Pelleted seed of the crisp lettuce variety Pennlake was sown on five occasions with units from either the experimental dibber drill designed by the National Institute of Agricultural Engineering or a Stanhay S870 drill. There were three dibber-drill treatments: seeds left in open holes or covered with peat–vermiculite or perlite. Seedling emergence and growth from each sowing of the four drill treatments were compared under different moisture regimes.

There were large differences between drill treatments in emergence percentage, time to emergence of 50% of the seedlings which emerged (t50) and seedling weight at all sowings but there was a significant effect of drill treatment on the standard deviation of seedling emergence times at only one sowing. Of the dibber-drill treatments, only very occasionally did open holes or perlite cover give significantly better emergence than peat-vermiculite cover, which gave the most consistent results. In general, the dibber drill with peat-vermiculite cover gave significantly faster and higher emergence and heavier seedlings than the Stanhay drill. Differences in percentage seedling emergence tended to be greater under dry conditions.

First (I1), second (I2) and third-generation (I3) inbreds were compared with openpollinated spring-sown onion populations in field trials at five sites over 2 years. The open-pollinated populations were earlier maturing and gave higher yields and a lower proportion of bullnecked plants than the inbreds but the latter had a lower proportion of unmarketable double bulbs. The mean level of expression of each character differed considerably between individual trials. The effect on sprouting within each year resulted from factors operating prior to storage; bulbs from all sites were stored at Wellesbourne in a common environment yet large differences in the proportion of sprouted bulbs from different sites occurred by the following spring.

Interactions were found between the type of population (inbred and open-pollinated) and the macro-environment. Inbred populations showed a greater linear response to environment for yield, skin colour and proportion of bullnecked plants, but were less responsive for percentage of double bulbs.

The results are discussed in relation to the evaluation procedures for inbreds.

Contour diagrams, computed from analyses of soil around bands of aqueous ammonia injected under grass, show the distribution of both NH4-N and nitrifying bacteria.

When applied at 155 kg NH3-N/ha, either as 4·7 or 9·3 g N/m of injection slit, using knives spaced either 30 or 60 cm apart, aqueous NH3 was recovered and nitrified more slowly in the bands 60 cm apart. Cumulative yields of grass after 32 weeks were the same (715 ±30 g/m2) from plots injected at either spacing but growth was more even throughout the season from slits 60 cm apart.

The fertility, especially potassium status, of the Barming series in East Kent was studied by laboratory and pot test procedures to determine the effect of indigenous glauconite. Half of 12 otherwise similar soils contained appreciable glauconite.

Glauconite contributed positively to the potassium status of the soils, especially the B horizons (45–65 cm), and was associated with higher values of exchangeable potassium, cation exchange capacity, nitric acid soluble potassium and intensity of potassium supply as measured by ΔḠ. More potassium was taken up and more released from initially non-exchangeable sources to ryegrass from the glauconitic soils. The available magnesium content of the soils was also positively correlated with glauconite content but available phosphate was not.

A fast and simple method for analysing volatile compounds in Asyrtiko wines has been developed, with good reproducibility and suitability for routine analysis, and which is able to quantify many of the major odorant compounds in a single chromatographic run. The method allows satisfactory determination of fusel alcohols and their acetates, short-chain fatty acids and their ethyl esters. The linear dynamic range of the method covers the normal range of occurrence of analytes in wine, with typical r values of 0·992–0·999. Reproducibility ranges from 0·036 to 0·092 (as relative standard deviation; RSD). The method was applied for two consecutive years to wines from cv. Asyrtiko from Santorini, in order to establish the effect of pre-fermentative cryomaceration on the odorant compound levels of the resulting wines. Pre-fermentative cryomaceration significantly increased the levels of hexan-1-ol for both the vintages studied, while hexanoic acid and 2-phenylethyl acetate levels were higher in the classical vinification samples. The vintage (year) effect was important. Difference tests revealed significant differences between the samples using sensory analysis tests but preference tests did not reveal any preference for one or other treatment.

Leaf development was studied in eight related grasses, grown in field swards cut at 5-week intervals, during the year of sowing and the subsequent year (1989 and 1990). The rate of leaf expansion was in the order Westerwolds ryegrass > Italian ryegrass (Lolium multiflorum), Italian ryegrass × meadow fescue > hybrid ryegrass > perennial ryegrass × meadow fescue, meadow fescue (Festuca pratensis), tall fescue (Festuca arundinacea) and perennial ryegrass (Lolium perenne). The order of grasses was similar, but not identical, for rate of leaf appearance, rate of leaf extension, weight of leaf blade emerging per shoot per week and rate of increase in length of exposed leaf sheath, and the order was approximately the reverse for weight per unit area of emerging leaf blade. The area per leaf blade increased greatly between May and October of the year of sowing, particularly in Westerwolds, Italian and hybrid ryegrasses and Italian ryegrass × meadow fescue. Area per leaf blade in tall fescue increased greatly between May and July of the year of sowing and May–July of the subsequent year. Rate of leaf expansion in meadow fescue was much higher in May of the year after sowing than in the previous May.

A field experiment was carried out at Harper Adams in Shropshire to investigate the effect of supplying the spring N application to winter wheat as different proportions of urea as a solution, rather than as conventional soil-applied solid urea, on N recovery in the above-ground crop, autumn soil mineral N and nitrate leaching over the subsequent winter. A solid ammonium nitrate treatment was also included to represent alternative commercial practice to solid urea. Treatments were repeated on the same plots over the 3 years 1992, 1993 and 1994. N recovery was measured in all 3 years by difference in N uptake between fertilized and unfertilized plots, and in 1993 for selected treatments, N was applied as 15N-labelled fertilizer to determine direct uptake of fertilizer N in the crop and soil. Both urea sprays and solid soil N applications were labelled with 15N. Urea sprays were split over several days to reduce scorch, whereas solid fertilizer was applied as a single dressing. For some urea spray treatments, apparent N recovery in the above-ground crop in 1992 and 1994 was less compared with soil-applied N treatments. These urea spray treatments were applied in the morning rather than the evening, and gaseous losses, most likely by volatilization, are suggested. In 1992 application of a large proportion of N as urea sprays, such that application of some N as urea solution was delayed to around GS 37, was associated with an increase in physiological N use efficiency. In 1993, there was no difference in direct or apparent recovery of fertilizer N in the crop or soil for N applied as ammonium nitrate, solid urea or as urea sprays. Mean nitrate concentration in the drainage water at 1 m was elevated for all N treatments in all years, but only in 1992 did nitrate concentration and leaching loss decrease with increasing proportion of N applied as urea sprays. It may therefore be possible to reduce gaseous losses by application of urea sprays under cool conditions in the evening and exploit the increased physiological N use efficiency for urea sprays applied later, such that total fertilizer N applied and N losses are reduced.

Three successive generations (parents, F1, F2) and backcrosses of the common bean (Phaseolus vulgaris L.) hybrid between the cultivars Swedish Brown and Seafarer were used in this study.

The investigation has concentrated on assessing the relationship between the seed weight per plant and the protein percentage of the seed. Protein percentage showed a higher estimated heritability and a greater stability over environments than seed weight.

Partial dominance for low percentage protein and low seed weight was noted. Negative and low regression coefficients between these two characters was also observed.

SDS-gel electrophoresis was used to examine the variation in banding patterns of total seed polypeptides and their stability over environments.

Soluble ammonium nitrate (AN) and urea were compared with slow-release oxamide and sulphur-coated urea (SCU) as N sources for clipped annual ryegrass (Lolium multiflorum) or common bermuda grass (Cynodon dactylon) in four greenhouse experiments. Mixed and surface applications of a wide range of N rates were evaluated for 9 to 14 cuttings of grass forage. Both granular oxamide and SCU exhibited slow-release N properties, especially when surface-applied. Uptake distribution of N with high application rates of AN and urea tended to resemble that with the slow-release sources. Slow-release properties of oxamide and SCU were accentuated at high application rates. Lower N recovery from surface-applied urea than from AN indicated volatilization loss of urea N. Volatilization loss also occurred with oxamide, but low N recovery from oxamide and SCU resulted largely from incomplete dissolution of the granules during the 18- to 34-week experimental periods. Very low N recovery was obtained from urea formaldehyde having an activity index of 42.

1. Two experiments designed to investigate the effects of different times of ploughing a clover ley on the growth and yield of the subsequent winter wheat crop are described and the results discussed.

2. Although the different times of ploughing led to considerable differences in the growth of the wheat, their effect on yield was not consistent. This in agreement with the results of an earlier series of experiments. The effects of time of ploughing are attributed mainly to the resulting differences in the physical condition of the seed-beds.

Four adult swamp buffaloes (Bubalus bubalis) and four adult Brahman cattle (Bos indicus), maintained in climate rooms, were provided ad libitum with a pelleted NaOH-treated barley straw ration (10·7 g N/kg dry matter) supplemented with sulphur, minerals and vitamins and 0, 14·5 or 22 g urea/kg. The animals were given each diet when housed at 32 °C and, in addition, were given the urea unsupplemented diet at 22 °C. All animals received all treatments for periods of 21 days, measurements being made during the last 8 days, after the animals had been given single doses of two nonabsorbable markers (Cr-fibre and Co-EDTA). Intake, digestibility and gastro-intestinal passage rate were low on the unsupplemented N-deficient (10·7 g N/kg dry matter) diet at both temperatures. Urea supplementation to provide diets of 17·3 and 20·7 g N/kg dry matter was associated with increased intake and digestibility of the feed and increased rate of passage of digesta through the gut.

Despite differences in respiration rate and plasma thyroxine (T4) and triiodothyronine (T3) concentrations at the two temperatures, no effects of temperature on intakes and digestion of the unsupplemented diet were seen. Differences between species were seen in respiration rate at 32 °C and plasma T4, which were higher, and mean retention time of Cr in the gut at 22 °C and water intakes, which were lower, in Brahman cattle than in buffaloes. There were no significant species differences in response to dietary urea supplementation.

Sets of data were selected from 66 nutritional experiments on crop plants with large beneficial effects of at least two of the nutrients, nitrogen, potassium and phosphorus, and the data, the logarithms of the data, and the reciprocals were statistically analysed. It was shown that the beneficial effects of the nutrients were additive much more often on the reciprocal scale, than when a logarithmic transformation, or none at all, was used.

The current paper presents information from a survey of the practices associated with the control of ectoparasites on sheep in Northern Ireland in 2005, including the estimated total quantities of pesticide active ingredients used. It also provides comparative data to that obtained from previous surveys in 1981 (Jess & Marks 1986), 1988 (Foy et al.1995) and 1997 (Jess et al.2000). The total number of sheep farms in Northern Ireland decreased by 25% to 8822 farms with a consequent 26% reduction in total sheep population to 2·1 million sheep compared with the previous survey in 1997. During this period, the number of sheep treated for ectoparasites decreased by 40%. The total quantity of organophosphorus (OP) compounds used for ectoparasite control decreased by approximately 67%, from 7·8 tonnes in 1997 to 2·6 tonnes in 2005, during which an estimated 0·38 of all sheep treated for ectoparasites received the OP active ingredient diazinon. The survey results indicate a decline in the practice of plunge-dipping sheep for ectoparasite control with the proportion of farms using this treatment method decreasing from 0·58 to 0·16 between 1997 and 2005. In 1997, an estimated 0·8 of all sheep treated for ectoparasites in Northern Ireland were plunge-dipped, which reduced significantly to 0·28 during 2005. Conversely, the use of alternative methods has increased with pour-on formulations of insecticides, macrocyclic lactones and growth regulators being applied to 0·33 of all sheep treated in 2005 compared with 0·09 in 1997. Use of intramuscular or subcutaneous injections of macrocyclic lactones for ectoparasite control has also increased to 0·24 of all sheep treated in 2005 compared with 0·1 in 1997. The proportion of sheep treated in communal spray showers also increased from 0·01 in 1997 to 0·14 in 2005. Control of blowfly maggots (Lucilia spp.) and prevention of sheep scab (Psoroptes ovis) were the main reasons given by farmers for sheep treatments. On the farms that plunge-dipped, an estimated 0·68 of surplus dip wash was disposed of immediately after dipping took place, with 0·8 of farms emptying the dipping tanks using a vacuum tanker and 0·54 spreading the surplus dip wash directly onto land. An estimated 0·35 of these farmers mixed the dip wash with slurry pre-disposal. The survey suggests that the products used for spray showers are those recommended for plunge-dipping as there are no contemporary products recommended for use in spray showers. Macrocyclic lactone injections recorded in the survey had the dual function of controlling both endo- and ectoparasites.

The incidence and distribution of haemoglobin types and potassium and sodium concentrations in whole blood of 411 Sudan Desert sheep and 11 Merino sheep were determined. Haemoglobin types were distinguished by electrophoresis in starch gel and blood potassium and sodium levels by flame photometry.

Of the 411 animals examined, 396 possessed haemoglobin B in the homozygous state while only 15 possessed haemoglobin AB. The homozygous AA haemoglobin was not detected. No bimodality was found in whole blood potassium and sodium levels and the distributions were normal.

Six early maturing inbreds from maturity group I of Indian cauliflowers were selected and diallol crosses were made to study the combining ability of inbreds and identify the desirable parent(s) for hybridization. Seven characters, i.e. curd weight, curd size index, maturity, plant height, number of leaves, leaf size index and plant spread were studied both in F1 and F2 generations. Though the estimates of both general and specific combining ability variances were highly significant for all the characters, the magnitudes of general combining ability variances were higher than that of specific combining ability variances. The performance of the inbreds was in general associated with their general combining ability effects. The inbred 103 was found to be best combiner for all the characters and the cross 105 x 108 showed maximum yield potential.

Four experiments conducted over three seasons (2002–05) at the Crops Research Unit, University of Reading, investigated effects of canopy management of autumn sown oilseed rape (Brassica napus L. ssp. oleifera var. biennis (DC.) Metzg.) on competition with grass weeds. Emphasis was placed on the effect of the crop on the weeds.

Rape canopy size was manipulated using sowing date, seed rate and the application of autumn fertilizer. Lolium multiflorum Lam., L.×boucheanum Kunth and Alopecurus myosuroides Huds. were sown as indicative grass weeds.

The effects of sowing date, seed rate and autumn nitrogen on crop competitive ability were correlated with rape biomass and fractional interception of photosynthetically active radiation (PAR) by the rape floral layer, to the extent that by spring there was good evidence of crop: weed replacement.

An increase in seed rate up to the highest plant densities tested increased both rape biomass and competitiveness, e.g. in 2002/3, L. multiflorum head density was reduced from 539 to 245 heads/m2 and spikelet density from 13 170 to 5960 spikelets/m2 when rape plant density was increased from 16 to 81 plants/m2. Spikelets/head of Lolium spp. was little affected by rape seed rate, but the length of heads of A. myosuroides was reduced by 9% when plant density was increased from 29–51 plants/m2.

Autumn nitrogen increased rape biomass and reduced L. multiflorum head density (415 and 336 heads/m2 without and with autumn nitrogen, respectively) and spikelet density (9990 and 8220 spikelets/m2 without and with autumn nitrogen, respectively). The number of spikelets/head was not significantly affected by autumn nitrogen.

Early sowing could increase biomass and competitiveness, but poor crop establishment sometimes overrode the effect. Where crop and weed establishment was similar for both sowing dates, a 2-week delay (i.e. early September to mid-September) increased L. multiflorum head density from 226 to 633 heads/m2 and spikelet density from 5780 to 15 060 spikelets/m2.

The objective of the present study was to determine the optimum plant density of four pigeonpea genotypes, representing early, medium and late maturing types, grown in five contrasting environments in Tanzania. ICPL 86005 (early), Kat 50/3 and QP 37 (medium) and Local (late) were grown at four plant densities (40 000–320 000 plants/ha) in irrigated and rainfed conditions at Ilonga and under rainfed conditions at Kibaha, Selian and Ismani. At maturity, total above-ground biomass and seed yield (SY) were measured. The highest yields were obtained in the irrigated experiment at Ilonga, where the medium/late genotypes produced 25 t biomass/ha and 5·6 t seed/ha. The lowest SY were at Kibaha, 0·58 to 1·76 t/ha, where a severe drought occurred. In nearly all cases the response to density was linear or asymptotic. The response of ICPL 86005 was significantly different from the other three genotypes. The optimum density for SY varied from 37 000 to 227 000 plants/ha in ICPL 86005, compared with 3000 to 101 000 plants/ha in the medium/late genotypes. The highest optimum density was at Selian and Ismani and the lowest at Ilonga and Kibaha, where drought occurred. Optimum densities therefore varied greatly with genotype (duration) and environment, and this variation needs to be considered when planning trials.

Integrated crop-livestock systems (ICLS) are currently promoted agricultural production systems that aim to use better resources through production integration and intensification. While this system reduces some risks, it adds complexity and new risks to businesses due to interdependence between the agricultural modules. To deal with these issues, integrated risk management is required to reduce the effects of risks and to take advantage of the opportunities of an ICLS. Generically, enterprise risk management (ERM) meets this need by proposing comprehensive and coherent risk management, instead of managing agricultural module risks individually. However, there is a need to customize the ERM approach to ICLS. Therefore, the current study aims to develop a method to manage risks for ICLS based on ERM, integrating the management of risks and aligning risk management with the strategic objectives. A literature review, a pilot study, interviews with experts, four case studies and 20 practitioners supported the method development and evaluation through three versions. As a result, the method identifies and relates risks through process mapping with a qualitative and quantitative analysis of their impacts, determines risk responses based on willingness to take risks, and helps identify processes to control, communicate and monitor the risks. The method also stimulates the implementation of ICLS in market-oriented farms, providing an approach to increase the chances of ICLS success. The main difference from previous research lies in the integrative management of multiple risks, the alignment of risks with strategy and the consideration that a risk might be considered an opportunity.

The aim of this work was to verify the possibility of intercropping rice with green manures, as well as the impact of the dry biomass yield of these intercropping systems on common bean in succession, evaluating the agronomic and qualitative performance of grains from both crops. The experiment was conducted in Southeastern Brazil in the years 2018 and 2019, with succession of rice (spring/summer) and common bean (autumn/winter). The treatments were composed of cropping systems with rice as a sole crop and intercropped with forage peanut, calopo, Crotalaria breviflora, Crotalaria spectabilis, stylo, jack bean and dwarf pigeon pea. No intercropping increased the system's yield compared to sole-crop rice, but intercropping of rice with forage peanut and stylo promoted grain yield and quality similar to those of sole-crop rice. Intercropping with C. breviflora affected the agronomic and qualitative performance of rice. Common bean yield after rice intercropped with dwarf pigeon pea, C. spectabilis and C. breviflora was similar in yield after sole-crop rice, while the other intercrops reduced common bean yield. Common bean grain quality was not affected by the cultivation of rice as sole crop and intercropped with green manures. Although none of the intercropping systems increased yield compared to sole-crop rice (control), it can be concluded that the intercropping of upland rice is viable depending on the green manure species, allowing greater biomass production per area that can help long-term soil conservation and increase the system's yield.

Most acid sulphate soils (ASSs) in the Pearl River Delta of South China have been traditionally reclaimed for rice cultivation, but the rice yield in most of these paddy fields is lower than the average rice yield in China due to extremely high soil acidity. In the present study, a range of sulphate and acidity parameters were investigated in ASS profiles in three types of paddy fields in Taishan City (Guangdong Province, China) divided based on the local rice productivity (4500, 3000 and 1500 kg/ha) using an abandoned ASS (uncultivated) as the control treatment to ascertain key yield constraining parameters. Soluble acidity (SA), exchangeable acidity (ExA), soluble sulphate (SS) and net acid-soluble sulphate (NAS) increased with increasing soil depths from 0 to 100 cm and then decreased abruptly with further increases in the depth. However, the depth distribution of exchangeable sulphate (ES) was uniform. The soil acidity and sulphate contents differed significantly in three sampled paddy fields. The values of SA and SS in the soils at depths of 0–100 cm in the studied ASS were lower compared with those in the uncultivated ASS and the ExA in soils at depths of 0–40 cm in ASS were lower compared with those observed in the uncultivated ASS. A correlation analysis revealed that SA was strongly correlated with SS and ExA with NAS. Soluble acidity, ExA, SS and NAS in the ASS were significantly associated with rice yield. Exchangeable acidity in the plough layer (0–20 cm) of soils was the most sensitive indicator of soil quality affecting rice yield among those in soils from 0 to 140 cm depth. It is interesting to note that SA, SS and NAS were more sensitive indicators of soil quality affecting rice yield at 60–100 cm than at 0–40 cm depth. Principal component analysis showed that pH value, ExA and ES in soils at depths of 0–40 cm and SA, SS and NAS in soils at depths of 60–100 cm constituted the critical soil acidity and sulphate characteristics that were strongly correlated with rice yields. This finding implies that controlling the ExA in the plough layer and the SA and NAS in the Jarosite layer should be the major focus of studies aimed at the amelioration of ASSs.