Pasture production, pasture composition and quality, and liveweight, body condition and wool growth of Merino weaner wethers were monitored over 2 seasons and at 2 stocking rates (4 and 8 sheep/ha) on a mixed annual grass-legume pasture sprayed with propyzamide to control grasses. Propyzamide virtually eliminated annual grasses from the pasture (less than 5 kg/ha of grass dry matter in spring v. 403 kg/ha on untreated pasture in 1981) and this carried over into the second season (61 kg/ha v. 647 kg/ha in spring 1982). Propyzamide treated pastures had less total dry matter (P = 0.05) throughout 1981: however, except for a single sample date, there was no effect of propyzamide on total available pasture in the second season. Increased growth of clover and capeweed compensated for the absence of the grasses. The higher stocking rate reduced available clover, capeweed and total dry matter (P = 0.05) throughout both years. Sheep grazing grass-free pastures had lower liveweights during winter in both years, but made compensatory gains during late spring and summer consistent with the higher quality (1.6 v. 1.07% nitrogen when sampled in January) of propyzamide treated pastures. In 198 1, wool growth rates were reduced at the higher stocking rate and total clean wool production was reduced from 4.55 kg/sheep at 4/ha to 3.65 kg/sheep at 8/ha. Pasture treatment had no effect on wool production in either year. The implications of using selective herbicides to remove the annual grass component of legume-based annual pastures in south-western Australia are dis cussed in relation to pasture and sheep production.

Field trials on cereals over four years have consistently shown that wider spaced rows reduce grain yields, and these effects are not influenced by the environment, soil type or variety. Stubble modification during the previous harvest by cutting low and using straw choppers, or reducing stubble levels by careful grazing or raking before seeding are perhaps better methods of overcoming tine spacing on seeders. Wheat sown in rows 9 cm apart produced significantly higher yields than wheat sown at the conventional 18 cm spacing. Topdress sowing of wheat may approach the plant arrangement seen in rows 9 cm apart, but unreliable plant establishment has caused yields to be lower than with the 18 cm spacing.

Growth and reproductive phenology of field-grown, non-irrigated L. angustifolius (cv. Unicrop) were studied by periodic sampling of plants. Anthesis occurred when plant carbon content was only 15% of its final maximum. Flowering and the main periods of pod growth and seed filling took place, respectively, 0-6, 5-9 and 8-12 weeks after anthesis. Over 80% of the plant's gain of carbon in dry matter occurred 0-8 weeks after anthesis, after which drought-induced defoliation curtailed dry matter accumulation. 14CO2 was fed to selected plants at weekly intervals over the period 0-12 weeks after anthesis and time courses of transfer of 14C-labelled assimilates to fruits were assayed non-destructively by periodic sampling of phloem sap from fruits. Average specific radioactivity of carbon of phloem sap samples from primary, secondary and tertiary fruits of each feeding treatment were compared with specific 14C activities of the respective fruits harvested at maturity. The agreement between data was very close with times of 14CO2 feeding up to 8 weeks after anthesis. With later times of feeding, average specific radioactivity of phloem sap was higher than that of fruits as labelled sap was collected for only the latter part of the life of the fruit and before the fruit had accumulated unlabelled carbon. Carbon from photosynthate fed before or during flowering contributed mainly to protein of the seed, that from photosynthate formed during fruiting mainly to non-protein seed components. Distribution of 14C between amino and non-amino compounds of fruit phloem sap of plants fed 14CO2 at anthesis or in late fruiting reflected this effect. Estimates of contributions of carbon of photosynthate to fruits suggested that only 2% of the fruit's carbon came from photosynthesis before flowering and only 3 % from photosynthesis 0-3 weeks after anthesis, while 18, 28 and 23% came from photosynthate formed respectively 3-6, 6-9 and 9-12 weeks after anthesis.