THE EFFECT OF THE ADDITION OF ARACHIS OIL ON THE CONSERVATION OF HEAVILY–WILTED HERBAGE SEALED IN POLYTHENE FILM

A conservation experiment is described in which arachis oil was used to improve the energy content of heavily-wilted herbage of approximately 46% dry matter. The 2 oil-treated herbages and 2 control silages were enclosed in polythene film. The DM losses from all 4 silos were high compared with losses normally encountered in completely sealed silos. This is attributed to secondary fermentation which occurred after the silos were opened. The oil had a depressing effect on the digestibility of the mineral matter of both grass and silage. The metabolizable energy values of the silages are reported and discussed.     

THE CONSERVATION OF HEAVILY–WILTED BALED HERBAGE IN SEALED POLYTHENE CONTAINERS

A conservation experiment is described in which the losses in ensiling heavily–wilted, baled herbage of 49–58% dry–matter content in a completely sealed polythene film is described. In addition, a comparison is made between silages with and without sodium metabisulphite added as a preservative. The mean DM loss for the control silages was 11.1%, and that for the metabisulphite–treated silages 12.8 %. These losses, and the individual crude–nutrient and digestible–nutrient losses are compared with those obtained for heavily–wilted and conventional silage made in lined trench silos. Metabolizable energy values for the grass and silages are also presented.     

A NOTE ON THE USE OF THE POWER-DRIVEN SHEEP-SHEARING HEAD FOR MEASURING HERBAGE YIELDS

3-inch sheep shears powered by various motors have been used extensively for sampling in grazing experiments at Hurley since 1958. General observations on their use are made and the results obtained in comparisons of sampling methods made in 1958 and 1959 are discussed.     

LOSSES IN THE NUTRITIVE VALUE OF HEAVILY-WILTED HERBAGE ENSILED IN EVACUATED AND NON-EVACUATED POLYTHENE CONTAINERS

A conservation experiment is described in which the losses entailed in ensiling heavily-wilted herbage of 37–43% dry-matter content either by complete sealing in polythene alone, or by complete sealing followed by evacuation of air, were investigated.
The metabolizable energy values of the grass and silages were determined, and the silage volatile-acids fraction investigated by gas chromatography. The results indicate that there are no significant fermentation differences between the two types of silage. The mean dry-matter loss for the sealed, unevacuated silos was 6.5% and for the evacuated silos 7.8%. These losses, and the individual crude- and digestible-nutrient losses, are discussed in relation to other published work.     

LOSSES IN THE CONSERVATION OF HEAVILY-WILTED HERBAGE SEALED IN POLYTHENE FILM IN LINED TRENCH SILOS

A conservation experiment is described in which the losses in ensiling heavily-wilted herbage, of approximately 50% dry matter, in lined trench silos, with and without a polyethylene film seal, are compared. The composition and digestibility of the silages produced in the sealed silos were comparable with those of the original herbage. The content of organic acids in the sealed silos was low, suggesting that fermentation was suppressed by the partially gas-tight seal. In the unsealed silos there was considerable spoilage, 70% of the material being inedible. In the 2 sealed silos losses of dry matter were 8·2 and 5·2% and losses of SE 11·5 and 7·8%, respectively. The losses recorded are compared with those usually encountered in lined trench silos.     

STUDIES ON THE MAGNESIUM CONTENT OF MIXED HERBAGE AND SOME INDIVIDUAL GRASS AND CLOVER SPECIES

The magnesium contents of mixed herbage and four individual grass and clover species were studied under four treatments—control, magnesium sulphate, magnesian limestone and carboniferous limestone.
The magnesium values were lowest in the spring and early summer and then increased to maximum values by the autumn. The seasonal variations, however, differed appreciably from year to year.
The effect of magnesian limestone on the magnesium content of mixed herbage was relatively small in the year of application, but increased during the following years and reached a maximum in the fourth year after application. The increase in magnesium uptake from the magnesium sulphate treatment was small after the first year, whilst carboniferous limestone slightly depressed the magnesium content. This depression, however, was very small and probably of no practical significance.
The magnesium content of red clover was about 50% higher than that of Italian ryegrass, cocksfoot and white clover. In the second year after application magnesian limestone had a much greater effect on the magnesium content of the clovers than on that of the grasses.     

STUDIES ON THE ROOT DEVELOPMENT OF HERBAGE PLANTS

Various methods of root sampling are reviewed and discussed in relation to the type of information required. The root sampling techniques at the Grassland Research Institute are described and examples of sampling errors are given. Details of a root washing machine are given.     

STUDIES ON THE ROOT DEVELOPMENT OF HERBAGE PLANTS

The influence of defoliation on the root, stubble and herbage weights of perennial ryegrass during establishment was studied on spaced plants in the greenhouse and field.
In the greenhouse trial the rate of root elongation was reduced by a single defoliation. In both the field and greenhouse, cutting reduced the number of roots and tillers per plant but increased the number of roots per tiller. A few weeks after defoliating plants in the field there was a lower root weight on the cut plants than on the uncut. Eventually the influence of a single cut disappeared, but if the cutting was in the laie summer or autumn the plants commenced the winter with a smaller amount of root and stubble, and this appeared to have a deleterious effect on the earliest spring growth.
Herbage growth in March and April was positively correlated with both root and stubble weights in the previous November.
As the number of cuts during the establishment period (March-November) was increased from 0–4 the root and stubble weight per plant progressively decreased.
The root and stubble weights decreased during the winter.     

STUDIES ON THE ROOT DEVELOPMENT OF HERBAGE PLANTS

Herbage, stubble and root weights were recorded for thirteen months on various leys subjected to two treatments differing in frequency of cutting.
The root-weight per unit area of a ryegrass/white-clover ley was not affected by the frequency of cutting, but the less frequently cut plots had fewer tillers per unit area; the root- and stubble-weight per tiller was, therefore, higher on the less frequently cut plots, On a cocksfoot ley the root-weight was not affected by the cutting treatment, but in late summer and early autumn the stubble-weight was considerably higher on the less frequently cut plots.
When cocksfoot was grown in rows 2 feet apart, the more frequent cutting decreased both the root- and stubble-weight.
On grass leys root-weights were heaviest in the summer and thereafter decreased until the following spring.
The root-weight of lucerne decreased from May to July, increased to a maximum in December and then decreased in weight. The changes in root-weight under lucerne leys were mainly due to changes in the weight of the tap-roots.
The vertical distribution of roots was recorded, and, in the case of the cocksfoot in rows, the lateral distribution of roots is also given.     

STUDIES ON THE ROOT DEVELOPMENT OF HERBAGE PLANTS

Two cutting treatments were applied to a cocksfoot sward, and the changes in fructosan and soluble–sugar contents of the roots, stubble and herbage were studied over a complete year.
Both the soluble-sugar and fructosan contents of roots were at a low level throughout the experiment. The total soluble carbohydrate in the roots never exceeded 4%. It is concluded that cocksfoot roots are not important storage regions for soluble carbohydrates.
The total soluble carbohydrate in herbage varied with season and reached a maximum of 10%. It was not affected by cuuing treatment.
In stubble the total stubble-carbohydrate content fluctuated markedly with season and reached a maximum of 18% in October; it was generally higher on the infrequently-cut swards than on those cut frequently. The soluble-sugar content was small and changed little with season or cutting treatment; the fructosan content, however, varied from 2 to 16–6% and accounted for most of the changes in the soluble-carbohydrate content. Stubble is apparently the major storage region for soluble carbohydrates in cocksfoot.
Under sward conditions, the quantity of soluble carbohydrates in the stubble of cocksfoot may have a positive effect on the herhage growth immediately after winter defoliation. However, when swards are actively growing in spring, other factors, such as tiller size and number, may be equally important in determining the amount of herbage recovery growth.     

乙烯吸收剂延长香蕉贮运寿命的研究与应用

香蕉、大蕉和粉蕉经防腐剂处理后用聚乙烯薄膜袋包装并加入乙烯吸收剂,在常温下可延长其贮藏寿命20～40天。每公斤蕉用1克、2克或5克乙烯吸收剂活化铝,对其贮藏寿命没有明显的影响。用活化铝颗粒、沸石颗粒、蛭石和珍珠岩等不同材料作高锰酸钾载体制成的乙烯吸收剂延长果实贮藏寿命的效果不同。以活化铝颗粒或珍珠岩作载体效果较好。将乙烯吸收剂应用于商业性香蕉运输保鲜,使好果率从62.5％提高至95.7％,取得显著的经济效益。     

THE USE OF RUMEN-FISTULATED STEERS IN THE DIRECT DETERMINATION OF NUTRITIVE VALUE OF INGESTED HERBAGE IN GRAZING EXPERIMENTS

A rumen-fistulated steer was used for the manual collection of samples of freshly swallowed herbage, in a grazing-management experiment on a perennial ryegrass sward. Diurnal and seasonal changes in the in vitro digestibility of the herbage selected by the grazing animal were studied under both strip- and continuous-grazing methods of management.
There was no appreciable change in digestibility as the sward was grazed down from upper to lower layers under strip-grazing management in April and May. In June to October a within-day fall in digestibility was found, much of which was attributable to an increase in the amount of old dead herbage grazed from the lower regions of the sward. Dead herbage taken in by the grazing steer was considerably lower in digestibility in August than in May. The in vitro digestibility of herbage samples, cut to ground level before and after grazing in a strip-grazed treatment, fell markedly as the proportion of dead herbage in the sample increased, giving a high negative correlation.
In a continuous-grazing management there was no pattern of diurnal variation, and the seasonal variation in digestibility of the ingested herbage was less than in strip grazing. The implications of these results are discussed in relation to indirect methods of digestibility determination (faecal-index technique), the measurement of herbage intake, and to some aspects of grazing management.     

INVESTIGATIONS ON THE DRYING OF HERBAGE AT TEMPERATURES UP TO 50°C*

Experiments to determine the exposed layer drying rate of cut leaves and stems of a tetraploid (Sabel) and diploid (S23) ryegrass are described. Drying was achieved by passing air through the crop; the changes in weight were monitored continuously. Airflow was fixed throughout the experiments at 37·5 ft/min (0·190 m/s) and the temperatures were controlled in the range 25°C to 50°C. Comparisons were also made of the drying rates at different stages of maturity. Drying curves were determined and moisture content was shown to decay exponentially with time, the relationship approximating closely to a two term exponential.