Time taken to plan for next year’s winter feed crops will pay dividends in crop yields, livestock performance and in reducing soil damage, contaminant loss to waterways and the loss of valuable top soil.
Often paddocks are selected for growing winter feed crops as part of a pasture renewal programme but Matt Ward, Beef + Lamb New Zealand’s General Manager North Island, says some paddocks may be unsuitable for growing feed crops because of slope, soil type, drainage and proximity to water bodies. The class of livestock also needs to be taken into account- while some paddocks may be fine for sheep, they may not be suited for wintering cattle.
High-risk paddocks can be renovated grass to grass rather than going through a winter feed crop regime.
Matt recommends selecting winter feed crop paddocks well away from waterways to reduce the risk of top soil, phosphate, pathogens and nitrogen reaching water bodies.
Paddocks that have extensive networks of mole or pipe drainage systems should also be avoided for winter cropping as this increases the risk of contaminants draining directly into waterways.
If sloping land is the only option available for cropping, farmers should identify critical source areas such as gullies that connect to waterways. Ideally these need to be fenced off and left uncultivated and ungrazed to reduce the risk to waterways.
Heavy soils are often at greater risk of structural damage and sediment loss during intensive winter grazing while lighter soils may be at greater risk of nitrogen (N) leaching.
Matt says it is important farmers consider catchment-specific water quality issues when selecting paddocks for winter feed crops.
In catchments trying to reduce N loadings, then ensure crops are not grown on light soil types which carry an increased risk of N leaching to groundwater.
In locations where phosphorus and sediment migration through migration are relevant, avoid growing crops on poorly drained soils and steep slopes.
The vulnerability of soils to pugging and compaction should also be considered. Visual soil assessments may help identify any soil structure issues and may help determine whether or not a paddock is suitable for growing crops.