Economic significance of dry-land farming in the arid northern Negev of Israel

The effects of annual precipitation and its distribution on grain yield of dryland cereals

“…Apparently, this and other environmental factors are the reasons for inconsistent results on critical growth stages of cereals for moisture stress (Day et al 1978;Day & Intalap, 1970;Lomas & Shashoua, 1973;Lomas, 1972). In Cyprus most of the dry matter of cereals is produced during March and April.…”

“…The varieties grown under dryland conditions. highest average yield response to irrigation in Negev was obtained during the first 40 days after planting (Lomas, 1972). In another study Day et al (1978) using mobile shelters at Rothamsted found large decreases in grain yield of barley but little evidence that any developmental stage was particularly sensitive to drought.…”

“…In such areas only a (1973) reported that annual rainfall alone explained narrow range of crops, mainly cereals, can be 52 and 66% of the variation in wheat yields and the grown which, however, very frequently fail to give distribution of rainfall explained a higher percenteconomic yields, age, 61 and 78%, respectively. However, the In a review of literature relating to the effect of improvement in the correlation was not significant, precipitation on grain yield of rainfed cereals Additional rainfall above the average prior to sow- Lomas (1972) and Lomas & Shashoua (1973) re-ing or during the period of germination and initial ported that variation in rainfall accounted for 55-growth was beneficial to the crop, while above-66% of the variation of wheat yield in Texas, 36-average rainfall during mid-winter (end of January-80% in the semi-arid Great Plains of U.S.A., 37% February) and the end of the growing season in South Dakota, U.S.A., and Saskatchewan, (March-April) affected the crop adversely. In Canada, 51 % also in areas of Canada (June-July another Negev area they found positive effects of rainfall), 52-66%, 77% and 61-79% in different additional rainfall during November and April but studies in Negev areas in Israel.…”

“…In another study Day et al (1978) using mobile shelters at Rothamsted found large decreases in grain yield of barley but little evidence that any developmental stage was particularly sensitive to drought. Other studies reviewed by Lomas (1972) showed that the most important time for additional moisture is between shooting and the flowering stage.…”

A Comparison of Statistical and Soil Moisture Modeling Techniques in a Long-Term Study of Wheat Yield Performance Under Semi-Arid Conditions

“…Analysis by statistical methods, first tried by Fisher (1924), were used by Staple & Lehane (1954), Gangopadyaya & Sarker (1965), Lomas (1972) and others. In view of the economic importance of wheat, and the fact that it is one of the few crops to be grown without irrigation even in arid regions, it has been the subject of numerous studies relating crop yield to rainfall.…”