Ammonia (NH3) volatilization may decrease the fertilizer efficiency of surface-applied slurry and may cause the unwanted deposition of nitrogen (N) in oligotrophic ecosystems. We studied the effect of soil water content on the infiltration of slurry liquid and how infiltration affected NH3 volatilization. NH3 volatilization was measured with dynamic chambers through which air was drawn continuously. Slurry spiked with bromide (Br−) to trace slurry infiltration was applied to a loamy sand in steel cylinders (diameter 6·7 cm and height 12 cm) adjusted to water contents of 0·01, 0·08, 0·12 and 0·19 g H2O per g soil (g g−1). At different time intervals after slurry application the soil columns were cut into slices and Br−, ammonium (NH4+) and nitrate (NO3−) concentrations were determined. At soil water contents >0·12 g g−1 nitrate content increased significantly from 24 to 72 h, and at 96 h NO3− content was equivalent to 75–130% of the NH4+ present at 0·5 h after slurry application. Nitrification may have contributed to a low NH3 volatilization from 24 to 96 h by reducing NH4+ concentration and contributing to acidity, and most of the NH3 volatilization occurred, therefore, during the first 24 h after application. Low soil water content enhanced the infiltration of slurry liquid and hence the mass transport of NH4+ into the soil. Transport of NH4+ by diffusion, on the other hand, was highest at the highest water content. Transport of NH4+ from the slurry at the soil surface down into the soil at 0·01 g g−1 reduced NH3 volatilization to c. 70% of the volatilization from slurry applied to soils at higher water contents. Diffusion of NH4+ into the soil did not significantly decrease NH3 volatilization.

Cowpea and sorghum grain crops, fertilized with 26 kg of phosphorus (P) per ha from either a P-soluble (SP) or a slightly P-soluble fertilizer (Kodjari, a natural rock phosphate (RP) indigenous to Burkina Faso), and cowpea and crotalaria (Crotalaria retusa) green manure crops, either unfertilized or fertilized with 26 kg P/ha from RP; were studied for their effects as preceding crop treatments for maize. The experiment was conducted in semi-arid West Africa (SAWA) at Farako-Bâ in Burkina Faso in 1983–86. Nitrogen (N) and soluble P fertilized and unfertilized subtreatments, applied to maize the following year, allowed the effects of the preceding crop treatments in improving soil fertility and the direct effects of P and N fertilizers applied to the maize crop to be assessed. Maize productivity was increased both by P fertilization and by soil improvements following cowpea and crotalaria; N fertilization in excess of 60 kg N/ha was not beneficial. Cowpea grain crop treatments, especially when fertilized with a P-soluble source, maximized maize yields, whereas cowpea and crotalaria green manure treatments were either similar to the cowpea grain treatment fertilized with RP or were intermediate between the latter and the sorghum treatment fertilized with SP. Sorghum, regardless of the source of P-fertilizer used, appeared not to be a suitable preceding crop for maize in SAWA.

The effects of plant density on the growth and yield of winter oilseed rape (Brassica napus) were examined in a series of five multifactorial experiments at Rothamsted Experimental Station between 1984 and 1989. Plant densities, manipulated by changing the seed rate and row spacing, or because of overwinter losses, ranged from 13·5 to 372 plants/m2. Normalized yields for the multifactorial plots increased with densities up to 50–60 plants/m2. In very high density plots in 1987/88, yield decreased as density increased >150 plants/m2. Plants grown at high density had fewer pod-bearing branches per plant but produced more branches/m2. Branch dry matter (DM) per plant was decreased by 42%, the number of fertile pods per plant and pod DM/plant by 37%. There was no effect of density on the number or DM of pods/m2. Over 74% of the fertile pods were carried on the terminal and uppermost branches of plants grown at high density in 1987/88 compared with only 34% in plants grown at low density in 1988/89. Seed DM/plant decreased with increase in density but seed size (1000-seed weight) increased. There was no effect of density on seed glucosinolate or oil contents.

Inverse yield–density relationships were used to evaluate how competitive balances in mixed plant species associations may influence productivity, as measured by three indices : Relative Yield Total (RYT), Relative Land Output (RLO), and Total Land Output (TLO). Parameters of the inverse relationships, which express competitive influences and plant growth potential in the absence of competition, were incorporated into expressions used to predict RYT, RLO and TLO. Initial parameter values were derived from 25 experiments on binary species mixtures, and parameter values were systematically varied over a 100-fold range. Response to parameter manipulation was also investigated in five specific binary associations representing a broad range of relative mixture productivity. As indicated by RLO or RYT, and in accord with ecological concepts of niche differentiation, high productivity of mixtures relative to monocultures occurred if between-species competition was low. As indicated by TLO, the total combined productivity of the mixed species was enhanced by higher potential growth per plant in the absence of competition. Lower within- and between-species competition also increased TLO. There was a significant positive correlation between RYT and RLO. Relative and total measures of mixture productivity, however, showed different responses to parameter manipulation, and were not correlated.

The solvent extraction of alkanes from faeces and herbage samples at two different temperatures (cold: 15–25°C and hot: 65°C) was studied in four samples of different matrix types (cattle faeces, sheep faeces, hill grass and heather), in two experiments performed at Villaviciosa, Asturias, Spain in 1994. Two internal standards (IS) of different chain length (C22 and C34) were used to estimate alkane concentrations. Significant differences were detected in alkane extraction derived from temperature of extraction, IS and sample matrix. At the cold temperature, long-chain alkane extraction was not complete, resulting in errors in the estimation of alkane concentration when a long-chain alkane (C34) was used as the only internal standard. However, under hot extraction, long- chain alkanes were completely extracted by the heptane, although estimates made with C22 or C34 as IS were not identical. These results suggest that it would be appropriate to use two internal standards with short and long carbon chain, such as C22 and C34, in routine analyses to establish the completeness of alkane extraction, even under hot conditions, by calculating the relative ratio of both IS in extracts compared to the original C22[ratio ]C34 ratio added to the samples. Any increase or decrease in expected peak areas could be adjusted for all the alkanes in the extracts, and the accuracy of alkane concentration measurements (and therefore the reliability of estimates of intake and especially of diet selection) would be improved.

The combined effect of two rapid multiplication techniques (sprout and top-shoot cutting) was assessed using four Dutch potato cultivars during 1991/92–1993/1994 at the Tuber Crops Research Centre (TCRC), Bangladesh Agricultural Research Institute (BARI), Gazipur-1701, Bangladesh. On average, a 70–80 g tuber produced 29 sprout cuttings which were subsequently used for taking top-shoot cuttings. Top-shoot cuttings were taken at a number of dates from 25 November and continued at 10 day intervals, thereafter, until 15 January. The number of top-shoot cuttings produced by 29 sprout cutting-derived plants varied (P<0·01) from 761 to 663 across the cultivars. Cardinal gave the greatest yield. Most of the characters studied varied (P<0·01) between cultivars but not over years while the interaction between cultivars and years was significant (P<0·01).

Early planted top-shoot cuttings produced more tubers per plant (4·0) with a greater mean tuber weight (>22 g) than from the late planting (1 tuber and 5·5 g). On average, about 2·8 tubers per plant were produced with a mean tuber weight of 15·8 g. Cardinal and Patrones produced the most tubers per plant (2·9) and Diamant the greatest mean tuber weight (16·8 g). Cardinal gave the greatest yield (P<0·01) of tubers (268) followed by Patrones (241). The 29 sprout cutting plants derived from a 70±5 g tuber produced 160 tubers while the 771 top-shoot plants derived from 29 sprout cutting-derived plants produced 1420 tubers. The rate of multiplication of the combined two RM techniques was 1580[ratio ]1 against 11[ratio ]1 for the conventional method.

The interaction between headbugs (Eurystylus sp.) and grain mould (GM) on sorghum was examined in field trials carried out at Samaru, Nigeria in the 1995 and 1996 wet seasons. The results obtained show that in all three sorghum cultivars tested, insect damage increased the number of fungal colonies associated with the grain. This resulted in lower germination, 1000-grain mass and yield in such treatments. Insect damage also altered the relative abundance of the common fungal flora species as, following insect damage, Fusarium moniliforme (≡Gibberella fujikuroi), Phoma sorghina and Curvularia lunata (≡Cochliobolus lunatus) were the most common fungi in decreasing order of frequency as against the normal order of P. sorghina, F. moniliforme followed by C. lunata. These results are the first clear evidence of interactions between headbugs and GM in Nigeria.

A field experiment was conducted for 5 years (1992/93–1996/97) on Tolewal sandy loam soil (Typic Ustochrepts) in the subtropical region of northwest India (Ludhiana), to evaluate the effect of four rates of fertilizer P (0, 20, 30 and 40 kg P2O5/ha) applied at three frequencies representing direct, residual and cumulative P treatments on crop yields, P uptake, fertilizer P-use efficiency and fertilizer P recovery by groundnut (Arachis hypogaea) and mustard (Brassica napus) grown in a rotation.

Groundnut responded to an application of P up to 20 kg P2O5/ha when the preceding mustard crop did not receive fertilizer P. However, when the mustard received 40 kg P2O5/ha, the succeeding groundnut crop did not respond to additional P applied to it, but obtained the required P from that which was in the soil including the residue from the previous application. The mustard crop responded significantly (46%) to P up to 40 kg P2O5/ha rate but there was a much less response (13–27%) to residual P that was applied to the preceding groundnut. The differences between these two crops are due to differences in climate between the mustard and groundnut growing seasons and corresponding differences in soil conditions, and perhaps also to differences in the P-solubilizing abilities of the two crops. The results suggest that in groundnut–mustard rotations grown under these climatic conditions, a direct application of 40 kg P2O5/ha to mustard would suffice to meet the P needs of both crops. This would be the most efficient way of using fertilizer P, increasing P recovery and improving total biomass partitioning to mustard seed or groundnut pod yield.

Tissue flow measurements of leaf material in Lolium perenne (perennial ryegrass), Agrostis capillaris or Poa annua, and Trifolium repens (white clover) were made at three upland sites in Scotland (Hartwood, Sourhope and Fasque) in 1992/93 to determine if there were differences in seasonal growth, senescence and losses to herbivory between species in their response to more extensive sward management. The measurements were made monthly from May until October in established predominantly perennial ryegrass/white clover swards receiving three different treatments. One treatment received a conventional annual fertilizer application of 140 kg N/ha plus maintenance P and K and was grazed by sheep at a sward height of 4 cm (4F), whereas the other two treatments were unfertilized and grazed to maintain a sward height of 4 cm (4U) or 8 cm (8U).

Significant sources of the variation in leaf appearance, increase in green lamina/petiole length (leaf extension), senescence and losses to herbivory were attributable to site, sward, species and date of measurement. The rate of leaf extension for all three measured species was less in 4U than 4F swards, and less in 4U than 8U swards. Leaf extension of L. perenne exceeded that of the other species, even in unfertilized swards, but rates of leaf appearance were less. There was some evidence in spring of a reduction in net growth as a consequence of removing fertilizer inputs and maintaining a sward height of 4 cm. Species differences in the losses of leaf tissue to herbivory were dependent on sward management. In the 4F treatment, leaf loss to herbivory from L. perenne tillers was greater than that from either A. capillaris, P. annua or T. repens in May, June and September. In the 4U treatment more leaf tissue was also lost from L. perenne than from T. repens. In contrast, there was no difference between grass species in losses to herbivory in either unfertilized sward. The responses of species to changes in fertilizer and grazing management were similar at three sites of differing fertility. The results are discussed in relation to plant competition and species dynamics in extensively managed swards.

The response of linseed to treatment with two plant growth regulators (PGRs), chlormequat and ethephon, applied at a range of growth stages (corresponding to average mainstem lengths of 10, 23, 46, 55 and 64 cm) and in various combinations (single and repeated applications of chlormequat and ethephon, either alone or mixed) was studied in field experiments over two seasons in 1992 and 1993 at the University College of Wales, Aberystwyth. Reduction in mainstem length was dependent upon the type of PGR and the timing of its application. Chlormequat alone was consistently more effective than ethephon alone, while a mixture of the two at half rates was similar to chlormequat alone. The largest reductions in mainstem length (16·6% with chlormequat and 6·1% with ethephon, averaged over the two years) were achieved when the PGRs were applied when mainstems averaged 22–23 cm in length. Response to PGRs became progressively smaller with later applications. However, the reduction in mainstem length, when expressed as a percentage of that part of the stem yet to extend (i.e. final untreated stem length−stem length at the time of PGR application), was shown to be remarkably consistent across all (apart from the first) timings of application, with average values of 28·4 and 7·4% for chlormequat and ethephon respectively.

Application of both PGRs increased tillering and increased significantly the number of stems per unit area at maturity. This response occurred irrespective of timing of application and was greater following treatment with ethephon than with chlormequat. In the first year, the effects of PGRs on dry matter production and seed yield were small and not statistically significant. In the second year, significant reductions in seed yield were associated with those PGR treatments which promoted tillering most, i.e. early application of ethephon. Smaller yields were the result of fewer capsules per plant. Furthermore, a significant correlation between mainstem length and the number of seeds per capsule indicated a reduction of 0·78 seeds per capsule for every 10 cm reduction in stem length. While total oil content of seed remained unaffected by PGR applications, treatments which included chlormequat at an early growth stage (either alone or in combination with ethephon) altered the relative proportions of fatty acids, reducing the content of linolenic acid while increasing that of oleic acid.

Saponins of Quillaja saponaria bark and the water extract obtained on homogenization of Yucca schidigera plants were used during urea-ammoniation to reduce ammonia loss. In Expt 1, chaffed wheat straw (2–5 cm length) was urea-ammoniated (50 g kg−1 urea, 400 g kg−1 moisture) for 25 days at 37°C with and without Quillaja saponins (QS) or Yucca plant homogenate, YPH (corresponding to 1 and 2 g kg−1Yucca powder). The crude protein (CP) content of untreated straw was 34 g kg−1. After 25 days, CP values of 90 g kg−1 (urea; no saponin), 82 and 86 g kg−1 (urea+QS at 1 and 2 g kg−1) and 102 and 92 g kg−1 (urea+YPH at 1 and 2 g kg−1) were obtained. The ammonia-nitrogen bound (as percentage of urea-nitrogen added) to straw after the treatment was 39 (urea; no saponin), 33 and 36 (urea+QS at 1 and 0·2 g kg−1), and 47 and 40 (urea+YPE at 1 and 2 g kg−1). As the extent of ammonia bound to straw was higher with Yucca plant powder, especially at 1 g kg−1, Yucca plant powder at 0·75 and 1 g kg−1 was used in Expt 2. In Expt 1, the Yucca plant extract was used after homogenization of the Yucca plant powder, which is not feasible at farm level. Therefore, two simpler approaches (overnight soaking of the powder in water (Yucca powder extracted, YPE) and mixing of Yucca powder with the straw followed by urea-ammoniation (Yucca powder, YP) were used besides homogenization. Otherwise, conditions for the urea-ammoniation treatment were similar to those in Expt 1. The ammonia–nitrogen bound (as percentage of urea-nitrogen added) to the straw varied from 47 to 54% in the presence of the Yucca plant powder, which was substantially higher than that observed in its absence (38%). The ammonia-binding efficiency of Yucca plant powder to the straw was highest at 1 g kg−1. Among the three methods tried, addition of the Yucca powder to straw followed by treatment with urea was the easiest, and the binding efficiency was similar to that observed when using the powder after homogenization. In both experiments, the true dry matter- and NDF-digestibilities, calculated organic matter digestibility and metabolizable energy, as well as rate and potential extent of gas production, were significantly higher (P<0·05) in the treated straw than in the untreated straw. These values were affected neither by the source of the saponins nor the manner in which the Yucca powder was applied.

Potted 1·5-year-old apricot plants (Prunus armeniaca L.), growing under polycarbonate glasshouse conditions with a cooling system, were subjected to two successive water stress/recovery periods until pre-dawn leaf water potential (Ψpd) reached values between −2·0 and −2·5 MPa, during summer 1996. Control plants were irrigated daily to maintain the soil matric potential at c. −20 kPa. Water stress limited plant growth and induced a significant reduction in leaf area, caused by mature leaf abscission. The parallel behaviour of leaf turgor potential and epinasty in stressed plants indicated that these movements are turgor-dependent. Osmotic adjustments of 0·27 and 0·60 MPa were observed at the end of the first and second stress period, respectively. Relative apoplastic water content (RWCa) values were high, ranging from 27 to 42%, and were not affected by water stress. The rapid decrease in leaf conductance (gl) from the beginning of the stress periods, together with the delay in stomatal reopening after rewatering the plants, indicated that stomatal behaviour was not a simple passive response to water deficits. Net photosynthesis decreased only at the end of both stress periods and recovered quickly. These observations indicate that leaf productivity may be affected only slightly by short-term water stress. The results indicate that drought resistance in apricot is based mainly on avoidance mechanisms, such as stomatal control, epinasty and limitation of transpiration by reducing leaf area. However, some tolerance characteristics, including osmotic adjustment, high RWC a and low leaf osmotic potential at turgor loss point (Ψtlp) values were observed.

A field experiment was conducted with lemongrass (Cymbopogon flexuosus) at Bangalore, India during 1993–95 under three oil moisture regimes (0·75, 0·50 and 0·25) irrigation water:cumulative pan evaporation (IW:CPE) ratios and four rates of nitrogen application (0, 50, 100 and 150 kg ha−1). The soil moisture regime maintained at 0·75 IW:CPE ratio significantly increased crop growth characters such as plant height, leaf area index, herbage and essential oil yields, compared with those having 0·25 and 0·50 IW:CPE ratios. An application of 100 kg N ha−1 was found to be optimal for crop yield. Oil content and quality of oil were not affected by irrigation and nitrogen rates.

The effect of environmental conditions immediately before anthesis on potential grain weight was investigated in wheat at the experimental field of the Faculty of Agronomy (University of Buenos Aires, Argentina) during 1995 and 1996. Plants of two cultivars of wheat were grown in two environments (two contrasting sowing dates) to provide different background temperature conditions. In these environments, transparent boxes were installed covering the spikes in order to increase spike temperature for a short period (c. 6 days) immediately before anthesis, i.e. between ear emergence and anthesis. In both environments, transparent boxes increased mean temperatures by at least 3·8 °C. These increases were almost entirely due to the changes in maximum temperatures because minimum temperatures were little affected. Final grain weight was significantly reduced by higher temperature during the ear emergence–anthesis period. It is possible that this reduction could be mediated by the effect of the heat treatment on carpel weight at anthesis because a curvilinear association between final grain weight and carpel weight at anthesis was found. This curvilinear association may also indicate a threshold carpel weight for maximizing grain weight.

A grazing experiment, conducted for 55 days (from 4 March to 29 April) in the late summer/autumn of 1997, at Massey University, Palmerston North, New Zealand, compared the reproductive efficiency and wool growth of ewes grazing Lotus corniculatus (birdsfoot trefoil) or perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) dominant pasture (pasture). Half the ewes grazing each forage were given daily oral polyethylene glycol (PEG: molecular weight 3500) supplementation to inactivate the condensed tannins (CT) in lotus. A rotational grazing system with 200 mixed age ewes (54·2±0·88 kg/ewe; 50 ewes/treatment) was used.

The effect of forage species and PEG supplementation upon voluntary feed intake (VFI), concentration of plasma metabolites, reproductive efficiency, wool production and wool characteristics was measured during two synchronized oestrous cycles. The ewes were restricted to maintenance feeding for the first 12 days of each oestrous cycle and then increased to ad libitum for the 6 days prior to and including ovulation. Lotus contained 17 g total CT/kg dry matter (DM) in the diet selected. There were only trace amounts of total CT in pasture. In vitro organic matter digestibility (OMD) was higher for lotus (0·82 v. 0·74) than for pasture, whilst lotus contained less nitrogen (N; 37·8 v. 44·5 g/kg OM).

Mean ovulation rates (OR) for CT-acting and PEG sheep grazing pasture and lotus were respectively 1·33 v. 1·35 and 1·78 v. 1·56, with corresponding lambing percentages being 1·36 v. 1·36 and 1·70 v. 1·42. Fecundity (number of corpora lutea/ewe ovulating) was greater for ewes grazing lotus than pasture (P<0·01), and tended to be greater for CT-acting than for PEG sheep grazing lotus (P=0·06). In unsupplemented sheep, ewes grazing lotus had increased plasma concentrations of branched chain amino acids (BCAA; 57%) and essential amino acids (EAA; 52%) compared to ewes grazing pasture.

In ewes grazing pasture, PEG administration had no effect on plasma concentrations of urea and free amino acids, VFI, reproductive efficiency and wool production. However, in sheep grazing lotus, plasma concentrations of urea were significantly lower and concentrations of most amino acids were significantly higher for CT-acting than for PEG supplemented ewes (CT not acting); there was no difference in VFI between these two groups. Compared to ewes grazing pasture, ewes grazing lotus had similar VFI but produced more wool with longer staples and thicker fibre diameter, with there being no effect of PEG supplementation.

It was concluded that feeding lotus increased the efficiency of both reproduction and wool production without an increase in VFI, and that a possible cause was the action of CT in increasing plasma EAA and especially BCAA concentration.

In NW Europe a major limitation to the yield of sugarbeet is development of the foliage canopy in May and June, too late to capture much of the available solar energy. This problem could be solved if the crop was sown during autumn so that the seedlings survived the winter and developed a large leaf canopy in early spring. This has led to a search for mechanisms to control flowering so that plants remain vegetative after the winter. However, there has been no serious attempt to estimate the effect of advanced canopy development on the likelihood of water stress. This study has used a combination of modelling of growth to predict yield of rainfed crops and an analysis of the literature to examine the likely consequences for pest and disease incidence if autumn sowing could be achieved without bolters. Compared to spring sowing, a potential yield advantage averaging 26% could be achieved, but this is likely to be overturned by any one of several beet-specific pathogens. For example, beet yellows virus would become more difficult to control and this has the potential to halve yield. Downy and powdery mildew and beet cyst nematode would be more expensive to control. The change from spring to autumn sowing would not allow harvest to be significantly earlier; this would be prevented by dry, strong soil conditions. Nevertheless, the increased emphasis on autumn work on arable farms would be costly.

Three successive experiments, of similar design, were carried out during 1986–88 at Mount Derrimut, Australia. Mature Merino ewes were mated to Poll Dorset rams and then allocated to either a control group (C) or a treatment group (R). Ewes from each treatment were slaughtered 60, 70, 100 or 140 days post-conception and the development of their foetuses was compared in terms of body size and muscle characteristics. In Expts 1 and 2, some ewes were allowed to lamb and the progeny in each group were slaughtered after reaching a body weight of 35 kg, for comparison of growth rates, muscle characteristics and meat quality.

In each experiment, treatment extended from mating to day 70 of pregnancy and, during this period, both groups were housed. Ewes in group C were kept as one group and fed ad libitum and ewes in group R were individually penned and fed a restricted ration of the same diet as that given to group C in order to achieve a steady loss of body weight. In Expt 1, this loss was 8 kg but, in Expts 2 and 3, feed intake was controlled according to condition score and, during this period, group R ewes lost 25–35% of their body weight at mating. After day 70, all ewes were kept grazing and were offered supplementary feed at rates sufficient for a steady increase in ewe body weights.

Foetuses in group R were lower in body weight (P<0·05), crown-rump length (P<0·05) and girth (P<0·01). However, birth weights and mean ages of the 35 kg lambs at slaughter did not differ significantly between treatments.

There were no significant differences between treatments for the semitendinosus (ST) and semimembranosus (SM) muscles in total muscle weight, DNA content, protein content, nor in the ratios of muscle weight[ratio ]DNA and protein[ratio ]DNA. However, there were significant differences between experiments, which indicated that cell size in the ST and SM muscles was lower in Expt 2 than in Expt 1.

In day 70 foetuses, the cross-sectional area of α fibres was greater (P<0·05) in group R than in group C but by day 140 the difference was no longer significant. At day 70, there was also a positive correlation (r=0·65, P<0·01) between the cross-sectional area of β fibres and the number of α fibres surrounding each of them. There were no significant differences between treatments at any age in the percentages of βR, αR and αW fibres.

Meat from group R lambs was more tender than that from group C lambs as indicated by significantly lower means in the SM muscle for adhesion (P<0·01) and Warner–Bratzler Peak Force (WB PF) measurements (P<0·05).

Although some effects of nutritional restriction were found, severe feed shortage in early pregnancy in sheep is unlikely to have significant effects on the production of prime lamb meat provided that adequate nutrition is available during late pregnancy and post-natal growth.

Field experiments were conducted during the wet seasons of 1995 and 1996 at the Central Rice Research Institute, Cuttack, Orissa, India using two rice cultivars, Matangini (improved) and Champaisali (local) to study the advantages of organic manuring in conjunction with inorganic fertilizer with the objective of enhancing rice productivity under semi-deep (0–65 cm) lowland conditions. In 1995, application of 10 t FYM/ha increased grain yield compared with no FYM. The yield produced with FYM alone was similar to the yield following the application of N fertilizer at 20 and 40 kg/ha. There was no significant difference in grain yield due to the application of 20 and 40 kg N/ha in plots treated with FYM. Nitrogen fertilization was effective only when FYM was not applied. In 1996, FYM application alone or in combination with N fertilizer had a beneficial effect on crop growth and grain yield. This was contrary to the results obtained in 1995 when N fertilization at 20–40 kg/ha did not prove beneficial in plots where FYM was applied. The yield due to application of FYM alone was similar to that from the application of 40 kg N/ha as urea. However, the maximum yield was produced when FYM application was supplemented with 40 kg N/ha. There was a significant interaction between N application rate and cultivar. Cultivar Matangini outyielded Champaisali in both years.

In order to learn more about the feeding value of stovers and straws, seven diets were compared in one experiment and nine in another. The diets in the first experiment were: the upper and lower parts of lucerne (Medicago sativa) hay, the leaves, upper stem and lower stem of maize (Zea mays) stover and the leaves and stem of sorghum (Sorghum vulgare) stover. The diets in the second experiment were: the upper and lower parts of lucerne hay, the leaves, stem and whole stover of millet (Setaria italica), the straw and chaff of wheat (Triticum aestivum), rice (Oryza sativa) straw and sweet potato (Ipomoea batatas) haulm. The diets were fed to sheep to record rate of intake, voluntary intake and in vivo digestibility. The diets were analysed for cell wall (as neutral detergent fibre), crude protein and lignin. Organic matter degradation and cell wall degradation were recorded in nylon bags in the rumen of cattle.

The highest rates of intake (6·8–9·6 g dry matter/min) and voluntary intake (75–103 g dry matter/kg W0·75/day) were with sweet potato haulm and the upper, leafy part of lucerne hay. The voluntary intake of millet leaves, wheat chaff and the lower, stemmy part of lucerne hay was moderately high (46–70 g dry matter/kg W0·75/day). Voluntary intake of leaves was higher than that of stems in the case of millet, sorghum and to a lesser extent maize. The lowest rates of intake were with millet stem, sorghum stem and rice straw (1·8–2·4 g dry matter/min). In vivo digestibility of organic matter was highest (59–67%) for the upper part of lucerne hay, sweet potato haulm, the lower part of maize stem and millet leaves. The leaves of maize were less digestible than the stem, while the reverse was the case with millet. Cell wall content was particularly high (74–78% of dry matter) in millet stem, wheat straw and chaff, rice straw and sorghum stem. Lignin content was low (3·6–4·2% of dry matter) in millet leaves, maize leaves and the upper part of maize stem. Organic matter degradation after 24 h incubation in the rumen was highest (80%) in sweet potato haulm and lowest (39–44%) in millet stem, wheat straw and chaff and rice straw. Cell wall degradation after 96 h in the rumen was highest (76–81%) with the leaves of maize, sorghum and millet and lowest (40–59%) with lucerne hay, millet stem and stover, wheat straw and chaff and rice straw.

A rotational grazing experiment using weaner deer was conducted at Palmerston North, New Zealand, during the autumn, winter and spring, to compare the voluntary feed intake (VFI), liveweight gain (LWG) and carcass production of deer grazing chicory with those grazing perennial ryegrass/white clover pasture. Deer were either treated with anthelmintic at 3-weekly intervals (T) or anthelmintic was withheld until trigger-treatment (TT) criteria were attained. Pure red and 0·75 red: 0·25 elk hybrid stags and hinds were given forage allowances of 5 kg DM/deer/day in autumn and early-mid winter, 6 kg DM/deer/day in late winter and 7 kg DM/deer/day in spring. Deer grazed chicory or pasture in autumn and spring, with all deer combined on pasture during winter when chicory was dormant. Organic matter digestibility of diet selected was greater for chicory than for pasture in both autumn and spring.

Anthelmintic-treated deer grazing pasture in autumn had significantly higher VFI and LWG, contributing to higher carcass weights, than TT deer. Anthelmintic treatment had no effect on these measures for deer grazing chicory in autumn. Clinical signs of lungworm infection were evident in pasture TT deer during autumn and winter, and in chicory TT deer grazing pasture during winter. Faecal egg counts (FEC) were significantly greater for pasture TT deer during autumn and early winter than all other groups. Faecal lungworm larval counts (FLC) were significantly greater for chicory TT deer following transfer to pasture, than for all other groups in early winter, although both FEC and FLC were low. Faecal larval counts were poorly related to clinical signs of lungworm infection during autumn, but were a better guide in winter. Plasma pepsinogen concentrations appeared unrelated to gastrointestinal parasite infection. Trigger-treated deer grazing pasture required five anthelmintic treatments during autumn and winter. The chicory TT group required no anthelmintic treatment when grazing chicory during autumn, but required two treatments after transfer from chicory to pasture during winter.

There was no effect of anthelmintic regime on VFI and LWG in spring, and LWG was greater for deer grazing chicory than those grazing pasture. Hybrid deer had greater spring LWG and carcass weights than red deer when grazing chicory, but similar LWG and carcass weights when grazing pasture.

It was concluded that grazing chicory offers the potential for reducing anthelmintic use in farmed weaner deer, particularly during autumn.