THE SYNERGISTIC ROLE OF ARBUSCULAR MYCORRHIZAL FUNGI, RHIZOBIUM INOCULATION, AND IN-FIELD RAINWATER HARVESTING TECHNIQUES IN GROWTH AND YIELD IMPROVEMENT OF MAIZE IN YIRBA DUWANCHO DISTRICT, SIDAMA REGIONAL STATE, ETHIOPIA.

Abstract

Various climatic factors, such as temperature and rainfall variability, have a significant impact on rain fed agricultural productivity, especially in Ethiopia's water-stressed arid and semi-arid regions. The objective of this study was to assess the possible impact of arbuscular mycorrhizal fungus (AMF),Rhizobium® inoculation and in-field rain water harvesting system on maize (Zea mays) growth and production in a moisture-prone (low rainfall) location of Yirba duwancho village of Boricha woreda in Ethiopia. The experiment was laid out in a randomized complete block design (RBCD), with 8 treatments and 3 replication including the control. Consortia AMF inoculums and Rhizobia were used as bio-inoculants and a blended fertilizer in the form of NPSB was used as additional agricultural input. The highest height (140.6cm) growth was recorded for the maize-haricot bean intercropping treatment. This was followed by AMF+F (113.5cm) treatment. Stem collar diameter was bigger (1327mm) in maize-haricot bean intercropping followed by AMF+R (86.9mm). Records for Leaf area index, Shoot weight weight, Shoot dry weight, Root weight weight, and Root dry weight were inconsistent. The better (1853cm2) Leaf area index was recorded for R treatment. Shoot dry weight was better in AMF+R (830.6g) treatment. However, Root dry weight was higher (69.6g) in AMF+R+F treatment. Maize yield/plot and per hectare was higher for intercropping treatments followed by AMF+F and AMF+R respectively. For all control treatment was recorded the lowest values. Treatments on the Effect of the Suitability of In-field Rainwater Harvesting Technique with Respect to the Width of its Runoff Strips showed Application of Tide-Ride is the best technique to hold water in soil followed by IRWHI. The lower values were recorded for IRWH1.5 and the conventional broadcast treatment. This tells us the broader the width of runoff the least rain water retained in soil. Besides, better root colonization and spore density was recorded for intercropping followed by Sole AMF treatment, while mycorrhizal dependency and maize tissue nutrient uptake was much better in AMF+R treatment. However, in almost all cases the control treatment was inferior. Overall, results of this study suggest that mycorrhizal and rhizobium inoculation and application of infield rain water harvesting techniques enhances nutrient uptake and maximizes maize biomass under low soil moisture conditions. Mycorrhizal plants produced higher biomass, with greater tissue nutrient content than the control plants. These results indicate that establishing efficacious AMF and rhizobium with maize could be an efficient alternative for growers in drought prone areas than relying on fertilizer application and its associated costs and environmental concerns.