In two experiments the yield, digestibility, protein and cell wall contents of several autumn-sown triticale cultivars were compared with rye at defined growth stages. Yields at each growth stage were highest in the triticale cultivars. The content of leaf blade and sheath fell with increased maturity while stem and ear content increased. There were differences between cultivars in the contribution of individual stem internodes. Digestibility also declined with maturity for all plant parts, and differences were apparent between plant parts and between cultivars. Leaf blade showed a slow decline in digestibility whereas stem digestibility showed a rapid reduction so that, at growth stage 43, young stem internodes were of much higher quality than older ones. Spring-type triticales (A208 and A476) had the highest digestibility at stages from flag leaf emergence to anthesis. The relationships between digestibility, plant part contents and cell wall characteristics are discussed.

In a 2-year field study, leguminous fodder crops (cowpea (Vigna unguiculata) and cluster bean (Cyamopsis tetragonoloba)) responded more to P than did nonleguminous fodder crops (maize (Zea mays), sorghum (Sorghum bicolor) and pearl millet (Pennisetum americanum)). The local cultivar of tall wheat, C306, yielded more when sown after fallow or legumes than after nonlegumes. Wheat sown after fallow or legumes produced more ear-bearing tillers and more grains per ear than when sown after nonleǵumes. Wheat sown after fallow or legumes responded to N application of up to 20 kg/ha, while when sown after nonlegumes it responded linearly to the highest rate of 60 kg/ha. Thus, preceding fallow, cowpea and cluster bean reduced the N requirement of wheat by 20–40 kg/ha compared with preceding maize, sorghum and pearl millet. Nitrogen increased grain yields only at applications of up to 40 kg/ha because lodging occurred at the higher rates. A cluster bean-wheat cropping sequence proved the most profitable.

The responses to treatment with chlormequat of winter oats at various rates of applied N were investigated in field experiments over two seasons. Chlormequat, applied at crop growth stage (GS) 32, significantly reduced stem length by an overall average of 25·3% in 1985/86 and 27·4% in 1986/87. The percentage reduction was not significantly influenced by variety or by the rate of N applied. All intcrnodes apart from the basal one were significantly shortened. The third internode from the base showed the largest percentage reduction and the uppermost internode the largest actual reduction in length, in all three varieties. Stem shortening was always associated with an increase in the weight per unit length of stem. In 1985/86 lodging in untreated control plots became more severe as N rate increased, but was completely controlled by the application of chlormequat at all but the highest rate (150 kg N/ha).

Combine-harvested grain yields of the variety Pennal in 1985/86 and of Bulwark and Pcnnal in 1986/87 were reduced where chlormequat had been applied. Hand-harvested samples from these treatments did not show the same reductions in yield, but revealed a significant increase in the number of grains per panicle and a significant reduction in their mean individual weight. The grain characteristics of Peniarth were unaffected.

The lengths of the main-stem panicles and primary branches in the panicle were shortened as a result of chlormequat application. In addition, the degree of branching and the number of spikelets were increased in the lower third of the panicle but reduced in the upper two thirds. In both Bulwark and Pennal the numbers of sterile grains were increased by the application of chlormequat and, in Bulwark only, the number of fertile grains was reduced. In Peniarth the numbers of fertile and sterile grains were unaffected.

Immunoreactive (I) and biologically active (B) luteinizing hormone (LH) was measured in jugular vein and carotid arterial plasma of four cows 110–140 min after luteinizing hormone releasing hormone (LHRH) injection. Plasma was separated on Ultragel AcA54 and fractions corresponding to those containing authentic bovine luteinizing hormone (bLH) were assayed. Immunoreactivity in venous or arterial plasma occurred mostly in fractions corresponding in molecular weight to bLH. Low activity was measured in several other fractions. Biological activity was also high in the same fractions from venous plasma, though it was not so pronounced in arterial plasma.

A veno-arterial difference across the head for immunoreactive LH was found in all animals, and there was a significant difference in biologically active LH (mouse Leydig cell assay). The mean B:I value for immunoreactive LH was similar in venous and arterial plasma for three out of four animals, 0·72 and 0·66, respectively. In a fourth cow with a clinical history of infertility, the B:I value was low in both venous and arterial plasma, 0·19 and 0·08, respectively. The results indicate that infertility in this latter instance was associated with LHRH-induced secretion of a compound similar in molecular size and immunoreactivity to LH but deficient in biological potency.

Three in vitro methods, one enzymic and two microbial, were applied satisfactorily to the determination of the dry matter digestibility of forages, but failed when applied to a variety of concentrate feeds. The microbial methods had the advantage that the proportion of weight lost from forages during the in vitro process approximated closely with their determined in vivo digestibilities.

The microbial method based on sheep faeces was as effective as that using rumen liquor in digesting ruminant feedstuff's in vitro. Since sheep faeces are readily obtained from intact animals, the faeces liquor method would seem to have a distinct advantage in use.

Growth and water use of kabuli-type chickpea was measured during the 1982/83 and 1983/84 growing seasons in northern Syria under rainfed conditions. Winter-sown (November) and springsown (March) crops of cv. ILC 482 were grown in 1982/83 while in 1983/84 spring-sown crops of contrasting genotypes (ILC 482, ILC 1929 and ILC 3279) were compared.

In 1982/83, shoot dry matter and seed yields of the winter-sown crop were almost twice those of the spring-sown crop although the water use of both crops was almost the same. Root growth of both crops was most rapid before flowering but continued until maturity (early June) in the winter-sown and until mid to late pod filling (also early June) in the spring-sown crop. Root dry weight (c. 45 g/m2) and length (c. 45 cm/cm2) were similar in both crops during pod filling.

In 1983/84, shoot weight, root weight and root length were similar in all genotypes but the later maturity of ILC 3279 resulted in lower seed yield and hence harvest index, and greater water use.

The root length density decreased approximately logarithmically with depth in the soil profile although comparison between seasons and with other published results showed that the relations could not be used predictively. Water use efficiency was poorer in the second, drier season and was almost doubled by winter sowing.

A Mediterranean grassland was grazed with beef cattle at 0·5, 0·67 and 0·83 cows/ha, all the year round for 5 years. Range forage became increasingly scarce during the dry season, especially at high stocking density, and more supplementation was needed to maintain the animals. Herbage consumption was calculated from standard requirements for recorded body weight and performance. Maintenance requirements were multiplied by a grazing activity factor of 1·6.

Mean annual herbage dry matter production was estimated at c. 3·06 ± 0·137 t/ha. Most of the variation between years was due to a particularly productive year in 1978. Contrary to expectation, stocking density had a small effect on total herbage production, despite significant differences in animal performance. It appears that herbage production of the seasonally temperate herbaceous range, typical of the basaltic hills in eastern Galilee in Israel, is not limited by total annual rainfall. Alternative limiting factors are nutrient deficiency and restricted rooting zone, or a combination of both.

A total of 51 grass swaths was dried in a wind tunnel under controlled conditions of temperature and humidity. The swath treatments covered a range of conditioning treatments, crop types, maturities and porosities. Drying rates of the swaths were related to crop and swath properties to establish which variables were important in influencing the overall drying rates of the swaths. Multiple regression analysis was used to assess the statistical dependence of drying rate on variables reflecting crop and swath properties: the dependence on swath structure was approximately four times greater than the dependence on crop conditioning. Improved swath drying rates could be achieved by lesssophisticated machinery than the current mower conditioners.

The lentil (Lens culinaris Medik.) cultivars Titore and Olympic were sown at Canterbury, New Zealand, on eight dates, from April to November in 1984 and in May and August in 1985. Of the four important physiological growth stages (sowing to emergence (S–E), emergence to flowering (E–F), flowering to physiological maturity (F–Pm) and physiological maturity to harvest (Pm–H)), the duration of all except E–F depended upon accumulated thermal time above 2 °C. The mean accumulated thermal times for E–F, F–Pm, Pm–H were 116, 565 and 293 °C days, respectively. Stage E–F required from 1165 °C days for an April sowing to 509 °C days for a November sowing. There was a highly significant positive relationship (r2 = 0·99) between the rate of development during E–F and mean temperature. Photoperiod also affected development rate.

Neither of the two cultivars studied had a vernalization requirement for the induction of flowering. In both years, the development rate during E–F was highly dependent upon photoperiod-corrected temperature. The relationships presented show that development of lentil crops in Canterbury can be accurately predicted using accumulated temperature and photoperiod-corrected temperature.

The functional relationships between loge diameter and loge weight, and between length and diameter of the storage roots in carrot and red beet were described by two linear equations. These equations were fitted to data from three red beet and two carrot experiments. The agreement between the fitted and observed data was close. With increasing plant population density of red beet, the slope of the relationship between length and diameter decreased and the intercept increased. Although these changes in slope and intercept were statistically significant (P < 0·05), their magnitude was of negligible practical importance. The relationship between loge diameter and loge weight was little affected by length; the relationship between length and diameter was little affected by loge weight.

Using these equations in independent experiments, the diameters of roots of both species were predicted from measured root weights. The roots were then assigned to various commercial diameter grades on the basis of either the measured or the predicted diameter. Except for a few roots of red beet greater than 85 mm in diameter, there was close agreement between the observed and predicted number of roots in each grade.

Any model which predicts root weight might be extended to predict yield of marketable size grades, using these equations as a calibration between weight, diameter and length.

Densities of physiologically independent plants of white clover were studied in New Zealand in pastures stocked at 22·5 ewes plus lambs/ha by set stocking, rotational grazing or a combination of both systems. Plants were sampled once a month for 1 year (1984/85) by taking turves and washing out the plants. Numbers of growing points and stolon dry weight per plant were obtained. At each sampling fifty, 50 mm diameter pasture plugs were taken from each sward and growing point density and stolon mass/m2 of white clover were measured. The density of white clover plants in the swards was estimated on the basis of both stolon dry weight and number of growing points.

The two estimates gave similar results. There was a trend of lowest densities in set-stocked pastures (334/m2), intermediate densities in combination management pastures (431/m2) and highest densities in the rotationally grazed pastures (553/m2). The overall mean density of white clover plants was 439/m2 and the range was 193–811/m2.

The structure of swards under the three systems of grazing differed and this was considered to contribute towards the variation in density of white clover plants in the various swards.

The voluntary feed and water intakes of five llama × guanaco crossbreds (New World camelids) and five sheep, and their abilities to digest various feed components and to utilize nitrogen, were compared using a diet of threshed ryegrass straw in New Zealand in 1987.

The camelids ate more than the sheep, but intakes were similar relative to metabolic live weight (mean 37·6 g dry matter/kg W0·75 per day). They drank 0·62 times as much water as sheep per kg W0·75, and 0·57 times as much per g DM intake (P < 0·05). Mean apparent digestibilities of dry matter (47.7%), energy (41·6%) and cell-wall fractions (48·4%) were similar in both species, in spite of the sheep selecting a higher-N component of the diet. Variation in digestibility (e.g. organic matter digestibility) among individual sheep was inversely associated with the percentage of cell-wall constituents consumed. The faeces of camelids contained a significantly higher proportion of particles longer than 0·5mm than those of the sheep (17 v. 11% total DM), indicating a slightly larger threshold to passage from the forestomachs in the camelids.

All animals were in negative N balance during the trial, but net loss of N was less in the camelids than in the sheep (27·6 and 49·5 g N/100 g N intake, respectively; P < 0·05), because of lower urinary N excretion (36·5 and 60·3 g N/100 g N intake, respectively; P < 0·05) of the camelids. The results suggest that camelids may be better suited than ruminants for production from poor-quality feeds, especially if water supply is limited.

Tannin content of the testa was estimated in crosses among six Vicia faba lines of diverse origin using the vanillin-HCl method. Additive genetic variance was predominant in the inheritance of tannin content. Two white-flowered parents possessed different genetic information for tannin content when the pleiotropic effect of genes for white flowers was eliminated. The genes controlling red testa (r), spotted flower (Sdp) and yellow pigment on the flower (yf) negatively influenced tannin content in the testa. Breeding for low tannin content in Vicia faba is feasible and selection can be based on plants with yellow-spotted flowers and red testas.

Losses of NH3 from a number of swards grazed by cattle were measured through 2 (1986–87) grazing years using a mass balance micrometeorological method. Comparisons were made of grass swards receiving 420 or 210 kg fertilizer N/ha per year and a grass-clover sward (GC) dependent upon fixation under rotational grazing managements. In one year a continuously grazed sward was also examined. Rates of NH3 loss were usually greatest whilst animals were present, especially during early and late season. This was not always the case, however, and losses sometimes continued into the next grazing period; there were also large day-to-day variations in fluxes. Seasonal trends were also not distinct, but losses tended to be lower during early and late grazings.

The annual losses from 420 and 210 kg N/ha and GC treatments were 25, 10 and 7 kg N/ha, respectively, and the differences between treatments were still marked when losses were expressed on a per animal basis. Total loss under continuous grazing was 61 % of that under the rotational system. Although the losses represent only 7·8, 5·6 and 3·7% of the inputs to420N, 2 ION and GC treatments, there was a good relationship between inputs and total losses, and also between the concentration of N in the herbage and losses per animal. The effects of the measured rates of loss on the input of NH3 from grazed grassland to the atmosphere are discussed.

Topping of tobacco (Nicotiana tabacum L.) plants (removal of the inflorescence) is not practised in Cyprus. Two field experiments were carried out at Akhelia Station, in 1985 and 1986, to test whether topping increased the yield or improved leaf quality of flue-cured tobacco grown under different types of irrigation. In contrast to the results of other studies, topping when the corolla had appeared on half the flowers did not increase yield. Topping when the inflorescence was just clear of the leaves (21 leaves harvested from topped plants v. 32 leaves from untopped plants) increased fresh yield by 7·0% but dry matter yield by 18·0%. The effects of topping were more marked on the leaves reaped at the third and fourth harvests, which constituted 52% of the fresh yield or 60% of the dry matter yield. At these harvests, leaves from topped plants had a lower percentage of midrib material (18·5 v. 21·0%) than leaves from untopped plants but a higher dry matter content (19·2 v. 17·2%) and specific leaf weight (80·0 v. 56·0 g/m2). Leaves of the fourth harvest from topped plants (27% of the total fresh yield) contained appreciably more nicotine (1·34%) than leaves from untopped plants (0·40%) but had a similar content of reducing sugars (20%). Topping did not influence the N, P and K contents of the leaves.

Irrigation increased fresh yield from 12·0 t/ha (225 mm water) to 24·0 t/ha (450 mm water) and dry matter yield from 2·0 to 3·8 t/ha, respectively, in Expt 1.

As Cypriot tobacco growers are paid for fresh yield delivered to the curing plant, the marginal increase of fresh yield with topping will hardly cover the cost of the extra operations involved.

Losses c. off. 95 % in dry herb yields of Egyptian henbane (Hyoscyamus muticusL.) were observed due to natural weed growth in experiments conducted on a sandy loam soil of pH 7·8 during the winter (rabi) seasons 1984/85 and 1985/86 at the Central Institute of Medicinal and Aromatic Plants, Lucknow. The period between 30 and 75 days after sowing was most critical for weed competition, when weeds with 12·5% of their total growth (in terms of dry matter) reduced henbane dry herb yields by 60%.

Recovery of applied nitrogen by the rice crop is invariably low, often 30–50% (Prasad & De Datta 1979). The poor recovery has been attributed to different types of losses occurring in the rice field. Recovery improved with split application, delayed application or deep placement (Pillai & Vamadevan 1978; Craswell & Vlek 1979), indicating that the management factor plays an important role in increasing fertilizer nitrogen efficiency. To investigate such factors, and seasonal effects, field experimentswere carried out using 15N-labelled urea (PU) and urea supergranules (USG). The recovery of fertilizer 15N by the plant and retention in the soil were studied in both dry and wet seasons.