Modeling the Influence of Floriculture Effluent on Soil Quality and Dry Matter Yield of Wheat on Vertisols at Debre Zeit, Ethiopia

Abstract

Floriculture is one of the booming sectors in Ethiopia. With its expansion, there is a growing concern as to its adverse effect on the environment. The objectives of this study were therefore, to provide concrete information on the influence of floriculture effluents on soil quality and crop productivity. Two permanent greenhouse experiments were conducted at Debre Zeit Agricultural Research Center on soils samples collected from farmer's field using wheat as a test crop. The soil samples were divided into two equal parts as sterilized and non-sterilized. Seven rates of floriculture effluents (0, 15.0, 30.0, 45.0, 60.0, 75.0 and 90.0 ml pot^-1) were used as treatment in CRD with four replications. The effluent was characterized by high pH, EC, N, P, S and basic cations (K, Ca, Mg and Na), low in micronutrients (Cu, Fe, Mn and Zn) and very low in heavy metals (Mo, Ni, Cd and Cr). Accordingly, its application did not significantly influence the texture and water holding capacity (WHC) of the soil, though decreasing values of FC, PWP and WHC were obtained both from sterilized and non-sterilized soils. Chemical properties were highly influenced by effluent additions. The pH, EC, exchangeable bases and micronutrients of the soil were significantly raised after first and second harvest. Organic carbon and Total Nitrogen increased with increasing volume of effluent, but decreased at high levels. Shoot dry weight of the wheat was also significantly affected by increasing volume of effluent. In non-sterilized soils, addition of low volume effluent increased shoot dry weight which later followed the same trends as sterilized soils. The decreasing trend in shoot dry weight was in line with that of soil organic matter, whereas continuous increments in pH, CEC and ESP resulted in changing the neutral soil to saline. Hence, floriculture effluent was found to affect the performance of wheat and soil quality parameters, where the effect was pronounced for sterilized soil. Future research should focus on long-term effects of floriculture effluents on physical, chemical and biological properties of soil and crop productivity.

Keywords: Effluents, floriculture, non-sterilized, sterilized, soil quality