Experiments in 1976 and 1977, in south-east Scotland, with sunflower (cv. Fransol) examined the effects of bitumen mulch applied after sowing, date and depth of sowing on emergence, flowering and yield. Bitumen mulch increased soil temperatures in April and May by 1–4·5 °C resulting in earlier emergence (6–7 days), more complete emergence under adverse conditions of early and deep sowing, and earlier flowering (2–5 days). Delaying sowing from 7 April to 5 May reduced emergence time and time from sowing to first anthesis. Larger seedlings, having an increased leaf area, resulted from bitumen mulching and early sowing.

In the laboratory, increasing temperatures from 5 to 20 °C reduced the average germination time by 0·75 days for each increase of 5 °C. Germination percentage was not affected by temperature over this range.

Average seed yields and oil content were markedly different in 1976 and 1977; 2·22 t/ha and 44·7% for 1976 and 0·95 t/ha and 36·9% for 1977. Bitumen mulch and sowing depth had no effect on seed yield or oil content but delaying sowing until 5 May reduced both. Lower seed yields in 1977 resulted from fewer and smaller seeds. Infection of the seed heads with grey mould (Botrytis cinerea) after flowering was high in both years.

Ten Scottish soils were cropped in a glasshouse with three sowings of perennial ryegrass (Lolium perenne, cv. Dutch Barenza) without added magnesium. After 25 cuts (185 weeks) growth was poor in some soils, but soil Mg was not limiting growth in others.

Uptake of Mg and the Mg concentration in the ryegrass correlated well over the entire cropping period with the equilibrium Mg-concentration ratio Mg/(Ca, Mg) = CR0, determined from the Mg quantity/intensity isotherms measured before cropping in 0·01 m chloride solutions. A CR0 value of 0·16 was required in the early stages of cropping to give 0·2 % Mg in grass dry matter.

Seven soils released 12–37 mg non-exchangeable Mg/kg, between one-fifth and one-third of the total Mg uptake. These reserves probably came from vermiculite minerals, but the release was too slow to maintain Mg concentrations of 0·2 % in the ryegrass.

To exploit the potential of ecological intensification during sunflower cropping, it is crucial to understand the potential synergies between crop management and ecosystem services. We therefore examined the effect of pollination intensification on sunflower yield and productivity under various levels of soil fertilization over two seasons in the eastern Free State, South Africa. We manipulated soil fertility with fertilizer applications and pollination with exclusion bags. We found a synergetic effect between pollination and soil fertilization whereby increasing pollination intensity led to a far higher impact on sunflower yield when the soil had been fertilized. Specifically, the intensification of insect pollination increased seed yield by approximately 0.4 ton/ha on nutrient poor soil and by approximately 1.7 ton/ha on moderately fertilized soil. Our findings suggest that sunflower crops on adequate balanced soil fertility will receive abundant insect pollination and may gain more from both synergies than crops grown in areas with degraded soil fertility.

Spreading of pruning waste over the soil surface may increase soil organic carbon, thus improving soil physical properties and serving as a source of nutrients and energy for microbial populations. The aim of this study was to test the effect of the environmental conditions and the biochemical composition of pruning waste from avocado, cherimoya, mango and gardens on their decomposition process in a Mediterranean subtropical climate. Bagged pruning and garden waste were placed on the ground at a distance of 1 m around the trunk of the three trees from each crop. The concentrations in C, N, lignin, cellulose, hemicellulose, other extracts and ash were determined at the beginning of the experiment (T0), after six (T6) and 24 (T24) months in the field. Initially, significant differences were detected for all types of waste, especially in lignin, hemicellulose, cellulose and other extracts. No significant differences were found in the N content and the C content in mango pruning waste was significantly lower than that in avocado. The greatest weight loss recorded at T24 (63.2%) was related to the lower content in lignin, cellulose and other extracts. Weight losses and C concentrations showed negative correlations with lignin content. Despite the intense decomposition of all the waste, between 55 and 36.8% of the original weights were recorded at the end of the experiment. Recalcitrant C could be the result of the lignin concentrating in the case of the garden waste applied to the different crops.

Experiments made over a period of 3 years (1971–73) at Pantnagar, India, on the effect of plant density and spatial arrangement of a hybrid variety of maize (Ganga 2) and a local cultivar (Rudrapur) indicated that a density of (at least) 75000 plants/ha is necessary to obtain maximum grain yield. With increasing density from 25000 to 75000 plants/ha the date when 75 % of plants were silking was delayed 2–5 days and the percentage of barren plants increased from 1·7 to 28·7. In dense stands, grain yield of the hybrid variety was less affected by increasing row width from 60 to 90 cm than it was in the local cultivar.

The average increase in yield with narrow (60 cm) row width as compared with wider (75 cm) row width was 6.8 % and it is argued that, in the context of the national need for increased food production, this increase cannot be overlooked.

The digestibility for poultry of a variety of huskless oats recently placed on the market has been investigated, and a comparison made with a widely grown variety of more usual fibre content.

It was shown that the fibre of the huskless oats was completely undigested, while that of the control variety had a digestibility coefficient of 8·8 per cent.

The digestibility of the crude protein in huskless oats was higher than in the variety Victory. It is suggested that this difference has resulted from the same cause as that which operates in ruminants, whereby fibre has a depressant effect on protein digestibility.

Both the organic matter and N-free extract were digested to a greater extent in the huskless oats than in the control variety. This is in keeping with the findings of other workers on the relation between fibre content and the digestibility of these constituents.

The present study was made to evaluate the protein quality of 11 samples of fish meal (FM) covering a wide range of nutrient content to find a suitable laboratory method for predicting nutritive quality. The nutrient content of the samples ranged from 34 to 62% in crude protein, 28 to 48% in true protein and 0·99 to 2·87% in available lysine. The true protein content of FM was further partitioned into myogen, myosin and stroma proteins. The stroma protein accounted for 61% of total crude protein suggesting that a large portion of FM comprised scales, viscera, cartilage, bones and other inedible parts of fish (head, tail, etc.). Neither true protein nor its different fractions was found suitable to detect differences in protein quality of FM although there was an inverse relationship between stroma protein and nitrogen solubility.

Available lysine content and relative nutritive value (RNV) were found accurate and reliable laboratory tests for assessing the protein quality of FM. The linear equations to predict gross protein value (GPV) from available lysine content and RNV are

GPV = 11·2×% available lysine+34·5;

GPV = 0·55×RNV+51.

The correlation coefficients between biologically assayed and predicted GPV from available lysine and RNV were 0·71 and 0·62, respectively. The findings suggest that the screening of FM samples for their nutrient content is essential before compounding diets for different categories of chickens.

Two pairs of young heifers were fed on a weighed and analysed diet, and their dung was sampled and analysed both in the fresh and in the rotted states.

It was found that the fresh dung contained about ¾ths of the nitrogen, ⅔rds of the phosphoric acid, and ⅞ths of the potash consumed by the animals in food and litter.

The dung made by the cake-fed animals was found to be more readily fermentable, and consequently more liable to loss during storage, than that made by the animals fed on roots and hay only.

The loss was found to fall chiefly on the ammoniacal nitrogen in which the cake-made dung is comparatively very rich.

Taking as a base-line the amounts of nitrogen and phosphoric acid in the dung of the animals fed on roots and hay only, it was found that the fresh dung of the cake-fed animals contained 82 per cent, of the nitrogen, and 70 per cent, of the phosphoric acid, of the cake they had consumed.

So great however was the loss of ammoniacal nitrogen from the cake-made dung, that after 6 months' storage under cover in the solid undisturbed state in which it was left in the boxes by the animals, only 37 per cent, of the nitrogen of the cake still remained in the rotted dung.

Dung is not usually kept so long as this, nor through such a hot time of the year, so that the average loss will probably be less than that found in the experiment, and ½ the nitrogen of purchased foods may very well be the average amount recovered in the dung.

The experiment shews however that, without any very flagrant mismanagement, the proportion recovered may fall considerably below ½, especially if the dung suffers further loss while lying on the surface of the land in dry weather.

A comparative study of sorption maxima (simple and double Langmuir equations) and buffer capacity of acid soils was made in order to select the most useful P-sorption parameter. Data were obtained from 20 acid soils from Galicia (north-west Spain) and selection was made by linear and multiple regressions among sorption parameters, and between these and some soil characteristics related to phosphate sorption (clay and organicmatter content, pH in NaF, and 0·5 M-CuCl2-extracted Al).

The phosphate buffer capacity, determined by the slope of the regression ‘sorbed-P v. logc’, was the best parameter to represent soil phosphate sorption behaviour. 0·5 M-CuCl2- extracted Al was the edaphic characteristic which best related to sorption properties.

Brassica oil seeds grown in India are occasionally damaged by frost, causing severe losses. A technique was developed to screen germplasm at the seedling stage. Twentyfour lines of B. campestris, B. juncea and B. napus were grown in plastic boxes in a glasshouse in a mixture of peat and sand. The seedlings were frozen after hardening for 2 days at 1 °C. Observations were recorded after 4 days, using a five-point scale. Frost tolerance index (FI) is calculated as the average value for injured plants for each line. Eight lines for each of the three species were tested. B. campestrisas a group showed better frost tolerance. Some lines of Indian mustard also showed good tolerance of low temperature (– 5·5 °C). These findings show good agreement with observations recorded in the literature. The method is detailed and discussed. Suggestions for future programmes are made.

While reading the two interesting papers on immune wheats in the last number of this Journal it occurred to us that our observations on rust resistant wheats in India might be of some interest. During the past two years a large number of varieties of Indian and European wheats have been grown by us at Pusa in Behar and at Lyallpur in the Punjab, one of the objects being to obtain wheats immune or at least resistant to rusts which would serve as parents in raising rust resistant hybrids. Biffen last year suggested that a trial should be made with Einkorn (Triticum monococcum vulgare, Kcke.), and kindly supplied us with a sample of the seed.

In anaerobic glyoolysis lactic dehydrogenase (LDH) is the terminative enzyme in the sequence of reactions that promote the breakdown of sugars to lactate. The LDH activity of cattle semen and seminal plasma together with its relationship with various characteristics of semen have been reported (Stallcup & Hayden, 1960; Roussel & Stallcup, 1965). Such work in respect of buffalo semen is not available, although there are some reports on LDH activity of spermatozoa and seminal plasma (Singh & Sadhu, 1972; Chauhan & Srivastava, 1973). The present investigation was undertaken to determine the LDH activity of buffalo whole semen as well as of seminal plasma and to find correlations with some physical characteristics of semen.

In a 2-year field study, all the maize cultivars tried (Partap-1 Ageti-76, Ganga-5 and DHM-103) produced similar length of ears and equivalent grain yields. However, Partap-1 and Ganga-5 produced greater 100-kernel weight and greater grain yield per ear but fewer ears per hectare than Ageti-76 and DHM-103. The yield attributes and grain yields of maize sown on 19 December, 29 December and 8 January were identical and were superior to those of the 19 January sowing. Maize sown on 19 December, 29 December and 8 January exhibited longer ears, more ears and fully developed kernels and thereby produced greater grain yields than the 18 January sowing.

During 1983–4, in the 19 December and 29 December sowings all the cultivars gave identical grain yields. In the 8 January sowing Partap-1 and Ageti-76 produced similar yields and proved better than Ganga-5 and DHM-103. In the 18 January sowing Ageti-76, Ganga-5 and DHM-103 yielded more than Partap-1.

It is now a well-established fact that the ammonia, which is formed in the cultivated soil by the breaking down of nitrogenous organic matter through the action of bacteria and moulds, is itself converted by oxidation into nitrates. The latter process, “nitrification“ proper, is effected in two stages by two distinct species of bacteria, the one carrying the oxidation to nitrite, and the other changing the latter compound into nitrate. It is also known that, in the absence of a base, nitrification does not take place. The most usual and most available soil base is calcium carbonate, which is, however, present in some arable soils to only a very small amount, less than ·05 per cent.; in such soils, and in others where its presence cannot be detected, nitrification is still active, a fact which seems to suggest that other substances may replace it and serve as bases for nitrification.

Studying and understanding the sources of variation in early life traits in farmed deer are fundamental for management and/or breeding purposes. Data from a captive white-tailed deer population were analysed to identify non-genetic and genetic factors affecting the birth weight (BW) of fawns. The year, type of birth and sex were included in a fixed linear model to examine their significance. All of the examined non-genetic factors had a highly significant effect on BW (P<0·001). The examined years showed variation attributed to food availability affecting the gestational conditions of does. Male fawns were 193 g heavier than female fawns at birth (P<0·001), and singleton births were associated with a higher BW (2·97±0·043 kg) compared with twin (−0·261 g) and triplet (−0·642 g) fawning (P<0·001). The best-fitting animal model was selected by comparing reduced and complete models. Based on the selected animal model, which included direct genetic and common maternal effects, genetic components and parameters were estimated. The direct heritability was found to be 0·28±0·126, and a small but important contribution of common maternal environmental effects was identified (c2=0·15±0·062). The results support the importance of certain environmental factors affecting BW and indicate the relevance of direct genetic and maternal environmental influences to sustained genetic changes in BW and positively correlated traits in farmed white-tailed deer populations.

1. The digestibility of samples of heather of 3, 7 and 14 years of age has been determined.

2. The experimental technique was the same as that used in the previous digestibility studies of heather.

3. The digestibility of the organic matter, and of all its components other than crude fibre and ether extractives, was found to decline with advancing age. This decline became apparent in heather of 7 years of age.

4. Gross digestible energy values were determined for the three ages of heather under investigation. Starch equivalents derived from these values proved to be lower than starch equivalents calculated in the usual way.

5. Confirmation of earlier conclusions concerning the value of heather as a source of energy has been obtained.

1. The effect of rest during the autumn and winter on the dry-matter production and botanical composition of a cattle-grazed pasture was studied for four consecutive seasons.