Effects of urban wastewater on the growth, photosynthesis and yield of chickpea under different levels of nitrogen

Abstract

The reuse of wastewater in agriculture for irrigation needs specific studies to evaluate its effect on different soils, crops and agro-climatic conditions. This study was therefore conducted to observe the suitability of wastewater for irrigation, and Cicer arietinum L.cv. avrodhi was used as a test crop. The experiment was conducted in the winter season of 2006–2007 to evaluate its effect together with the basal application of four doses of nitrogen (N₀, N₁₅, N₃₀, N₄₅, kg ha⁻¹). Wastewater irrigation resulted in the increased growth, photosynthesis and yield of the crop. Lower fertilizer dose of nitrogen @ 15 Kg ha⁻¹ together with wastewater irrigation proved optimum, resulting in greater leaf area, plant fresh weight, dry matter (DM), photosynthetic rate (P_N) and stomatal conductance (g_s) and leaf N content, number of pods per plant, 100 seed weight and protein content relative to control and even to higher N doses. Thus fertilizer rates could be lowered without reducing yields when using wastewater for irrigation. Physicochemical characteristics of wastewater were also tested and most of them met the irrigational quality, being well within the permissible limits set by FAO.

Key words:

• wastewater
• photosynthesis
• yield
• chickpea
• nitrogen