KVIRS

Improving the efficiency in soil water use and crop nutrient uptake can increase production. To achieve this efficiency gain, knowledge on the interaction of soil moisture and nutrient dynamics in relation to the farming system is a prerequisite. The spatial and temporal variation in soil moisture and nutrient availability needs to be analyzed in relation to existing nutrient management strategies (including nutrient fluxes and balances) to develop and target appropriate technical options. The Khanasser watershed has been selected as an integrated research site to address a range of problems that are characteristic of marginal dry lands such as severe seasonal drought, nutrient deficiencies (P, Zn, Fe etc.) and imbalances (alkalinity, salinity). Barley is one of the key crops of the region, providing food and feedstuff for small ruminants.

Nutrient availability is limited by low soil moisture (drought) and by unfavorable soil chemistry (pH, salinity). Increasing soil moisture will improve nutrient availability. Since rainfall is low, the cropped land in the valley bottom will depend on water influx from adjacent slopes. We hypothesize that slope characteristics (length, steepness, etc.) and slope use (vegetative cover, reforestation and water harvesting) will determine the extent of water supply to the valley bottomland and differ with regards to the distance of the cropped area from the slope as well as on physical soil characteristics (texture, organic matter).

Plants' ability to cope with drought and low nutrient availability is likely to increase with the crop plants capacity for nutrient acquisition and/or the supply of the limiting nutrient. Thus well-fed plants will develop a stronger root system to exploit the soil profile for moisture and be better able to adjust to drought stress through morphological as well as physiological response mechanisms (regulation of transpiration and water use efficiency, rooting depth, leaf rolling, etc.). Since some of the limiting nutrients (mainly P, Fe and Zn) may show little effect when surface applied (precipitation / immobilization under high pH conditions) and since low-input farmers are unlikely to supply large amounts of fertilizer to an inherently risky environment (uncertainty of the outcome of such an investment), we hypothesize that technologies that are acceptable and adoptable by the farmers must be low-cost and largely seed-based.

The choice of the option and its appropriateness to correct site - and system - specific nutritional disorders in barley are likely to depend on physical soil characteristics and the soil moisture content as well as its seasonal variations. These will vary in space and time.