Kazuji Osaki

Studies on the Relation between Persistence of Volunteer Cereals and Cropping System in Upland. VI Separating characteristics of rough rice separaters to contaminated barley by mixing of volunteer wheat grain.

We investigated the separating characteristics of rough rice separaters to contaminated barley grains by mixing of volunteer wheat grains.A principal factor in separation by rough rice separater was the difference ratio of grain length. So the difference ratio of grain length for barley and volunteer wheat grain were 1:0.78.The performance of a rough rice separater for removing volunteer wheat grain from barley grain was poor, when separating the rice from the chuff. When the pan oscilation was 160rpm and pan slope, 16°, the rough rice separater efficiently removed volunteer wheat grain. So barley grain had met the standerd requirements at inspecting.Then Newtons efficiency was 0.7. But thirty percent of the barley grain were discharged with wheat grain.This operation was an emergency measure of prevention against the contamination of barley grain by mixing of volunteer wheat grain. Because barley grain loss on separating by rough rice separater resulted from falling in shipment of barley.

Studies on the Relation between Persistence of Volunteer Cereals and Cropping System in Upland. (VII) Control of volunteer wheat by inter-cultivation and ridging.

The mixing of barley grain with volunteer wheat grain causes a serious problem in wheatsoybean-barley rotation. This report describes the relationship between the persistence of volunteer wheat and the mechanical weeding method in soybean culture. Control of volunteer wheat by inter-cultivation and ridging in soybean fields was effective. During the summer, most volunteer wheat plants died from drying or burying.Inter-cultivation and ridging had killed wheat grain and wheat seedlings at a soil layer of 0-6cm deep. So when inter-cultivation and ridging were used in the cultivation of soybean, volunteer wheat decreased in fields where barley were planted by no tillage. But when inter-cultivation and ridging were also used in the cultivation of soybean, volunteer wheat increased in fields where barley were planted by rotary tillage. The reason why volunteer wheat increased in this field was that the wheat grain at a soil layer of 7-15cm deep was moved to suitable depth of emergence by rotary tillage.In wheat-soybean-barley rotation, the best means were to prevent the mixing of barley grain with volunteer wheat grain by the combination of inter-cultivation with ridging in the cultivation of soybean, and by no tillage in the cultivation of barley.

Studies on the Relation between Persistence of Volunteer Cereals and Cropping System in Upland. III On the growth of volunteer wheat in barley fields under the alternating system between barley and wheat in Ibaraki prefecture.

Contamination of barley grain by mixing of volunteer wheat grain is now causing a serious problem in barley production under the alternating cropping system between barley and wheat. We chosed 8 upland fields of 7 farmers, whose growing area was rather large, and 7 upland fields converted from paddy fields by 4 farmers. We investigated the growth of volunteer wheat plants in those fields and discussed how harmhul volunteer wheat was to the production of barley in Ibaraki Prefecture.The fields were investigated regarding cropped barley and wheat alternately so as to prevent a yield decrease caused by continuous cropping or the yellow mosaic disease.In the fields where barley was planted after harvesting wheat, the contamination of barley grain by mixing of volunteer wheat grain occurred in the upland fields, regardless of summer cropping.The volunteer wheat plants grew on both the inter-row spaces and ridges in the barley fields, so it was difficult to control volunteer wheat plants using cultivators.The benefit of barley production decreased by 14-57% due to the contamination of barley grain by mixing of volunteer wheat grain. The alternate cropping system between barley and wheat has been of interest to the farmers in the areas infected with yellow mosaic. However, the best way to control volunteer wheat plants is still being sought.