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Mehdi akbari; Fariborz Abbasi; Abolfazl Nasseri; Afshin Gomrokchi; mostafa goodarzi; Amir Eslami; masoud Farzamnia; r alimohammadi; Nader Kouhi Chellehkaran; Reza Bahramloo; Ali Ghadami Firouzabadi; seyed abolghassem Haghayeghi moghaddam; Ardalan Zolfagharan; Jamal Ahmadaali; Mohamad Abasi; Hamid Riahi; Mohammad Mehdi Nakhjavanimoghaddam
Abstract
In this study, volume of irrigation water, water productivity, and yield of alfalfa were measured in 300 farms in Zanjan, Fars, Chaharmahal and Bakhtiari, Hamedan, East Azerbaijan, Semnan, Khorasan-Razavi, Isfahan, West Azerbaijan, Central, Qazvin and Kerman provinces under farmers management and surface ...
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In this study, volume of irrigation water, water productivity, and yield of alfalfa were measured in 300 farms in Zanjan, Fars, Chaharmahal and Bakhtiari, Hamedan, East Azerbaijan, Semnan, Khorasan-Razavi, Isfahan, West Azerbaijan, Central, Qazvin and Kerman provinces under farmers management and surface and sprinkler irrigation, various water sources, different water salinities, soil conditions, and varieties, during the growing season of 2018-2019. The results showed that the difference between average volumes of water applied by farmers, yield, and water productivity, in the studied sites were significant at 1% probability level. The average amount of applied water by farmers was 8502, 8901, 9226, 9459, 11481, 12796, 14311, 14821, 15198, 15916, 18351 and 23920 m3/ha, respectively, and the average was 13284 m3/ha. The dry yield of alfalfa varied from 2500 to 30000 kg/ha with an average of 13841 kg/ha. Irrigation water productivity varied from 0.2 to 4.5 and its average was 1.28 kg/m3. The average irrigation water plus effective rainfall productivity for alfalfa was 1.19 kg/m3. The results showed that the average applied water and alfalfa yield in surface and sprinkler irrigation methods were 15076 and 10653 m3/ha, respectively, (p<1%). These results showed that in sprinkler irrigation method, applied water was 30% less and irrigation water plus effective rainfall productivity was 41% higher. Accordingly, in order to reduce the volume of irrigation water and improve alfalfa water productivity, it is recommended to use sprinkler method in suitable climatic conditions where irrigation water is of good quality and the technical criteria of design, implementation, operation, and economic considerations are met.
Nader Kouhi Chellehkaran; h d
Abstract
Crop growth models facilitate management of irrigation water and fertilizer because less on-site (filed) visits and direct measurements are required. On the other hand, these models are complex and difficult to be understood and require input data that is not available, thus, using them in management ...
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Crop growth models facilitate management of irrigation water and fertilizer because less on-site (filed) visits and direct measurements are required. On the other hand, these models are complex and difficult to be understood and require input data that is not available, thus, using them in management decisions, which should be done before cultivating season, will be difficult. The objective of this study was to develop a model for grain yield prediction of Corn (Zea maize) based on simulated leaf area index (LAI) under water stress conditions. In this study, corn LAI was simulated based on cumulative degree-days and water stress index. The model used crop and soil as well as meteorological data including daily maximum and minimum air temperature (oC), precipitation (mm), and solar radiation (MJ.m-2d-1). The model was developed based on the 2013 growing season data for single cross 704 cultivar under full irrigation and water stress conditions, and was validated with 2014 growing season data. The highest values of simulated LAI in the 100% water requirement (WR) treatment were between 6.14 and 5.78, in the 80% WR between 5.63 and 5.4, and in the 60% WR was between 4.11 and 3.47, which varied by 0.13 (2%), 0.14 (2.5%) and 0.29 (6.6%), respectively. In the mid- stage of growth, the estimated LAI was more consistent with measured values (2%). In treatments under stress (except for the fourth stage of sampling), the LAI estimated by the model was 6.6% higher than the values observed. In all treatments, the high correlations (R2) between the values of the simulated LAI and observed LAI in both years of the experiment were between 0.9 and 0.99.