Cultivating a plan

Different crops require different seedbed conditions. Swedes and fodder beet, for example, require a fine tilth for optimum seed to soil contact, while some large sized arable seeds tolerate establishment in medium to course seedbeds. Seed size and current soil status influence the choice of mechanical tool for the job.

First, start with a Visual Soil Assessment (VSA) by looking at multiple sites across your paddock for signs of poor drainage and/or poor aeration. Choose a test site representative of your paddocks. If your paddocks’ characteristics vary, it is worth testing soil in multiple locations.

With a spade, dig a hole to check if plant roots can penetrate deeply. Are the roots well distributed throughout the soil profile? Or are they limited to a few channels? Are roots restricted by barriers such as a plough pan? Will the slope of the paddock increase soil erosion risk once cultivated? Can machinery work the paddock easily and safely? Soils with large, dense clods or fine unaggregated particles yield less than soils with a nutty, well-aggregated porous structure.

Soil structure has a marked effect on crop production. Working soil when it is too wet or too dry may negatively impact its structure. Ploughing when soil is too wet can contribute to the formation of a thin plough plan which occurs just below the tillage depth and limits root penetration. These roots grow at right angles and cannot penetrate through the pan.

Conducting a ‘worm’ test is a simple way to assess soil moisture before cultivation.

Take a small amount of soil between the palms of your hands and roll it into a ‘worm’ shape approximately 5cm long, 4mm thick. If the soil does not form (for example, sandy soils) or cracks before the worm forms, then conditions are suitable for cultivation. If you form a worm, then your soil is too wet to cultivate. Should you need a more accurate soil moisture assessment, use a soil moisture probe or tape.1

A little preparation before cultivating sets the stage for a successful crop.

If you would like to talk further about selecting the right paddock before cultivation, contact your local PGG Wrightson Technical Field Representative.

1The worm test: “Soil management guidelines for cropping and pastoral grazing on flat to rolling country.” Graham Shepherd, Craig Ross, Les Basher, and Surinder Saggar.