Nitrogen fixation by white clover in hill pasture

An experiment is described in which the amount of nitrogen fixed by the white clover component of a surface-sown hill sward was determined using small quantities of ¹⁵N-labelled ammonium sulphate. Between 11 July and 22 August 1974 25 kg ha^?1 N was fixed. No evidence of a transfer of N from clover to the associated perennial ryegrass was detectable over this period although the N content of the grass growing with the clover was higher. The relative advantages of the isotope technique and the acetylene reduction assay are discussed.     

THE ELECTRONIC MEASUREMENT OF SMALL HERBAGE YIELDS USING A HIGH SENSITIVITY CAPACITANCE METER

The capacitance meters available in the past for estimating herbage yields have lacked sensitivity at the extremes of their range of measurement. The preliminary evaluation of a highly sensitive capacitance meter described here indicates that accurate measurement is possible in the range 0.1100 kg DM/ha. The implications of this development for the measurement of herbage of low availability are discussed.     

The potato in hakluyt

Summary Richard Hakluyt (ca. 1553–1616) collected together and published first-hand accounts of the voyages of English seamen, including several 16th century voyages to South America. These accounts provide some of the earliest published references to the potato, but unfortunately they make no mention of its introduction into Europe.     

LOSSES IN THE CONSERVATION OF HEAVILY-WILTED HERBAGE SEALED IN POLYTHENE FILM IN LINED TRENCH SILOS

A conservation experiment is described in which the losses in ensiling heavily-wilted herbage, of approximately 50% dry matter, in lined trench silos, with and without a polyethylene film seal, are compared. The composition and digestibility of the silages produced in the sealed silos were comparable with those of the original herbage. The content of organic acids in the sealed silos was low, suggesting that fermentation was suppressed by the partially gas-tight seal. In the unsealed silos there was considerable spoilage, 70% of the material being inedible. In the 2 sealed silos losses of dry matter were 8·2 and 5·2% and losses of SE 11·5 and 7·8%, respectively. The losses recorded are compared with those usually encountered in lined trench silos.