Quinoa produces a cereal-like grain with a higher protein content and a better balanced amino acid composition than the major cereals. It is cultivated at high altitudes in the Andes, and is believed to have potential for temperate regions. In the development of quinoa as an arable break crop, sowing date, sowing rate and row spacing are identified as agronomic variables having a high priority for investigation. The variety Baer, from high latitudes at sea-level in Chile, and the variety Blanca de Junin, from the inter-Andean valleys of Peru, were sown on 25 March, 14 April and 7 May 1982 at spacings between rows of 0·8 and 0·4 m and sowing rates within rows of 0·2, 0·4 and 0·6 g/m, at Cambridge, England. These varieties were chosen for their strongly contrasting origins and plant types. In another experiment sown on 15 March 1984, Blanca de Junin was replaced by another valley variety, Amarilla de Marangani, somewhat better adapted for cultivation in England. Between-row spacings of 0·4 and 0·2 m, and sowing rates of 15, 20 and 30 kg seed/ha were used. Weed competition was more intense after later sowings, causing the plots sown in May to be abandoned. At the higher sowing rates, plants were shorter, a higher proportion were stunted, branching was reduced and maturity was earlier. These effects were more marked in the valley varieties, particularly Blanca de Junin. Increases in within-row density caused greater increases in competition effects than corresponding reductions in row width, except for the effect on the proportion of branched plants. The highest grain yield, 6·96 t/ha, was obtained with Baer sown in March in rows 0·2 m apart at 20 kg seed/ha. However, Amarilla de Marangani produced a higher yield at 30 kg seed/ha than at 20 kg seed/ha, which is surprising since valley varieties are normally sown with low target population densities or in intercrop, and Amarilla de Marangani was, in other respects, less tolerant of competition than Baer. The implications of these results for the cultivation of quinoa in mechanized farming systems, both in temperate and in highland tropical regions, are discussed.

Hand harvesting is a major constraint to lentil production in North Africa and West Asia. This study, in north Syria, compared hand harvesting, cutting by mower (double-knife) and cutting with angled blades on two lentil cultivars differing in standing ability and using two sowing methods (broadcast and drilled) both with and without the use of a heavy bar for field levelling in the 1984/85 season. Seven treatments were selected for testing in five locations in the 1985/86 season; and in the 1986/87 and 1987/88 seasons, agronomic comparisons of mowing v. hand harvesting were conducted on five farmers' fields.

Both machine methods of harvesting resulted in significant harvest losses compared with hand harvesting. The angled blades performed well on a ridged broadcast crop, but tended to mix soil with the harvested crop. The loss of straw associated with harvesting by mower was reduced by levelling the seedbed after sowing. The superiority in seed yield of cultivar 78S26002 over the local cultivar increased from 9% when hand harvested to 39% with mowing because of its lower likelihood of lodging. In the 1986/87 and 1987/88 seasons, the seed yield from a hand harvest was 1650 kg/ha compared with 1508 kg/ha following harvest by mower, representing a loss of 8·6% from mechanization. The corresponding straw loss was 16·6% of the mean from a hand harvest of 2140 kg straw/ha. However, the harvest losses from mechanical harvesting by mower were compensated for by the reduced labour costs compared with hand harvesting.

Chinoli (Brassica campestris subsp. oleifera × subsp. chinensis), Marnoo and Apetalous (B. napus), with contrasting morphological characters, were compared over four seasons in Tasmania in 1985/86 and 1986/87. The total water use estimated from a depth of 70 cm increased in proportion to irrigations. Before irrigation all the crops had a similar pattern of moisture extraction but differences between the lines, and due to irrigations, emerged after the irrigation treatments. The genotypic differences were clearer in the winter sowing of 1986/87, when the growing season was longer. Apetalous, when unirrigated, extracted a greater amount of water from the lower, wetter regions of the soil profile, particularly in the longer winter sowing when its water use was the same as in the treatment receiving one irrigation. With consistently higher stomatal conductance, Apetalous used more water than chinoli or Marnoo. It also maintained a higher turgor at lower osmotic potentials, suggesting a greater degree of drought tolerance than found in the short duration chinoli which, although it had a lower water use, also gave lower seed yields.

The effect of bee visits to the flowers on flower longevity and capsule, seed and oil production in linseed (Linum usitatissimum L.) cv. Antares, was investigated in two very different growing seasons (1988 and 1989); plots caged to exclude insects, plots caged with a honeybee colony and plots uncaged and open-pollinated by honeybees and bumblebees were compared. The experiments were conducted at Rothamsted Experimental Station Farm in Hertfordshire.

Although honeybee visits to the flowers resulted in earlier petal fall, they did not increase capsule or seed production. It is concluded that the crop is self-fertile, self-pollinates well, and that inadequate pollination is not a factor limiting yield.

In 1984 and 1985, the growth of axillary buds of Brussels sprouts plants was studied at Cockle Park, Northumberland, UK. Bud growth commenced in late September or early October and continued at all nodes until the final harvest in December. Total bud yield increased at a broadly constant rate until late November but at a decreasing rate thereafter. Plants produced c. 100 nodes with buds ≥ 5 mm diameter. The largest buds were c. 40 mm diameter and 25 g fresh weight. Bud size increased from the base of the stem upwards to between the 20th and 40th nodes and then decreased towards the apex. Nodes 20–40 (20% of the total) produced c. 40–45% of total bud yield. The size profile of leaves along the stem followed a similar pattern to the buds and the largest buds were in the axils of the largest leaves. There were close relationships between bud fresh weight and size, bud fresh weight and size, bud fresh weight and volume and log10 bud fresh weight and log10 bud size (r2 ≥ 0·995). The density of buds was c. 0·8 and bud fresh weight doubled for each 5 mm increase in bud diameter.

Current photosynthesis of the leaf canopy was apparently the major source of assimilates for bud growth. A C14 tracing experiment suggested that growth of individual buds was mainly supported by their subtending leaves. There was no evidence of re-translocation of dry matter from dying leaves or the stems to buds or of substantial production of dry matter by the buds themselves. Rates of bud photosynthesis were only about 10% of the rate of leaves. The continued increase in bud fresh weight and size at the lowest nodes when leaves were senescing rapidly and after they had abscissed was probably mainly the result of water uptake rather than dry matter accumulation.

Lentils were grown in 1984/85, 1985/86 and 1988/89 in Canterbury, New Zealand. Results showed that lentil canopies were capable of intercepting a maximum of 95% of incident solar radiation at a leaf area index of 7. Autumn sowings attained canopy closure, but late spring sowings did not. At the highest population density used (500 plants/m2), only 65% of incident solar radiation was intercepted by a late spring-sown crop. In all three growing seasons there was a highly significant positive relationship between cumulative absorbed radiation and dry matter (DM) production. Over all seasons, 1·6 g DM/m2 was produced per MJ of absorbed photosynthetically active radiation (PAR). The final utilization coefficient (u) was not affected by sowing date but in a late-sown, diseased crop, u was 38% less than in a disease free crop. In 1984/85, dryland crops had a utilization coefficient of 1·39 while irrigated crops had a u of 1·54. Growth efficiency of lentils was low, at 2·5%.

Dormancy in seeds of Adansonia digitata (L.) can be attributed partly to the testa and partly to the pulp. Several methods, such as wet heat treatment, total or partial seed decoating and scarification of seeds with concentrated acids, herbicides, fungicides and growth regulators, were tested in 1988 and 1989 to break dormancy. The most effective was scarification with HNO3 or H2SO4, which gave 86 and 98% germination, respectively, while total decoating, partial decoating, wet heat treatment and ethrel gave 85, 80, 75 and 70%, respectively. Seeds treated with herbicides and fungicides did not germinate. Inhibition of germination caused by the pulp was overcome by thorough washing of seeds and soaking in water for 3 days.

In pot and field experiments at Xichang, China, in 1984–85, (NH4)2MoO4 applied alone or with KH2PO4 to Vicia faba var. major increased total N, soluble sugar and chlorophyll contents and photosynthetic rate. The growth of root nodules and N fixation were stimulated, and more assimilate was distributed to seeds. Treatment with (NH4)2MoO4 combined with KH2PO4 gave the highest total N, soluble sugar and chlorophyll contents, the most root nodules, fruiting branches, fertile pods and seeds/plant and the highest 100-seed weight, and consequently produced the highest seed yield.

The objective of this study was to identify traits related to growth and yield response under drought stress in the field which would show less variation than yield itself. Experiments were conducted in 1987, at Durango, Mexico and at Michigan, USA. Twenty-six dry bean genotypes were sown under supplementary irrigation and terminal drought stress. Plant samples were taken at 50% flowering, mid-pod-filling and physiological maturity. At both sites, leaf expansion rate and crop growth rate at mid-pod-filling were greatly reduced by drought stress, resulting in significant reductions in total dry matter (DM) above ground and seed yield at physiological maturity. Because of differences in the timing and intensity of the drought stress, the yield components were affected differently at each location. Total DM content at physiological maturity, harvest index and number of pods/m2 were the only traits positively correlated with yield under stress at both locations. In order to evaluate a group of genotypes for adaptation to drought on the basis of seed yield, the genotypes should be grouped according to their phenological characteristics to stress them evenly.

Experiments to evaluate the suitability of lentil lines using an innovative dual-season approach for improved and reliable production under the harsh environmental conditions of the highlands of west Asia were conducted in Balochistan for 3 years (1986/87, 1987/88 and 1988/89) by the Arid Zone Research Institute. Two ICARDA-bred lines, ILL5865 and ILL5677, when assessed using a wide range of seeding times, appeared to be sufficiently flexible and well adapted to the conditions of extreme cold and aridity to be able to replace the ultra small-seeded local landrace. These ICARDA lines have seed sizes approximately double those of the local landrace and results of consumer acceptability studies suggest that the lines will have desirable marketing qualities. These two lines were selected for further larger-scale agronomy trials at multiple sites in Balochistan in subsequent seasons. Other lines, ILL5690, ILL1939 and ILL5730, have also shown potential, but only at certain seeding times and, as such, will be retained for further assessment in ongoing germplasm evaluation trials.

Initial findings indicate that there are now good prospects for identifying dual-season lentil lines suitable for introduction into highland farming systems. However, further research will be required before new lentil lines will be an attainable reality for a large proportion of the dryland farming community of west Asia.

The median concentration of phosphorus and potassium in a total of 867 samples of wheat and barley straw at harvest in England in 1986–88 was 0·07% P and 1·00% K in the dry matter. Variation was significant between years and between crop species. The concentration of potassium in wheat and barley straw increased with increasing rate of applied nitrogen at 60% of the sites where this was tested. The results have been incorporated into practical recommendation systems for farmers.

The intake of temperate forages by herbivores can be determined using the C33 alkane naturally present in the forage and dosed C32 alkane. To determine whether the technique can be used with tropical forages, the concentrations of C33 alkane were determined in seven species.

The leaves of Brachiaria decumbens, Digitaria decumbens, Pennisetum glaucum and Stylosanthes scabra contained sufficient C33 alkane (> 50 mg/kg DM) for the estimation of dry matter intake. Low concentrations of C33 alkane were found in the leaves of Setaria sphacelata, Sorghum sp. and Leucaena leucocephala. Setaria sphacelata was found to contain high concentrations of C27 alkane and therefore intake could be estimated by using C28 as the dosed alkane although the intake would possibly then be underestimated by c. 8%. Leaves of Sorghum sp. contained > 50 mg C31 alkane/kg DM and, with C32 as the dosed alkane, intake would possibly be underestimated by c. 5%. Leucaena leucocephala contained insufficient alkanes to estimate forage intake. The concentration of n-alkanes in Pennisetum glaucum and Sorghum sp. leaves decreased with age.

It was concluded that some tropical forages contain insufficient C33 alkane for the measurement of intake by the double alkane technique. In these species, a shorter chain length alkane can sometimes be used, but only with a reduction in accuracy in estimating intake.

Ammonia losses from surface-applied cattle slurry were measured under field conditions using a wind tunnel system that allows variables affecting ammonia loss to be examined under controlled conditions. The experiments were carried out on a sandy soil with seven different surface covers. This report considers the effect of wind speed, temperature and water vapour deficit on the ammonia loss over a series of 6-day periods. During October 1986 to November 1989 42 treatments were examined, using slurries taken from the same slurry tank to provide slurries of similar chemical composition.

When temperatures were near zero, the rate of ammonia loss was generally low. The accumulated loss over 6 days was high, however, because the rate of loss was constant throughout the period. In these experiments the soil was saturated with water and partly frozen, and the infiltration of slurry into the soil reduced. At 19 °C initial loss rates were high but, after 12 h, almost no further loss occurred. Apart from these extremes, the ammonia loss rates within the initial 24 h were significantly affected by temperature and wind speed.

Ammonia volatilization after 6 h was exponentially related to temperature (r2 = 0·841) but the correlation weakened with time after slurry application. An increase in ammonia volatilization with increasing water vapour pressure deficit was considered to be an effect of temperature.

The ammonia loss rate increased when wind speeds increased up to 2·5 m/s. No consistent increase in ammonia volatilization was found when the wind speed increased from 2·5 to 4 m/s. Ammonia loss after 24 h increased with increasing initial pH of the slurry.

A two-stage pattern for ammonia volatilization from slurry is proposed. During the first stage (the initial 24 h) ammonia loss rate is high due to an elevated pH at the slurry surface followingv application, and temperature significantly affects the loss rate. In the next stage, pH declines and the rate of ammonia volatilization decreases. During this stage other factors, including the dry matter content of the slurry, control the rate of ammonia loss.

Herbage samples were collected in late June, and again in early September (1987) from permanent mountain meadows situated in North-western Spain (León). Botanical composition was determined by grouping the species into grasses, legumes and herbaceous ‘weeds’. Rumen degradability of the dry matter (DM), crude protein (CP) and neutral detergent fibre (NDF) of the botanical groups in each harvest season was determined by the nylon-bag technique.

Grasses and legumes differed in their degradation characteristics, and the comparisons between forage species were different for the two harvest seasons. There were no significant differences between September grasses, June legumes and September legumes in the potential degradabilities of the DM (86·9, 87·1 and 88·4%) and CP (94·2, 92·4 and 93·8%). The NDF of grasses harvested in September was degraded to a greater extent (80·6%) than that of legumes from both harvests (70·9 and 73·6% in June and September respectively). However, June grasses showed significantly lower potential degradabilities for the DM (77·0 %), CP (84·3%) and cell wall (65·9%). Legumes were degraded at a faster rate than grasses (mean DM degradation rates of 0·143 and 0·057 respectively), and lag times were longer for grasses (4·7 h) than for legumes (2·5 h). Rumen degradation characteristics of the herbaceous ‘weeds’ were estimated, but it should be remembered that many other factors may limit their utilization by ruminants.

It was concluded that the major constraint to the nutritive value of these permanent swards would be the maturity of the grasses harvested in June, which markedly reduced the rumen degradability of the forages.

Losses of ammonia (NH3) through volatilization from the excretal returns from sheep grazing a range of swards in S.E. England were determined over two seasons. Four swards were examined: grass + 420 or 0 kg N/ha per year, grass/white clover and clover monoculture. These were grazed continuously to sustain a constant sward height of 6 cm. The patterns of NH3-N concentration above the sward changed with treatment and throughout the season: there were, on occasion, irregularities in the concentration profiles which may have been due to differential behaviour of paniculate and gaseous forms. Significant losses of NH3 occurred on all treatments, although on some occasions the low input systems appeared to be acting as sinks rather than sources of NH3. There were trends for the losses to be greater during the middle of the grazing season. In contrast to previous studies there was little relationship between seasonal N losses and changes/differences in dietary N content. The overall losses, whether on a per unit area or per animal basis, were generally in the order, clover > grass + 420 kg N > grass+ 0 N > grass/clover. Mean annual losses from grass + 420kg N and grass/clover were 94 and 1·2 kg N/ha, respectively. For a comparable fertilizer N treatment, losses were lower than previously found with swards which were rotationally grazed by cattle. The present losses, although dependent upon level of N input, whether from fertilizer or from biological fixation, were relatively small, ranging from 05 to 11·2 kg N/ha per year, and represented small proportions of either the N input to the system or the excretal returns from the animals.

In 1989 three experiments with up to three different treatments each were carried out in North Germany to determine the ammonia flux densities after the application of liquid slurry using the micrometeorological mass balance method.

In Expts 1 and 2, pig slurry was applied with a conventional surface spreader to wheat stubble. The results demonstrated the influence of meteorological conditions and that of incorporation on the extent of ammonia volatilization. In comparison to warm and windy conditions, NH3 losses decreased from 56% of the NH4-N applied to wheat stubble to 42% during a cool and rainy period. When slurry was incorporated immediately into the soil, ammonia losses were significantly reduced to 20 and 10%, respectively, of the applied NH4-N. The highest losses (67% NH4-N) were found when slurry was applied during warm weather on wheat stubble covered with chopped straw. Soil cultivation of the wheat stubble before the application of slurry diminished the ammonia emission from 42 to 28% of the NH4-N.

In Expt 3, cattle slurry was applied to rape. It was found that compared with a conventional surface spreader the ammonia volatilization was reduced from 68 to 58% of the NH4-N when an alternative distribution system consisting of drag hoses was used for the application.

Various physiological characteristics of castrate male sheep fed ad libitum were studied between 1986 and 1987 in Australia. The sheep were between 20 and 45 kg live weight (LW) before and during fattening. Sequential data on body composition, estimated from TOH space (starting at 10 kg), established that the weight gain contained 19% fat and 13% protein below c. 26 kg LW and 55% fat and 10% protein above. For a given feed intake, the rate of fat gain was constant but the rate of body protein gain was 45% lower above 26 kg LW. Voluntary feed consumption per unit weight peaked at 26 kg LW and declined thereafter. There was an increase at 45 kg LW in weight of rumen digesta per unit feed intake and in digestibility; metabolizable energy (ME) per kg feed was increased as a result by 6–9%. Efficiency of use of ME, determined by calorimetry, increased from 44% in the lower weight range to 53% in the higher; utilization of nitrogen decreased from 37 to 28%. Partition of ME and energy gain suggested that the energetic efficiency of neither fat nor protein deposition changed between the two weight ranges. Change in the amount of DNA (‘cell number’) rather than g tissue/mg DNA (‘cell size’) accounted for weight change in three muscles and most digestive organs. Exceptions were the rumen, in which cell number and size both contributed to gain and the large intestine, in which cell size diminished during growth. It was concluded that fattening in sheep reflects diminution of the protein content of weight gain due to a decrease in the efficiency of protein utilization at the tissue level.

The nutritive value of taro leaf (Colocasia esculenta) silage, with or without various crop or crop byproducts as additives, was evaluated in two experiments in Western Samoa in 1988 and 1989. In Experiment 1, laboratory silos were used to assess the quality of eight taro leaf silages which were either ensiled fresh or wilted overnight. Taro leaf ensiled alone was poorly preserved with a pH of 5·4 and high concentrations of ammonia-N and volatile fatty acids. In contrast, silages with crop byproduct additives rich in water soluble carbohydrates (WSC), mainly molasses, ripe banana or papaya pulp, were of high quality with pH levels of c. 4 and low concentrations of volatiles. Copra meal, although low in WSC, was able to produce a satisfactory silage when added to taro leaf through its ability to restrict fermentation.

Despite only a small increase (14·2%) in silage dry matter (DM) content, wilting of taro leaves resulted in silage of significantly higher quality than that made from fresh leaves. Most of the benefit of wilting was attributed to better fermentation conditions rather than a restricted fermentation.

Two of the better silages from Experiment 1, taro/molasses and taro/banana, were prepared on a larger scale in earth pits and fed to goats in a second experiment. Both silages were highly palatable and digestible; DM intakes of 47 and 63 g/kg W0·75 per day and organic matter digestibilities of 69·0 and 74·9% were recorded for the banana and molasses silages, respectively.

It was concluded that taro leaf is a suitable forage for ensilage, and when combined with additives rich in WSC, a forage of high nutritive value can be produced.

Prairie grass (Bromus catharticus) straw (13·7 g N/kg DM) was fed ad libitum to six goats and seven sheep kept in metabolism cages at Palmerston North, New Zealand in 1986 and 1987.

Goats had greater voluntary feed intake (VFI) (56 v. 36 g DM/kg W0·75 per day), greater apparent DM digestibility (36·8 v. 32·6%) and a larger rumen pool of DM and liquid (W0·75) than sheep. Goats also had greater apparent digestibility of fibre, especially of lignin, and greater rumen fractional degradation rates (FDR) of cellulose, hemicellulose and lignin. Goats had a higher rumen ammonia concentration (115 v. 80 mg N/l), lower rumen pH (6·73 v. 6·90), a smaller proportion of large particles and greater proportion of small particles in rumen contents than sheep. Passage through a 1 mm sieve was established as the threshold particle size to have a high probability of leaving the rumen in both goats and sheep. Voluntary water intake/unit DM consumed was lower in goats than in sheep and, whilst rumen fractional outflow rate (FOR) of water and particulate matter also tended to be lower in goats, the difference was not significant. Irreversible loss rate of rumen NH3 and the amount of N calculated as recycled to the rumen, both expressed as mg N/kg W0·75 per day, were greater for goats than for sheep.

It was concluded that the ability of goats to maintain a higher rumen NH3, concentration than sheep, their larger rumen pool and the higher proportion of small particles in rumen contents were all contributing factors to their greater VFI and fibre digestion of this low-quality roughage.

Twenty-eight male castrate kids and 28 male castrate lambs were assigned to a comparative slaughter experiment to compare energy and protein utilization. The experiment was conducted from January to March at Lincoln, New Zealand. Ten animals of each species comprised the initial slaughter group while the remaining 18 animals were randomly allocated to five feeding regimes. Animals were offered high-quality meadow hay for 13 weeks and then slaughtered. The energy retained in the body was regressed against metabolizable energy intake (MEI) to obtain estimates of maintenance energy requirement (MEm) and efficiency of energy utilization for growth (kg).

Kids tended to have a higher MEm (0·44 v. 0·37 MJ ME/kg W0·75 per day in kids and lambs, respectively) and a higher kg (0·28v. 0·22) though these differences were not significant. There was no difference between the species in the composition of gain of the fleece or hair-free body with a protein energy to gross energy ratio in the gain of 0·20. The fleece or hair-free body composition was similar for both species (initial 0·51v. 0·48; final 0·36 v. 0·32; protein energy:gross energy, kids and lambs, respectively). Overall, the values for kg in both species were low and could not be explained solely by the composition of the gain.

The efficiency of use of apparently absorbed amino acid (AA) for fleece or hair-free body protein deposition was higher for kids (0·52 v. 0·29) and, when the fleece or hair was included, the value increased markedly for lambs (0·50 v. 0·41, kids v. lambs, respectively). The protein energy apparently absorbed in the small intestine/MEI was not high or different between species (mean 0·18). The efficiency values for both species are low and not explained by the supply of protein relative to energy, which was not high.

It was concluded that, with high-quality forage used to promote live weight gain, there was little difference between kids and lambs in the utilization of forage energy, and that the efficiency of utilization of absorbed protein for protein deposition was lower than expected in both species.