h m; a a; h a; p r
Abstract
To study the effects of irrigation water (50%, 75%, and 100% of plant water requirement) and potassium fertilizer (0, 50%, and 100% required potassium fertilizer based on soil test) on the dynamics of root, yield, and shoots of sorghum varieties (Pegah, Karaj, and Speedfeed), a research was conducted ...
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To study the effects of irrigation water (50%, 75%, and 100% of plant water requirement) and potassium fertilizer (0, 50%, and 100% required potassium fertilizer based on soil test) on the dynamics of root, yield, and shoots of sorghum varieties (Pegah, Karaj, and Speedfeed), a research was conducted in the Agricultural Research Center of Semnan province (Shahrood) in 2014. This research was conducted in pots and in field experiment. The experimental variables were irrigation water, potassium fertilizer, and varieties of forage sorghum. The treatments were arranged as split plots based on a randomized complete block design with three replications. In the pot experiment, 243 plastic pots with diameter of 30 and height of 60 cm were used. Irrigation water was calculated with Penman-Monteith method. Drip irrigation was used as irrigation system. Sampling was carried out from the roots in three phases during the season. The root volume was determined by immersion in water method. Shoots parameters such as leaf area, leaf dry weight, stem dry weight, and shoot weight were measured. The results showed that the effects of irrigation water, potassium fertilizer, and sorghum varieties were significant on the forage yield, root volume, and dry weight of roots and shoots of the plants. The highest yield was obtained from the W100K100 treatment (102.8 ton/ha). Pegha variety showed the maximum yield. The maximum water use efficiency was obtained from the W75K100 treatment (20.5 kg/m3/ha). The W75K100Vp < /sub> treatment was introduced as a superior treatment. Potassium fertilizer could compensate the loss of yield. The mathematical equations expressing root volume and dry weight with time were determined during the season. The relationships between some parameters of the shoots and roots were determined.
J P; H A; S SH
Abstract
Water distribution method based on the type of water conduits can be divided into two groups, namely, open and closed systems, while on the basis of the energy of the water flow, the two groups are gravity flow and pressurized flow. Open channel type conveyance and distribution is achieved by gravity ...
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Water distribution method based on the type of water conduits can be divided into two groups, namely, open and closed systems, while on the basis of the energy of the water flow, the two groups are gravity flow and pressurized flow. Open channel type conveyance and distribution is achieved by gravity and includes channels made by embankment construction, excavation, or construction of prefabricated sections, as well as the use of underground pipes or closed ducts in which water flows by gravity (no pumping). If the required pressure for the flow of water is less than 10 meters, the conveyance and distribution method is grouped as low-pressure. In this research, the irrigation and drainage network of Sistan, which is a strategic region in east parts of Iran facing severe water shortage, was studied to suggest proper strategies. Three crops, namely, wheat, barley, and alfalfa were studied for economic analysis. The results showed that using a piped conveyance system would increase the net income and the gross benefits of the wheat and alfalfa growing farmers compared to open channel systems, but the area of barley should decrease. Furthermore, due to high costs of construction and low irrigation efficiency and poor water management, the net benefits of farmers under the two conveyance systems would not be significantly different. Thus, by using pressurized water conveyance systems from Chah-Nimeh reservoirs, the existing efficiency of 20%, would rise to 90%. Results revealed that the main problems in the network were deterioration of canals lining, poor performance of the regulating and distribution structures, and low efficiency of the network. Overall, the economic analysis of the project showed that water conveyance by pipe was economically more justified than open channels.