Browsing by Author "Molatakgosi, Goitsemodimo"

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    Impact of infield irrigation management by Botswana cabbage farmers on soil salinity
    (Cranfield University, Cranfield University at Silsoe, 2006-11-08T14:51:56Z) Molatakgosi, Goitsemodimo; Hess, Tim M.
    Some vegetable farmers in the semi- arid Botswana are struggling or closing down their enterprises citing the cost of irrigation and salty water as the problem. Irrigation with water from the salt-laden underground water is known to be the main sources of salts for arid and semi-arid agricultural land. Crops grown in saline environments show symptoms similar to those shown by drought-affected crops hence more irrigation is needed therefore increasing the irrigation cost. Research from other semi arid areas shows that water with high salinity levels can be used for irrigation without increasing soil salinity to values beyond critical levels. A lot of studies have been done which show that the impacts of saline irrigation water depend on the irrigation management. This study therefore aims at recommending infield irrigation management practices to be used by cabbage farmers in Botswana without increase in soil salinity to levels that will affect crop yield. A survey was conducted to identify the infield irrigation management practices presently used by cabbage farmers in Botswana. Rootzone salinity trend due to the identified infield irrigation management was simulated for 20 years using WaSim simulation model. Recommendations on irrigation management practices were made for those soil salinity trends that reached critical levels. It was realised that there are no common infield irrigation management used by farmers. The way farmers manage infield irrigation could not be identified with the factors involved in irrigation scheduling. Infield irrigation management by the farmers contribute to the soil salinity increase in their fields and some of the farmers are already using saline soils. Most farmers are not aware of the saline conditions they are farming on and those who know do not know about the soil salinity measures. The study recommends a need to educate farmers on irrigation under saline environments and also a need for farmers to include soil salinity control in their irrigation planning.
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    Irrigation management practices of cabbage farmers in Botswana using saline groundwater.
    (Elsevier Science B.V., Amsterdam., 2009-02-01T00:00:00Z) Hess, Tim M.; Molatakgosi, Goitsemodimo
    All horticultural production in Botswana is irrigated, as average rainfall is less than average reference evapotranspiration in all parts of the country for all of the year, and most of the irrigation in the country is used for horticultural crops. In the main, the water used for irrigation comes from groundwater, and much of this can be classified as moderately saline. A survey was carried out of 60 cabbage farmers in five regions of the country to identify the level of salinity of irrigation water and the irrigation practices used. It was concluded that there was no relationship between the irrigation rate (average irrigation depth divided by average irrigation interval) and the salinity of the water used or the salinity of the soil, such that some farmers were over-irrigating and others under-irrigating. This means that water is being wasted and yields are likely to be reduced. In addition, there is a risk of long-term build-up of salinity and soil degradation.