2. Various management practices based on reducing the salt zone for seed germination and seedling establishment: The early seedling establishment and tillering phase are generally the most sensitive stages to salinity. Any management practice that could provide an environment of reduced salt concentration during these stages would mitigate the salinity effects and benefit the crop by promoting plant densities and early seedling growth. A number of approaches have been used.
2.1. Scraping and removal of surface soil: Due to continuous evaporation the salt concentration is the highest in the surface soil. The top soil can be scraped and transported out of the field. The practice has been used in many areas of the world (Qureshi et al., 2003).
2.2. Pre-sowing irrigation with good quality water: Where available, irrigation with good quality water prior to sowing helps leach salts from the top soil. This helps in promoting better seed germination and seedling establishment. The benefits of this practice were documented in a long-term study by Goyal et al (1999 a,b).
2.3. Appropriate use of ridges or beds for planting: The impact of salinity may be minimized by appropriately placing the seeds (or plants) on ridges. Where exactly the seeds should be planted on the ridge or bed will depend on the irrigation design. If the crop planted on ridges would be irrigated via furrows on both sides of the ridge, it is better to place plants on the ridge shoulders rather than the ridge top because water evaporation will concentrate more salts on the ridge top or center of the bed. If the crop is irrigated via alternate furrows, then it is better to plant only on one shoulder of the ridge closer to the furrow that will have water. For additional benefits, this approach may be combined with pre-irrigation (2.2) via furrows or sprinklers which will help reduce salt concentration in the area where seeds or plants are to be placed.
2.4. Planting into a pre-flooded field: An interesting approach has been widely used in the San Joaquin Valley of California to grow safflower crop on salt affected soils. Prior to planting, the field is flooded with good quality water. Just as most of the water has percolated into the soil and only a few millimetres of standing water is left, the seeds are flown over the field via an aircraft. The seeds traveling under the force of gravity get imbedded into the muddy soil surface where the salt concentration is expected to be the lowest. The approach has provided good seed germination and seedling establishment (Goyal et al., 1999 a,b).
2. Various management practices based on reducing the salt zone for seed germination and seedling establishment: The early seedling establishment and tillering phase are generally the most sensitive stages to salinity. Any management practice that could provide an environment of reduced salt concentration during these stages would mitigate the salinity effects and benefit the crop by promoting plant densities and early seedling growth. A number of approaches have been used. 2.1. Scraping and removal of surface soil: Due to continuous evaporation the salt concentration is the highest in the surface soil. The top soil can be scraped and transported out of the field. The practice has been used in many areas of the world (Qureshi et al., 2003). 2.2. Pre-sowing irrigation with good quality water: Where available, irrigation with good quality water prior to sowing helps leach salts from the top soil. This helps in promoting better seed germination and seedling establishment. The benefits of this practice were documented in a long-term study by Goyal et al (1999 a,b). 2.3. Appropriate use of ridges or beds for planting: The impact of salinity may be minimized by appropriately placing the seeds (or plants) on ridges. Where exactly the seeds should be planted on the ridge or bed will depend on the irrigation design. If the crop planted on ridges would be irrigated via furrows on both sides of the ridge, it is better to place plants on the ridge shoulders rather than the ridge top because water evaporation will concentrate more salts on the ridge top or center of the bed. If the crop is irrigated via alternate furrows, then it is better to plant only on one shoulder of the ridge closer to the furrow that will have water. For additional benefits, this approach may be combined with pre-irrigation (2.2) via furrows or sprinklers which will help reduce salt concentration in the area where seeds or plants are to be placed. 2.4. Planting into a pre-flooded field: An interesting approach has been widely used in the San Joaquin Valley of California to grow safflower crop on salt affected soils. Prior to planting, the field is flooded with good quality water. Just as most of the water has percolated into the soil and only a few millimetres of standing water is left, the seeds are flown over the field via an aircraft. The seeds traveling under the force of gravity get imbedded into the muddy soil surface where the salt concentration is expected to be the lowest. The approach has provided good seed germination and seedling establishment (Goyal et al., 1999 a,b).
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