Photosynthetic activity of sweet sorghum fertilised by sewage sludge

Abstract

ABSTRACT Sewage sludge is a promising fertiliser for sweet sorghum growing on marginal land. We investigate the effects of different doses of sludge on the characteristics of chlorophyll fluorescence. Two types of sewage sludge were used: without flocculant and treated with flocculant. Sludge application helps to reduce the amount of inactive chlorophyll in the reaction centres, increases photosynthetic activity, and reduces the sensitivity of the photosynthetic apparatus to adverse environmental factors. Flocculated sludge had the more beneficial effect, particularly at the early stages of development; the optimal dose was 40-60t/ha.