Leaflet movement in soyabean (Glycine max (L.) Merr.) is considered to be an important physiological adaptation for intercepting sunlight for photosynthesis. Solar tracking may serve to increase plant production by maximizing light interception. The objective of this study was to determine the response of A (leaflet net assimilation rate), τ (stomatal conductance) and Ci (internal leaf carbon dioxide concentration) when penultimate fully expanded leaflet angles were changed. Soyabean (cv. Enrei, Maturity group VI) was planted at Niigata University, Japan, at two densities (25 and 16 plants/m2) in mid-May of 1992 and 1993. PFD (photon flux density), A, τ, and Ci were measured with a portable leaf photosynthesis instrument. The more towards vertical the leaflets were moved, the lower the PFD and A were. A measured at R5 showed no light saturation, but did show this at V13 and R3. While A measured at 09.00 h showed no saturation point, there was saturation at 12.00 h and 15.00 h at or less than 1500 μmol/m2/s. At R3 a high correlation (r = 0.89, P < 0.01) was found between PFD and A for naturally oriented leaflets, but not for horizontal ones. These results suggest that leaflet movement is an adaptation to optimize A.

A spaced plant experiment and a sward experiment were conducted at INIA La Estanzuela, Uruguay in 1996 with six red clover (Trifolium pratense L.) populations, to study the efficacy of selecting genotypes for sward performance in a spaced plant nursery. This was examined through: (a) the ranking of the best linear unbiased predictors (BLUP) of populations and (b) the ratio of the correlated genetic advance in swards by selecting under spaced plant conditions to the direct genetic advance of selecting under sward conditions. From the eight characters analysed, only the rankings of BLUPs for leaf size and flowering were significantly the same between populations. The other six characters performed differently according to the level of competition imposed. Post-grazing leafiness and the difference between pre- and post-grazing leafiness (the two most important characters to measure preferential grazing) achieved greater genetic advance when selection was done as spaced plants: while for pre- and post-grazing height genetic advance was greatest by selecting under sward conditions. For other characters, the best conditions to select depended on the selection intensity achievable.

Nine high-oil varieties of sunflower were evaluated for their reactions to salinity during emergence in salinized soil culture ranging from 0 to 12·80 mmhos/cm under controlled temperature of 27±1 °C. The varieties were Louck, Vniimk-8931, Chernianka-66, Record, Armarisky, Peredovik, Orizont, Mhjak and Zarea.

Soil salinity decreased the percentage of emergence in all varieties of sunflower. The rate of decrease in emergence of some varieties was greater than others. Among varieties tested Vniimk-8931 (a tall variety) and Chernianka-66 (a dwarf variety) showed the highest and the lowest tolerance to salinity at 7·60 mmhos/cm, respectively. For electric conductivities above 7·60 mmhos/cm, the nine varieties of sunflower could be classified in three categories. Vniimk-8931, Record, Louck, Peredovik and Armarisky as high salt tolerant, Mhjak and Orizont as medium salt tolerant and Chernianka-66 as low salt tolerant varieties.

Sowing date directly affected the grain yield of chick peas. Optimum sowing date was found to be between the end of October and the end of November, but different soil types showed some differences within this optimum.

Grain yield was highly correlated with number of pods per plant and number of plants at harvest.

Plant loss at the seedling stage was highly correlated with daily mean maximum air temperature, and was also significantly associated with sodium accumulation in shoots.

The response of late-sown mustard (Brassica juncea L.) to four rates of irrigation (ratio of irrigation depth to cumulative pan evaporation, ID:CPE = 0·2, 0·4, 0·6 and 0·8) and nitrogen (0, 30, 60 and 90 kg/ha) was investigated at Haryana Agricultural University, India, in the winter seasons of 1986/87 and 1987/88. Increases in the amounts of water and N fertilizer applied increased leaf water potential, stomatal conductance, light absorption, leaf area index, seed yield and evapotranspiration and decreased canopy temperature. Water-use efficiency was highest for the 0·4 ID:CPE irrigation treatment in both seasons, and for the 60 kg N/ha N treatment in 1986/87 and the 90 kg N/ha treatment in 1987/88. The combination of 0·6 ID:CPE with 60 kg N/ha gave a significantly higher seed yield than lower rates and equalled that from the highest irrigation and N treatment combinations. The amount of water used by the mustard crop decreased with increasing soil depth irrespective of treatment. In the deeper soil layers, the percentage of total moisture use was greater under less irrigated than under more frequently irrigated plots. Leaf area index showed a significant positive linear relationship with evapotranspiration and light absorption and a negative linear relationship with canopy temperature. Seed yield was linearly related to leaf area index and light absorption coefficient.

Six-day disease of chicks is a disease of intestinal putrefaction, and may be fostered by any ration which contains the following:

(a) Animal proteins which show evidence of putrefaction.

(b) Excess of fibre, or sponge-like fibre such as palm-kernel meal or sugar-beet pulp, which assist in the proliferation of putrefactive microbes.

(c) Residual oils which destroy vitamin A.

(d) Starch or carbohydrate insufficient to maintain an acid reaction to the lower end of the intestines.

Results of this study show that daily intake of dry matter (DM) and digestible energy (DE) was lower for the ‘warm’ environment and ‘high’ fibre groups. Efficiency of DM utilization was also lower for these groups. However, efficiency of DE was essentially the same for both rations, being lower in the ‘warm’ group. The lower intake in the ‘warm’ environment was attributed mainly to the longer length of time that animals spent resting, which resulted also in lower growth rates. The data indicate that increasing the caloric density of feed, to compensate for reduced consumption, would make it possible to obtain proportional increases in energy intake. As interactions were negligible, this situation would apply to both environments studied.

The gross energy and nitrogen contents of muscle, fat, and connective tissue of calves were determined, and from these data and feed analyses the gross energetic (GEE) and nitrogen efficiency (GNE) of growth, and the gross efficiencies of accretion since birth (GEA, GNA) were calculated.

The percentage range of actual efficiency values for calves were GEE 55·3–7·7, GEA 18·1–1·4, GNE 58·1–22·8, and GNA 28·1–7·3. Within each treatment group these values were higher in the heavier calves. An hypothesis for the apparent temporary rise in these values in the heavier calves is that a compensatory mechanism acts in calves on low energy and possibly low N intake to enable them better to utilize their food. The results were obtained in calves whose diet was comprised of a reconstituted milk of low-solid content which led to low growth rates.

The occurrence of xanthin calculi in the kidneys of sheep on certain poor pastures on the Moutere Hills in the Nelson district is reported and described. The incidence of xanthin calculi is associated with poor stock results over large areas. Poor lambing returns, high mortality of stock in certain seasons, low milk yields and inability to fatten stock are common features of many farms on the Moutere Hills soil. On one small farm, grazing 120 sheep, no less than 12 sheep which have died or have been killed during the last six months have had calculi in the kidneys.

The Moutere Hills soil type is shown to be highly deficient in both lime and phosphate. Great increase in crop production invariably accompanies the application of lime and phosphate to the land.

1. The day to day variability in the yield of milk and fat of cows is affected by many factors, two of which are stage of lactation and season of the year. Variability is high during the first month of lactation (particularly during the first few days after the calf is weaned), but after this a fairly constant variability may be expected. Under the conditions of management in the herd under discussion and probably in most herds in Southern England variability is highest during the month of May and also tends to be higher during the summer than the winter months.

2. A method is presented of calculating the variability in the yield of mixed milk from a herd of cows and the error to be expected when milk records and fat percentages of individual cows are calculated from a few samples.

3. When cows are milked twice daily at unequal intervals the yield of milk obtained in 24 hours is slightly less variable if a morning milk yield is added to the subsequent evening yield, than if an evening yield is added to the subsequent morning yield.

1. A balanced factorial experiment was carried out with 48 Merino ewes. There were two levels of each of the four factors: environmental temperature, thyroxine status, vitamin A intake and progesterone status. Each ewe was killed at 25 days' pregnancy. The thyroid was removed, weighed and examined histologically.

2. Thyroid weight in the hot-room animals was significantly decreased by large doses of vitamin A. It was not affected by any of the other treatments.

3. With respect to the number of follicles per unit area of cross-section, the following interactions were significant: temperature × vitamin A; temperature × progesterone; temperature × vitamin A × thyroxine. The directions of the effects of vitamin A and of progesterone were reversed by the higher temperature.

4. There were no significant effects on nuclear height in the follicular epithelium.

5. The frequency of marked ‘scalloping’ at the edge of the colloid was significantly higher among those ewes receiving thyroxine injections than in the remainder. This feature was not significantly affected by any other factor.

Twenty-nine bunch groundnut genotypes were grown in the Kharifseason 1980 and the summer season 1981 at Bangalore. Growth and yield analysis showed that the total dry-matter accumulation was low up to 30 days after sowing and increased linearly up to the 86th day in the Kharifand up to harvest in the summer season. There were significant differences between genotypes in leaf area indices (LAI), the leaf area duration (LAD) and LAD between pod initiation and harvest (LADP) in both the seasons. The mean LAI of genotypes did not vary much between the Kharifand the summer seasons up to the 66th day. However, during the later stages of growth the LAD was higher in the summer. The higher biological yield and productivity in the summer was attributed to the high LAD and LADP during the later stages of crop growth. LAD and total dry-matter accumulation at harvest were significantly correlated both in the Kharif(r = 0–75) and the summer (r= 0–81). The mean total number of flowers over all 29 genotypes did not vary, but total number of pegs formed per plant differed significantly between genotypes in both the Kharifand summer seasons. The percentage of flowers which produced pegs was 72–2 in summer as against 51–2 in Kharif. The primary branches contributed 86'7 and 90–1 %to the total number of pods per plant in the Kharifand summer seasons respectively. The contribution of the first four nodes of primary branches was 85 %in both seasons. The number of fruiting points (nodes having mature pods) per plant, found to be the most important yield-determining component, showed significant variation amongst the genotypes in both the Kharifand summer seasons. In summer, length of mature-pod-bearing zone (MPBZ), number of nodes in MPBZ and number of kernels per plant were higher than in the Kharifseason. It is suggested that selection and breeding should concentrate on improving LAD and LADP, total dry matter per plant, more primary branches per plant, more pods in the distal nodes of primary branches and more fruiting points (nodes in MPBZ) per plant.

1. An account is given of the geology and mineralogy of the soils of a small area characterised by diverse rock groups, which are mainly covered by glacial drift. The topography is also varied. The soils are mainly derived from boulder clay, glacial sands and gravels, and alluvium, the remaining soils being formed on screes and hill-wash. The underlying rocks are lavas of Old Red Sandstone age and sandstones and shales of Carboniferous age.

2. A similarity in mineral content of the soils on glacial material and alluvium is shown. All these soils have a high content of fresh ferro-silicates. The soils on the screes and hill-wash are characterised by their content of rock fragments and iron oxides, but minerals from glacial material are also present, though to a minor extent.

3. The soils on the drift material contain potash, phosphate and lime-bearing minerals.

4. The varied nature of the parent materials has given rise to varied textures in the soils. The soils on the boulder clay are the heaviest, while, the soils on the fluvio-glacial material are very variable.

5. The mineral content of the matrix of the boulder clay is similar to that of the local rocks, only the rarer minerals being derived from external sources.

Field investigations conducted at Ludhiana (India) showed that the foliar application of 2-chloroethyltrimethyl-ammonium chloride (CCC) (50% a.i.) at 300,600 and 900 ml/ha about 5 weeks after planting did not depress plant height. The dose of 600 ml CCC/ha was most effective and increased seed yield by 1·31 and 0·74 t/ha over the control (water spray) in 1978–9 and 1979–80, respectively. The corresponding increases in total yield were 1·37 and 0·86 t/ha. However, in 1980–1 when CCC was applied 3 weeks after planting even the lower dose of 300 ml/ha depressed the plant height. Then the treatment of CCC increased significantly the number of tubers of seed size and seed yield by decreasing the ‘ware’ yield but did not influence the total yield. The yields of potatoes were not affected signifioantly by the application of N-dimethyl amino succinamic acid (B 9) and succinic acid (SA).

In an experiment where the interaction of nitrogen and CCC was studied both factors not only increased the seed yield but also increased the total yield. However, there was no interaction between nitrogen and CCC.

1. The results are presented of two series of digestibility trials. The first series consists of six grass hays, cut at different stages of growth, and two legume hays cut at the flowering stage. The second series consists of trials using seven species of grasses at the ‘standing hay’ stage.

2. Good-quality grass hays are obtained from grasses at the flowering stage. More mature grasses yield poor- or very poor-quality hays of low-protein content.

3. The legume hays were of good quality, being particularly high in digestible protein.

4. The grasses at the ‘standing hay’ stage are generally of poor feeding value, Brachiaria brizantha, a drought-resistant species, being the best of the seven studied.

5. From these results a tentative conclusion is drawn that, during the dry season, the extensive grazing areas of East Africa are capable of providing, at the most, for the maintenance requirements of ruminants.

The difference between the power to accumulate nitrates in the soil after various rotations has been determined by incubating the soils at the termination of these rotations, and measuring the nitrate formed between January and May, a period of 4 months. The test has been repeated during 8 successive years, and the mean result is presented. The previous treatments, each of which lasted 3 years, consisted of (a) a ley grazed off each season by sheep, (b) a crop of lucerne which furnished two or three crops of hay each yer, and (c) and (d) an arable rotation of potatoes, wheat, and either a hoed crop of kale or a mixed ryegrass and clover crop of hay.

In each case, the ammonia capable of distillation with magnesia was reduced during the incubation to an amount which differed little in all the soils, while the nitrate made an almost steady increase—most regular, however, after the previous cropping with lucerne—at least for a period of 4 months. The soil after the previous grass and clover hay crop started at a lower level of nitrate than the others and, even after the longest incubation period, never quite reached the accumulation which occurred in the other cases. Comparing the accumulation which occurred after the two 3-year ley crops (grazed ley and hayed lucerne) with that after the arable cropping, there was very little difference.

1. A volumetric method for the determination of sodium which can be separated as a triple salt (uranium zinc sodium acetate) from mixed solutions is described. The reduction of the uranium with titanous chloride, upon which it depends is shown to be quantitative.

2. Calcium, magnesium, and relatively large proportions of potash do not interfere. The procedure for the removal of iron, aluminium and phosphates by gentle ignition is simple and obviates the risk of error by the introduction of sodium as an impurity in the chemical reagents necessary for precipitation methods.

3. 0.1 mg. of sodium can be determined accurately.

Two experiments were conducted with eight rams in a latin-square design of four treatments with different lucerne hay (LH): maize grain (MG) ratios: 100:0, 80:20, 50:50 and 20:80. In Expt 1 the amount of food offered was restricted to 1 kg/day. In Expt 2 the rams were offered 1·5 kg/day, which was about the maximum amount the animals in the 100% LH treatment were able to consume. Animals were kept on each treatment for 4 weeks; during the final 8 days the faeces were oollected and weighed for each animal and analysed for dry matter, organic matter (OM), crude fibre and δC

The values of δC in LH, MG and different faeces samples were used for direct determination of LH and MG digestibilities of mixed diets in the different treatments.

The increase of MG in the ration and the decrease of LH improved the digestibility of total OM. The effect of MG was more pronounced at the low than at the high level of consumption. At the low level of intake, an increase in the amount of MG in the ration did not affect the digestibility of LH, and MG digestibility was close to the extrapolated value. At a food intake level 1·5 times that of Expt 1, the addition of grain to more than 50 % of the ration caused a marked depression in digestibility of LH.

Results of the δC method were discussed in comparison with calculated values of LH and MG digestibilities and with whole ration crude-fibre digestibility.

1. Various portions of barley plants were made available for chemical tests from manurial experiments which were designed to test the effects of K treatment (broadcast and placed with the seed) on grain yield.

2. The experiments were located at three centres differing in soil characters and K status. Centre A was severely deficient in K; centre B was moderately deficient and at centre C, K was adequate.

3. A comparison was made between the results of the following tissue test methods for K, Mg, Ca, P and Mn: (a) diffusion method, using young leaf, mid-stem leaf, and internode respectively; (b) Waring blendor, and (c) ash analysis. Mn was not determined by the blendor method.

4. The coefficients of variation for the quick tests compared favourably with those of ash analysis for K, Mg, Ca, P and Mn respectively. Variations in results in tissue tests for Ca were, however, significantly greater than those of ash analysis, at centre A (second sampling).

5. Correlation coefficients between results of ash analysis and the tissue test methods for K, Mg, Ca, P and Mn were positive and significant for totals, treatment and treatment × sites, except for Mn in young leaf by diffusion method. The error term for P was also significant for the quick methods, thus decreasing the value of the correlations for this nutrient.

6. Correlation coefficients of yields with ash analyses, Waring blendor and diffusion method (mid-stem leaf) analyses respectively were significant and positive for K and negative for Mg, Ca, P and Mn. This confirms an interaction of K with the other nutrients.

7. Minimum K levels, determined 5 weeks after seeding, above which no further increase in yields may be expected at the three centres, were: by diffusion method, using young leaf, mid-stem leaf and internode, 700, 500 and 600 μg. extracted per. g fresh weight respectively; by Waring blendor using ‘tops’, 2000 μg. extracted per g. fresh weight; by ash analysis of tops 1·5% K in dry matter. There is evidence that these critical levels fall later in the season, especially in mid-stem leaves, presumably through translocation of K to the ears.

8. Minimum levels of K required for optimum yields are above those associated with the onset of deficiency symptoms of the element. Thus chemical methods only can determine suboptimal levels of nutrients in relation to final yields.

The Agricultural Research Council's system of feed evaluation provides a method of predicting the most profitable ration composition, given information about available feedingstuffs and the values of the parameters in the beef-feed production functions. Because these functions are non-linear, parametric estimation based on average data for a group of animals will give biased results. A method of determining unbiased estimators of the parameters is derived and the magnitude of the bias is shown to be small. Some simplifications of the ARC formulae are proposed.