PLANT GROWTH, FOLIAGE SENESCENCE AND RHIZOME YIELD OF TURMERIC (Curcuma domestica L.) AS AFFECTED BY INORGANIC AND ORGANIC FERTILIZERS

Abstract

Integrated plant nutrient management is one of the key components of sustainable agriculture. It reduces the cost of production while enhancing the revenue of growers. The present study was conducted to examine the effect of sole and combine applications of inorganic fertilizer and organic fertilizers on plant growth, foliage senescence and rhizome yield of turmeric (Curcuma domestica L.) in container gardening. Eight treatments comprise sole applications of different types of organic fertilizers including vermicompost, compost and matured cow dung, and inorganic fertilizer schedule recommended by the Department of Export Agriculture, Sri Lanka together with combinations of inorganic and organic fertilizers. Sand: topsoil: partially burned paddy husk (1:1:1 v/v) were used to fill the black plastic pots with 30 cm in diameter. Due to the variation of shade of the experimental site, the experiment was setup as a randomized complete block design with three replicates. The number of leaves per shoot, leaf length (cm), leaf width (cm), height of the pseudo stem (cm), number of shoots per pot were taken five months after planting while the number of primary fingers/clump, number of secondary fingers/clump, fresh and dry weight of rhizomes/pot (g) were taken at harvest. Foliage senescence as visual senescence score was recorded from 32 weeks after plant establishment until foliage became dry. All measured quantitative parameters were significantly different between treatments, where the greater values were recorded when plants were treated with equal proportions of inorganic fertilizer and vermicompost as an organic fertilizer while the foliage senescence took a longer period in the same treatment when compared to other treatments. This might be due continuous supply of nutrients through an integrated approach of nutrient management and modification of physical and microbiological properties of the growth substrate by vermicompost application. Poor plant growth, early senescence and low fresh and dry yield of rhizomes were reported when plants were grown without inorganic or organic fertilizers may be due to an insufficient supply of nutrients to fulfil the demand of plant growth and development. Combine application of vermicompost and inorganic fertilizer could be considered as a promising combination of fertilizers for the growth and yield of turmeric under integrated plant nutrient management.