Quality assessment and evaluation of irrigation water and soil used for maize (Zea mays L.) production in Boloso Sore district, southern Ethiopia

Poor quality of irrigation water and soil are among the major factors determining maize productivity in Ethiopia. This study assessed and evaluated the quality of irrigation water and soil under maize production in Soke and Woybo irrigation schemes in Boloso Sore district, Ethiopia. Four water samples per site per season were collected from the first point of the irrigation schemes and farm gate for dry and rainy seasons in 2019/2020. Soil samples of 108 were collected from 36 points, from which 18 composited samples were taken for laboratory analysis. Results show that irrigation water of the two schemes is non-saline (electrical conductivity  potassium (7.3 mg l−1) > calcium (6.2 mg l−1) > magnesium (3.1 mg l−1). Moderate to severe sodicity (sodium adsorption ratio of 10.9) was also recorded. Sulfate, nitrate, and phosphate contents in water were trace, and increased during rainy seasons in downstream. Textural classes of soils are clay loam to clay, and less compact to restrict root penetration (bulk density ≤1.4 g cm−3), have slow infiltration rate (≤0.13 cm h−1), and medium level of total available water (≤178 mm m−1). Soils are strongly acidic to neutral (pH: 5–6.5), salt-free, and have low soil organic carbon (≤2.1%), low total nitrogen (≤0.1%), low available phosphorus and sulfur, and low Ca2+: Mg2+ ratio. It can be concluded that the irrigation water in the study area has cation imbalance (poor quality) which affects soil quality and maize productivity. Likewise, soils of the study area have poor quality. Lime application, efficient fertilizer use, and organic matter applications can be suggested. Further study on optimizing fertilizer rates and irrigation levels has to be conducted to improve maize productivity

Response of maize to irrigation and blended fertilizer levels for climate smart food production in Wolaita Zone, southern Ethiopia

Sustainable development needs climate-smart food production systems. This study examined maize responses to irrigation levels of 70, 85, and 100% crop evapotranspiration (ETc) and blended fertilizer rates of 0, 50, 100, and 150 kg ha−1, in factorial combinations. Blended fertilizer contains nitrogen, phosphorus, sulfur, and boron (NPSB). A field experiment was conducted for two seasons (2020 and 2021) in a randomized complete block design with three replications. Results indicate that the earliest tasseling (68 days), silking (73.5 days), and maturity (117 days) were recorded at the interaction effect of up to 30% deficit irrigation with 100 kg ha−1 NPSB. In response to the interaction effect of 30% deficit irrigation with the highest fertilizer level, the highest canopy cover (2.5) and stem diameter (4.35 cm) were recorded at 70% ETc × 150 kg ha−1 NPSB. Plants also produced the highest leaf area index (4.47) and height (2.53 m) at full irrigation level with the highest fertilizer. The highest cob length (23.4 cm), number of kernels per cob (586), thousand kernels weight (395g), biomass yield (23.27 ton ha−1), and grain yield (8.8 ton ha−1) were recorded at 100% ETc × 150 kg ha−1 NPSB . The highest harvest index (32.33%) and fertilizer use efficiency (51.1 kg kg−1) were recorded at 85% ETc × 100 kg ha−1 NPSB, and 100% ETc × 50 kg ha−1 NPSB, respectively. The highest water productivity was obtained in response to the main effects of 30% deficit irrigation (2.71 kg m−3) and 150 kg ha−1 NPSB (3.21 kg m−3). The future maize productivity is projected to decrease by up to 15.11% by 2030, 2050, and 2070, under two representative concentration pathways (RCP4.5 and RCP8.5). Based on the results, using 85% ETc with 100 kg ha−1 NPSB is optimum. Policymakers and agricultural offices better consider climate-smart maize production systems in Ethiopia