Soil water management

In soil water management the size of aggregates in the seedbed controls the amount of water that can evaporate with an aggregate size of approximately 2mm, water evaporation is minimized. The straw at the soil surface also decreases the loss of water through reflecting solar radiation and preventing the soil surface from heating up.  The absence of rain after sowing, critically depend on how well the new crop can establish with the water present in and under the seedbed. It is important to retain this water and manage it carefully if the seed is to germinate.

Heat to the soil by the sun

When sun rises and begins to reflect on a newly sown field, the energy from the suns ray’s then heats up the soil, thereby heating up the water in and under the seedbed. Some of the water molecules acquire enough energy to convert to gaseous form and attempt to move out of the seedbed and into the air as water vapor.

Turbulence in the soil is created due to coarseness

Second maximum in evaporation rate is reached when the aggregate size exceeds 50mm, which is often the case in soils with high clay content. With such amount of coarse aggregates in the seedbed, the air flows become turbulent and the seedbed dries out. Between these peaks, there is a minimum water evaporation case where the aggregates have a diameter of around 2mm. These amounts of aggregates are not small enough to allow capillary transport of water, but not large enough to induce turbulent air flows. With aggregates of this size in a seedbed, a lid is put on and evaporation of water is minimized.

Soil water management