Soil salinity alkalinity effects on germination and seedling growth of vegetable crops in the Office du Niger zone

In 2010 and 2011, pot experiments were conducted at Niono Agronomic Research station to determine soil alkalinity/salinity effects on seed germination and seedling growth of vegetable crops. Three types of soil types with physical sign of salt effects were used for these experiments: salt affected black soil, salt affected white soil and soil presenting no physical sign of salinization. The test crops where 5 varieties of tomato, 5 varieties of cabbage, 5 varieties of onion, 5 varieties of okra and 2 varieties of red pepper. Three types of experiments were conducted: germination tests, seedling survival test and soil amendment test. The experiments were run in a randomized complete block design, using split pot treatment arrangements with soil types as main plot factors and crop varieties as secondary plot factors treatments. Each crop was grown in a separate experiment. The results of this study showed that the varieties of the different crop species generally are very sensitive to salt stress and none of them showed sign of resistance to salinity or alkalinity stress. While all species had high percent germination (95 to 98%) in the non-affected soil, none of them germinated in black or white salt soils indicating the seed quality was not a problem. Tomato, cabbage and onion are particularly sensitive to germination stage and seedling stage. Soil washing could mitigate salt effects on seedling growth but does not seem adequate for the total germination of seeds. Combination of organic amendments and soil washing reduced salt effects but did not insure satisfactory plant growth conditions. It was concluded that in the high alkaline soil, tomato, cabbage, onion and red pepper crops are not suitable.