Catch crop in maize (OK-Net Arable Practice Abstract)

Outcome: 1) Reduction of soil erosion, given a good development. 2) Suppression of seed-propagated weeds. 3) Better load-carrying capacity of the soil during harvest. 4) Fixation of nitrogen thanks to the legumes, and utilisation of nutrients in the soil after maize harvest. 5) Grazing possible immediately after maize harvest. \nInconveniences: 1) Competition for water in the case of severe drought. 2) Cost of seeds. \nHow to proceed: 1) Sow the maize at the beginning of May. 2) If possible, harrow a first time before appearance of the maize plants (blind harrowing). Second harrowing should take place at a plant height of 10 cm, when the maize plants are well rooted. Between a plant size of 10 to 20 cm a first hoeing should take place. 3) Apply liquid manure at 25-30 m3 per ha. 4) When the maize plants reach a height of about 20 to 30 cm (from 4- to 6-leaf stage), undertake a second hoeing. Combine the second hoeing with simultaneous sowing of the catch crop into the weed-free crop. 4) Recommended pure crops/crop mixtures: - Pure-clover crop: small-leaved white clover, hop clover, red clover (200 g/a) or sub clover (300 g/a). White clover and hop clover are less competitive than red clover or sub clover. Attention: Egyptian, Italian and Persian clover are normally too competitive. - Clover-mixtures are less risky: E.g. sub clover/red clover (at a mixing ratio of 5:2, a total of 300 g/a) or white clover/hop clover 1:1, a total of 200 g/a. - For farms with livestock, mixtures of grass and clover are an option. They can be used for grazing in autumn: E.g. white clover/smooth meadow-grass or meadow fescue or ryegrass (at a mixing ratio of 1:1, a total of about 250 g/a). Attention: ryegrass can be too competitive depending on the weather conditions. \nTips: 1) If possible, sow before a longer precipitation period. 2) Sowing of catch crops is only successful until the maize reaches a height of around 30 cm. Late sowings are strongly suppressed by shading of the crop and cannot properly develop. 3) During long drought periods, competition for water and nutrients can impair the development of the catch crop or, if the catch crop grows too lush, the development of the maize. 4) In the case of the presence of root spreading weeds like docks and couch grass, a catch crop is not recommended, as this would require tillage after the maize harvest. 5) The catch crop is only profitable if it remains for the duration of winter. Depending on its development and use, it could also be utilised in the following summer. If it is incorporated into the soil in spring, it has a high value as a green manure crop.