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1. Data on the dry-matter production of five grass species (each sown with white clover), over the period 1954–56, at six levels of compound fertilizer application, are reported. Perennial ryegrass (S. 101), meadow fescue (S. 215), timothy (S. 48), cocksfoot (S. 26) and bent (N.Z. browntop) were sown in 1953 at appropriate seed rates, each with 2 lb. per acre S. 100 white clover. The fertilizer treatments were 0, 1, 3, 5, 7 and 9 cwt. per acre of a compound of composition 10% N, 4% P2O5 and 9·5% K2O, applied in the early spring of each of the years 1954–56. The swards were cut three times a year in 1954 and 1956, but only two cuts were possible in 1955.2. The timothy mixture gave the highest total production of dry-matter over the 3 years, the bent and perennial rye-grass mixtures giving the lowest total productions. Differences between mixtures in annual yield varied in sign and in magnitude from year to year. For example, bent gave the lowest yield in 1954, but outyielded the meadow fescue and the cocksfoot mixtures in 1955, and the perennial rye-grass mixture in 1956. As regards the distribution of dry-matter production over the season, it was found that bent differed from the other mixtures in that a higher proportion of its annual yield was produced at the second and third cuts.3. There were significant linear relationships of dry-matter yield to fertilizer application rate in most of the data. On average over the 3 years, 1·6 cwt. of dry-matter were produced for each cwt. of spring applied fertilizer in the first cut, 0·7 cwt. per cwt. of fertilizer in the second cut, while very small and non-significant responses were found in the third cut. There was no evidence of systematic differences between grass mixtures in response to fertilizer level.4. The yield of clover dry-matter in 1956 (the third harvest year) was least from the cocksfoot and timothy swards, and was significantly and linearly depressed by fertilizer application in all three cuts.

Controlling weeds until 6 weeks after crop emergence gave a yield of soyabeans only 85 per cent that of the clean-weeded control treatment. Delaying weeding until 3 or 6 weeks after emergence gave yields 89 per cent and 69 per cent respectively of the control. Narrow crop rows (30-5 cm.) gave higher yields than wide rows (61 cm.). Defoliation of soyabeans reduced pod number, seed size and yields more with late and severe defoliation, and with lower plant populations. Delayed harvesting during the dry season led to seed shedding and yield was at the maximum for only about one week.There is currently considerable interest in soyabean (Glycine max (L.) Merrill) as a potential crop in the West Indies, partly because of a desire, and need, to reduce expenditure on imported feeding stuffs (of which soyameal is a major component) and partly because of the potential value of soyabean-based foods in human nutrition, particularly for children.Research on soyabeans within the Faculty of Agriculture, begun about 1967 in Trinidad and 1969 in Jamaica, has been reported in the Annual and HalfYearly Reports of the Faculty of Agriculture of the University of the West Indies, and Radley (1968) has summarized certain of the Trinidad investigations. The current paper reports three investigations carried out as part of the Faculty's programme of agronomic investigations of this crop. The first examined weed competition and time-of-weeding effects, the second investigated the effects of leaf removal to evaluate defoliation by leaf eating insects, animals or freak weather, and the extent of mutual shading within the leaf canopy, and the third studied the effects of premature and delayed harvesting on soyabean yields. MATERIALS AND METHODSAll three experiments were laid down on cambered beds on River Estate Loam on the University Field Station, Champ-Fleurs, Trinidad. The experimental sites were fertilized at the rate of 45 kg./ha. N, 45 kg./ha. P 2 O 5 and 67 kg./ha. K 2 O before planting. Plots were sown by hand and thinned if necessary, to give the desired plant populations. The soyabeans were harvested and threshed by hand. Random samples of ten plants were taken for height measurements and counts of pod number. A random sample of seed from each plot was oven-dried (85 °G) to correct yields and determine 1000-seed weights, and all yield data and 1000-seed weights refer to oven-dry seeds.Experiment 1 was sown 12 June 1969, with selection F62/3977, and harvested between 28 October and 13 November. Treatments comprised all combinations * Present address: Faculty of Agriculture, University of the West Indies, Mona, Kingston 7, Jamaica.

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A fine soil separate gave the highest and most rapid seedling emergence. This was considered to be due to its better moisture supply characteristics and the lower mechanical impedance compared with coarser seed-beds. There was no evidence that natural seed clusters are any less responsive to soil aggregate size than processed beet seed clusters.Consolidation slightly hastened emergence, though the mechanism of this is not clear. Sowing at ¾ in. was superior to deeper sowing (1½ in.), both in speed of emergence and in ultimate emergence. This was partly an effect of decreased mechanical impedance, and partly due to the shorter period over which the seedlings were susceptible to pathogens. Heavy dressings of soluble fertilizers were found to delay emergence, though without effect on the ultimate emergence.