Australian Mungbean Association
Australian-grown mungbeans have quality written all over them!
Nutrient management of mungbeans
Although the mungbean plant does have a relatively high nitrogen requirement (a 1.5 tonne/ha crop has a total nitrogen requirement of 100 kg N/ha), the crop generally shouldn’t need nitrogen fertiliser, provided plants have effectively nodulated.
Low rates of nitrogen fertiliser may be justified in situations such as:
In low vesicular-arbuscular mycorrhizae (VAM) situations (i.e. long fallows over 12 months duration or after canola), large responses to applied phosphate fertilisers are likely in situations where soil bicarbonate P levels are below 25 mg/kg.
Where soil VAM levels are high (double-crop situations or short fallows of less than six months) responses to applied phosphate fertiliser are only likely in situations where soil bicarbonate P levels are below 10 mg/kg.
Sulfur deficiency is most likely to occur in double-crop situations where soil available sulfur levels have been depleted by the previous crop. Sulphate ammonia at 20–30kg/ha will rectify a sulfur deficiency.
Mungbeans are very responsive to zinc. Crop responses are likely where soil test levels are:
Severe deficiencies stunt plants and produce dead leaf tissue between the veins. Mild deficiency can be diagnosed by the upward ‘cupping’ of the upper-most leaves.
Severe deficiencies can be corrected for a period of 4–6 years with a soil application of zinc sulphate monohydrate worked into the soil several months before planting.
In the first year after application, the soil applied zinc mono may not be fully effective, and a foliar zinc spray may also be required.
In zero-till or double-crop situations, deficiencies can be corrected by using one of the following options:
A foliar spray of 1.0 kg zinc sulphate heptahydrate + 1.0 kg urea in at least 50 L of water/ha plus wetting agent will correct a mild deficiency. One to two sprays will need to be applied within four weeks of emergence.
Foliar sprays containing zinc sulphate heptahydrate are compatible with dimethoate, but will cause nozzle blockages if mixed with Blazer.
Chelated forms of zinc are more expensive, but can be mixed with most herbicides and used in hard water.
Zinc seed treatments may be a cost-effective option in situations where soil P levels are adequate but zinc levels are likely to be deficient.
Agrichem recommend that Broadacre Zinc should be applied at 5 L of product per tonne of seed. To minimise any damaging effect on the rhizobia, the Broadacre Zinc treatment needs to be applied first and then allowed to dry before applying the inoculum.
Stunted growth and low yields are often a problem where mungbeans are sown on soil that has been fallowed for 12 months or longer. As VAM levels decline in the soil, deficiencies of phosphate and/or zinc become increasingly common. Crops such as mungbeans are highly dependent on VAM.
The need for higher rates of P and Zn should be considered in long fallow (low VAM) situations.
Alternatively, consider planting other crops such as sorghum, which handle long fallow disorder relatively better than mungbeans.