1. Rain-fed agriculture has failed to provide even the minimum food requirements for the rapidly increasing populations of SAT.

2. Lack of suitable technology for soil and water management and crop production systems.

3. Precipitation exceeds potential evapotranspiration at least 2 and at most 7 months.

4. Soils of shallow depth with limited water-holding capacity.

5. Rainy seasons are brief, rainfall patterns erratic and brief or extended droughts frequent.

6. High intensity storm cause runoff and erosion.

7. Only a portion of water available for crops.

8. During past 30 years, population of SAT doubled.

9. Tremendous increase in cropped area and livestock numbers.

10. Steep and erodible lands frequently being overcropped and overgrazed.

11. Forest land denuded.

12. Decreasing productivity of land increases the quest for more land.

13. Two major problems:

• 1. Low and unstable crop yields
• 2. Accelerating rate of soil erosion

1. Crises and emergency programs.

• During droughts and associated food crises, large sums of money are frequently spent for hastily conceived programs in various types of famine relief
• Sahel region of Africa today

• Includes a wide variety, from large gravity irrigations to small runoff storage (called tanks in India) and wells
• Wells are owned mostly by individuals.  However, the water may be drawn from an area exceeding the individual property boundaries
• Existing small runoff storage tanks are characterized by shallow depths
• Present water resource development in the SAT results in ?small? islands of relative wealth in a ?sea of poverty.?

• Total moisture storage capacity of the soil exceeds normal effective annual rainfall in many temperate semi-arid zones
• In SAT, total seasonal rainfall is often several fold the capacity of root zone to store moisture
• High intensity rainfall frequently exceeds the soil infiltration rate
• Vertisols in India, high intensity rainfalls cause soil erosion, surface sealing, and drastically reduces infiltration

• Well designed and maintained systems of bunds have been found to decrease soil erosion on a watershed basis
• Substantial erosion and sedimentation may occur in the areas between bunds
• Often farmers will not allow the contour bund to pass through their fields
• Cropping by the contour bund resulted in a negative effect on total production from bunding

1. Strategy for research and development.

• Most severe constraint to the development of agriculture in the SAT is the lack of appropriate technology to make the best use of the available natural resources (climate and soils)
• Low effective rainfall combined with low water use efficiency results in a very low ?rainfall use efficiency? in most of the present farming systems
• New soil and water conservation technology must be associated with crop production systems which will provide immediate and clearly visible increases in yield levels and stability

• Watershed (catchment) is the natural focus for research on water management in relation to crop production systems and resource
• Cropped watersheds where velocity of flow of water is controlled
• Protection against soil erosion 

1. Studies on bed and furrow systems.

• Systems involving graded beds (ridges) separated by furrows which drain into grassed waterways
• The 150 cm bed and furrow system can be easily prepared and maintained with bullock-drawn implements
• Ridges or beds function as mini-bunds
• When runoff occurs, its velocity is reduced and infiltration opportunity time is increased
• Excess water is carried off the land in a large number of very small flows, minimize soil erosion, better infiltration
• Additional advantages of bed and furrow system:
• Only minor earth movement required
• Implementation with animal power
• Furrows guide for draft animals/speeds up planting-more uniform row spacings
• Top of beds dry out more quickly - earlier planting

• Runoff greatly reduced by improved management of deep vertisols

• Improved systems of farming used a much higher proportion of the rainfall for crop production than the traditional practices

• Results of supplemental irrigation to crops were quite spectacular

• Four phases:
• Variety
• Fertilization
• Soil and crop management
• Supplemental water (if needed)

• Rue's were higher on both soils in all cases where improved technology used
• Single crop sorghum in the post rainy season gave a Rue of only 9
• Rue's of from 12 to 58 with improved technology

1. Vertisols watersheds.

• Establish 150 cm bed and furrow system
• Kill weeds and stubble and cover cracks with cloddy mulch to conserve residual moisture
• Reshape beds after show in February - June period
• Apply starter fertilizer (1-2 weeks before planting) (0-18-46)
• Plant "dry" about 1 week before expected rainy season (Vertisols are sticky when wet)

• Establish bed and furrow system on a permanent basis
• After harvest, kill weeds and form rough cloddy surface
• Delay planting until after rains have moistened the soil to a depth of 15-20 cm

• Cultivate and hand weed early
• In intercropped systems, remove the cereal as soon as possible
• Remove light and moisture competition from the long duration crop
• Where ratooning sorghum, a few days delay in harvest reduces rotoon crop
• Remove monsoon crop as early as feasible and cultivate land between stubble