Growing a high yielding crop

The yield of a crop is dependent on a number of factors – some of which we have total control over and others we have no control. With your agronomist, discuss the factors that we have control over:

• soil fertility and pH
• sowing date
• fertiliser use
• cultivation practices and seed bed preparation
• spraying for weeds and pests.

Many agronomists are happy to visit the farm on a regular basis to monitor your crops for weeds, pests, diseases and any nutrient deficiencies. Discuss your expectations with your agronomist before the crop is planted.

Fertiliser N use

Applying more Nitrogen fertiliser than the crop requires will result in a higher crop nitrogen content. The appropriate Nitrogen fertiliser regime will depend on soil mineral N content and possible crop yield, and will be different between paddocks. Over applying nitrogen fertiliser may result in crops with high nitrogen content, beyond those required to reach maximum yield. This may have negative impacts on animal production and can increase N losses when crops are grazed.

To ensure you are using the correct amount of Nitrogen fertiliser:

• test winter crop paddocks for soil mineral N
• develop an appropriate fertiliser plan with your fertiliser rep.

Cultivation to reduce soil loss

Soil cultivation removes vegetation and exposes the soil to the weather increasing the risk of soil runoff during bad weather. Management strategies can reduce the risk of soil loss during the crop establishment period.

Where safe, cultivate across slopes rather than up and down. Up and down can speed up overland flow of water during heavy rainfall events. If the paddock is too steep to cultivate across the slope, it is likely that it is not suitable for cropping and another paddock should be chosen.

Leave an uncultivated buffer around waterways to act as a filter for overland flow. Buffers should be at least 3m wide for flat paddocks and wider for areas with a greater slope (ie. A 7 degree slope should have a buffer of 10-15m). Regulations around buffer widths differ between Regional Councils. Contact your regional council for details about buffer zone requirements in your region.

Farmer tip:

"I use the paddock plan to show the contractor where I want cultivated, and where the critical source areas are that I don’t want cultivated. Sometimes I have found that even with giving them a plan they sometimes go too close on the gullies and swales. I now use a few electric fence standards to mark the edge of where I don’t want cultivated. This also keeps my contractor safe."

Leave Critical Source Areas (CSAs) uncultivated. These areas will provide a filter and slow down water movement, allowing it time to soak into the soil rather than running off. The areas lost to buffer strips and CSAs are generally low yielding areas anyway.

Consider direct drilling instead of conventional cultivation when establishing a crop to minimise soil exposure and soil loss. This option is not advisable in all situations as it may negatively impact on crop yield and the prevalence of pests and diseases. Discuss the benefits and risks direct drilling in your system with your agronomist.

Set up the crop early

Setting up the crop early will save you valuable time over winter. Get together with your farm team in early Autumn while ground conditions are good and use your paddock plan to set the winter paddock up. Take time to consider how you will transition your cows onto crop while you are planning how you set up your paddock. Perhaps you could put extra baleage in the transition breaks.

In Southland and some parts of Otago it is common to lay out the winter crop supplement in autumn while ground conditions are drier. It is important to carefully plan where supplement is placed to minimise environmental impact and to ensure that cows have adequate supplementation.

Place bales away from waterways and CSAs. Cows will spend a lot of time around the bale which will result in greater soil damage in these areas.

Farmer tips:

"I use electric fence standards to show them where I want bales of baleage placed in the paddock. I leave room close to the gate, so if crop yields are lower than budgeted, more supplements can be easily added."

"I put the baleage in well before winter, I plan the amount of baleage assuming a good crop yield. That means there is enough baleage, if there is a bit of extra baleage it doesn’t matter. Once I know the crop yield at the start of winter, I can match the mob size to the paddock."