Effect of the Soil Amendments on the Mechanical Harvest of Potato Crop Grown under Centre Pivot Irrigation System

A field trial was conducted at TADCO to evaluate the mechanical harvest of autumn potato crop under different soil amendments: sand, gypsum, cow manure, and granular sulfur. The application of the sand amendment to the soil of the pivot showed easier mechanical and semi-mechanical harvest. The potato yield under the mechanical harvest was less than semi-mechanical harvest by 15.48% at the different soil amendments. More bruises were observed on the potato tubers harvested by mechanical harvest which ranged 9.34-16.33%, while bruises at semi-mechanical harvest ranged 4.28-4.75%. The final yield of stored potato was less than harvested yield by 10.68, 7.78%, 14.85, 11.08 for the sand, gypsum, cow manure, and sulfur amendments respectively. The stored yield of the different treatments was significantly less than the yield of the test harvest by around 24.03-32.24% at J34 and by 29.64 -56.27% at F18 and this was due to harvest method, cleaning out the damaged potato and moisture loss. The results of this trial highlighted the importance of selecting pivots for growing potato to be with less clay and more sand; also, it highlighted the importance of leaving the wheat straw to decompose in the soil instead of burning to improve the soil structure to be suitable for mechanical harvest. The sand amendment was not suitable for TADCO crop production as it is difficult to apply, need more time to execute besides less productivity. Due to one-month delay in planting potato, the average yield of stored potato from the trial pivots reached 20.2 M.T. /Ha which is significantly less than the yield of stored potato from the other pivots at TADCO of the same season with a range of 27-43 M.T. /Ha. Keywords: Mechanical Harvest; Soil Amendment; Test Harvest; Soil Clods; Potato Yield; Tubers Bruise