Experiments at Sutton Bonington in 1973 and 1974 compared the growth and yield of sugar beet which was handweeded at different stages with that where weed control was entirely by pre- and post-emergence herbicides, used alone and in various combinations. Data from the series of handweeding treatments enabled the crop's minimum weed control requirements to be specified. They indicated that an ideal herbicide would kill all the weeds present when applied at the six-leaf stage, persist in the soil to prevent weed infestation for 4 weeks, but not check the crop to the extent that recovery was incomplete. That the crop was capable of recovering from a degree of early check was clearly evident from the handweeded treatments; it proved possible for crops whose weights had been depressed by 25–30 % when first weeded to recover completely by harvest.

The performance of all post-emergence treatments fell short of these requirements. When the crop was at the six-leaf stage, the earliest emerging weeds were too far advanced to be killed by the herbicide. By themselves, pre-emergence herbicides gave weed control equivalent to only 2 or 3 weeks of handweeding but they did pave the way for more effective use of post-emergence treatments by restricting the spectrum of weed sizes present and sensitizing those plants which did establish. The most effective herbicide regime used in the experiments was the sequence of chloridazon applied pre-emergence followed by two post-emergence applications of phenmedipham. However, phenmedipham clearly checked the crop. Two weeks after application crop dry weight was usually depressed by one-third. Provided weed control was adequate, recovery was usually complete by the end of the season.

1. Two basic slags differing widely in solubility and phosphate content have been treated for long periods with boiling ammonium chloride solution.

2. The low-grade slag lost 70 per cent. of the total lime and very little phosphoric acid; a residue with nearly 40 per cent. phosphate was obtained from an 18 per cent. slag.

3. The high-soluble slag also lost a large percentage of the total lime but large amounts of phosphoric acid were also found in solution. The residue from the 30 per cent. slag after 24 hours' treatment contained nearly 46 per cent. phosphate.

4. It is shown that a silico-phosphate is present in the high-soluble slag, but not in the low-grade slag.

5. The solubility in citric acid of the phosphates in the various residues has been determined.

6. The value of basic slags in supplying exchangeable calcium is discussed.

7. The effect of hydrofluoric acid on the slag residues has been investigated.

8. Experiments with fluorspar slags are described which confirm the view that the phosphate present is fluorapatite of very low solubility in citric acid.

1. Radioactive phosphorus was injected into young sheep that had been fed diets low in either phosphorus, phosphorus and vitamin D or calcium. Forty-eight hours after the injection the animals were killed and samples of bone and teeth were removed for specific activity determinations.

2. The specific activities of bone varied according to the site from which it was taken, but in general a strong inverse relationship was found between specific activity and the quality of the skeleton.

3. In teeth that were formed during the period the diets deficient in phosphorus or phosphorus and vitamin D were fed, the specific activities of the dentine and enamel were greater than for corresponding tissues from the control animals.

In an earlier paper (Little, McLean & Winter, 1977) we reported a technique for the measurement of the phosphorus content of the diet consumed bygrazing cattle, which recently has been used successfully to measure the dietary intake of phosphorus by sheep grazing Mitchell grass (Astrebla spp.) pastures in western Queensland (Beale & McMeniman, 1978). In this technique, phosphorus of salivary origin is distinguished from that of plant origin in samples extruded by oesophageally nstulated animals by prior labelling of salivary phosphorus with the isotope 32P following the intravenous infusion of Na2H32PO4. The difference in specific activity between saliva and extruded bolus is used as the basis of the calculation of the phosphorus content of consumed herbage. Oesophageally nstulated animals may graze experimental pastures for an hour or more while samples are collected from them. It is important to have an accurate measure of saliva speoific activity, representative of that secreted during the grazing period; therefore, application of the technique is facilitated if the rate of change in saliva specific activity during collection periods is slow and linear.

1. The fungicidal properties of solutions containing sulphur in polysulphide form, viz. sodium, potassium, calcium and barium polysulphides, were tested by application to the conidial stage of Sphaerotheca Humuli growing upon young hop leaves in the greenhouse.

2. Four samples of sodium polysulphide solutions, two prepared in the laboratory and two commercial products, were examined. When applied with 1 per cent. soft soap as the spreader, solutions containing 0·5 per cent. polysulphide sulphur proved fungicidal. With 0·5 per cent. gelatine as the spreader, fungicidal strength did not begin to be attained until the concentration of polysulphide sulphur reached 0·11 per cent. The results suggest that the nature of the spreader may influence the fungicidal properties of polysulphide sulphur.

The effect of fertilizers in increasing the yield of clover seed was examined by a series of manurial trials. The initial mineral status of the crop and the extent of the uptake of the applied nutrients were determined by analyses of the leaf. The techniques for sampling and analysing leaves to determine mineral status are described.

The high yields of seed and lack of response to fertilizers in trials at Cambridge led to their being repeated at Saxmundham on land known to be extremely deficient in minerals. Even then there was a response only to phosphate which although significant was small.

Leaf samples were also collected from commercial crops of red clover in 1955, 1956 and 1957. The analyses of these samples indicted that none of them was as deficient as the crops at Saxmundham, and no relationship was found between mineral status and seed yield.

It is concluded that yields of red clover seed in Eastern England are not likely to be increased materially by the application of fertilizers.

A total of 886 cows of two herds belonging to the Ministry of Agriculture, Egypt, were used in this study to investigate the effects of inbreeding and cross-breeding on dairy traits. The first herd consisted of the native breed Domiatty (D), Shorthorn (S) and different grades between them while the second of Jersey (J) and its different crosses with D. There were 1027 lactations from the first herd and 460 from the second. Inbreeding coefficient (F) averaged 0·06 in the first herd and 0·08 in the second, both ranging from 0·00 to 0·30. The range was partitioned into three classes: the first with 0·0 ≤ F ≤ 0·1, the second 0·1 ≤ F ≤ 0·2 and the third F ≥ 0·2. Traits studied were first and second lactation 305-day milk yields, age at first calving, first calving interval and first dry period.

Inbreeding had no statistically significant effect on any of the traits except dry period in the first herd. Inbreeding was not associated with decrease in yield when F ≤ 0·2 in the first herd, while there was consistent decrease with inbreeding in the second herd. No clear trend could be observed on the effect of inbreeding on any of the other traits in the first herd whereas in the second the rise in inbreeding was always associated with greater age at first calving, with wider calving interval and with longer dry period.

The major portion of nitrogen nutrition of flooded rice is met through the mineralization of organic forms of N present in soil. This is true even when fertilizer nitrogen is added. The mineralization of organic matter under waterlogged conditions is governed mainly by the prevailing chemical and biological conditions. In recent years, attempts have been made to characterize the products of hydrolysis of soil organic nitrogen (Asami & Hara, 1970; Shinde, 1978; Subba Rao & Ghosh, 1981). Information on different fractions of nitrogen in waterlogged rice soils is scanty.

Six hybrids, either pure dent or flint x dent crosses, together with two open-pollinated flint varieties of early maturity, were grown at Oxford, England, and the yield of grain determined over a range of 15 densities (5.30.8 plants/m2). The relationship of yield to density was studied by fitting mathematical functions to the observed yields. Only two functions, (1) the inverse quadratic on yield per unit area, and (2) the linear regression between density and the logarithm of grain yield per plant, were satisfactory fits. The linear regression was preferred because of its ease of calculation and interpretation. Between genotypes the largest differences in grain yield per unit area were found at densities either above or below those which are employed in normal practice.

The ranking of the genotypes for grain production depended upon the density. Whereas at the lowest density a very short, early-maturing flint genotype, GaspéFlint, yielded least, and a tall, full season dent hybrid, 0X324, yielded most, this position was reversed at the higher densities. Maximal levels of yields of the open-pollinated flint varieties were low, and it is apparent that the incorporation of this source of germplasm in hybrids is limited if commercially acceptable yields are to be attained. Maximal yields of 600 g/m2 were produced by three hybrids, but the optimal densities were markedly divergent. They ranged from 6.2 plants/m2 for 0X324 to 9.7 and 10.8 plants/m2 for INRA 270 and INRA 200. Possible reasons for such differences are discussed in terms of the interactions of density and genotype on the components of yield.

A total of 1659 ejaculates was collected from four Friesian bulls imported from Europe and ten of their offspring born in Iraq while in regular artificial service at the Abu-Ghraib Experiment Station. The work covered a period from 1 January 1965 to 30 June 1967.

The five semen characteristics, volume, density, mass activity, individual motility and pH were studied and the influence of age of bull and season on these characters was investigated. The relationships between the characters were also investigated.

Deterioration was observed in volume of ejaculate, density, mass activity and individual motility in the Iraqi Friesians. Influence of season on all semen characters lacked significance with the exception of mass motility in the European Friesian bulls (P < 0·05). Highly significant positive correlations were found between most of the characters studied.

Cowpea and hyacinth bean nodulated and grew well at 11–14 h and poorly at 8 h light duration. Nodulation and plant growth increased with increase in light intensity from 1·4 to 17·1 W/m2 but the natural light intensity (228·3 W/m2) inhibited nodulation in July and plant growth in December.

Nodulation and growth of both crops were best at ‘moderate’ temperature and cowpea tolerated ‘warm’ more than ‘cool’ temperatures whereas hyacinth bean showed the reverse situation.

Inoculation improved nodulation of cowpea but not hyacinth bean. Application of nitrogen did not improve the growth of plants affected by light and temperature.

In the last two decades significant progress has been made in understanding the factors and processes affecting the K requirement of crops. Simultaneously analytical techniques to study the behaviour of K in soil have been developed, on the understanding that soil controls the supply of nutrients to crop plants by adsorbing and sometimes fixing nutrients. As in solution culture, the concentration of K in the soil solution governs the uptake of K by plants. The soil matrix serves as a reservoir from which the soil solution is replenished. Monitoring K status of the soil solution under fixed crop sequences can provide a useful basis for improving fertilizer recommendations. Kconcentrations in the soil solution have, therefore, been measured on a soil in which a number of crops have been grown in fixed annual sequences in field experiments.

A study of the birthcoat and its relation to kemp succession in the adult fleece of coarse-wool Awassi and Hamdani sheep was carried out, as an aid to early selection. Lambs were covered, at the age of 2 months up to 15 months, by fixing patches of canvas on six body positions.

Both Awassi and Hamdani birthcoats had high halo hair grades. The animals played the dominant role in affecting different traits of the birthcoat which indicated the importance of genetic factors in further development of the birthcoat. The birthcoat of both types of lambs showed only coarse (plateau) and less coarse (saddle) fibre type arrays.

Hamdani had more kemp as Gt and G2 (first and second generations respectively) than Awassi sheep. The shed Gx following the different fibre type arrays, showed some overlapping between plateau and saddle. The same arrays of the birthcoat behaved differently on the different positions, where generally the anterior positions had less kemp than those posteriorly. Percentages of shed fibres were 100, 17·14, 2·38 and 0·35 of halo hairs, super sickles, sickles and chalky curly tips respectively in Awassi. Corresponding figures were 100, 29·26, 5·87 and 7·73 in Hamdani. In Awassi, halo hairs, of the birthcoat, showed a relatively high correlation (P < 0·01) with G1 kemp on the hip and britch. Within saddle array, in Awassi, the correlation between halo hairs and Gx kemp showed the highest values (P < 0·01), whereas in Hamdani the correlation between super sickles in the birthcoat and G2 kemp showed medium values (P < 0·05).

Selection of high halo hair grade lambs, in the birthcoat, that have saddle arrays, with high percentage of sickle fibres in Awassi and with low percentage of super sickles in Hamdani, would result in low percentages of kemp in the adult fleece. High halo hair grades would be necessary for early survival of lambs.

Crosses and reciprocal crosses were made between English material of Vicia faba major × Vicia faba equina and minor.

Half the major type plants had the stem apex removed before pollinations commenced. Apical dominance affected the success of crosses between major × equina, minor. On higher nodes and, on lower nodes when the apex was removed, there was no evidence of unilateral incompatibility. All crosses produced seed.

An experiment was conducted to examine the effect of fertilizer (triple superphosphate) and stocking rate on animal and pasture productivity on Sumba Island, Eastern Indonesia. The Ongole heifers used in the 1-year experiment gained weight during the wet season and lost weight during the dry season at stocking rates of 0·5 and 1·0 head/ha when grazing native Themeda pasture. The dryseason weight loss was arrested when a prepared seed-bed pasture, which contained 21 % Siratro at the start of the experiment was grazed at a stocking rate of 1·5 head/ha. Increasing the stocking rate to 2·5 head/ha on this pasture resulted in an increase, in the weed component of the pasture from 12 to 84% in 1 year.

The mineral content of plucked samples of pasture indicated that levels of Ca and Mg were generally adequate for growing beef cattle and that Na supplementation would be beneficial. Plant N concentration was below 1·5% in the Themeda and Imperatacomponent but above this in the legume at the prepared seed-bed site. The P concentration in the Themeda and Imperata was always below the 0·24 % level required by cattle, as it was in the legume at the end of the experiment.

The introduction of herbaceous legumes into pastures under set stocking conditions can lead to pasture instability.

The percentage emergence from monogerm sugar-beet seed in field experiments was reduced by high soil moisture content and soil compaction, but was unaffected by soil temperature. Seed lots were differentially influenced when the soil conditions were very adverse. Pelleted seed emerged a little better in good soil conditions and was not more sensitive to high soil moisture content than raw seed.

The relation between laboratory germination and the number of emerged seedlings was variable and followed no obvious trends, and there was no consistent rank order in the emergence ability of four commercial cultivars.

Field investigations were carried out to study the effect of partial defoliation on dry-matter production and seed yield of urd bean. Partial defoliation during the vegetative and/or reproductive phase reduced seed yield. The severity of yield reduction was dependent on the stage of crop development and the degree of defoliation. The reduction of total dry-matter production by defoliation was accompanied by a decrease in crop growth rate and leaf/plant weight ratio. The net assimilation rate was higher in defoliated plants from 40 to 60 days after sowing. The reduction in seed yield due to defoliation was highly due to a reduction in the number of pods per plant, and also sometimes in the number of seeds per pod and in 100-seed weight.

Thirty-two milk-fed Murrah buffalo calves of 3 weeks of age were randomly allotted to four dietary groups: milk, concentrate-berseem hay in the ratios 1:1 and 1:3, or berseem hay alone. Milk intake was gradually reduced and completely stopped after the sixth week of age in the groups given dry feeds. Two calves from each group were slaughtered at 6, 9, 12 and 15 weeks of age. In addition, four buffalo calves were slaughtered at 21 days of age for comparison.

Observations on ruminal tissue weight, content weight and the ruminal capacity indicate that the ruminant stomach of buffalo calves weaned on dry food after the sixth week of age becomes structurally developed by 9 weeks of age, whereas the rumen remains underdeveloped in calves fed milk to 15 weeks of age.