Soil quality assessement for land use suitability at Karugwa Mixed Farm

Abstract

Soil degradation especially through nutrient mining is widespread and alarming in most parts of Uganda, although little attention has been paid to this problem. This study was aimed at pre-soil status evaluation prior to allocation land uses with suitable soil capabilities through investigating the soil physio-chemical properties keeping other factors (climate and slope) constant. Using Karugwa mixed farm as a case study, a total of 24 composite samples soil samples were collected randomly at double depth of (0-15 and 15-30 cm) from four different land uses; pineapples (the dominant land use), eucalyptus, orchard and vegetables. The soil samples were analyzed for total N, available P, soil pH, soil organic matter (SOM), exchangeable bases (K+, Ca 2+ and Na+) as well as soil texture. Statistical analysis was performed using Genstat Statistical package and later incorporated into Arc GIS 10.2 for suitability classification of the land uses for pineapple production. Results indicated that soil pH was in the best favorable range for pineapples (4.5 to 5.6) and does not affect availability of other nutrients like phosphorus. SOM content did not differ significantly across the land uses (1.23 ± 0.43 %), but deficient across land uses as compared to the required amount by pineapples > 4.81. Consequently, management measures are required to build up organic matter levels in the farm. Available phosphorus was significantly different across land uses (27.6 ± 10.75 ppm) which was sufficient as compared to the standard (critical value) for pineapples >12 ppm with most of the soil samples having P content higher than the critical. However, the soil was severely deficient in the most crucial nutrient Nitrogen (1.1254 ± 0.04189 %) as compared to the critical of for pineapples (> 4.81%)., Exchangeable bases (Ca2+, K+, Na+) differed significantly (0.09 ± 0.03 cmol kg-1) across the different land uses. It can be concluded that, the land at Karugwa mixed farm has a huge potential to support pineapple production but nutrient deficiency should be corrected especially nitrogen and organic matter for optimal yields.