Golden Syrian hamsters fed a cholesterol-free diet containing 25% casein had higher plasma total triglyceride and cholesterol levels and VLDL + LDL cholesterol levels than animals fed a 25% soybean protein diet. Hamsters fed the cholesterol-free casein diet also had higher HDL cholesterol levels than animals fed the soybean protein diet, but these differences were not statistically significant. Addition of cholesterol to the diets caused even greater mean differences between the animals fed different types of protein, but the increased inter-animal variability of response to the added cholesterol resulted in less statistically significant differences. Although less responsive than the nonhybrid Golden Syrian hamsters, hybrid F1B hamsters showed similar effects of dietary casein vs. soybean protein on plasma lipids. These results indicate that the hamster may be a useful model to examine the effect of different types of protein and the interaction with dietary cholesterol on various plasma lipids and lipoproteins.

SUMMARY1. Two experiments were conducted, the first during May, July and August, 1958, and the second during August 1960. The first experiment measured the intake and digestive efficiency of cattle fed on fresh cut herbage from low-and high-nitrogen manuring treatments with and without irrigation. The second experiment tested the effect of water added to fresh cut herbage on the intake of cattle.2. Rainfall during the summer of the first experiment was high and irrigation had no effect on any of the criteria used.3. Although the dry-matter content of the fresh herbage from the high nitrogen treatment was consistently lower than that from the low nitrogen treatment (16·6% compared with 19·7% on average when free of surface moisture) the dry-matter intake was the same at 1·97 lb. dry matter per 100 lb. live-weight, on both herbages.4. The average digestibility of the high and low nitrogen treated herbage was 77·6% and 75·4%, the difference being significant. No scouring occurred. Digestibility was 78·9% in May, 76·1% in July and 74·5% in August (average of N levels).5. Rain water carried on the leaf surface was shown to have no effect on dry-matter intake.6. It is concluded that the dry-matter intake of cattle feeding on fresh herbage is unlikely to be restricted either by a high internal water content in the herbage or by rain water on the leaf surface.

A study was made of the effects of seedbed compaction and use of fertiliser (application rate, placement, and the choice of ammonium or nitrate forms of nitrogen) on the availability of manganese to barley in light soils in East Scotland. Generally, the uptake of manganese by the plants was increased by increasing the amount of fertiliser applied and by compaction of theseedbed, althoughno significant increase inextractable soil manganese was detected. The increase in uptake from wheel-tracks (where the compression had resulted in an element of fertiliser placement), compared with nonwheeled areas, was much greater than the effect due to overall plot compaction by tractor wheels in the absence of a fertiliser placement effect. Combine-drilling of fertiliser with the seed resulted in large increases in plant uptake of manganese in non-wheeled areas, compared with uptake where the fertiliser had been broadcast, but had no significant effect in the wheel-tracks where growth and uptake were generally better. In some, but not all, experiments, significant reductions in pH occurred in the soil beneath the wheel-tracks which were very closely correlated with increases in extractable manganese. Use of ammonium sulphate as nitrogen source also reduced the pH, compared with calcium nitrate, and this, too, increased extractable manganese and greatly improved plant growth. The probable cause of enhanced manganese availability was soil acidification brought about by nitrification of ammonium fertiliser and/or by H+ ion secretion by roots to balance the uptake of ammonium and other cations. The uptake of manganese by the plant was further improved either through concentration of fertiliser in the root zone by placement, or by soil compaction which resulted in shallow sowing of seed and a closer active relationship between roots and broadcast fertiliser. Other possible factors involved were (a) a greater exudation by roots of compounds able to dissolve insoluble manganese, in compacted soil; (b) contact reduction processes; (c) stimulation of root growth, leading to more efficient uptake by the plant, where higher rates of fertiliser were used or where the fertiliser was concentrated in localised zones in the soil..

Continuous hourly records of soil temperature were collected at 1, 5 and 20 cm, throughout two growing seasons, 1973 and 1974, under crops of spring barley in the east of Scotland. Measurements were obtained from three cultivation treatments, deep ploughing, normal ploughing and direct drilling, at two nitrogen fertiliser levels, 0 and 150 kglha. Compared with ploughed soil, directdrilled soil had a higher surface reflection coefficient and a higher thermal diffusivity between 5 and 20 cm; overall, this resulted in lower heat sums ("C hours/day over 5 "C and 10 "C) in directdrilled soil at 1 cm and 5 cm during the first 20 days after sowing. The thermal regimes of normally and deeply ploughed plots were very similar. Nitrogen fertiliser caused significant lowering of soil temperature a t all three depths in the latter half of the growing season, due to increased shading of the soil surface by the crop canopy. Some implications of these findmgs for cultivations for cereals are discussed.

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