Forage Yield and Nutrient Uptake as Influenced by Secondary Treated Wastewater

Abstract

The effect of irrigation of forage crops with treated wastewater on the yield and nutrient uptake was evaluated under field conditions. Three field experiments were conducted at a farmer's field near Ramtha Wastewater Treatment Plant, Jordan. Corn (Zea mays) was planted for two seasons as a summer crop while vetch (Vicia sativa) was planted for one season as a winter crop during 1994–1995. Plots were irrigated with either potable water (PW) or wastewater (WW) in amounts according to the following treatments: (i) PW equivalent to 100% class A pan reading (PW); (ii) WW equivalent to 100% class A pan reading (WW1); (iii) WW equivalent to 125% class A pan reading (WW2), and (iv) PW with application fertilizer equivalent to nitrogen (N) and phosphorus (P) content of WW1 (PWF). Treatments were replicated four times in randomized complete block design. Plant samples were taken during the growing seasons and were analyzed for dry weight, yield, yield components, and nutrient uptake. The results indicate that WW irrigation increased the yield of both corn and vetch. Both rates of WW application had similar effect on crop production. Supplemental fertilization with the potable water irrigation (PWF) enhanced vetch production and increased grain weight for corn in the second season (1995). The uptake of macronutrients and micronutrients by corn increased with WW irrigation, while the uptake by vetch increased with both WW irrigation and PW supplemented with fertilization. It was concluded that under the conditions of this study, secondary treated WW could be a source of plant nutrients and can be reused for irrigation to increase forage crop production.