A replicated field plot experiment was carried out in Northern Ireland in 1996 with flax, cv Ariane, and linseed, cv Flanders, each grown at seed rates of 500, 1000 and 1500 seeds/m2, in which a comparison was made between retting of the standing crop, following desiccation by the trimesium salt of glyphosate (Touchdown, Zeneca Ltd.), and water or dew retting of the pulled crop. Application at 4 litres/ha on 9 August, 33 days after the mid-point of flowering (MPF), achieved both desiccation and partial retting of the crop within 14 days. Over 16% clean long fibre was extracted by scutching the stand-retted flax straw, yielding 800 kg/ha fibre, while water retting achieved 20% extraction and 980 kg/ha yield and dew retting 8·5% and 420 kg/ha respectively. The dew retting was uneven, resulting in high losses during fibre extraction, while water retting for 7 days at 25 °C did not achieve complete retting resulting in a high content of woody fragments in the fibre. Fibre yields increased by almost 50% with the high v. low seed rate. Linseed was less well retted than flax and contained higher levels of impurity in the extracted long fibre which, after retting, yielded 120 to 310 kg/ha at extraction rates of 2·9% to 7·5%.

In a second experiment in 1998 flax cvs. Viola and Evelyn were treated with the timesium salt of glyphosate at rates of 2, 4 or 6 litres/ha 10, 20, 30 or 40 days after MPF on 5 July. Viola desiccated satisfactorily at all spray dates with 4 and 6 litres/ha glyphosate. The 20-day treatment desiccated more slowly than the 30-day and the 2 litres/ha rate did not achieve complete desiccation, but the trimesium salt of glyphosate achieved better desiccation at this timing than that found in earlier studies with the original form of glyphosate. Evelyn desiccated more slowly and less evenly than Viola particularly at the 20-day and 40-day timings. Spraying at MPF+10 days interrupted early development of the seed and fibre significantly reducing yields. Due to slower desiccation the 20-day timing was no better than the 30-day, which was well retted by harvest 44 days after spraying, and gave the highest yield of clean long fibre. The spraying 40 days after MPF was considered too late in the season to be of practical use. It was concluded that retting of standing flax following desiccation with the trimesium salt of glyphosate was more effective than with the earlier formulation and that retting of the standing crop could achieve equivalent or better retting with similar fibre yields to traditional retting methods. The optimum spray timing was found to be about 30 days after MPF with 4 or 6 litres/ha, the lower rate being adequate for glyphosate responsive varieties such as Viola.

Small-grain farming systems in Mediterranean climatic regions are characterized by poor quality soils, high climate variability, and resulting heavy agrochemical reliance. The adoption of Conservation Agriculture, based on minimum tillage, permanent soil cover, and crop rotations, has improved soil quality, enhanced crop productivity, and help mitigate financial risk. However, emerging issues that threaten sustainability, such as herbicide resistance, inputs costs rising disproportionately to product prices, and increasing climate variability and unpredictability, drive the need for innovation in small-grain Mediterranean-based CA systems. The aim of the review was to evaluate a set of agroecological practices which constitute a Regenerative Agriculture (RA) concept, for their potential to address these challenges from a soil quality, crop productivity and whole-farm economics perspective. Organic soil amendments derived from agro-wastes, offer promising perspectives for supplying appropriate quantities of nutrients to reduce or replace mineral fertilisers and offset their economic and agroecological costs. Although the viability of microbial bioeffectors in small-grain agroecosystems was largely under question, non-microbial bioeffectors and certain combination options represent more efficient and cost-effective uses of this technology. Their widely reported abiotic stress priming functions and crop productivity enhancement under poor growing conditions may improve yield stability and financial resilience in small-grain Mediterranean CA systems. Finally, multi-species cover crops subjected to adaptive multi-paddock (AMP) grazing as a phase within the crop rotation may reduce weed pressure, enhance soil multi-functionality, and resilience against environmental stresses. To validate the potential of these technologies in Mediterranean small-grain systems, more long-term and context-specific research is called for.

Yield (or other variate) values from crops recurring on the same plots in long-term experiments are subject to correlations known as serial plot correlations. Neglect of these plot correlations can result in loss of efficiency in the estimation of treatment effects and bias in the estimation of error.

Serial plot correlations are calculated from 12 experiments on arable crops in England and Wales, for yields 4, 6 or 8 years apart. They are usually positive, with average value 0·2. In one set of experiments the losses in efficiency caused by plot correlations of this magnitude are shown to be small, but some of the biases in the estimates of error are large. Biases in the variances of treatment means can be wholly or partly eliminated by separating two components of error, plot error and plot x year error.

Weed infestation is a major yield-reducing factor that also decreases crop water productivity. Yet weeds are often neglected in crop productivity simulation studies, because existing empirical equations and mechanistic models are not widely applicable or have a high demand for input data and calibration. For that reason, AquaCrop, a widely applicable crop water productivity model, was expanded with a weed management module which requires only two easily obtainable input variables: (i) relative leaf cover of weeds, and (ii) weed-induced increase of total canopy cover. Using these inputs, AquaCrop directly simulates soil water content, crop canopy development and production as it is observed in weed-infested fields. Despite this simple approach, AquaCrop performed well to simulate soil water content in the root zone (relative root-mean-square error (RRMSE) of 5–13%), canopy cover (RRMSE of 15–22%), dry above-ground crop biomass during the season (RRMSE of 21–39%) and at maturity (RRMSE of 5–6%) and yield (RRMSE of 11–25%) of barley and wheat grown under different weed infestation levels and environments. The current study illustrates that the AquaCrop model can be used to assess the effect of weed infestation on crop growth and production, using a simple approach that is applicable to diverse environmental and agronomic conditions, even in data-scarce regions.

The effects of some plant growth regulators on the growth and development of two cultivars of oil-seed sunflower (cvs Flambeau and Luciole) were examined in 1977 and 1978. Sunflower is a marginal crop for the United Kingdom, being late maturing and susceptible to infection by grey mould (Botrytis cinerea) during the seed-filling period.

An experiment in 1977 indicated that suitable growth regulators might improve sunflower husbandry principally by shortening the stem, allowing late applications of fungicide and insuring against lodging. A mixture of mepiquat chloride and ethephon (BAS 098 OOW) was the most effective stem shortener. Daminozide gave variable effects on yield depending on the rate and time of treatment. The number of seeds per m2 was the major determinant of yield; 1000-seed weights and oil contents were similar for all treatments. The proportion of linoleic acid in the oil was very high in all experiments.

In 1978 a second experiment involving daminozide and two sunflower cultivars revealed seasonal and varietal differences in response. The timing of growth regulator application seemed critical to affect seed yield. The third experiment, in 1978, investigated the results of applying BAS 098 OOW to four plant population densities varying from 40000 plants/ha to 160000 plants/ha. High plant population density advanced maturation by 2 weeks, but in these plots the crop lodged in the absence of growth regulator treatment.

Field experiments from 1959–60 to 1963–4 showed that when blackarm resistant strains of Egyptian type cotton were sown around the beginning of August and adequately protected from fleabeetle, the resultant crop was of higher yield and considerably better average quality than that from the normal mid-to-late August sowings. Effective length, maturity ratio, standard fibre weight, bundle strength and lea-count × strength product were all improved. Sowing in early July, tested in one season only, gave rather better quality but lower yield than sowing in early August. Sowing in late August or in September depressed both yield and quality. The importance of direct climatic effects and of blackarm, fleabeetle, bollworm, other insect pests and wilt in controlling the choice of, and response to, sowing date is briefly discussed.

Thanks are due to the Sudan Gezira Board for kindly supplying the results of the large-scale sowing date trials and for the grading of experimental cotton, to the Shirley Institute of Manchester for the fibre and spinning tests and to the Chief, Agricultural Research Division, Ministry of Agriculture, Sudan, for permission to publish this paper.

At Shika in a subhumid environment of Nigeria, a 3-year study was carried out to select newly developed groundnut varieties for use in crop–livestock production systems. The study examined 11 groundnut varieties. Emergence time, plant stands at full emergence, forage and seed yields and yield components were examined. Whole plant samples were analysed for crude protein (CP) content. Varieties ICGV 87123 gave the lowest forage yield and cultivar M517-80I, the highest, with seven varieties recording forage yields above 5 t/ha. The CP content of forage was lowest (14·8%) for variety M576-80I and highest (21·6%) for variety M554-76. Mean seed yield (over 3 years) varied significantly from 0·73 to 1·68 t/ha. Only two varieties had mean seed yield >1 t/ha. The relationship between seed and forage yields was positive and significant (r = 0·529, P < 0·006). Varieties RMP 12, 88-80I and M517–80 were most promising for both forage and seed production.

The mechanisms and host plant responses that are indicative of tolerance to the African rice gall midge, Orseolia oryzivora Harris & Gagne were investigated in four promising donor rice cultivars, Cisadane, Bw 348-1, Tox 4093-17-1 and ITA 306 (local check), in a screen house at the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria. Results indicated that Cisadane was tolerant to infestations on the basis of higher (P<0.05) percentage seedling survival, production of significantly higher number of fertile tillers, productive panicles and significantly higher grain yield per infested plant than the control. Both single infestation at one larva per plant and adult infestation once at 14 days after seeding were positively correlated to higher fertile tiller production per infested plant (at 80 days after transplanting) and higher grain yield per infested plant at maturity. The grain yield per infested plant was significantly higher (P<0.05) in the tolerant variety (Cisadane) than in the control.

Blood samples were collected three times weekly for 21 days before and after calving (day 0) from 29 buffalo cows and 22 buffalo heifers. Plasma concentrations of progesterone and total oestrogens were quantified by validated radioimmunoassays. Ovarian activity and uterine involution were monitored by rectal palpation at the sampling times and extended up to 60 days postpartum. The concentration of plasma progesterone in cows declined from 3·0 ± 0·2 ng/ml (mean ± S.E.) during days 21–17 before calving to 2·1 ± 0·1 ng/ml at day −3, followed by a rapid fall during the last 3 days of gestation, reaching 1·2 ± 0·3 ng/ml at the day of parturition. In heifers, plasma progesterone values increased slightly from 2·9 ± 0·2 ng/ml at days 21–19 before parturition to 3·4 ± 0·3 ng/ml by day −1 and then fell sharply to 2·1 ± 0·1 ng/ml at calving time. During the postpartum period, plasma progesterone decreased gradually and reached baseline values after day 15 postpartum, when the residual corpus luteum of pregnancy had completely regressed in all the animals studied. The plasma concentrations of total oestrogens started to increase at day −15 in cows and day −5 in heifers from below 40 pg/ml to 122·5 ± 51 pg/ml for cows and 100·7 ± 3·4 pg/ml for heifers by day −1. This was followed by a sharp increase to 251·2 ± 17·3 and 240·5 ± 10·1 pg/ml in these animals at the day of calving. Immediately after parturition, total oestrogens dropped abruptly to the lowest values and remained below 30 pg/ml in all cows and heifers until the end of the sampling period. We concluded that female foetuses significantly (P < 0·05) increased the maternal total oestrogens. Moreover, animals having postpartum disorders had significantly higher values for progesterone (P < 0·05) and lower values for total oestrogens (P < 0·01) than those having normal puerperal periods, but the magnitude of this difference varied in samplings between cows and heifers.

1. The aneurin content of samples of whole oat grain representing six commonly used varieties grown in different districts in Scotland and Wales did not vary widely and there were no appreciable varietal or geographical differences.

2. There was a significant positive correlation between aneurin and protein content (r = 0·42).

3. During the growth of the oat plant from the flowering stage a steady storage of aneurin in the kernels was observed until the crop was harvested, and there was a simultaneous decrease in the aneurin content of the dry matter of the hulls, leaves and straw, suggesting a translocation of aneurin from the leaves to the kernels during the maturation of the plant.

1. The water intakes of ten Holstein × Zebu milking cows, yielding between one and two gallons of milk a day, were analysed on the basis of (a) freewater drunk, and (b) feed-water consumed with the herbage. Trials took place during a 10-day period in both the wet season, 1959 and the dry season, 1960. During both seasons the cows were rotationally grazed on Pangola grass pastures.

2. The results showed a difference of only 24% in total water intake between seasons. However, the mean intake of free water increased from 18·5 lb. per cow in the wet season to 81·5 lb. per cow per day in the dry season, and the intake of feed water decreased from 94·9 to 59·2 lb. per cow per day, respectively. The between cow coefficients of variation were 9·7 and 8·7%, respectively.

3. Results are presented for the drinking habits of Holstein × Zebu cattle grazing Pangola grass pastures. For 567 observed cow-days in the wet season, the cattle were found to drink water on average 0·8 times per day from troughs present in the pastures. For 332 observed cow-days in the dry season, the cattle increased their drinking habits to a mean figure of 1·4 times each day.

The biochemical decomposition of plant residues and other organic matter in the soil is of fundamental importance for soil fertility. It causes the breaking down of coarse plant fragments which otherwise might open up the soil too much: it leads to the production of colloidal complexes known as humus which exert many beneficial effects both chemical and physical, and it brings about the formation of nitrates, the most important of the nitrogenous plant nutrients.

An account has been given of an investigation which was designed to test the efficacy of the process of ensilage in the stack for preserving hay crops which are in danger of spoiling in consequence of adverse weather conditions.

The character of the ensiled crops and the weather conditions at the time of ensiling, together with the process of building the stack, have been described in detail.

The results of continuous temperature readings in the stack have been given in graphical form. The significance of the two distinct temperature maxima which characterized the temperature curve has been discussed, and the importance of this method of investigation in regard to the elucidation of the processes which go on during ensilage has been emphasized.

The chemical character of the “sweet” silage samples obtained from experimental bags buried in different parts of the stack has been investigated. The losses of dry matter resulting from fermentation and drainage have been determined and the changes affecting the individual constituents of the crop have been followed quantitatively. The results so obtained have been compared with similar figures referring to the process of ensilage in the tower and the clamp.

It has been shown that the loss of dry matter in the “sweet” silage layers of the stack compares satisfactorily in magnitude with the losses accompanying the preservation of crops in the tower silo and is appreciably smaller than that associated with the production of “sour” silage in the clamp.

The objective of the present study was to examine the effect of the level of phosphorus (P) intake on ruminal P kinetics in sheep. Twelve Santa Inês male sheep (average body weight 36 kg) were fed a basal diet consisting of roughage (coast cross hay), concentrate mixture (cassava meal, soya bean meal and urea) and a mineral premix. The treatments consisted of the basal diet supplemented with 0, 1·5, 3 or 4·5 g/kg dry matter (DM) of mono-ammonium phosphate to provide increasing P levels representing treatments T0, T1, T2 and T3, respectively. The P content of experimental diets was 1·5; 2·0; 2·5 and 3·0 g P/kg DM, and considered highly deficient, deficient, adequate and in excess, respectively, compared with standard recommended allowances. Animals were injected with 32P and thereafter samples of blood were collected over 7 days, while samples of rumen fluid and saliva were collected 4 and 6 days after injection. Phosphorus intake affected P concentration in ruminal fluid, whereas P concentration in saliva was not affected. The values for P turnover time in the rumen were 1·42, 1·23, 1·18 and 1·04 days, whereas values of endogenous P entry into the rumen were 1·05, 1·37, 1·53 and 1·91 g/day for T0, T1, T2 and T3, respectively, both affected by P intake. The specific activity (SA) of P in saliva, rumen and plasma were also all affected by P intake. The relationship between saliva and rumen SA emphasizes that most endogenous P in the rumen came from saliva. The possibility of an extra P source besides saliva contributing to endogenous P in the rumen is discussed. It is concluded from the results that, regardless of P intake, the flow of endogenous P into the rumen contributes to ensure a minimum supply of this essential element, which may be important in matching the requirements of the rumen microbes.

The frost susceptibility of Australian commercial cereal crops, in particular wheat and barley, has become an economically devastating issue for growers. The relative risk to frost damage of the currently available varieties is obtained through testing varieties in a series of field experiments at locations susceptible to frost events (FEs). The experimental design, measurement protocols and resultant data from these frost expression experiments (FEEs) are complex due to the unpredictability of the timing and severity of FEs, and the maturity of the plants at the time of the events. Design and protocol complexities include the use of multiple sowing dates and the recording of plant maturity. Data difficulties include a high degree of unbalance, and in the instance of multiple frosts in a FEE, there is a longitudinal aspect. A linear mixed model analysis was adopted to accommodate these characteristics of individual FEEs and the multi-environment trial analysis of 17 FEEs. Finally, an approach is demonstrated for dissemination of results that are of use to both growers and breeders.

In any systematic account of the work done on the moisture in soil and its behaviour under varying conditions, it is necessary to keep constantly in mind that the underlying hypotheses have been profoundly modified in recent years. When physical methods were first applied to the examination of soils, the results were interpreted on the obvious hypothesis that the soil could be regarded as composed of mineral particles of varying shapes and sizes, over the surfaces of which the water was distributed in a thin film. The movements of the film water and its average thickness at any time, under the varying meteorological and soil influences, could be predicted more or Jess completely from known physical principles such as surface tension, etc. Similarly, the concentration of the plant nutrients in the soil moisture was considered mainly as a matter of solubility in, and diffusion within, this moisture. The foundation of the subject of soil physics was laid upon these lines in the early 19th century by Davy and Schübler.

The growth and yield of five cultivars of sunflower (Frankasol, Cerflor, Sunbred 246, Sokota 2057 and Sigco EX 10), sown from the end of March to the beginning of May, were studied in three experiments at Long Ashton Research Station, UK, during 1986, 1987 and 1988. The time from sowing to emergence and to maturity (as assessed by seed moisture content) was shortened by later drilling, although earlier sown crops were still ready for harvest slightly before the later sown ones. Cultivars differed in speed of development; Frankasol and Cerflor were the slowest to develop and Sigco EX 10 the fastest. Plant heights, head diameters and yields were all affected more by cultivar than by sowing date. The slower maturing cultivars produced the highest yields. Infection levels with Botrytis cinerea seemed to be related to the date of flowering, as early sown and fast developing cultivars became infected earlier. There were few benefits from early sowing and the optimum time appeared to be mid- to late April. Overall, Sunbred 246 was the most successful cultivar in these experiments, combining reasonable yields with moderately early maturity.

In experiments at Rothamsted in 1984–86, seven factors, each at two levels, were tested in factorial combination on winter barley (cv. Panda) grown as a third take-all susceptible crop. The factors were seed rate, a growth regulator prior to stem extension, amounts of N in spring, ‘winter’ nitrogen, an autumn insecticide, a fungicide applied to the seed (‘Baytan’) and a programme of fungicide sprays in spring and summer. Sowing 50% more seeds than normal increased the number of ears/unit area but had no effect on mean grain yield because grains were smaller. There were, however, significant, but unexplained, interactions between seed rate and the fungicide ‘Baytan’ applied to the seed. A growth regulator applied prior to stem extension had little effect on crop growth and no significant effect on grain yield. If sufficient N was applied in April there was little benefit from applying ‘winter’ N (30 kg/ha in November and again in February/March) except in 1985 when the amount of NO3-N in the soil, measured in the previous October, was lowest. Insecticide sprays applied in autumn to control the aphid vectors of barley yellow dwarf virus (BYDV) had no significant effect on grain yield but infectivity indices were below the threshold needed for treatment in each year. On average, ‘Baytan’ applied to the seed increased grain yield by 0·28 t/ha and this was associated with decreases in the severity of take-all. Over the three years, programmes of fungicide sprays, applied during spring and summer, increased grain yield by 0·92 t/ha but the mean response was largest where most N was applied.

The experiments also allowed the importance of interactions between different agronomic factors to be examined. A combined analysis of grain yields for all three years (based on 192 plot values) showed that only six 2- or 3-factor interactions, out of the 73 estimated, were significant (P < 0·05). Two of these interactions reflected variable responses to ‘winter’ N and fungicide sprays in the three years and three of the remaining four involved ‘Baytan’.

Additional plots of barley grown after oats had little take-all and yielded 1·14 t/ha more grain than similarly treated plots grown after barley. These responses were obtained despite evidence that oat residues had adverse effects on the growth of barley seedlings. Additional plots of barley grown after a bare fallow also had little take-all and gave even larger total yields (grain plus straw) than did barley after oats but the mean yield of grain was less than after oats because more of the dry matter after a fallow was straw. In 1984, when take-all was relatively slight, plots after a fallow gave even less grain than plots after barley (−0·77 t/ha) despite producing 2·12 t/ha more dry matter in grain plus straw.

When planning a factorial experiment, it is often desirable (as pointed out by Yates (1937)) to include certain extra treatments falling outside the usual factorial scheme. I discuss here the exact analysis of an experiment of this type. Only standard principles of experimental analysis are involved, and the full exact analysis is not always required in practice, but the example may illustrate techniques that are useful in investigating more complicated designs that are sometimes encountered. I am grateful to the late Dr E. M. Crowther and Miss B. Benzian, of the Chemistry Department at Rothamsted, for discussion of the problem and for providing data for the illustrative example.

Field experiments were conducted on clay and sandy clay-loam soils to investigate the effects of sowing date on the incidence of plant losses. Early sowing dates from 2 to 23 September resulted in very low seed yield (360 kg/ha) mainly because fewer plants survived. High air temperature increased the rate of plant death which was highly correlated with degree days, r = +0·95.

Number of plants/m2 was the predominant factor determining seed yield and number of pods/plant could not compensate for loss of plants.