Potato is the fourth most important crop and consumed all around the world and is one of the main favorite vegetable in Ethiopia. However, the national productivity is very low as compared to the potential of the crop. One of the main reason for low productivity is low soil fertility. Hence, a field experiment was conducted from 2016-2018 with 9 combination of nitrogen, phosphorous and sulfur fertilizers arranged in randomized complete block design with three replications to assess response of potato to these rates. The application 110-19.74-50.8 kg•ha -1 N 2 /S 2 /P 2 O 5 fertilizer delayed days to flowering and maturity by 8 and 11 days at Darark and 10 and 14 days at Dabat. However, it increased plant height and number of stems per plant, which may positively contribute to increased photosynthetic area. The application of these fertilizers advanced marketable tuber yield by 153% and the total tuber yield by 86.6% relative to unfertilized plants. Furthermore, the partial budget analysis data showed that the highest net benefit and marginal rate of return (4453.6%) was obtained from 110-19.74-50.8 kg ha -1. Therefore, the current study results is indicative that potato can grow well and provide better yield at Dabat, Dabark and similar agro ecology by using 110-19.74-50.8 kg ha -1 N 2 /S 2 /P 2 O 5 , respectively.

The purpose of this research was to determine the optimum dehydration temperature and time length for a better physicochemical quality of tomato powders. The treatments consisted of 70, 80 and 90°C dehydration temperatures and 9, 11, and 13 h time durations arranged in a completely randomized design (CRD) with triplicates. The inlet and outlet air temperatures of the hot air oven dryer were about 24 and 60°C respectively with an air velocity of about 2.9 m/s. Fresh tomatoes were used as a control. It has been observed that the major quality parameters of tomato powders were significantly increased with increasing dehydration temperature and time up to 80°C and 11 h respectively. When the dehydration temperature and time length went beyond 80°C and 11 h respectively, the quality of tomato powders declined. The maximum TSS content (7.433 °Brix), titratable acidity (0.4967), rehydration ratio (3.437), lycopene content (0.4512 mg/100 g) and lower pH value (4.433) were obtained at 80°C temperature and 11 h dehydration time. Moisture content was reduced to 11% at the same dehydration temperature and time length without considerable physiochemical quality loss. Inversely, vitamin C was reduced as dehydration temperature and time increased. Generally, the results of this study showed that dehydration of tomatoes with 80°C and 11 h temperature and time length respectively, provides better physicochemical quality of tomato powders. Future research is suggested on consumers' acceptance of dehydrated tomato powders.

Lettuce (Lactuca sativa L.) is one of the most popular salad crops and occupies the largest production area among salad crops in the world. However, production of lettuce can be limited due to lack of improved production techniques. Farmers in northwestern Ethiopia didn’t apply mulching for lettuce. A field study was conducted at Teda in 2018 to evaluate the effect of different mulching materials on yield and yield component of lettuce (Lactuca sativa L.) under irrigation. Five mulching materials used as a treatment viz: white plastic, black plastic, teff straw, chickpea straw and control (without mulch). The treatments were laid out in Randomized Complete Block Design (RCBD) with four replications. Application of mulching increased leaf width, leaf number, plant height, biological yield, root volume, dry matter and plant height. The highest and lowest yield was recorded for black plastic mulch and no mulch, respectively. The study revealed that the black plastic is the best mulching material among the organic and inorganic once for the production of lettuce in the study area.