Assessing paddocks before cultivation
Cultivation aims to create a seedbed suitable for a seedling to establish. Correct cultivation enables successful crop establishment, helping maximise crop yield potential.
Before cultivation, consider the current fertility of the paddock and its crop rotation history. Assess its risk of diseases, pests, and identify paddocks with good stored moisture.
A visual examination of the paddock before cultivation provides an idea of the soil’s structure and whether the paddock is suitable for the crop selected. Look for signs of poor drainage and/or poor aeration. If there is a crop present, dig a hole and check if plant roots have penetrated deeply.
Are the roots well distributed throughout the soil profile or are they limited to a few channels? Look for signs of root restriction from barriers such as a plough pan. Will the slope of the paddock increase soil erosion risk once cultivated? Can the paddock and its soil conditions be worked by machinery easily and safely?
Working the soil when it is too wet or dry can negatively impact soil structure, including loss of soil structure.
The loss of soil structure can increase the risk of soil loss from wind when the ground is exposed and can affect the drainage and aeration condition of soil.
When the soil just below the cultivated layer becomes compacted and creates a hard barrier, this is known as plough pan. One of the main causes is continuously cultivated soil at the same depth.
If plough pan is suspected, the soil will be tight and firm down at the cultivated layer. Root channels will be missing due to the lack of root penetration and worms will not be present. Plough pan will impede the potential rooting depth of sown crops and the soil's ability to conduct effective drainage.
Conducting a worm test is a simple way of measuring soil moisture ready for cultivation. Note though, that this method is less accurate than others, such as using a soil moisture probe or tape.
To complete a worm test, take a small amount of soil and roll it into a 4 to 5 cm long and 1 cm wide worm between the palms of your hands. Once formed, the soil either starts to crack (for silty soils) or keeps its shape. If it remains in the worm shape, it is too wet; if it cracks, the soil is too dry. Knowing your farm’s soil texture indicates your target soil moisture status.
Depending upon the crop being planted, a seedbed requires different conditions. For instance, swedes and fodder beet require a fine tilth while some arable crops are established in medium to coarse seedbeds.
To achieve the correct seedbed, there are a variety of implements available. The most common include ploughs, rollers, harrows and cultivators so consider which is best suited for the job you require.
For help assessing and selecting paddocks ready for cultivating, contact your local PGG Wrightson Technical Field Representative.
