Abstract:
Compaction limits soil productivity especially plant growth. However, the effect of compaction in various South African soils on potato (Solanum tuberosum L.) tubers is not well understood. The purpose of this study was to investigate the effect of compaction in various soils on the number of stems, plant germination, number of tubers, plant vigour, plant height, biomass, size, shape, dry matter, fresh weight, specific gravity of potato tubers. It was hypothesized that soil compaction affects growth and quality of potato tubers. Soil samples were collected from four different potato farms and subjected to different levels of compaction, simulating field conditions. The experiment was conducted in a complete randomized design with a split plot treatment structure with three replications. Treatments were compacted, non-compacted soil and four different textures (loamy sand, sandy loam, clay and fine sandy). Sifra and Fandago potato cultivars were used to test response to the treatments. Potato tubers were harvested after 120 days. Analysis of variance was conducted using Minitab software version 17. The comparison of means was done using the Tukey method. It was generally found that size of tuber was decreased (>40%) by soil compaction for both cultivars. The shortest tuber size (46.1 mm) was obtained in the fine sandy loam soil. The clay soil produced the highest (21) specific gravity. Soil compaction slightly deformed some potato shapes but were not detected statistically. Fresh weight of tubers was decreased by 32% between the noncompacted and compacted soil. The highest plant vigour (3.4) was observed for loamy sand soil. Similarly, the tallest crop (38.2 cm) were observed in the sandy loam soil. Crop height was decreased by 38% at the compacted soil. It was apparent that Loamy sand and sandy loam soil seem to be suitable soil texture for potato production. Soil compaction had a negative impact, significantly producing small tubers, low yield, low specific gravity, crop height and number of potato tubers.
