r a; a a; h a; m k; e a
Abstract
Rice cultivation in Iran is dominantly under submerged condition, which requires plenty of water, nitrogen fertilizer application, very difficult and laborious land preparation, along with high labor costs. In order to assess the effects of different rice cultivation methods on increasing water productivity ...
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Rice cultivation in Iran is dominantly under submerged condition, which requires plenty of water, nitrogen fertilizer application, very difficult and laborious land preparation, along with high labor costs. In order to assess the effects of different rice cultivation methods on increasing water productivity and to find a suitable method of water and nitrogen application, an experiment was carried out in Rice Research Institute of Iran, Amol (RRII), in 2014. The experimental layout was split-split plot with 3 replications, using Keshvari rice variety. Two land preparation methods i.e. with and without puddling, were the main factors, while four levels of irrigation application were the sub-factors, with sub-sub plots allocated to four levels of nitrogen application (N0, N80, N120, N160 kg/ha) . The results showed that the effect of rice cultivation method on water use and water productivity (WP), and the effects of irrigation and nitrogen on yield-related traits, water use and WP were statistically significant at %1 level. The new cultivation technique -aerobic cultivation method- saves water use and increases WP, respectively, as much as 27.95% and 29.11%.With the increasing The application of nitrogen, increased yield and WP, in the form of linear equation. Applying 130% of Class A pan evaporation and nitrogen 120 kg was optimal yield and saving water and nitrogen, respectively 8.9% and 33%.
p sh; e a; s r; m a
Abstract
Today, even in humid areas, the water crisis is a major problem for agriculture and increasing the efficiency of water use is also one of the requirements for sustainable development. Regarding this, the use of plant growth simulation models as a tool for managing water crisis seems useful. In this study, ...
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Today, even in humid areas, the water crisis is a major problem for agriculture and increasing the efficiency of water use is also one of the requirements for sustainable development. Regarding this, the use of plant growth simulation models as a tool for managing water crisis seems useful. In this study, WOFOST model to simulate the performance of two soybean cultivars (DPX and SEPIDEH) under deficit irrigation was used in the Gorgan region. Using the measured plant yield and simulated water balance components from the model, the average productivity of evapotranspiration (Wp < sub>ET), based on seed yield, was obtained as 0.72 kg m-3. With increasing water stress, water use efficiency based on irrigation and precipitation series (Wp < sub>I+R) and water use efficiency based on irrigation (Wp < sub>I) increased in both cultivars, but the DPX water use efficiency under drought stress was higher than the SEPIDEH cultivar. According to the results and accuracy of WOFOST model, index of relative root mean square errors of seed yield and total biomass in both cultivars was less than 10%, the index of the coefficient of residual mass (CRM) was close to zero, the performance factor (EF) was 0.89, the coefficient of determination (R2) equaled 0.93, and the index of Willmott agreement (IOA) was about 0.89. Overall, based on the findings of this study, favorable performance of the model to simulate the growth process and water impact on soybean seed yield and water efficiency is confirmed and cultivar DPX is recommended for cultivation in the Golestan province.
k m; e a; b s
Abstract
Sustainable economical production of tea depends on the proper use of water and fertilizer. For this purpose, the role of supplemental irrigation and nitrogen fertilizer on economical production of tea plantations was studied by assessment of yield, production function, water use efficiency, and benefit/cost ...
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Sustainable economical production of tea depends on the proper use of water and fertilizer. For this purpose, the role of supplemental irrigation and nitrogen fertilizer on economical production of tea plantations was studied by assessment of yield, production function, water use efficiency, and benefit/cost ratio, and final return in a field experiment at Feshalam Tea Research Station in Fouman, Guilan, during 2008-10. The experiment was conducted by line-source technique of irrigation and the strip plot experiment with randomized complete block design with four replications. Six levels of zero, 100, 200, 300, 400, and 500 kg N ha-1 were mixed with the soil (source urea) in the main plots and five irrigation levels consisting of full irrigation (I4), deficit irrigation (I1, I2, I3) and no-irrigation (I0), were applied as sub-plots. The full irrigation (342 mm) by sprinkler method and application of 320 kg N ha-1 in mature tea bushes produced 3928 kg yield (made tea) ha-1 and water use efficiency of 7.2 kg ha-1 (made tea) for each mm of water used. The highest yield in rain-fed condition (1403 kg ha-1) and water use efficiency (6.1 kg ha-1 for each mm of rain water) were obtained with application of 200 kg N ha-1. The mean benefit/cost ratio for full irrigation and no irrigation were 1.75 and 1.17, respectively. According to this, although costs increased in full irrigation, but profit increased due to higher production and better quality of green leaf (first grade), compensating the costs.