Water management – larger yield and lower costs
Published in Scientific Papers. Series A. Agronomy, Vol. LV-2012
Written by Christian HALDRUP
Water is the limiting factor for plant production. From “black” soil, soil without plants, there is almost no evaporation. All plants are using water for growth and when the soil is covered by plants, no matter whether it is crops or weeds, it is consuming up to 5 litres of water per m2 per day. When the soil is cultivated under dry conditions, an evaporation of 15 litres per m2 of water can be expected. Weed control and soil tillage are key factors in water management. To avoid unnecessary evaporation, the weeds must be controlled from harvest, before harvest if possible, until a new crop is to be planted. And the weeds must be controlled in the early growth stages of the crops, to secure water, neutrinos and light for the crop. To minimise the evaporation, the soil tillage and the working depth by tillage must be reduced to a minimum. By new technologies no tillage and strip tillage are possible to reduce the evaporation, machine costs, and diesel and labour costs. To reduce the temperature of the soil, the speed of the wind and a better penetration of the precipitation, between 30-50 per cent of the straw and stubbles are recommended to be kept on the top of the soil. The water which is available for the crops depends on the precipitation, loss of water and crop rotation. Wheat grown after rapeseed, barley or wheat has about 120-150 more litres of water available per m2 than wheat grown after maize or sun flower, if good water management is practiced.