Soil is a non-renewable or finite resource and is the bank of nutrients for plant growth. Most soils in the tropical region including Ethiopia are highly weathered and infertile due to lower organic matter content and open nutrient cycling systems. These led to soil fertility depletion and crop productivity reduction in the country by different soil degradation agents. Therefore, the objective of this paper is to review soil fertility depletions and its management options under crop production perspectives in Ethiopia. The major drivers of soil fertility depletion are population pressure, land use pattern, free grazing of animals, lack of energy sources, land ownership and poor government policy problems. The major causes of soil fertility depletion are inadequate fertilizer use, complete removal of crop residues, continuous cropping systems, climate and soil types, lack of proper cropping systems and soil erosion and continuous cultivation. The promising technologies for improving soil fertility are integrated nutrient management, crop residue management, green manuring and cropping sequences, management of farmyard manure, applications of chemical fertilizers and soil amendments, agroforestry practices, applying conservation agriculture and application of soil-water conservation practices. Therefore, it needs a great attention by the community and the government to use innovative soil fertility management options to sustain soil fertility and crop productivity for the coming generations in the country forever enhancing nutrient input and recycling through following closed nutrient management systems in the cultivated lands.

Food and nutrition security is not only addressed by increasing production alone, it should also ensure by reducing food loss. Onion has a great contribution to both economic and health issues, however, its production and productivity in the country is low. Thus, the study was initiated to identify multiple constraints on onion production and postharvest handling practices and to determine the extent of postharvest loss along the supply chain in northwestern Ethiopia. The survey was conducted on production, marketing, and consumption at farm, wholesale, retailer, and consumers level. The multistage sampling procedure was employed. The present results revealed that sex, age, educational level, production experience, land covered by onion, and household size has a significant influence on onion production. Sex, age, education level, active household size, selling experience, amount purchased, and storage duration have a significant association with onion production and postharvest loss. Major onion production and post-harvest loss constraints were high perishability, nature of the crop, market, linkage problem and low market price, lack of awareness of using post-harvest technologies, absence of better storable varieties, shortage of fertilizer access, disease and insect pests. The whole purchased produce never reached the consumer's hands. The total postharvest loss of onion at the farmer, wholesale, retail, and consumer level was found to be 29.775%, of which the higher proportion of losses (35.5%) was observed at the farmer's level. Based on the findings of the present study, onion producers were challenged by timely and adequate supplies and unfair, high cost of major production inputs, and high post-harvest loss. Therefore, producers and handlers in each supply chain need to be trained on affordable and applicable postharvest technologies. In addition, continuous capacity-building training, improving infrastructures, and input access along the supply chain should be designed and implemented to improve better crop management and postharvest handling practices. Moreover, marketing cooperatives working on onion postharvest handling and marketing systems should be functional to absorb surplus production and ensure continuous supply to the market. Thus, meaningful interventions in the development and implementation of policy on sustainable production, handling practices, and supply of onion should be designed.

Field experiment was conducted during the 2019 irrigation season to evaluate the growth and tuber yield responses of potato varieties in the highlands of Ethiopia. The treatments consisted of four potato varieties (Belete, Shonkolla, Gudanie and Local) and three seed tuber sizes (small (31.5 ± 2.5 g), medium (57 ± 2.5 g) and large (77.5 ± 2.5 g). The experiment was laid out in factorial arrangement using randomized complete block design with three replications in factorial arrangement. The results showed that, variety and seed tuber size in their main effects significantly influenced almost all the tested parameters of potato. Tuber size and variety also interact to influence days to 90% maturity, plant height, large-sized tuber yield, marketable and total tuber yields. Large-sized seed tubers of Belete and Gudanie varieties recorded the highest marketable tuber yields of 39.13 t ha^-1 and 38.63 t ha^-1, respectively while the lowest (12.12 t h^-1) was recorded from local variety planted using small-sized seed tubers. Large-sized seed tubers of Gudanie variety gave the highest net benefit (131,376.50 ETB ha^-1) with unacceptable marginal rate of return (<100%) while Belete variety with small-sized seed tubers recorded the highest marginal rate of return (1657.14%) with relatively lower net benefit. Optimizing the seed tuber size is therefore necessary to increase productivity and profitability of potato production. In this regard, Gudanie variety combined with medium-sized seed tuber recorded relatively higher net benefit (123,410.80 ETB ha^-1) with acceptable marginal rate of return (100.9%). Accordingly, production of Gudanie variety using medium-sized seed tubers (57 ± 2.5 g) could be recommended for the economical production of potato and improvement of the income and food security of the smallholder farmers in the study area and areas with similar agro-ecologies.

Field experiments have been conducted with the objective of identifying optimum rate of the newly introduced NPS fertilizer for profitable production of potato at Koga Irrigation Scheme, Northwestern Ethiopia. Six NPS fertilizer rates and three potato varieties which were factorial combined and laid down in Randomized Complete Block Design in three replicates were tested on two different farmlands. Most growth, yield, and yield components of potato were increased with increasing rates of NPS fertilizer which differed with varieties and locations. Highest marketable tuber yields of Belete (55.37 t ha⁻¹) and Gudene (46.83 t ha⁻¹) varieties were recorded with the of 283.75 kg ha⁻¹ NPS fertilizer in location I (soil with low phosphorous content). The yields of Gudene variety recorded at the range of 181.6 to 283.75 kg ha⁻¹ NPS fertilizer were however statistically similar. Farmer`s local potato variety on the other hand recorded the highest marketable tuber yield (28.98 t ha⁻¹) in location II (soil with high phosphorous content) supplied with 227.0 kg ha⁻¹ NPS which was similar with yields at the range of 102.12 to 283.75 kg ha⁻¹ NPS fertilizer. On soils with low phosphorous content, production of Belete, and Gudene varieties with application of 283.75 and 181.60 kg ha⁻¹ NPS fertilizer rates, respectively, are recommended while on soils with high phosphorous content production of local, and Gudene varieties supplied with 136.20 and 181.60 kg ha⁻¹ NPS, respectively, are recommended for higher profitability of potato production at Koga Irrigation Scheme.