The grain yield, head structure and components of yield of a Nigerian long-season sorghum (Farafara) and an American hybrid short-season type (NK 300) were compared at three populations. The effect of thinning at initiation and at heading was also examined.

At each population, the grain yield per plant of NK 300 was larger than that of Farafara, mainly due to differences in the number of grains per head. This factor was also the main one responsible for a decline in yield per plant with increase in population. At all populations, Farafara plants showed an appreciable increase in stem weight after heading.

The results from the thinning treatments suggest that the main difference between the two varieties is in the number of spikelets present at head emergence: the number and/or potential size of developing grains in Farafara appeared to be largely determined by the time of initiation and was probably too small to accept all the currently produced assimilate.

Groups of lactating dairy cows were fed on grass which had received various amounts of nitrogen and potash fertilizers. In the early part of the season not only was the herbage concentration of calcium and phosphorus lower in grass which had received potash fertilizer but in addition the ‘availability’ of the calcium to cows was depressed. Grass which had received large amounts of nitrogen fertilizer had a comparatively low dry-matter content in the autumn. Cows fed such grass were in negative balance for calcium at this time. As expected high dietary potassium gave rise to high excretion of potassium in the urine which in turn was correlated with high excretion of magnesium. These various factors are likely to affect the incidence of metabolic disease.

The relationships between the cellulose-lignin complex, voluntary consumption and dry-matter digestibility were examined using forages of two varieties of Italian ryegrass and two legumes, lucerne and sainfoin. These forages had previously been shown to exhibit different intake-digestibility relationships. The cellulose, acid detergent lignin and acid detergent fibre contents of these forages as well as their digestibility coefficients were determined. Lignins were extracted from the fibre fractions and their ultraviolet difference spectra determined.

Changes in maturity of a forage during a single growth phase, produced changes in dry-matter digestibility which were closely associated with changes in the digestibility of the cellulose and inversely related to the lignin content of the forage. Differences in digestibility between varieties of forage were less closely associated with lignin content. As the grasses matured a lignin fraction forming a difference peak at 350 mμ became evident and this was associated with decreased cellulose digestibility.

Differences in voluntary food consumption resulting from changes in maturity of a single forage variety, in one growth phase, were also closely correlated with both dry matter and cellulose digestibility and inversely with lignin content. Differences between varieties and growth phases of the ryegrasses and between grasses and legumes were related less to the nature of the cellulose-lignin complex and more closely to the percentage of the total digesta deriving from cellulose.

Sainfoin was characterized by the formation post-ruminally of an artifact that analysed quantitatively as lignin and qualitatively resembled a non-conjugated phenolic lignin fraction. The production of this artifact apparently disturbed fibre digestibility estimates and may have affected dry-matter digestibility estimates. Degradation of lignin apparently occurred both in the rumen and in the hind gut.

The effect of nitrogen fertilizer on the yield of sugar beet was tested in 170 experiments done between 1957 and 1966; results of 88 experiments, some testing five and six amounts of N, have not previously been published.

On most sites, nitrogen increased sugar yields sharply and almost linearly up to an optimum beyond which yield changed little or decreased only slightly up to 1·8 cwt N/acre, the largest amount tested. In the two series of experiments giving most information, the mean increase from sub-optimal amounts of N was 2·5 cwt sugar/0·1 cwt N/acre.

Usually 0·4–0·8 cwt N/acre was enough for maximum yield; more was needed on a few sites and on about a fifth of them nitrogen fertilizer was not needed. In 7 of the 10 years, the average optimum was 0·6–0·8 cwt N/acre; less was needed in the other years, the driest three years of the decade.

In most, though not all, years, site-to-site differences in response between 0·9 and 1·8 cwt N/acre were no greater than could be expected from experimental error alone; much of the apparent difference in response between seasons were also attributable to this source.

After taking account of experimental error, there were substantial between-site differences in response to amounts of N up to 0·9 cwt/acre, but attempts to explain them in terms of weather, soil and husbandry factors had little success. There was slight evidence of diminished responses to N where sugar beet followed crops other than cereals, and of responses somewhat greater than average on Chalky Boulder Clay soils of the Hanslope and Stretham Series; no other relationships were large or consistent enough to be useful for prediction.

As between-site differences in response are largely unpredictable, and because a grower risks much greater crop losses by applying too little N than by applying too much, the recommended dressing is 1·0 cwt N/acre, substantially more than is needed, on the average, to obtain maximum yield. More N should be given on soils of the Hanslope and Stretham Series and on light sands poor in organic matter; less need be applied where crop residues are likely to supply much nitrogen.

Two changeover experiments, each on eight buffalo heifers, were conducted in two different years to determine the effect of wilting lucerne herbage (Exps. 1 and 2) and berseem herbage (Exp. 2 only) on voluntary dry-matter intake. The dry-matter content of the herbages increased by field wilting from 27 to 50 and from 26 to 44% for lucerne in Exps. 1 and 2 respectively, and from 21 to 31% for berseem. The drymatter intake, nutrient digestibility coefficients, nutritive value index and retention time of undigested residues were determined for each fresh and wilted herbage.

Wilting increased the dry-matter intake of lucerne from 2·3 to 2·8 and from 2·1 to 3·5 kg per 100 kg body weight in Exps. 1 and 2 respectively. Berseem dry-matter intake was increased from 2·2 to 3·1 kg per 100 kg body weight. Digestibility coefficients of all nutrients of both herbages increased by 6–20%. Retention times were unaffected by wilting. The nutritive value indices for lucerne and berseem in Exp. 2 increased by 160 and 60% respectively. In Exp. 2, the average loss of herbage dry matter due to wilting was 3·8%. The higher consumption of the wilted herbages is ascribed to their lower water content. The practical implications of these results are discussed.

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.

Applying large dressings of fertilizer nitrogen to the seed bed lessened nodulation of spring field beans by as much as 50%.

The largest mean responses to broadcast nitrogen ranged from 1·9 cwt grain/acre in 1967 (3 cwt N/acre) to 3·1 cwt grain in 1966 (3 cwt N/acre).

About one-sixth of the nitrogen applied to beans was used by a following winter wheat at Rothamsted, one-twelfth at Woburn.

The results suggest that there is no prospect for the economic use of fertilizer nitrogen in the seed bed for spring beans.

The largest mean responses to nitrogen ranged from 2·1 cwt grain/acre in 1966 (2 cwt N/acre) to 3·6 cwt grain in 1968 (1–5 cwt N/acre). Responses to the largest dressings were increased by dividing them, the increases ranged from 0·2 cwt grain in 1968 to 4·0 cwt grain in 1966.

In 1968 1·5 cwt N applied in late May increased grain yield by 5·5 cwt, more than the response to any other amount applied either to the seed bed or as a divided dressing. Removing the growing point of the plant at the 4-leaf stage promoted tillering but lessened yield by 5·4 cwt grain. Removing the growing point of the plant after flowering increased yield by 2·1 cwt grain in 1966 and lessened it by 1·7 cwt grain in 1967.

CCC (2-chloroethyltrimethylammonium chloride) had no visible effect on growth and lessened yield by 1·9 cwt.

B9 (N-dimethylaminosuccinamic acid) greatly affected growth and shortened stems by as much as 30%, depending on how much and when it was applied.

B9 had inconsistent effects on yield. Without fertilizer nitrogen, it increased yield by 2·5 and 2·6 cwt grain in 1966 and 1968 but decreased it by 2·1 cwt in 1967.

The main effects of B9 on the components of yield were to increase the number of stems and pods/acre and lessen 1000 grain weight. Plants given B9 in 1968 produced half a million more grains/acre than untreated plants. 1·5 cwt N had similar effects to B9 on the components of yield in 1968. Stems and pods/acre were increased, but there was also a small increase in 1000 grain weight. Plants given 1·5 cwt N produced half a million more grains/acre than plants not given N. A further1·5 cwt N lessened number of stems/acre but this was more than compensated for by an increased number of pods/stem, leading to a further increase of 160000 grains/acre. The effects of season were large and exceeded the effects of any of the treatments.

Eighteen trials were carried out to test factorial combinations of N, P, K and Na fertilizers on sugar beet over 3 years on deep light peat soils in the area surrounding the Wash. The average yield responses to all fertilizers were very small, and only rarely profitable, except to sodium. Nitrogen increased yield on a few sites, but there was no obvious way of distinguishing these, and on average there was no justification for using this fertilizer, which depressed sugar percentage. The difference from earlier work, which showed good responses to P and K, is ascribed to repeated heavy dressing of fertilizer given to these soils during the last two decades.

The total P contents of soils, analysed after fusion with sodium carbonate, were consistently larger than after digestion with boiling perchloric acid. For 37 soils from southern England, values by fusion analysis (Pf) were related to values after digestion with perchloric acid (Pp) by the following equation:

The recovery of P, applied to six soils as superphosphate, was the same by both methods of analysis.

A heat-exchange chamber made of perspex was inserted beneath the skin of a Merino sheep. By passing water at predetermined temperatures through the chamber, the normal subdermal temperature of 37°C was raised approximately 4°C for 4 days, then lowered approximately 5°C for 4 days.

In response to heating, the animal's temperature regulating mechanism was able to maintain a fairly constant subdermal temperature. However, it was unable to maintain as constant a subdermal temperature in response to cooling. There was, during the cooling period, an obvious nervous response to environmental disturbances manifested by sudden transient decreases in subdermal temperature over the chamber.

During the cooling period there was a decrease of 12% in mean length growth rate of wool over the chamber but mean fibre diameter was unchanged. Heating produced a small decrease in mean fibre diameter, but no change in mean length growth rate. Heating appeared to produce a slight reduction in pigmentation of some fibres but neither heating nor cooling produced demonstrable changes in crimping.

The fibre length and diameter distributions of the wool of two Merino flocks were evaluated at the neck, mid-side and breech positions, to determine the incidence of fibres which were off-type by reason of excessive length, diameter or possession of a medulla.

The ranges of fibre lengths for 10·5–11·0 months' growth were 1·0–17·5 cm. in flock 1 and 1·0–16·5 cm in flock 2. There was no evidence of a bi-modal length distribution in either flock.

Fibre diameters at 15–16 months were observed in the range 6–69 μ in flock 1 and 5–52 μ in flock 2. Medullated fibres ranged from 7 to 50 μ in flock 1 and 5–64 μt in flock 2. The incidence of medullation increased in an antero-posterior direction from 0·17 to 0·28% in flock 1 and 0·11 to 0·28% in flock 2.

Tests for homogeneity of variance were applied to the estimates of fleece characters in this study as well as estimates of other workers. From these comparisons it is suggested that sheep in the present study are representative of the Merino breed in staple length, fibre diameter and to a lesser extent crimp frequency. The considerable between-animal variation in the observed incidence of medullation should aid in selection against that character with a consequent improvement in wool quality.

Estimates of the incidence of coarse fibres and medullation were made from 1014 bales of Merino greasy wool, from the five major wool-selling centres in Australia. A full range of wool types was represented from the fault-free spinners types to the burry, dusty, inferior topmakers' types. The wool consisted of 36 processors' lots ranging from 1 to 120 bales.

The mean diameter of the 36 lots was 20·7 ± 5·3 μ 2·4% of the fibre population exceeded 30 μ the incidence of medullation was 1·1%.

Mean diameters of the individual lots ranged from 14·7 to 25·3 μ Twenty-one of the 36 lots had coefficients of variation of mean fibre diameter which exceeded 23%. The range of clean, oven-dried yield was 49·4–69·1%. The between-lot variation in fibre medullation was 0–3·1%.

It is concluded that fibre coarseness as measured by diameter was not a problem in the wide range of wool sampled. However, the incidence of medullation is an increase on previous estimates and should be a cause of concern to breeders.

Twenty-six Finnish Landrace × Scottish Blackface ewes, mated to a Dorset Horn ram, produced 58 lambs. Protein concentrations in the ewes' colostra during the first week of lactation, and in the ewes' and lambs' sera on the 3rd day after parturition were compared with those in pure-bred Finnish and Blackface sheep. In cross-bred and Blackface lambs the total serum protein and γ-globulin concentrations decreased significantly as litter-size increased. Litter-size had much less effect in Finnish lambs. When litters of the same size were compared, cross-bred lambs tended to have higher concentrations than Blackface lambs, but had much lower concentrations than Finnish lambs. The mean protein concentrations in sera and presuckling colostra from Finnish × Blackface ewes were almost exactly the same as in Finnish ewes, but were considerably lower and higher, respectively, than in Blackface ewes. When suckling began the concentrations in the colostra decreased much faster in Finnish ewes, even when ewes nursing the same number of lambs were compared. Differences in suckling behaviour on the day of birth may therefore partly account for the variations in the amounts of maternal protein obtained by lambs of different breeds.

Crotonylidene di-urea (CD-urea) in a sandy-loam and two clay-loam soils decomposed slowly at 7°C, and from 8 to 15% was recovered as mineral-N after 24 weeks. At 25°C, it decomposed faster in the sandy-loam than the clay-loam soils; with 100 ppm N, a maximum of 86% was recovered after 16 weeks, and 80% of 1000 ppm N after 24 weeks. Recovery after 24 weeks ranged from 30 to 60% in the clay loams.

Ryegrass grown in pots produced more extra dry matter, containing more N, during 16 weeks when given ammonium sulphate than it did during 50 weeks with CD-urea.

Wheat, ryegrass and kale were grown with ammonium sulphate (treated with a nitrification inhibitor) or calcium nitrate supplying 50 and 100 lb N/acre, and without fertilizer-N. Plants were sampled at various stages, dry weights measured, percentage N determined and N uptakes calculated.

Initially wheat and ryegrass grew better and took up more N with ammonium fertilizer than with nitrate. Final yields of dry matter did not differ between forms. Kale produced more dry matter with calcium nitrate than with ammonium sulphate. All crops produced more dry matter with fertilizer-N than without. Fertilized crops contained greatest weights of N 109 days after sowing, when wheat and ryegrass had more with ammonium than with nitrate and kale had less. The 50 lb N/acre as calcium nitrate produced the most wheat grain/lb of fertilizer-N.

During the period when growth and N uptake were fastest, wheat grew faster with ammonium than with nitrate, ryegrass grew similarly with both forms, and kale faster with nitrate; wheat and ryegrass took up N faster from ammonium sulphate and kale from calcium nitrate.

Mature wheat recovered 58% of the fertilizer-N from calcium nitrate and 43% from ammonium sulphate. After 21 weeks of growth, kale recovered more N from calcium nitrate (50%) than from ammonium sulphate (24%), whereas grass recovered about 40% from each.

Quantity/potential relationships, between gain and loss of K by the soil and K potential (RT In ακ/⊧αca+Mg) were determined on twenty-seven Rothamsted and Woburn soils. K extracted by neutral N ammonium acetate, by H-resin and 0·5 M sodium bicarbonate (pH 8·5) were also measured.

The ability of an extractant to remove soil K is equated to a K potential (derived from the quantity/potential curve) which the soil attains on removing K equal to that taken out by extractant. Mean values for all soils were – 4995 ± 97 cal/equiv for the ammonium acetate, – 6081 ± 88 cal/equiv for the H-resin and – 4336 ±117 cal/equiv for the sodium bicarbonate extractants. For the first and last extractants the ability to remove K was less in rich than in poor soils.

Varying the ammonium ion concentration from 0·1 N to 1 N in ammonium acetate/acetic acid mixtures, N in acetate ions, did not greatly affect their ability to remove K.

The potassium potential which limits uptake of K by ryegrass, ‘the uptake potential’, was derived from the uptakes of K and from the quantity/potential relationships of a number of soils by a method which avoids exhausting the soil by cropping. This potential was – 5600 cal/equiv in Rothamsted soils, but the method was unsuitable for Woburn soils. In Rothamsted soils uptake of K was more closely related to quantity than to potential of K, but in Woburn soils it was equally well related to both. From 28 days until 82 days, when the initially available K had been used in most soils, diffusion in the soil seemed to control rate of uptake of K. On longer cropping, much initially nonavailable K was released, the grass still grew and the mean K potential had fallen to only –5189 cal/equiv in Rothamsted and –5336 cal/equiv, in Woburn soils.

The potassium quantity/intensity (Q/I) relationships, which relate change in exchangeable K content (Q) to change in activity ratio were measured in soil samples from manuring experiments at Rothamsted and Woburn. Within each experiment, Q/I curves for different K-manuring treatments were super-imposable on each other and on the curve relating exchangeable K to Io, the activity ratio at which the soil neither gains nor loses K. The distances on the Q axis between the curves were equal to the differences in exchangeable K.

The buffer capacity, dQ/dI, was related to the K saturation of the cation exchange capacity (CEC) by the equations

(Q and CEC in m-equiv/100 g)

Broadbalk and Hoosfield soil, and

for Barnfield soils (b= 3·08; m= 1·0) and for Woburn market garden soils (b =2·41; m= 0·6) but for soils from other Woburn experiments, dQ/dl did not vary significantly with Q/CEC.

Six field experiments (1963–8) in eastern England compared solid fertilizer with liquid fertilizer or anhydrous ammonia for sugar beet. Two glasshouse experiments investigated the interaction between depth of placement of fertilizer and soil moisture.

Yields of sugar were the same from broadcast solid and sprayed liquid in all the experiments, but nitrogen uptake by the crop was less from liquid than from solid. Three experiments tested placement of liquid 4 in to the side and either 2 or 6 in below the seed. Plants with deep-placed fertilizer consistently out-yielded those with shallowplaced fertilizer, but yields were never significantly different from broadcast solid fertilizer. Dry-matter yields of sugar beet grown in containers indoors showed that the crop responded to deep placement when the surface soil was watered infrequently.

With anhydrous ammonia injected during seed-bed preparation, sugar yield and nitrogen uptake were the same as with solid fertilizer in the seed bed, and were greater than with anhydrous ammonia injected in the ploughed land during early spring. A side-band injection of anhydrous ammonia before singling gave a crop containing as much nitrogen at harvest as, but less sugar than, nitrogen applied in the seed bed.