جستجوی مقالات مرتبط با کلیدواژه "irrigation water use efficiency" در نشریات گروه "آب و خاک"

Water and nitrogen fertilizer management is essential for increasing water productivity, increasing product production and reducing environmental hazards in modern irrigation systems. The aim of this study was to investigate the interaction of water and nitrogen fertilizer on total biomass (TB) and irrigation water use efficiency (IWUE) of silage maize under drip-tape irrigation system. Four irrigation levels, including two deficit irrigation levels (W1=0.86ETc, W2=0.93ETc), a full irrigation level (W3=ETc), and an over irrigation level (W4=1.06ETc) and three nitrogen fertilizer levels, including no nitrogen fertilizer (N0), 150 kg N ha-1 (N150), and 200 kg N ha-1 (N200) were considered. The twelve experimental treatments arranged in a strip-plot design with complete randomized blocks with three replicates. The studied indices were stem height and diameter and total biomass during growth period. Irrigation management was performed, based on the calculation of corn evapotranspiration by using FAO-Penman Monteith (FPM) equation and soil moisture measurement in the root depth before each irrigation. The result showed that there was a significant effect of irrigation on total biomass and IWUE (P < 0.05). There was a significant effect of nitrogen on TB and WUE (P < 0.01). The minimum TB obtained for W1N0 treatment, 14537 kg/ha, and the maximum TB obtained for W4N200 treatment, 27893 kg/ha. The minimum IWUE for total biomass was 3.09 kg/m3 for W2 level and maximum was 3.57 kg/m3 for W4 level. Overall, TB and IWUE increased with increasing nitrogen. In general, the results showed that drip-tape irrigation system through increasing irrigation efficiency and decrease of soil surface evaporation would save water consumption and increase the water use efficiency and yield production.

Owing to drought, increasing demand for fresh water resources and low water use efficiency, the optimum use of water is essential in the agricultural sector. Therefore, this study was conducted to investigate the effect of different levels of irrigation water on quantitative and qualitative Characteristics of potato (Burren cultivar) and determination of its optimum consumptive use of water under Shahr-e kord environment.
This study was conducted at the Agricultural Research Center and Natural Resources in Shahr-e kord with longitude and latitude of 32˚18΄ and 50˚51΄ , respectively, in 2013. This experiment was performed in randomized complete block design with 7 treatments consisted of different levels of irrigation water and 3 replications. Different levels of irrigation water were: 40, 55, 70, 85, 100, 115 and 130 % of the soil moisture deficit. Potato seeds (burren cultivar) were planted with distance of 20 cm from each other and furrow width of 75 cm. Irrigation program were performed based on the measurement of soil moisture deficit. The irrigation intervals were considered as a fixed 7 day. Irrigation levels were applied to 105 days after planting and the total growth period was 130 days from planting to harvesting. The samples were taken from the two middle furrows. The evaluated parameters were included weight of tubers per plant, tuber diameter, weight of tuber in seed size, weight of tuber production in a plant in marketable size, tuber dry weight, the starch percent, percent of soluble sugars, nitrogen percent. The starch content was determined by Polarimetry method. The soluble sugars content was measured by Colorimetric method, the nitrogen content was measured by wet digestion method and using the Kjeldahl set. Then, the optimal depth of water consumption in conditions of limited water resources were determined by English method Statistical analysis of data and drawing graphs were done with SAS and EXCEL software, respectively.
Results The effect of different levels of irrigation water on yield was significant at 1%. The yield increased with increase of irrigation water. The minimum and maximum yields were belonged to 40 and 130 % treatments with 13.2 and 45.2 tons per hectare, respectively. Whereas, the results revealed that treatments which recieved100, 115 and 130% of the soil moisture deficit had no significant effect on potato yield at 5% level. Thus, potato yield in 115 and 130% treatments were only 2.3 and 3.9% more than treatment receiving full irrigation, respectively. The potato production function was obtained using the depth of water which consumed during the growing season and yield in each treatment. The results showed that the effect of different levels of irrigation water was significant on yield, starch, soluble sugars, dry matter, irrigation water use efficiency and the weight of tuber production per plant in marketable size As the level of irrigation water increased, the yield, soluble sugars content and weight of tuber per plant in marketable size increased and the starch and dry matter content decreased. Moreover, effect of different levels of irrigation water on nitrogen percent and the weight of tuber in seed size were not significant. Maximum and minimum of irrigation water use efficiency were belonged to 85 and 40% with values of 6.96 and 4.84 Kg m-3, respectively. Maximum and minimum percentages of starch were belonged to 40 and 130% treatments with values of 76.6 and 61%, respectively. The soluble sugar content in potato can causes discoloration and darkness of the product, and accordingly it makes the non-marketability of the product. Maximum and minimum soluble sugar contents were belonged to 130 and 40% treatments with values of 2.12 and 3.07%, respectively. In addition, the increase of irrigation water caused to the increase of weight of tuber per plant in marketable size. Therefore, the highest marketable tuber yield was belonged to 130% treatment and it was 1.5 kg per plant and the lowest one was belonged to 40% treatment and it was 0.61 kg per plant. The applied water which maximized the income was 821 mm during the growth period.
The use of 82% full irrigation (533mm) can result in maximum net income and irrigated area can increase by 22% compare to full irrigation. If the purpose of planting is get to the maximum yield, the use of 130% irrigation treatment is recommended and if the purpose is the production of seed potatoes, the use of 85% irrigation, treatment is recommended.