SUMMARYMaize (Zea mays L.)–common bean (Phaseolus vulgaris L.) intercropping is a recent practice in north-western Ethiopia and there is limited information on its productivity. A field experiment was conducted at South Achefer and Mecha in north-western Ethiopia during the 2012 and 2013 crop growing seasons to determine combinations of intercrop planting arrangement (IPA) with nitrogen (N) and phosphorus (P) rates for optimizing maize–common bean intercrop productivity and profitability. Treatments consisted of factorial combinations of two IPA (single row of common bean between maize rows and paired rows of common bean between paired rows of maize), two N rates (92 and 128 kg N/ha) and two P rates (20 and 40 kg P/ha). A sole crop maize with recommended fertilizer rate of 128/40 kg N/P/ha was used as a control treatment. The treatments were laid out in a randomized complete block design with three replications. Results indicated that land equivalent ratio was more than unity, and the intercrop system was 20% more productive relative to the sole crop. Maize equivalent yields were highest for most of the intercrop treatments relative to mono-crop maize with yield advantage of 14% from single row IPA with 128/20 kg N/P/ha. Single row IPA with 128/20 kg N/P/ha and paired row IPA with 92/20 kg N/P/ha increased financial returns by 16 and 8% relative to sole crop maize, respectively. Smallholder maize-based cropping of north-western Ethiopia could be nutritionally, agronomically and financially improved through maize–common bean intercropping of single row IPA with appropriate nutrient management.

Nitrogen is a critical yield-limiting plant nutrient for crop production in Ethiopia. The demand for synthetic fertilizer is significantly increasing. Urea is the main source of synthetic nitrogen fertilizer that mainly applied in the surface resulting in significant nitrogen loss. UREA stabil fertilizer is urea with N-(n-butyl) thiophosphoric triamide (nNBPT) that reduce the rate of urea hydrolysis by urease to reduce nitrogen loss and increase crop productivity. The research was conducted in Yilmana Densa district, Ethiopia for two years to evaluate the performance of UREA stabil compared to urea. The research evaluated the effect of UREA stabil fertilizer technology on bread wheat and tef at Nitisol and Vertisol. The finding of this research denies our prior hypothesis that UREA stabil could give better yields of tef and wheat with lower rates of nitrogen at single application rate compared to urea. Reducing the amounts of nitrogen by one third using UREA stabil resulted in an intolerable significant yield penalty for all the study sites and both years on wheat. Both the grain and straw yields were increased by splitting the UREA stabil , indicating that the enzyme that hydrolysis urea was merely inhibited. Considering a nonsignificant yield difference between the conventional urea and UREA stabil for all crops, soils, rates, and forms of applications UREA stabil is not promising. Further research with different rates of nNBPT as well as different nitrification inhibitors