Drip Irrigation: Watermelons Open System in Poly Bags: Rocky Areas

Drip irrigation in rocky areas (difficult to till) can work if plants are planted in poly bags filled up with good quality soil. Mr R.D. Burger from the Omaruru Agriculture Extension office experimented with watermelons planted in poly bags irrigated with a simple home made drip system.
Statistics:
Fertilizer: Urea, Potassuim Sulphate and Phosphoric acid dissolved in water and applied through drippers
Soil type: Sandy loam well drained with compost
Planting density: Rows 1.5m apart
                         Poly bags 1m apart in rows
                         2 plants per poly bag
                         1500 poly bags
                         3000 watermelon plants
                         3000 watermelon harvested
Observations: The poly bags works in  rocky areas. Unfortunately watermelon has a very aggressive root system that is confined by the poly bag and therefore only one good size watermelon per plant is produced. It will work well with patato, tamato, green pepper and other vegetables with less demanding roots. Covering (shade netting) will help to limit evaporation. Soil borne pest were non existent as new soil was used in poly bags. It is extremely hard work to full and space the bags.

                                                        Rocky soils with slope