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In planning forest management we have the considerable advantagesin Great Britain of an almost clean sheet, fast growth, amplespecies, resourceful engineers, and inexhaustable markets. Wemust organize so that it pays to grow trees. The kind of timberwanted is discussed; how it should be presented for sale; annualquantities needed by an efficient sawmill; and the level ofprices to be paid. 相似文献
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A. Kraai 《Euphytica》1962,11(1):53-56
Bees are used to pollinate plants in isolation cages. Usually the bees have previously flown about freely in the open air and may have gathered pollen from the same plant species.Now the question arises whether the bees can contaminate with this pollen plants with which they are enclosed in an isolation cage. In this connection a number of experiments were undertaken to find out how long bees are loaded with germinable pollen. It appeared that the risk of contamination was practically eliminated by keeping the bees in a house or empty isolation cage for 12 hours. 相似文献
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Two experiments were conducted to study the effect on nutrient loss and feeding value of making hay by different means, using a barn-drier, a forage-harvester, a crimper and conventional tedding. Both forage-harvesting and crimping of the herbage significantly increased the rate of drying, compared with tedding alone. In Exp. 2 this effect enabled the crimped and forage-harvested hays to be baled for storage 3 days earlier than the tedded hay. The use of the forage-harvester significantly reduced the yield of herbage compared with conventional mowing. Nutrient losses from cutting until storage were highest for the forage-harvested hays, the loss of dry matter between cutting and storage in the forage-harvested hays being 39·9 and 19·3%, respectively, in Expt 1 and 2 with corresponding losses in the conventionally made hays of 7·1% and 9·3%. Crimping the hay resulted in higher nutrient losses than tedding. In Expt 2 there was a loss of dry matter of 17·5% in the conventionally made hay during an 18-week storage period, compared with 3·6% in barn-dried hay, 10·8% in forage-harvested hay and 8·8% in crimped hay.
In Expt 2, in which digestibility determinations were made, conservation decreased the total digestible nutrients and starch equivalent in all treatments. The use of the barn-drier gave the most efficient conservation of total digestible nutrients, followed by the crimped, forage-harvested and conventional treatments in that order. The starch equivalent values of hays made from the same sward were 43·0 when barn-dried, 39·8 when crimped, 38·6 after forage-harvesting and 31·6 after tedding. 相似文献
In Expt 2, in which digestibility determinations were made, conservation decreased the total digestible nutrients and starch equivalent in all treatments. The use of the barn-drier gave the most efficient conservation of total digestible nutrients, followed by the crimped, forage-harvested and conventional treatments in that order. The starch equivalent values of hays made from the same sward were 43·0 when barn-dried, 39·8 when crimped, 38·6 after forage-harvesting and 31·6 after tedding. 相似文献
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Dr. A. Müller 《Journal of pest science》1925,1(10):117-119
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