In a long-term experiment on a boulder-clay soil Ralph & Ridgman (1981) found that the response of potatoes to freshly applied K fertilizer was independent of the amount of K that had been applied during the preceding 10 years. The greatest yield was obtained from plots which had received the greatest amount of K during the preceding 10 years together with the optimum amount of freshly applied K (120 kg K/ha in this case) and the addition of an extra 60 kg K/ha to plots which had received less K previously did not increase the yield. Similar benefits from residual K had been reported by Johnston, Warren & Penny (1970). In view of the continuing disagreement about the need for applying K to cereals on boulder-clay soils it was decided to attempt to quantify these effects more precisely.

The composition and feeding value of the common heather has been extensively studied by Thomas et al. (1934, 1935, 1953, 1955, 1956). He has shown that as the heather ages the protein content declines. Thus, samples from 2-year-old growths had a crude protein content (on a dry-matter basis) of 11·9% while that of growths 8 years old was 6·5–6·9%. Little or no information, however, appears to be available on the quality of heather protein, as judged by its amino acid composition.

Numerous investigations have been made on the amounts of combined nitrogen in rain and snow in different parts of the world during the last 60 years.

Interest is increasing in the Navy bean (or baked bean) as a breakcrop from cereals in southern England. As little experimental work has been carried out on the fertilizer requirements of this crop in the U.K. we undertook a trial in 1973 to investigate its response to four levels of nitrogen.

1. It is shown that in the extracts of mangold leaves and stalks optically active impurities are always present which are not precipitated by basic lead acetate and hence vitiate the estimation of the dextrose and laevulose. These substances are possibly acid amides (such as glutamine and asparagine) or amino-acids (such as glutamic and aspartic acids) which form soluble lead salts.

2. These impurities occur in the leaves, but are much more abundant in the mid-ribs and stalks.

3. In the leaves the dextrose and laevulose appear to be present in approximately equal amount, as would be expected if they were formed from saccharose by inversion. When the ratio departs from unity it is probably owing to the presence of a dextro-rotatory impurity (glutamine?) which increases the amount of dextrose apparently present; but at certain times of the day a laevo-rotatory impurity seems to predominate so that the ratio becomes less than unity.

Eighteen Double Muscled (DM), 18 Beef Synthetic and 18 Hereford bulls, serially slaughtered from approximately 250 to 800 kg live weight, were used to examine the influence of maturity type and Double Muscling on individual muscle growth patterns and distribution.

Breed types differed significantly in the relative growth rate of five of the 95 muscles. Individual muscles grew and developed at relatively different rates with muscles associated with locomotion being early developing followed by those associated with structure or posture and finally those which respond to sexual maturation or luxury muscles which were late developing. Individual muscle growth patterns revealed an increasing disto-proximal gradient along the limbs and an increasing caudo-cranial gradient along the whole body. However, within any anatomical region considerable variations with well defined growth gradients were found for individual muscles. In the proximal region of both limbs increasing medio-lateral growth gradients were apparent.

At the same total side muscle, breed types differed significantly in adjusted mean weights of 33 of the 95 muscles. When comparison was made at the same total side muscle, DM showed a range of hypertrophy of + 28% to -28% when compared with the more normal breed types.

Muscular hypertrophy followed a disto-proximal gradient along the limbs and an inner–outer gradient across the muscle layers with the superficial and bulkiest muscles being the most hypertrophied. At the same total side muscle, DM had heavier expensive or luxury muscles than normal cattle.

Nineteen populations of Lolium perenne were grown near Aberystwyth as small plots (sown in 1988) in the field, and as pot plants (sown in 1989) in the glasshouse and controlled environment (CE). In the summer of 1989 they were subjected to drought, and then rewatered. Herbage growth and water relations characters were measured. There was significant diversity between populations (narrowsense heritability) for: herbage production and yield stability before, during and after drought; tillering; osmotic potential and adjustment; tissue water content; and membrane stability (MS) following heat shock. There were no such differences in leaf water conductance, MS following desiccation shock, or chlorophyll stability under osmotic stress. The range of expression of characters was very different in the three environments, as was the ranking of populations, emphasising the danger of working in unnatural environments. Correlation analysis revealed no relationships between growth and physiological characters that were consistent across environments. Nevertheless, hierarchical cluster analysis indicated that some populations having a ‘hay-type’ morphology performed well over all three environments, and merit further study.

The determination of sodium by Barber and Kolthoff's and Kahane's methods has been investigated with special reference to their suitability for the determination of exchangeable sodium in soils. Bray's modification of Barber and Kolthoff's method, involving 48 hours’ standing, was found to give a poor separation from even small amounts of potassium salts, leading to high results for sodium. Kahane's method was more convenient and gave very satisfactory results, precipitation being complete in 30 min. It is a great improvement on the older classical methods which involve the separation and weighing of sodium and potassium chlorides.

In 1913 the National Association of Millers was invited by the Board of Agriculture to formulate a definition of the term “Millers' Offals.” After some discussion the Association forwarded the following resolution: “That millers' offals, or wheaten offals sold as such, are the products of wheat and of the vegetable substances extracted from the wheats of commerce in the process of cleaning; but the proportion of such extraneous matter shall not exceed the percentage found in the wheats imported into the United Kingdom.”

A Unique correlation has recently been obtained from some experimental data at Rothamsted. In the autumn of 1924 a set of 47 unmanured plots were laid out in Sawyer's Field, and were sown with wheat to test the uniformity of the fertility of the soil. The plots were each ·098 acre. The produce of grain and straw from each was recorded, and an examination of the figures showed that the straw yield recorded for plot 1 A was much lower than one would have expected under normal circumstances. A careful enquiry into the matter revealed that by an oversight a weighing of straw had been removed from the scales before the weight had been entered in the record. As it was impossible to verify the exact value of the missing entry, the yields from this plot were omitted from all statistical reductions of the data, leaving 46 plots upon which to base an estimate of the various statistics.

The soil was found to be very variable in fertility, the average yield of total grain per plot being 149·57 lb., with a standard error of 6·39 lb. and the average yield of total straw per plot was 194·35 lb., with a standard error of 7·55 lb.

The grain and straw yields of the 46 plots are shown in the accompanying diagram. The very close association between the total weight of grain and total weight of straw is evident. The amount of the relationship was measured by correlating the 46 pairs of values.

In a previous study (Bromfield, Debenham & Hancock, 1980) sulphur deposited in rainwater was measured in central Kenya some 450 km from the Indian Ocean. The study reported here was complementary and measured sulphur deposited in 1979 at the Kenya coast, adjacent to the Indian Ocean, in a small but important agricultural area. Sodium was also measured since it is an element of marine origin, present in air in particulate form, and can be compared with sulphur which is largely present in the air in gaseous form.

Yield calibration of soil tests in western Nigeria savannah has been difficult owing to low response to P and response to only low P rates despite low available P in the soils. A study on the distribution of P forms in 60 surface soils of the savannah derived from igneous and metamorphic rocks and grouped into 11 classes was made. Average total P was 0·018% and organic P, which varied between 44 and 114 mg/kg, constituted 41% of total P. Active P components made up 40% of total inorganic P, the bulk of which was in the Fe-P fraction. All P forms except non-extractable P correlated significantly with organic matter.

The amounts of P needed to increase available P by 1 mg/kg in the soils, an index of P fixation, was correlated with pH and the free oxides of Fe and Al. The direct role of Fe-oxides and probable indirect effect of organic matter were indicated by regression analysis.

There was minimal maize yield response to P application and this was obtained only at low P rates from which an optimum rate of 20 kg P/ha was suggested. An attempt to use phosphorus sorption capacity (PSC) for P recommendation was not successful probably because of the low PSC values. A quick P recommendation based on available P status, fertilizer factor of 3·0 mg/1 and an optimum available P level derived from the relative yield v. soil P calibration curve was therefore suggested.

It is shown that whereas the platinum chloride method of estimation is uncertain and liable to give varying results, the perchlorate method described is at once more simple in manipulation and more uniform and exact in its results. An improvement has been introduced which consists in washing the perchlorate precipitate with 95% alcohol saturated with potassium perchlorate by means of which any error due to the solubility of the precipitate is obviated. This is of importance when dealing with small quantities of precipitate. The following other advantages may here be enumerated:

Chick pea Rhizobium strain RG3 was treated with 30 μg/ml of N-nitrosoguanidine and two mutants isolated were resistant to 2000 μg phorate/ml yet retained the capacity to form nodules. On the basis of number of nodules, their dry weight, N2ase activity, total pyridine nucleotides and active iron contents, mutant strains G11 and G26 were found to be equally effective with and without phorate and resulted in significantly greater grain yield.

A new and improved type of dynamometer is described which by a simple interchange of parts can be used with the same percentage accuracy for all types of work from the lightest to the heaviest.

The instrument consists of (a) an hydraulic link weighing 16 1b. and placed in the hitch, (b) a recording mechanism weighing 15 lb. carried on any convenient part of the implement, and (c) a control box weighing 4 lb. carried by the operator. When packed in a stout box for transit and with all accessories the total weight is less than 100 lb. The instrument is of robust construction and has a minimum number of moving parts. Adjustments for stylus pressure, etc., are provided, but the necessity for using them hardly ever arises.

The instrument operates by recording the amount of movement in a Bourdon tube filled with oil and connected by narrow bore copper tubing to the oil in the hydraulic link.

The root-knot nematode, Meloidogyne javanica, is a major problem for the production of Sacha Inchi plants. We examined the effects of strip intercropping of Sacha Inchi/Chinese leek of 3–4 years on the seasonal dynamics of plant and soil traits in tropical China. Results indicated that in the intercropping system, a partially temporal divergence of belowground resource acquisition via niche separation occurred throughout the growing seasons, besides a complete spatially-separated plant height between the two crops. Compared with Sacha Inchi monoculture, the increased seed yield per unit area in the intercropping system was mainly attributed to the higher plant survival rate, rather than the enhanced plant traits of healthy plants. Intercropping greatly suppressed M. javanica populations only in the wet season, compared with monoculture; which may be associated with the combined effects of the direct allelopathy and indigenous microbe induced-suppressiveness. Intercropping did not affect microbial richness and α-diversity in the rhizosphere, except for the decreased fungal richness. Both bacterial and fungal composition and structure were diverged between monoculture v. intercropping system. The relative abundances of the dominant bacterial genera (Bacillus, Gaiellales, Lactococcus, Massilia and Lysobacter, etc.) differed significantly between the two cropping systems. For fungi, intercropping decreased the relative abundances of Fusarium and Gibberella, but increased those of Nectriaceae_unclassified, Chaetomiaceae, Humicola and Mortierella. Overall, Sacha Inchi/Chinese leek intercropping suppressed M. javanica populations and shifted microbial compositions (especially decreased pathogen-containing Fusarium). The increased yield and economic returns in this intercropping system provide valid information for the effective agricultural management.

There is evidence that a large volume of saliva containing a significant quantity of urea is poured into the rumen, and also that blood urea is diffused into the rumen through the ruminal epithelium (Houpt, 1959; Weston & Hogan, 1967). Egan (1965) reported that, with sheep fed a low protein cereal hay, cellulose digestion in the rumen was increased by abomasal urea infusion. Furthermore, the utilization of recycled urea nitrogen has been investigated in sheep (McIntyre, 1971) and cattle (Vercoe, 1969) using the intraruminal and intravenous infusion techniques. The objective of the present experiment was to determine whether or not the abomasal administration of urea to adult goats fed a low quality hay would influence the nitrogen retention in the body.

Regression models were constructed to predict the yields and digestibilities of herbage cut in different sequences of harvests.

The yield model used a seasonal production curve modified by the effects of defoliation. Values for the model parameters were obtained by fitting the model to experimental data using a non-linear regression procedure. When these parameters were used, to predict treatment effects in another series of experimental data, good agreement was obtained. The digestibility model incorporated the effect on digestibility time of year, regrowth time and yield.

Using the models to interpolate between the results of cutting experiments, annual yields were shown to increase with the date of first cut and also with the interval between subsequent cuts, whereas the average digestibility of the harvested material ecreased with the date of first cut and with the subsequent cutting interval. Finally, a procedure was devised for combining the two models in order to find an optimum cutting strategy for a hypothetical animal production system.

A series of three experiments on loam to sandy loam soil at Woburn, all following winter or spring wheat, tested the effects of six different 1-year set-aside treatments and crops of winter wheat in 1989, 1990 and 1991 on two following winter wheat test crops. Effects of the treatments on overwinter changes in soil mineral nitrogen (SMN) and plant N in the set-aside years and in the first test crops were measured, as were the grain yields of both the first and second test crops.

Differences in net overwinter changes in SMN plus plant N between set-aside treatments were variable and dependent on rainfall. During a wet winter, SMN plus plant N losses were large under fallow and natural regeneration, intermediate under winter wheat and small under Italian ryegrass (Lolium multiflorum). Ryegrass restricted the growth of the following wheat but yields were unaffected where fertilizer N was applied. Ryegrass proved difficult to control in the subsequent wheat test crops. Forage rape (Brassica napus) took up large amounts of N but after topping did not compete well with weeds.

Yields of the first wheat test crops after winter wheat were smaller than after the set-aside treatments, take-all was probably the cause of this yield depression. No consistent yield differences were recorded in the second wheat test crops.