|Author:||Kashefipour, S. M. ; Nasab, S. B. ; Ghannad, S. T.|
|Book Group Author:||NA|
This study conducted during February-June 2002 in Dezful Safi-Abad, Khoozestan, Iran, describes the relationship of irrigation water application, water stress, CWSI and crop yield for the spring maize hybrid SC704. Irrigation was scheduled using accumulative pan evaporation. Five treatments including 50 (T1), 70 (T2), 90 (T3), 110 (T4) and 130 mm (T5) based on the accumulative pan evaporation were used as the main plots. Crop water stress indexes (CWSI) were calculated using two different methods described by Idso and Jackson in the literature. A good linear equation was developed using the least square method between the grain yield and the CWSI (Jackson method) in the form of Ys=-10.295CWSIj+13.196 with a correlation coefficient of R2=0.97. The average CWSI using the Jackson method were 0.05, 0.15, 0.36, 0.43 and 0.50 for T1 to T5 treatments, respectively. Another equation was also developed, in which the relative humidity, the net receiving solar radiation, the depleted soil moisture from the root zone and the wind speed were related to the canopy-air temperature difference. This equation may be applied to schedule the irrigation programme without measuring the soil moisture. In conclusion, the lower and upper baselines that related water vapour pressure deficit to the canopy-air temperature difference were determined in the form of the separate equations for April and May. The results showed higher grain yield but lower water use efficiency with increasing water application. The maximum grain yield was 12.4 t/ha, with the corresponding CWSI being 0.05. The maximum water productivity (19.8 kg/mm) was obtained for the treatment with 60 cm depth of irrigation which this amount of water application was 15% less than the fully irrigated treatment. The maximum allowable canopy-air temperature differences were also correlated with some environmental parameters.
|Pages:||401 - 405|
|Journal:||Journal of Agronomy|
air temperature, canopy, crop yield, irrigation, irrigationscheduling, maize, plant water relations, relative humidity, soil water,solar radiation, water stress, water use efficiency, Iran, Zea mays,Zea, Poaceae, Cyperales, monocotyledons, angiosperms, Spermatophyta,plants, eukaryotes, West Asia, Asia, Middle East, Developing Countries,Threshold Countries, corn, leaf canopy, soil moisture, sunlight,watering, Field Crops (FF005) (New March 2000), Plant Water Relations(FF062), Plant Production (FF100), Soil Water Management (Irrigation andDrainage) (JJ800) (Revised June 2002) [formerly Soil Water Management],Meteorology and Climate (PP500)