Moisture stress shows

3 October 1997

Moisture stress shows

FARMERS are measuring grass growth rates ranging from 25 to 45kg DM/ha/day, writes New Zealand consultant Paul Bird, who is working for the British Grassland Society.

Farms with free draining, shallow soils are experiencing moisture stress which is reducing grass growth. But at the time of writing, rain is due in most areas and with soil temperatures are above 10C (50F) grass growth is likely to increase in these drier areas.

Milk production from summer and autumn calved herds on well managed, grazeable farms is ranging from 26 to 34 litres. Cows are being fed 4 to 7kg concentrate, getting 13 to 15kg DM from grazing and receiving no silage. These results are coming from farmers who in previous years believed grazed grass had no value in October and November.

Farmers focusing on extended grazing should be planning one more grazing rotation around the farm.

For those who want to stay out grazing until Nov 20, a 50-day rotation will be required (1/50th of the farm every 24 hours). Excellent responses from light applications of urea will continue if soil temperatures remain above 7C (44.6F).

When grass covers are low silage can be fed economically and this will help to lengthen the rotation. In wet conditions graze for two to four hours after each milking and then bring the cows inside. This will minimise poaching and protect regrowth.

The last grazing rotation should begin on the driest fields on the farm as these will be the ones required in late winter/early spring for early turnout. This means that the paddocks grazed in November may be wet. Planning must, therefore, go into access and grazing techniques in these areas. For practical suggestions on grazing wet soils, see Livestock Sept 19, p48.n

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