Recovery and reactions of amprolium from poultry manure added to soil

Amprolium, a coccidiostat added to poultry feed, occurs in excreta at concentrations of 204 μ g^?1 and investigations were made of the effect of this quantity of amprolium on the biochemistry of soil to which manure had been applied.Greenhouse experiments showed that 0.8 μg g^?1 amprolium was found in soil pots 80 days after treatment with manure at the equivalent of 56.1 t ha^?1 and was detectable 20 days following treatment at the equivalent of 11.2 t ha^?1.Laboratory experiments indicated that amprolium was differentially adsorbed to two complexing media, soil and manure. Since amprolium was a constituent of treated manure, it was expected that the amprolium manure-soil system would offer various sites for adsorption of amprolium. Mixing amprolium with soil and with soil plus untreated manure yielded approximately the same effect on amprolium adsorption based on recoveries in water solution, and as methanol extractable. However, total recovery of amprolium from treated manure added to soil was only a fraction of the above, indicating the high complexing capacity of the manure.No effect on soil respiration was observed by either pure amprolium or amprolium as a constituent of treated manure. The higher rate of manure application caused greater respiration due to the presence of more readily oxidizable organic matter, but the respiration pattern attributed to the manure component was not unlike the respiration pattern of the Guelph loam soil.     

The spread and development of Rhododendron ponticum L. on dunes at Winterton,Norfolk, in comparison with invasion by Hippophaë rhamnoides L. at Saltfleetby,Lincolnshire

A survey was made in 1972, of the status of Rhododendron pronticum L. at Winterton, Norfolk, and aerial photographs were used to assess its spread in recent years. The ecological implications of the continuing presence of this invsive alien shrub on the dunes are discussed. Comparisons with the highly successfull dune shrub Hippophaë rhamnoides L. help put into perspective the present and likely future role of Rhododendron at Winterton. The implications of controls are discussed together with methods by which this may be achieved.     

The effects of rates of nitrogen application on seven perennial ryegrass varieties

The dry matter and crude protein production of the perennial ryegrass varieties S24, S23, Premo, Houba, Barlenna, Melle and Sceempter Pasture at annual nitrogen application rates of 212, 425, 637 and 1062 kg ha^?1 were studied for the years 1972–74 inclusive. The DM and CP response curves for the variety Melle were steeper than those for other varieties tested and levelled off at a higher N application rate. The results suggest that Melle is a variety with a genotype capahle of utilizing N more efficiently at higher rates than the other varieties tested.     

Formation of volatile sulfur compounds by microbial decomposition of sulfur-containing amino acids in soils

Evolution of volatile sulfur compounds from soils treated with S-containing amino acids was studied by sensitive gas chromatographic techniques involving use of a flame photometric detector fitted with a sulfur filter. The following volatile sulfur compounds were identified as products of microbial decomposition of S-containing amino acids in soils under aerobic or waterlogged conditions: methyl mercaptan, dimethyl sulfide and dimethyl disulfide (evolved from soils treated with methionine, methionine sulfoxide, methionine sulfone or S-methyl cysteine); ethyl mercaptan, ethyl methyl sulfide and diethyl disulfide (evolved from soils treated with ethionine or S-ethyl cysteine); and carbon disulfide (evolved from soils treated with cystine, cysteine, lanthionine or djenkolic acid). Small amounts of dimethyl sulfide and carbon disulfide were evolved from soils treated with homocystine, and trace amounts of carbonyl sulfide were evolved from soils treated with lanthionine or djenkolic acid. No volatile sulfur compounds were evolved from soils treated with cysteic acid, taurine, or S-methyl methionine. The amounts of sulfur volatilized from soils treated with the 14 S-containing amino acids studied represented from less than 0·1 per cent to more than 50 per cent of the sulfur added as amino acid. Hydrogen sulfide could not be detected as a gaseous product of microbial decomposition of S-containing amino acids in soils under aerobic or waterlogged conditions.     

Egg incubation and larval rearing of navaga (Eleginus navaga Pall.), polar cod (Boreogadus saida lepechin) and arctic flounder (Liopsetta glacialis Pall.) in the laboratory

The embryonic and larval development of three White Sea cold-water fish species, rate of yolk sac absorption, age at first feeding and their survival and growth when fed different food organisms, were studied.Eggs were obtained from spawners in the Bay of Kandalaksha, White Sea, and incubated in troughs and aquaria at a mean temperature of 1.5 °C, slightly above that of the sea. The incubation period for polar cod eggs lasted 35 days, for arctic flounder, 42 days and for navaga eggs, 48 days. Emergent larvae were 5.5–6.0 mm long and began feeding at 2–4 °C, 5–6 days (navaga) and 12–14 days (polar cod) after hatching, when their yolk sac was still fairly large.They were fed day-old Artemia nauplii and zooplankton taken from the sea and consisting of Calanus and Pseudocalanus nauplii 400–600 μ in length.The period of establishing first feeding is the most critical for larvae.