The practice of growing summer crops such as maize and turnips is common on North Island dairy farms.

More recently biennial (chicory) and perennial (plantain) crops are becoming popular. Growing summer crops to increase the supply of feed in the system alone is unlikely to increase whole farm profitability.

Numerous farm systems studies have found that, at typical crop yields achieved by farmers, the increase in utilisable dry matter grown from summer crops was insufficient to cover the costs of growing the crop, replace the dry matter that would have been grown by pasture and show a profit. This point is simply demonstrated in Table 1 where the relative crop yield (gross yield less the pasture that would have been grown) divided by the costs of growing the crop is calculated. The cost per kg DM can be compared to other feed options such as purchased feed.

Reasons other than increasing the feed supply such as renewing pasture, more effective use of effluent areas, managing spring surplus pasture and protecting pasture from over-grazing in the summer, may justify growing summer crops on farm.

If pasture renewal is a key reason for growing a summer crop, selection of the right crop to achieve pasture renewal target dates is most important.

Whenever a paddock is sprayed out, the farm is exposed to increased risk until the new crop or pasture is established.

Management practices must ensure that the crop has the best chance of success as high yield and utilisation are important, regardless of the reason for growing the crop.

For more information on summer crops read The place of summer crops in dairy farm systems in the September edition of DairyNZ's Technical Series.

Supplied by DairyNZ.