Seed Placement

Obtaining a satisfactory stand is often a problem when furrow irrigating with saline water. Growers sometimes compensate for poor germination by planting two or three times as much seed as normally would be required. However, planting procedures can be adjusted to lower the salinity in the soil around the germinating seeds. Good salinity control is often achieved with a combination of suitable practices, bed shapes and irrigation water management.

In furrow-irrigated soils, planting seeds in the center of a single-row, raised bed places the seeds exactly where salts are expected to concentrate (Figure 3). This situation can be avoided using "salt ridges." With a double-row raised planting bed, the seeds are placed near the shoulders and away from the area of greatest salt accumulation.

Alternate-furrow irrigation may help in some cases. If alternate furrows are irrigated, salts often can be moved beyond the single seed row to the non-irrigated side of the planting bed. Salts will still accumulate, but accumulation at the center of the bed will be reduced.

With either single- or double-row plantings, increasing the depth of the water in the furrow can improve germination in saline soils. Another practice is to use sloping beds, with the seeds planted on the sloping side just above the water line (Fig. 3b). Seed and plant placement also are important with the use of drip irrigation. Typical wetting patterns of drip emitters and micro-sprinklers are shown in Figure 4. Salts tend to move out and upward, and will accumulate in the areas shown.