Bread wheat (Triticum aesativum L.) is one of the most important cereal crops produced and consumed in Ethiopia. It stands third among cereals in terms of area cultivated annually and grain production next to barley and tef (CSA, 2016). Traditionally, wheat grains are used to prepare household bread, beverage and pancake. It is also processed in factories to produce flour for commercial production of bread for consumers in cities and towns. Despite its importance and growing demand for bread wheat in Ethiopia, its production and productivity are desperately very low. The current average productivity of wheat is below 3 t ha− 1 (CSA, 2016) despite its potential productivity greater than 5tha− 1 (Birhan et al., 2016). Consequently, the country imports large amounts (30–50% of total annual demand) wheat grains every year from abroad to meet domestic demand (Minot et al., 2015) which has grave consequence on foreign currency reserve of the country.
Declining soil fertility is one of the major factors that accounts for low productivity of wheat in Ethiopia (Yesuf and Duga, 2000; Amsal et al., 1997) which is caused by soil erosion, continuous cropping of same land year after, deforestation, depletion of organic matter is the main challenge not only to wheat production but also to the production of all crops (Birhan et al., 2016). It is an issue of great concern in Ethiopia as soil nutrient depletion is becoming severe and severe with time since little efforts are being made to reverse the problem.
There were several occasions whereby the yields of crops produced per unit area were increased by more than 100% in many areas of Ethiopia (Kelsa et al., 1992). For example, Gebreyes (2008) reported that application of 92 kg N ha− 1 increased grain yield of wheat by 185% over the control in central Ethiopia. Thus, due to dramatic positive impact, there was a steady increase in annual fertilizer consumption from 14000 mt in 1974/75 to 500, 000 mt in 2010 (IFPRI, 2012). However, crop yield gain due to N and P fertilizer application is declining over time despite steady increases in fertilizer consumption in Ethiopia (IFPRI, 2010). Declining crop yield responses to N and P fertilizers is attributed to decreasing soil organic matter (SOM) content (IFPRI, 2010). Moreover, depletion of other nutrients in addition to N and P could be additional factor for decreasing response of crops to N and P fertilizers (Wassie and Tekalign, 2013).
Sulphur (S) could be one of the most likely limiting nutrients in Ethiopia soils. Sulphur is one the plant essential nutrients required for their growth and developments and a building block of protein, key ingredient in the formation of chlorophyll (Duke and Reisenaue, 1986). It plays important role in protein synthesis as it is the component of two essential amino acids called cysteine and methionine. It is also a key component of many enzymes in plants. For instances, the S is important component of nitrogenase enzyme, an enzyme that fixes atmospheric nitrogen in legume-rhizobia biological nitrogen fixation system. Sulphur also interacts with nutrients in soils and the interaction could be positive or negative depending on several factors. For example, Aulakh and Chhibba (1992) observed enhanced root uptakes of P and S when both nutrients were supplied at low rates. Increased uptake and assimilation of N by crops has reported by with adequate than low supply of S (Kumar et al., 2012). Thus, deficiency of S in soils will have adverse consequences on protein synthesis, biological nitrogen fixation, chlorophyll synthesis, enzyme activity etc. ultimately compromising yield and quality of crops. It has been reported that S deficient plants exhibits reduced plant height and stunted growth, reduced tillers, spikelets and delayed maturity. Sulfur deficient plants are shown to be less resistance under stress conditions (Doberman and Fairhurst, 2000).
In this regards, emerging research evidences are showing that S one of the nutrients becoming deficient in some Ethiopian soils limiting crop production. For instance, Assefa (2016) studied the response of wheat to S application on 18 sites reported that wheat significantly responded to S fertilizer application in 72% of experimental sites. He further reported that soils of responding sites had S content below critical level (11–13 mg kg− 1 SO4 − 2-S) for optimum production of wheat.
However, the current assertion that S is becoming nutrient in some Ethiopia soils is based on results of only few experiments and thus it can’t be conclusive and definitive that Ethiopian soils are deficient in S. Thus, further research is needed to be done to verify the existing claims that S limiting in Ethiopian soils in different soil types. In this regard, there is little or no information so far on the response of wheat to S application in Basona worena district of north Shewa, Ethiopia. Thus, experiment was conducted to determine effects of S application under balanced fertilization on the growth, yield components and yield of wheat and to determine economic feasibility of S fertilizer application of wheat grown on famers’ at Basona werna District under two soil types of Vertisols and Cambisols.