The distribution of leaf area and light intensity within wheat crops differing in row direction, row spacing and rate of sowing is described. Regardless of the manner of planting, 75% of the total leaf area was found within a band 31/2 in. wide, centred on the centre of the row. Light penetration within crops spaced at 14 in. was greater than within those spaced at 7 in. Light penetration within rows running N.–S. was more uniform and higher, particularly around noon, than within rows running E.‐W. Within N.‐S. rows the position midway between rows received the highest amount of light, but light decreased on either side until it was least beneath the rows. Within E.‐W. rows at 14 in. spacing, maximum light was recorded at 101/2 in. on the southern side of a row, decreasing progressively as the row was approached.

Irrigated plots of a mixed sward of Lolium perenne, Paspalum dilatatum, Bromus unioloides, Dactylis glomerata and TrifoUum repens were used in 2 experiments during 4 years. In the first experiment, die treatments comprised factorial combinations of heights of cutting of 3, 6 and 10 cm (1-2, 2-4 and 3-9 in.) above ground level, and heights of growth of 5,13 and 20 cm (2 0, 51 and 8-0 in.) above the height of cutting. In the second experiment, 8 comhinations of dose (3 cm or 1-2 in.) or lax (10 cm or 3-9 in.) cutting were applied at various times during eadi year.In the first experiment, DM production for cutting heights of 3, 6 and 10 cm was 50, 44 and 43 t/ha (19 8,17-5 and 171 ton/ac), respectively; the DOM production was 37,32 and 32 t/ha (14 7, 12-7 and 12-7 ton/ac). DM production for growth heights of 5,13 and 20 cm was 45,46 and 48 t/ha (17-9, 18 3 and 191 ton/ac), respectively. DOM production, 34 t/ha (13-5 ton/ac), was not affected by height of growth.Percentages of protein (26, 22 and 20) and DOM (76, 72 and 71) declined as the height of growth was increased; but cutting height produced no significant effects in them. As cutting height was increased the percentage of clover declined (40, 31 and 23) and that of grasses increased (52, 66 and 72); diere were smaller changes with changes in height of growth.Hie second experiment showed that the difference between close and lax cutting became significant only when lax cutting was applied for at least half of the cuts each year. DM production was similar for treatments witii the same number of close or lax cuts, regardless of the time of year at which the two heights of cutting were applied.

Irrigated plots of a mixed sward of four grasses and white clover were cut to a height of 3 cm in either June, August, Octoher, Decemher or February. The plots cut at each commencement date were harvested when the height of growth of the pasture was either 10, 18, 25, 32, 40, 48 or 55 cm. At each harvest, the pasture was cut at 7 to 8 cm intervals down to a height of 3 cm. DM production, hotanical composition, in vitro digestibility (DOM) and CP of each layer was determined.DM production declined from the lower to the upper layers for pastures shorter than 32 cm. For pastures taller than 32 cm, DM production declined from the lower to the middle layers, then increased in the upper layers, due maiuly to the presence of seed heads.Maximum percentages of DOM and CP were observed for the middle layers of the pastures taller than 25 cm. For pastures shorter than 25 cm, DOM and CP percentages increased from the lower to the upper layers, for all commencement dates. The percentages of DOM aud CP of each layer decreased as the height of growth increased.The percentage of DOM showed a positive correlation with the percentages of Lolium perenne. Bromus unioloides and Trifolium repens. and a n^ative correlation with the percentages of Paspalum dilatatum and chlorotic material. The percentage of CP showed a positive correlation with the percentages of Paspalum dilatatum, Dactylis glomerata and Trifolium repens and a negative correlation with the percentages of chlorotic material and the total of the four grasses within the pasture layers.The lower layers of the pasture produced large quantities of DM and, despite the lower in vitro digestibility of these layers, they produced more DOM than the other pasture layers. The DOM 'Present address: Veterinary Institute, Pucallpa, Peru production of the pasture increased with increasing height of growth, but decreased as the commencement date was altered from winter through to the end of summer.

Sowing pasture species with wheat caused a reduction in the growth and yield of the pasture species. This reduction was more severe with wheat drilled at 7 inch row spacing than at 14 in., and was least when the two crops were in alternate 7 in. rows. The reduction appeared to be due principally to the shade cast by the wheat. The pasture also reduced the growth and yield of wheat, but the effect of row spacing and position were opposite to and very much less marked than those of wheat on pasture. The yield of the pasture early in the following season was related to the seed yields in the year of establishment; later in the season, however, differences in yield among the various treatments disappeared.

White clover (Trifolium repens) was fermented in the presence of detergent extracts of thirty-two cocksfoot (Dactylis glomerata) cultivars and eight other pasture species, using a two stage in vitro technique. The in vitro dry matter digestibility of white clover was not depressed by the presence of the detergent extracts to any practical extent. The small depression observed was probably due to the presence of water soluble components of the pasture species. The presence of a detergent-soluble, metabolic inhibitor in cocksfoot cultivars, or the eight other pasture species, was not exhibited using the method described. The in vitro dry matter digestibility of white clover in the presence of detergent extracts of cocksfoot was not correlated with the digestibility values of the cocksfoot samples from which the extracts were made. This suggests that the wide variation observed in the digestibility of the cocksfoot cultivars (54 to 80 per cent) was not due to the presence of any detergent-soluble, inhibiting substances.