Potato is one of the priority vegetable crops in the highlands of Eritrea growing as a key component in the livelihood systems of farmers. Potato requires a variety of balanced plant mineral nutrients for growth and development without which yield and qualities of tubers are reduced. Potato growers in Eritrea commonly use Di-ammonium Phosphate, Urea and Farmyard manure while potassium fertilizers are overlooked assuming that the soil is developed from K rich parent material and contains sufficient amount of K to support crop growth. However this assumption is based on the result obtained forty-seven years ago. As a result the yield and quality of potato produced is very low as compared with international standards. Therefore the present experiment was conducted to assess the effect of potassium levels on growth and productivity of potato varieties at Hamelmalo Agricultural College, Eritrea. The experiment was conducted in factorial Randomized Complete Block Design with fifteen treatment combinations of three varieties (Ajiba, Zafira and Picasso) and five potassium levels (0, 75, 150, 225 and 300 kg K2O/ha) replicated thrice. The results of the study showed that both variety and potassium had significant effect on growth and yield parameters. Aerial stem number, leaf number per plant and plant height were increased with increasing K levels from 0 to 150 kg while number of days to maturity was increased in the range of 0 -300 kg K 2 O/ha. The result also indicated that variety Ajiba treated with 300 kg K 2 O/ha produced significantly highest tuber weight (1.14 kg) per plant and tuber yield of 49.38 t/ha. The economic analysis result revealed that maximum gross margin 13,665.816 USD/ha was obtained from the application of 300 kg K 2 O/ha. On the whole, it gives an impression that using potassium fertilizer according to soil requirements will have good influence on growth and tuber yield.

Potassium has significant effect on quantity and quality of tomato yield because of its vital roles in photosynthesis, favoring high energy status and appropriate nutrient translocation and water uptake in plants. However, little is understood or it is being overlooked under Eritrean condition. Besides, poor soil fertility is among the major production constraints in Eritrea. The field experiment was therefore conducted to investigate the effect of potassium levels on productivity and fruit quality of tomato at Hamelmalo, Eritrea. The experiment was conducted in Randomized Complete Block Design with nine potassium levels (0, 50, 100, 150, 200, 250, 300, 350 and 400 kg K 2 O/ha) replicated thrice. Data was collected on yield and fruit quality parameters and they were subjected to one-way analysis of variance (1-way ANOVA). The results of this study revealed that potassium had significant effect in all yield and quality parameters studied. Fruit diameter, fruit weight per plant, total yield, total soluble solids, specific gravity and fruit dry matter content showed significant increase with an increase in potassium level from 0 to 150 kg K 2 O/ha and thereafter decreased while fruit moisture content was increased in the range of 150 -400 kg K 2 O/ha. As a result, highest fruit weight (1.39 kg/plant), fruit yield (15.45 t/ha), total soluble solids (3.84 o Brix), specific gravity, (1.46) and fruit dry matter (5.68%) were recorded from 150 kg K 2 O/ha. Therefore it is recommended that potassium fertilizers should be used and balanced NPK fertilizers should be applied to improve yield and quality of tomato produced.

A field experiment was carried out Rabi season of 2017-18 at research farm of ICAR-NRCSS, Ajmer, Rajasthan to study the growth, yield and essential oil characterization of coriander variety Ajmer Coriander-2 (ACr-2) as influenced by nutrient levels and crop geometry. The experiment was laid out in Factorial Randomized Block Design with four replications. The experiment was comprises three treatment of each crop geometry and nutrient management. Crop geometry G1 (30 cm x 15 cm), G2 (30 cm x 10 cm) and G3 (30 cm x 5 cm) with nutrient levels N, P2O5 and K2O of kg/ha F1 (40:20:10), F2 (50:25:15) and F3 (60:30:20). The results revealed that the maximum plant height (91.38 cm), primary branches per plant (10.90) and secondary branches per plant (13.28) were recorded with application of 60:30:20 kg/ha NPK and crop geometry of 30 cm x 10 cm. Similar trends were found in yield attributes like number of umbel per plant (34.09) and number of umbellates per umbel (5.91). Seed yield per hectare (1271.25 kg/ha) and essential oil yield (6.74 kg/ha) was also observed with application of 60:30:20 kg/ha NPK with crop geometry of 30 cm x 10 cm. Based on the results it is concluded that nutritional level of 60:30:20 kg/ha NPK with crop geometry of 30 cm x 10 cm is better for realizing higher seed yields of coriander variety ACr-2.