Effect of saline waters on soil properties and plant nutrition in Kuwait

Abstract

A field and pot culture study was undertaken in an attempt to determine the effect of saline solabeya water on soil salination, gatch formation and plant uptake of nutrients. Three gatch and three sandy soil profile samples were used in this studyo The soil samples were virgin profile 'A' samples from the Experim.ental Farm Extension, cultivated profile 'B' samples from. the Experim.ental Farm and cultivated profile '0' samples from Bid'a Nursery of the Education Department. The gatch samples were collected from sites 'A', '0' and plot No.6, of the Experimental Farm. Extension, Bidta Nursery and Experimental Farm respectively. Three indicator plants Lettuce (Lactuca sativa, variety Great Lakes), green beans (Phaseolus vulgariS, variety Black Valentine), and Petunia (Petunia hybrida) were used. The effect of soil texture, change in the reaction of the medium, concentration of solabeya saline water and soil solution on gatch formation were studied. A coarse sandy subsoil horizon high in silica constituted the proper medium for gatch formation. The major cementing agents were silica and the carbonates and hydroxides of calcium and magnesium. Alumina, iron oxide and gypsum. playa minor role in cementation due to their low concentration. An increase in the alkaline reaction and concentration of the saline solution favored precipitation of potential cementing agents present as soluble constituents of the medium. The presence of gatch and use of solabeya saline water lead to the formation of saline perched water table and soil salination. Different irrigation waters, representing various dilutions of solabeya saline water were used for irrigation of pot cultures. Different increments of nutrient solutions, supplying nitrogen, phosphorus, P9tassium, calcium, magnesium, and sodium were applied to the respective treatments of the pot cultures. The development, sequence of appearance, and severity of visual symptoms of general salinity effect showed direct corrolation with salt sensitivity of the indicator plant and the degree of salinity of the medium. In all cases, the symptoms were earlier and more severe in bean, followed by lettuce and petunia. As a result of cationic and anionic antagonism and an increase in the salinity of the medium, plant uptake of N, P, Ca, K, Fe and Mn was reduced, as revealed by the level of these elements in the leaves of the indicator plants, whereas the levels of Mg, Na, B, Cl, and SO₄ increased in the leaves of the indicator plants. The application of different increments of N, P, Ca, and K to the respective treatments of the indicator plant cultures resulted in a relative increase in the level of these elements in the leaves and a specific decrease in the level of the antagonistic elements. But, due to the effect of the increase in salinity of the medium of the respective treatments, and decrease in yield of green weight, the level of these elements maintained a gradual specific decrease in. the leaves.