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This investigation documents the relationships between anomalous North Pacific sea-surface temperatures (SSTs) and the occurrence of growing season extended dry spells on the Canadian Prairies. Results show a significant correlation between extended dry spells and a positive SST anomaly gradient in the east-central North Pacific. The gradient exists between an area of anomalously cold water in the east-central North Pacific in the area 30"N40°N latitude and 165"W-l35"W longitude, and an area of anomalously warm water along the central west coast of North America in the area 45ON-55"N latitude and 130"W-l25"W longitude. A probability model shows that the longer this positive gradient persists,. the greater the probability of a major extended dry spell on the Canadian Prairies.

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The introduction of hybrid seeds in India has doubled the yield of foodgrains. The High Yielding Variety Seed Program (H.V.P.) has contributed to serious interregional disparities in agriculture. Surplus production of foodgrains is not the true measure of success of the Green Revolution; many areas in India remain unaffected by this program, and are still vulnerable to famines.

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Although dust storms are quite frequent in the Canadian Prairies, no scientific studies of the nature of dust storms of this area exist, to the authors' knowledge. This work is a preliminary step in depicting temporal and spatial variations of dust storms in the Canadian Prairies. Dust storms occur at least once to as often as five times per year, on average, in the agricultural prairies. This frequency indicates the risk of occurrence of the various impacts of dust storms, such as serious soil erosion. Dust storm frequencies exhibit a pronounced peak in the spring and a weak secondary peak in August. The spatial pattern of dust storms indicates a low risk of occurrence in the northern agricultural prairies and the highest risk in the south central prairies. Knowledge of these patterns in space and time should facilitate the control or avoidance of such impacts of dust storms as wind erosion of soils, crop damage, air pollution, and general environmental degradation. Studies should be carried out to further investigate the relationships of climatic factors with dust storms as well as their linkages with other environmental aspects.