SOil ORGANIC MAneR AND NUTRIENT STATUS OF SOME VEGETABLE GROWING SOilS IN MATARA DISTRICT

Abstract

The main function of a soil from an agricultural perspective is to produce a bountifulcrop with minimum mputsrTherefore, the maintenance of soil fertility and productivityis important to obtain a sustainable yield. Though, farmers prefer that their soil support •ideal crop growth, poor soil management practices adopted by them have caused adecreasing trend of yield continuously. Therefore, it is important to investigate thenutrient status of such soils and make recommendation for sustainable land management.This study was conducted to assess organic matter and nutrient status of selectedvegetable growing soils in the Matara District, Sri Lanka.

Ten vegetable growing fields were selected and soil samples were drawn randomly fromO-15cmdepth. Soil samples were analyzed to determine N, P, K and organic mattercontent using standard methods and soil samples were also taken from a forest on thesame soil type to compare cultivated and undisturbed soils.

Results revealed that the average soil N, P and K contents for the vegetable growing soilwere 0.14%, 404 mglKg of soil and 106 mgIKg of soil respectively, and thecorresponding figures for the forest soil were 0.17%, 65 mg/Kg of soil and 30 mglKg ofsoil. The average organic matter content of the vegetable growing soils was 0.65%,whereas the corresponding figure for the reference forest soil was 2.5%. Results revealedthat the average P and K contents of Vegetable growing soils were higher than the forestsoil and possible reason may be the regular application of synthetic fertilizer to vegetablegrowing soils. Results further indicated that more than 50% samples collected fromvegetable growing soils had N and organic matter contents below the average value.

According to the results, it can be concluded the most of the vegetable growing soils inMatara District are considerably low in N and organic matter contents. Hence preventingsoil erosion and sustaining or increasing soil organic matter levels by adding cropresidues, compost and organic manures may be the most important practices that growerscan adopt in managing soil nutrients status.