Effect of Moisture Regimes and Harvests on Efficiency of Water Use by Ten Forage Crops
1968
Powell, R. D. | Kardos, Louis T.
The total amounts and rates of depletion of soil water required to produce dry matter by 10 crops were studied. Two experiments with forages were conducted, one being managed to simulate pasture and the other being managed for hay. Three levels of soil moisture management were used in each experiment: control (M₀), irrigation when the available soil water at the 10 cm depth was 85% depleted (M₁), and irrigation when available soil water at the 10 cm depth was 30% depleted (M₂). On the basis of total harvest for all the species, most efficient use of water occurred at the M₀ irrigation level. Also, most efficient use of water occurred prior to the first harvest and least efficient use usually occurred during the period after the first harvest but prior to the second harvest. Ladino clover and ladino-orchardgrass (Trifolium repens-Dactylis glomerata) harvested to simulate pasture were less efficient in using water than the other forages which were managed for hay. Alfalfa swards (Medicago sativa) managed for hay were more efficient than the other swards and the legume-grass combinations differed only slightly from legumes alone. Measured values for rates of moisture depletion per day of all unirrigated forages were generally smaller than values computed by using the Blaney-Criddle formula. The measured values of the irrigated forages approached the Blaney-Criddle values more closely.
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