Contemporary Global Issue of Rising Water Scarcity for Agriculture: The Quest for Effective and Feasible Soil Moisture and Free-Water Surface Conservation Strategies (Report‪)‬

1. Introduction Soil moisture is, perhaps, the single most critical factor in crop production. Its status determines greatly the proportion of the year during which the soil is cultivated with the purpose of starting a new crop life cycle. This constraint is encountered not only in arid and semi-arid regions but also in sub-humid and humid regions where, according to FAO [1], the rains are partitioned into "productive" and "unproductive" water flows. In these regions where there is a theoretical need to dispose of excess water, Aina [2] argued that dry periods with water deficit frequently occur and cases of positive responses to moisture conservation techniques are common. Aina [2] noted that in rainfed systems, the constraint is not only the erratic rainfall distribution, but also the amount of rainfall that could be retained in the active root zone. This stored water, which is affected less in drier regions and more in wetter regions by deep percolation, is needed to survive drought stress period. Deep percolation is in turn affected by soil texture, among other factors. It seems that the epicenter of this agronomic problem is low soil water storage, and therefore should be an issue of major concern. Even in wet regions where the crop water requirements might be sufficiently met by rain input, the quantity of water stored in the root zone after cessation of the rains is always too small to permit all-year-round crop production.