| || || Sharma, Ami Chand|
| || || Soil fertility and productivity decline resulting from twenty-two years of intensive taro cultivation in Taveuni, Fiji|
Author:Sharma, Ami Chand
Institution: University of the South Pacific.
Subject: Soil fertility -- Fiji -- Taveuni, Soil productivity -- Fiji -- Taveuni, Taro -- Fiji -- Taveuni
Call No.: pac S 596 .7 .S53 2016
Copyright:20-40% of this thesis may be copied without the authors written permission
Abstract: Soil degradation is the loss of actual or potential productivity and utility of the soil and it implies a decline in the soil’s inherent capacity to produce economic goods and perform environmental regulatory functions. With short-term observations, the transient phenomena can be missed or misinterpreted. In general, observations made over a long period allow more rigorous conclusions with regards to decline in soil fertility. Soil data for “22-year period” was retrieved from the archival files at the Koronivia Research Station while other important information was gathered through survey questionnaire and ministry officials based on the Island. The effects of 22 years continuous cropping of taro on selected soil chemical properties and yields were studied on the island of Taveuni, Fiji. The high native fertility levels and production potential of Taveuni Andosols declined rapidly when the forest cover was replaced by the annual crop of taro. This was particularly evident from the trend analyses of the nutrient elements which, altogether with soil pH and taro yields, revealed significant declines, with the exception of exchangeable K. Significant associations between and dependence of taro yields on soil pH, Olsen P, exchangeable Ca and exchangeable Mg were also observed. In addition, significant changes in these four chemical parameters were observed when the pre and the post cultivation levels were compared. Olsen P and exchangeable Mg were identified to be the most limiting nutrients for the taro soils of Taveuni. The archival database provides an important tool for looking at soil test trends over time on taro commercial sites.