Effect of potassium fertilisers on crops grown on saline soils

Abstract

Two locally cultivated crops lettuce (Lactuca saliva) which is moderately salt sensitive and barley (H ordeum vulgare) which is moderately salt tolerant, were grown in pot experiments containing 3 kg of local soil in order to investigate the effect of potassium fertilisation on yield improvement of plants subjected to salinity. After a preliminary study on a local lettuce variety, the experiment was repeated on a ]oca 1 barley variety and on the 1oca] lettuce variety Two salinity ]evels 41mM an<l 80mM N~C'l nnd two levels of potassium fertiliser were used, l .25mM and 2.56mM K1S04. In these experiments there were three replications for each of the nine nutritional treatments-Control, KiSo, K1So, KoS1, KoS2, KiSi, K2S1, Ki S2, K1S2. Treatment was initiated 14DAS for harley and 34DAS for lettuce. Plant heights were recorded weekly and finally the dry mass of the plants and grains or seeds produced were used as growth indices. Analysis revealed that for barley salinisation at both levels improved dry mass and plant height over that of the control and that fertilisation of both salinity treatments was beneficial only at the low potassium level, however this nutti1ionul treatment fuiled lo raise grain quality to control levels. Similar results were obtained from the experiments on the local lettuce variety. Salinisation of 43mMNaCl increased dry mass and final plant height and fertilisation of this salinity level with both potassium levels resulting in an additional increase in yield. Fertilisation of the 80mMNaCl treatments with both levels of K2S04 caused further yield depression. Seed quality was adversely affected in all the salinity treatments .