from one side and increasing demand on the other side, have faced lots of areas in the world with a difficult situation. Water resource pricing in water management is essential. Currently, the water rate paid by farmers to irrigate agricultural crops does not reflect the true value of water. One of the most effective solutions for demand management is determining the real price of water in the agricultural sector. This helps in the more favorable allocation of this input between different agricultural products. Since the surface water availability variable is stochastic in nature, its value cannot be assumed as certain. Therefore, in this study, the shadow price of water in the irrigation network of Qazvin plain has been calculated with the help of the fuzzy planning model of limited chance, which is a combination of the limited chance planning model and fuzzy planning model. The results show that the economic value of each cubic meter of water in the Qazvin Plain irrigation network is equal to 17,882 rials, which is about 23 times more than the average selling price of water in the study area. Considering that the stock of water resources is decreasing, in order to prevent indiscriminate harvesting and waste of water resources, as well as the optimal allocation of water input between agricultural products in the region, the price of water equivalent to its real value should be received from the farmers.

A canopy cover percentage is considered one of the most important evaluation criteria for evaluating the ‎simultaneous effects of impressive factors on water efficiency. Since digital cameras are developed and ‎widely available, the use of discrimination indices in the visible spectrum is making it possible to calculate ‎the leaf area index and chlorophyll content of vegetation covers. Therefore, in this study, the ‎performance of five plant Vegetation Discrimination Indices (VIDs) and a variety of thresholding ‎algorithms was compared in order to distinguish the sugar beet's vegetation cover from its background, ‎among which two new indices were introduced. In comparison with the old VID of Excess Green minus ‎excess Red (ExGR), using the new VID of Excess Green minus excess Blue (ExGB) and Riddler-Calvard's ‎thresholding algorithm resulted in a 29.54 percent increase in vegetation cover segmentation accuracy. ‎Following this step, we determined which function would best predictdry beet weight from vegetation ‎cover percentage, and the power function did the best. In order to estimate the yield, the segmentation ‎method based on Riddler-Calvard thresholding and the New Canopy Index of Vegetation Extraction ‎‎(CIVEn) had an error of 12.09 Kg. With an error of 41.25 Kg, the segmentation method based on Otsu ‎thresholding and ExGR index performed worst.‎

Sensitivity analysis of crop models helps researchers to have the necessary information about the reaction of crop models to changes in input parameters before calibration and application. This makes it possible to introduce the input data to the model with more awareness and increase the accuracy of the model in the calibration stage. Due to using the AquaCrop model in recent years, in this study, the sensitivity of normalized water productivity (wp*), crop transpiration, initial canopy cover (CCo), canopy growth coefficient (CGC), canopy decline coefficient (CDC) and harvest index (HI) was analyzed using a new method. For this purpose, corn yield data collected from Research Institute of Seed and Plant Breeding during 2008-2010 were used. Data consisted of four irrigation levels (W1, W2, W3 and W4 indicate supply of 120, 100, 80 and 60% of water requirement, respectively) and four nitrogen fertilizer amount (N1, N2, N3 and N4 indicate supply of 100, 80, 60 and 0% of fertilizer requirements, respectively). The results showed that the AquaCrop was most sensitive to changes in harvest index (0.65≤Spi≤1.3) and normalized water productivity (0.55≤Spi≤1.2). The lowest sensitivity (0.02≤Spi≤0.07) was observed to changes in crop canopy decrease coefficient (CDC). Sensitivity coefficients were positive for all parameters except CDC. Therefore, by increasing the CDC value, the AquaCrop suffers from underestimated error. The sensitivity coefficients for treatments N1 to N4 were equal to 0.32, 0.41, 0.46 and 0.51, respectively. These results for irrigation treatments W1 to W4 were equal to 0.36, 0.39, 0.44 and 0.5, respectively. So, with increasing water stress and fertilizer, the sensitivity of the AquaCrop model to all parameters increased. The highest sensitivity was observed in W4N4 treatment.