Effects on growth, yield, and fruit quality in tomato (Lycopersicon esculentum Mill.) using a mixture of potassium humate and farmyard manure as an alternative to mineral-N fertiliser

Abstract

SummaryThe effects of potassium humate (KH) mixed with farmyard manure (FYM), as an alternative to mineral-N fertiliser, on the growth, leaf mineral composition, fruit yield and quality of tomato on newly-reclaimed soil were investigated. Mixtures of KH and FYM were applied at the rates of 50 kg KH + 25 metric tonnes (MT) FYM, 50 kg KH + 50 MT FYM, 100 kg KH + 25 MT FYM, and 100 kg KH + 50 MT FYM ha–1. No mineral-N fertiliser was included in any of these treatments. In addition, the recommended dose of mineral-N fertiliser was used as a control. Significant positive effects of 100 kg KH + 50 MT FYM ha–1 were observed on shoot dry weight (DW) plant–1, root DW plant–1, leaf free proline content, leaf mineral composition (N, P, K, Fe, Mn, and Zn), leaf and fruit nitrite (NO2–) and nitrate (NO3–) contents, total fruit yield ha–1, and fruit vitamin C and total soluble solids (TSS) contents when compared with the other three KH + FYM treatments. In contrast, there were no significant differences in these parameters between the 100 kg KH + 50 MT FYM ha–1 and the recommended mineral-N fertiliser treatments, except for leaf and fruit NO2– and NO3– contents, where significant reductions occurred in the 100 kg KH + 50 MT FYM treatment. The same trends were observed over two growing seasons (2008 and 2009).