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A vigorous stand of lucerne is the basis for profitable production.
The choice of a well-drained land, the correct preparation of the land, the establishment of soil fertility by means of soil samples, as well as the correct nutrient supple-mentation before and at sowing, is crucial.
Selection of Land
Lucerne needs well-drained soil for optimum production.
Waterlogged soil creates favourable conditions for a range of diseases and pathogens, such as Phytophthora, Pythium, etc., which cause seedling diseases, reduce yield and thin out the stands.
Establishing lucerne on such soil should not even be considered. Poor drainage lowers the amount of soil-oxygen that reaches the roots.
Cultivars with high resistance to root diseases, as well as the use of fungicides at planting time, will reduce problems caused by poorly drained soil.
Care is needed to prevent erosion at planting time if the lucerne is planted on a slope, especially in the first year.
Level lands with a relatively shallow slope may have areas where water may collect and cause a poor stand to develop.
Soil types having a gleyed E-horizon and a shallow A-horizon, for instance Kroonstad type, should be avoided because of the possibility of poor drainage.
Soil types where the orthic A-horizon is underlaid by hard rock, such as Mispah type, should also not be used for lucerne.
Any soil type which is well-drained, and where the nutrient content can be corrected economically, can be used for cultivation of lucerne.
Soils need to have adequate depth, at least 1.2 m, if they are to hold a sufficient reserve of water. Lucerne has a long tap root - up to about 6 m - which under favourable conditions penetrates deeply into the soil.
Medium to deep soil forms, with a clay content of not more than 35%, are considered as optimal for lucerne production.
The lands must not have any compacted layers or hardpan areas.
South African lucerne is grown in a variety of climatic zones and farming areas, where the nutrient status of the soil may vary widely.
To meet the nutritional require-ments of the plant, and to ensure optimal yield, the nutrient status must be ameliorated.
Correct soil nutrient status will ensure that the stand establishes rapidly and remains vigorous and productive.
The success and profitability of lucerne depends considerably on the original stand and the vigor of its growth.
Prevention of weeds
The lands must be free of perennial weeds such as kweek (Cynodon dactylon) before lucerne is established on them.
If thorough controls are not followed, the weeds will grow faster than the lucerne and result in poor stands.
There should also not be any carry-over of weedkillers which may affect the lucerne.
Annual weeds are often merely a temporary problem, and can be controlled by cutting.