GROWTH AND YIELD RESPONSE OF POTATO (Solanum tuberosum L.) VARIETIES TO DIFFERENT LIME APPLICATION RATES AT EZHA DISTRICT, GURAGE ZONE, CENTRAL ETHIOPIA

Abstract

Potato is the most important tuber crop for attaining the food security and providing an economic return to growers and the country. However, production and productivity are far below the global average. This is mainly due to poor soil acidity management and a lack of high-yielding adaptable varieties to acid soil. Thus, a field experiment was conducted to evaluate the effect of lime rates on the growth and yield of potato varieties and to determine economically feasible rates of lime for better tuber yield. The experiment was conducted in Ezha district during the 2022 main cropping season. The treatments consisted of factorial combinations of three improved potato varieties (Gudene, Belete, and Dagim) and five lime rates (0.0, 1.5, 3.0, 4.5, and 6.0 t ha-1 ) laid out in a Randomized Complete Block Design with three replications. Data were collected on phenological, growth and yield parameters and analyzed using SAS (software version 9.3). Liming raises soil pH (5.10 to 6.5), CEC (36.0 to 47.0 Cmol (+) kg-1 ), Av. P (2.08 to 4.6 mg kg-1 ), base saturation (28.33 to 77.39%), Ca (7 to 29 Cmol (+) kg-1 ), and Mg (2 to7Cmol (+) kg-1 ) contents, but reduces aluminum (1.27 to 0.0 ppm and hydrogen ion (1.53 to 0.4 ppm) concentrations in acidic soils. The results of this experiment showed that the interaction between lime rates and varieties significantly influenced most growth and yield parameters of potatoes. As a result, the highest percentage (13.19%) of smallsized tubers was recorded from Gudene with 0.0 t ha-1 lime application rate. Similarly, the highest stem number (7.36), percentage of medium-sized potato tubers (44.88%), and the highest plant height (70.96 cm) were obtained from the Gudene variety with lime rates of 6, 1.5, and 6 t ha-1 , respectively. The combined effects of the 4.5 t ha-1 lime rate and Belete variety resulted in the potato's relatively high average tuber weight (93.29g). The highest leaf area index (1.53), the highest number of marketable tubers (12.57), and the largest number of total tubers (14.66) were obtained from a variety Belete interacted with 6 t ha-1 lime treatment combinations. The maximum unmarketable tuber yield (3.5 t ha-1 ) was obtained from the Dagim variety with 0.0 t ha-1 lime rate. The highest percentage of large-size tubers (81.32%) resulted from the Dagim variety with a lime rate of 6 t ha-1 . Statistically the highest marketable tuber yield (46.42 t ha-1 and 47.38 t ha-1 ) and total tuber yield (47.82 t ha-1 and 49.12 t ha-1 ) were obtained from the interaction of variety Belete with 4.5 t ha-1 and 6 t ha-1 , respectively. The partial budget analysis revealed that the combined application of variety Belete with 4.5 t ha-1 lime application rate resulted in the highest net benefit (465,259 Eth Birr ha-1 ) with an acceptable marginal rate of return (3063.41%) which can be provisionally recommended for smallscale potato producers (farmers) at the study area. However, further research would have to be repeated to get the best conclusive result and a sound full recommendation for a specific area.