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Increasing maize production is vital for contributing to smallholder farmers' food security since it ranks second in production after wheat. However, the decline in soil fertility is a marked constraint to crop productivity in developing countries, particularly in maize production. Recently, organic amendments through liquid bio-slurry enhanced maize productivity and improved food security via changes in soil physico-chemical properties for smallholder farmers in developing countries like Ethiopia. However, the utilization of liquid bio-slurry as an organic amendment has not been extensively investigated in the study areas. Therefore, field experiments were conducted at two sites to determine the optimum combination of inorganic N and liquid bio-slurry for improving maize productivity. A factorial combination of two mineral N (0 and 46 kg ha-1) and five liquid bio-slurry (0, 6, 12, 18 and 24 t ha-1) rates were used in a randomized complete block design with three replications. The results revealed that the combined use of N and liquid bio-slurry improved the growth and yield of maize in the two experimental sites. Plant height, ear length, number of rows per ear, number of kernels per ear, above-ground dry biomass, hundred-grain weight, grain yield and straw yield of maize were all improved by applying 46 kg N ha-1 along with 18 t liquid bio-slurry ha-1. The highest grain yield (8.12 t ha-1) was achieved from the combined application of 46 kg N ha-1 with 18 t liquid bio-slurry ha-1. Thus, using 46 kg N ha-1 with 18 t liquid bio-slurry ha-1 is highly recommended to increase the yield of maize. [ABSTRACT FROM AUTHOR]

Although numerous factors contribute to wide yield gaps, low external inputs, particularly N, and poor cropping practices such as soil tillage and monocropping are among the major factors affecting low maize production. In view of this, field experiments were implemented on two sites with Cambisols and Chernozem soil types in two consecutive years to evaluate the impacts of different soil management practices on the grain yield and quality, nitrogen uptake, and selected soil properties. A three-factor experiment was arranged as a split-split plot arrangement randomized complete block design with three replications. The minimum tillage (MT) and conventional tillage (CT) were used as the main plot, haricot bean-maize rotation and maize monocropping were used as the subplot, and four levels of nitrogen fertilization (control, 20 t ha-1 compost, 46 kg N ha−1 + 10 t ha−1 compost, and 92 kg N ha−1) were used as the sub-subplot. Analysis of variance showed that soil management practices were significantly affecting grain yield, N-uptake, and soil properties. In sites, the conventional tillage and rotation system increased the grain yield and N-uptake in contrast to the minimum tillage and monocropping, respectively. Similarly, nitrogen evidently affected the grain yield, N-uptake, and selected soil properties. However, tillage methods differed in their effects on soil chemical properties; soil organic carbon and total nitrogen concentrations were improved through MT compared to CT. Grain yield was significantly associated with NDVI, grain N-content, and N-uptake. Therefore, a CT plus haricot bean-maize rotation system with the addition of solely 92 kg N ha−1 and integrated 46 kg N ha−1 + 10 t compost ha−1 could be recommended for Hawassa Zuria (Cambisols) and Meskan (Chernozem) districts, respectively. However, in order to ensure sustainable maize production in the investigated areas, an integrated N treatment with MT and a rotation system may be recommended, which could improve soil properties. [ABSTRACT FROM AUTHOR]