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The management of dual-purpose barley in Tasmania

B.C. Stewart and N.J. Mendham

Department of Agricultural Science, University of Tasmania, Hobart TAS 7001

In Tasmania the use of cereals for dual-purpose (forage and grain) crops has been a long standing practice. The value of modem high yielding cultivars for dual-purpose cereal crops needs investigating. In a previous experiment (1) it was demonstrated that with the correct management it was possible to graze a winter barley cultivar (cv. Ulandra) without significant loss of grain yield. To develop a suitable management program for grazing barley, information is needed on the effect of a range of sowing times.

Methods

Grazing experiments were carried out over three seasons at Thirlstane, north-west Tasmania, using Angus yearling heifers. Early and late April sowings were combined with the grazing and nitrogen treatments outlined in the previous experiment (1). There were four treatments providing differing amounts of forage removal (i) control, no grazing, (ii) early grazing (as soon as a reasonable amount of forage was available), (iii) late grazing (just prior to the shoot apex reaching grazing height), (iv) early and late grazing (a combination of grazing treatments (ii) and (iii)). Each treatment was split for 0 and 50 kg N/ha following grazing.

Results and discussion

Figure 1. The effect of forage removal on grain yield for (a) the early April sowing (mean of two seasons), and (b) the late April sowing (mean of three seasons), at N rates of 0 kg/ha (), and 50 kg/ha (), and showing lines of best fit for 0 and 50 kg N/ha.

Forage removed was calculated by subtracting crop dry matter after grazing from crop dry matter before grazing. The amount of forage removed was highest in those treatments which included late grazing. Grain yield was reduced as the amount of forage removed increased (Fig. 1). Regardless of grazing treatment the trend was for grain yield to be higher with later sowing (Fig. 1). Grazing, however, had a greater effect on final grain yield than sowing time. Nitrogen improved grain yields on all treatments (Fig. 1) including controls but an economic advantage is only likely with higher grain prices.

Unless a crop is grown for grain only the choice of sowing time will depend on when forage is most needed. A decision on the timing and amount of grazing will depend on the relative importance of forage versus grain yield as later grazing will increase forage yield but decrease grain yield (Fig. 1).

Reference

Stewart, B.C. and Mendham, N.J. 1989. Proc. 5th Aust. Agron. Conf., Perth. p. 484.

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