Potatoes are a rich source of nutrients and energy because of their high content of vitamins, minerals and essential organic compounds and are both a staple food and a cash crop.
Currently, the average potato yield is three to six tonnes per acre, with the dismal harvest attributed to mono-cropping, poor land preparation methods, planting the seed in a furrow rather than in a bed, substandard potato seeds, poor application of fertilisers and insufficient control of diseases with substantial harvest and post-harvest losses.
The local yield can be increased to between 20 and 30 tonnes per acre if we address several weaknesses, starting with the selection of the seed potato. In the Netherlands and Ireland, farmers harvest 60-70 tonnes per acre.
Currently, most farmers rely on farm-saved seeds, but the problem is that many of them sell the larger potatoes for cash, eat the medium-sized ones at home and use the smallest as planting material. This can be improved through use of certified seeds or farmers using farm-saved seeds planting the larger ones.
For good land preparation, it is important that potatoes are planted in beds with the correct tilth to allow for good and even multiplication of the tubers and easy lifting at the point of harvest.
Potatoes grow well in loose loamy soils and some areas of sandy loam soils where rainfall is higher. The soil needs to be ploughed and must be free of weeds before using a seedbed former, which is also known as the rotary ridger. It prepares the soil to give a bed with consistent tilth and good aeration to encourage the tubers to multiply sideways.
Thereafter, the planter plants the seeds at an even and set depth of 12cm at the centre of the bed with an even distance between plants of around 30cm to achieve the correct plant population.
QUALITY AND PROVEN EQUIPMENT
Accurate planting in the correct tilth, with the soil structure allowing for an even aggregation of 3mm paves the way for good multiplication and uniform potatoes.
During the growing period, to achieve good multiplication, a bed maintainer is necessary to ensure that the tubers always have soil cover and never see the light. Once light reaches potatoes, multiplication stops. This has to be done two to three times during the growth cycle.
Potato blight must be controlled by spraying, and unfortunately if not kept in check through preventive spraying, this leads to very poor yields of rotten potatoes.
Up to 50 per cent of farmers suffer harvest losses caused by cuts due to manual harvesting. This can be reduced to nearly zero by using a potato harvester.
This machine lifts the soil with potatoes just below the crop and the soil is sieved as it passes over the specially coated lifter chains that prevent potato skin damage.
The undamaged potatoes are then dropped back on the soil surface ready to be weather-hardened and bagged. Using this method, the land is left flat and level for easy planting of another crop directly.
To succeed with mechanised potato farming, it is important that quality and proven equipment is used with the necessary training for farmers on the correct handling and maintenance of equipment.
To curb post-harvest losses, potatoes should be kept in a cool dry place for up to two weeks. Thereafter, they should then be put in cold storage, which can extend the shelf life for a further two months.
Potatoes can be rotated with crops such as maize and beans. Avoid crops like tomatoes, which are in the same family.