Mohammad Mehdi Gharahdaghi; Seyed Mahmoud Tabatabaei; Eisa Maroufpoor; Farzad Hossinpanahi
Abstract
Proper design of the factors effective in hydraulic performance of drip-tape irrigation systems appropriate to the field and crop conditions is the key for their success. For this purpose, two important and sensitive parameters are lateral spacing and emitter spacing. Lack of correct selection of these ...
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Proper design of the factors effective in hydraulic performance of drip-tape irrigation systems appropriate to the field and crop conditions is the key for their success. For this purpose, two important and sensitive parameters are lateral spacing and emitter spacing. Lack of correct selection of these two parameters affects the drip-tape irrigation system performance and it has a significant impact on the cost of implementing such irrigation systems. To investigate the effect of the lateral and emitter spacing on winter wheat yield, its components, and water use efficiency, a factorial arrangement experiment with two factors based on randomized complete block design was conducted at the Soil and Water Research Institute Station, Karaj, Iran. The investigated factors included lateral spacing (at 30, 45, and 60 cm) and emitter spacing (at 10, 20, and 30 cm). Results showed that in most of the studied indices, the 20 cm emitter spacing in different lateral spacing was the superior treatment. The results showed that, although the 30 cm lateral spacing led to the highest yield, but based on the results of economic analysis, the highest economic performance for a wheat field could be achieved at 45 cm lateral spacing, which could be adopted by farmers.
m gh; m t; m h
Abstract
Using simulation models is a strategy in agricultural water use management and in predicting effect of saline water on crop yield and soil salinity. In this study, soil salinity and forage maize yield were evaluated under alternating application of saline water with fresh water using SWAP and SALTMED ...
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Using simulation models is a strategy in agricultural water use management and in predicting effect of saline water on crop yield and soil salinity. In this study, soil salinity and forage maize yield were evaluated under alternating application of saline water with fresh water using SWAP and SALTMED models. For this purpose, field experiments were carried out under different treatments of fixed and cyclic use of saline (salinity levels of 3.5 and 5.7 dS.m-1) and non-saline water (non-saline water application in every one, three, and five saline water application) in Karaj region. Electrical conductivity of the non-saline water was 0.4 dS.m-1. Crop yield and soil salinity were simulated via both models and compared with their corresponding measured values. In SWAP model, coefficient of determination (R2) values were 0.754 and 0.587 for soil salinity and crop yield, respectively, while these values were 0.758 and 0.846, respectively, for SALTMED model. Absolute Relative error (|RE|) of SWAP model varied between 1.7% and 26.3% in crop yield estimation and varied between 2.5% and 32.4% in soil salinity estimation. Also, |RE| of SALTMED model ranged from 0.9% to 24.7% in estimation of crop yield, and ranged from 2.2% to 38.2% in case of soil salinity estimation.