Hoesttid i vinterhvede, vaarhvede og vinterrug.

As continuation of the harvest time experiments with oats and barley mentioned in Report No. 1489 harvest time experiments with winter wheat, spring wheat, and winter rye were carried out in 1976-78. The harvest period lasted about 4 weeks, starting at yellow-ripeness when the water content is 25-30 per cent. Winter wheat: The largest grain yield was obtained when the harvest took place in the first half of August at the yellow-ripeness stage. A 2-3 weeks' postponement of the harvest time causes no essential yield reduction, depending, however, to some extent, on the variety. Even if, on the other hand, the harvest is only delayed until the end of the first week in September, there is a risk of considerable yield reductions averaging in these experiments about 10 hkg grain per ha, but with very great variations according to place and experimental year. As to quality characteristics, only the litre weight was essentially affected by the harvest time. The second harvest time gave the best litre weight which declined considerably at the subsequent harvests. Spring wheat: On account of the later ripening, the harvest with optimum yields falls in the latter half of August, the harvest period thereby becoming shorter than that of winter wheat. Any harvest taking place later than around September 1 gives yield reductions, on an average up to about 5 hkg grain per ha until mid-September, the variations according to place and year being, however, considerably smaller than those of winter wheat. The litre weight fell considerably through the harvest period towards the last harvest time. The other properties remained unchanged. Winter rye: On an average, the harvest in early August gave the highest grain yield, but as to yields there were no significant differences between the various harvest times. On an average, there were only inconsiderable variations according to place and experimental year. The litre weight was rising until the middle of the harvest period, and then there was a considerable decline. The grain weight was rising during the first part of the period, afterwards it remained stable. As to the baking qualities, the experiments showed that the best bread grain is obtained in winter wheat from the 2nd to 4th harvest times, in spring wheat from 1st and 2nd harvest times, and in winter rye from 1st harvest time.