EVALUATION OF NITROGEN FERTILIZER, LIME AND SOIL-WATER EFFECTS ON THE YIELD AND MALTING QUALITIES OF BARLEY (Hordeum vulgare L.)

Abstract

Barley (Hordeum vulgare L.) is a cereal crop that grows over a wide range of environments and in Kenya it is grown primarily for malting. Barley requires adequate nitrogen (N) for good grain yields and quality malting, but the balance between adequate and excessive N is important therefore an experiment was set up between July 2011 and July 2012 to address the problems of N fertilizer use and soil moisture effects on grain yield and malting qualities. The experiment was conducted at medium altitude at University of Eldoret (Chepkoilel) (2185m asl) and at high altitude in Mau-Narok (2740m asl). The objective was to evaluate effects of nitrogen fertilizer rates, liming and varying soil water on the grain yield and malting qualities of barley. The experiments were done in the field and in the greenhouse. For the field experiment, nitrogen as C.A.N fertilizer was applied at 5 levels 0, 30, 40, 50 and 60Kg N/ha, all at planting. Phosphorus inform of TSP at 45 Kg/ha as P205, and potassium in form of muriate of potash at 35 Kg/ha as K20, were applied both as blanket in plots with nitrogen treatments, and as a treatment. Lime was applied at 2 levels (0 & 1.5 t/ha). Split plot arrangement in RCBD design was used in the field. Two different experiments were conducted in the greenhouse; the first one being a simulation of the field experiment which had similar treatments as those in the field. The second greenhouse experiment was a split-split arrangement in CRD design, with 3 soil water contents (field capacity, 80% field capacity and 50% field capacity) applied in 4 nutrient types (nitrogen, phosphorus, lime and control having all combined) tested on the two site soils. The results indicated the soils of the two sites were acidic and deficient in phosphorus. Mau-Narok site had more soil N than University of Eldoret. The effect of Nitrogen on grain yield was highly significant (P 0.001). Increasing N rates beyond 40Kg N/ha increased the grain protein content beyond the malting range. Effect of lime on grain yield in the field was significant at (P 0.01) while (P 0.05) in the greenhouse for both site soils. Lime treatments had higher grain protein contents than non-limed ones but not significantly different. Lime-nitrogen interaction on kernel weight was highly significant (P 0.001) but not significant for grain yield. The differences in grain yield, kernel weight and biomass due to soil type were highly significant (P 0.001).There was a significant relationship (P 0.001) between soil moisture content and lime on barley growth. Limed treatments of both site soils utilized less water to produce mature grains compared to the un-limed ones. The effect of soil moisture levels on biomass and tillering was highly significant (P 0.001). Application of lime in combination with N rates at 30 and 40 N Kg/ha produced best results for grain yield (>7 t/ha for both field and green house), biomass, kernel weight and grain crude protein (10-13.5 %) with soil moisture contents of between field capacity and 80% field capacity being ideal for barley growth on both soils. Nitrogen rates at 30N and 40 N Kg/ha produced highest grain yield, highest kernel weight and ideal maltable grain protein content for both site soils and therefore was recommended as optimum agronomic rates for both sites. In addition, liming was recommended for Chepkoilel while increase in phosphorus use for Mau-Narok.