Crude extracts of root of the resistant pasture plants lucerne (Medicago sativa) and Lotus pedunculatus contain strong feeding deterrents for third instar Costelytra zealandica and Heteronychus arutor larvae. Purified saponins isolated from active crude lucerne root extract markedly reduce grass grub feeding and have an ED of 0.019%. Black beetle larvae are even more sensitive to the material. Separate and chemically distinct feeding deterrent fractions, active against the two insects, have been isolated from Lotus pedunculatus root. The role of feeding deterrents in mediating the non-preference of these insect pests for lucerne and Lotus is discussed.
Morphological observations and measurements are presented on the growth habit of Lotus pedunculatus Cav. Establishing plants are characterized by a limited shoot-forming potential, particularly in association with weak crown activity. Plant resilience is improved with rhizome development by providing regrowth sites, carbohydrate storage and a colonizing potential. In the established plant, underground organs are the dominant plant components and their expansion patterns are discussed. Aerial growth is initiated as crown shoots, axillary shoots and basal shoots arising from rhizomatous material,
In a trial at Wairakei Research Station, the effect of three spring grazing managements on subsequent summer and early autumn hay production of lucerne was assessed relative to hay management over the entire period. Overall the two rotational grazing treatments where the lucerne was grazed at an immature stage of growth (grazed at 12 to 15 cm, and at 25 to 30 cm) reduced subsequent production in two hay cuts by 20% and IS%, respectively. A rapid rotation of 4 days at a stocking rate of 30 hoggets/ha where the stocking rate was in harmony with the lucerne growth had an unexpectedly small effect on subsequent lucerne production. The intermittent grazing treatments allowed greater weed ingress than the rapid rotational or hayed treatments. Spring production was reduced, compared with hay production, by 58% by the two intermittent grazing treatments and while no permanent harm was done to the lucerne stands these systems cannot be recommended because of tht: large losses. Where it is necessary to graze the early spring growth of lucerne, the rapid rotational system at a light rate appears to be a suitable method but this should be changed to rotational grazing of mature lucerne as soon as possible, because of the assumed lower production under the former system.
Farm forestry must be viewed as a capital crop, the economics of which are considerably improved through complementary production from livestock grazing the forest floor. The grazing animals maintain a clean forest floor, do not significantly affect the rata of tree growth, and reduce the burden of financing the necessary silvicultural operations. The greatest disadvantage is in the time delay beltween establishment and final income, and farmers must ensure that areas planted on farms do not unduly constrain annual income from the remaining farm area, and thereby increase the requirement for large-scale financing from external sources.
Two experiments were conducted in which cereals and ‘Grasslands Tama’ ryegrass were overdrilled into lucerne in autumn, in one experiment following a prior light cultivation. The highest production was obtained from barley and oats when left uncut from sowing until early spring. Barley was distinctly superior to oats, ryecorn and Tama ryegrass when two cuts were taken in late winter and early spring. Tama ryegrass and to a lesser extent oats depressed lucerne growth, when they were growing and after their disappearance. Nitrogen doubled the weed content, where there was inadequate competition from overdrilled species.
Six trials were conducted in 1966-68 in which four cereals and two annual ryegrasses were overdrilled into lucerne in the autumn. Cereals were more productive than annual ryegrasses when left uncut until the spring. Nitrogen fertilizer improved the growth of the overdrilled species but also stimulated weed growth where there was inadequate competition from the overdrilled species. To make best use of the productive potential of the overdrilled cereals they should remain ungrazed from sowing until early to mid-spring, but this clearly has to be weighed against other management factors.
KEREKU Station is situated 40 km west of Hastings. The western; boundary adjoins Crown land on the Ruahine Range. It comprises 2429 hectares made up of permanent pasture (1613 ha), Iucerne and grain (79 ha) and gullies (732 ha) .
In a five-year trial, pasture and beef production of a traditional beef system using 6- t o 7-month-old Angus weaner steers and a dairy beef system using 3- to 4-month-old Friesian weaner steers were compared at three stocking rates.
The effects of inoculation and pelleting, with two storage periods, were investigated on the establishment of ‘Grasslands Maku’ Lotus pedunculatus at three sites. When seeds were sown one day after treatment, none of the treatments gave consistently better establishment than inoculationonly, although the addition of gum arabic adhesive alone significantiy increased establishment on one site. However, after 15-day storage of the seed, establishment was higher from gum arabic adhesive alone than from inoculated-only seed although the effect attained significance on only two sites. In contrast, establishment of pelleted seed, apart from rock-phosphate/dolomite on one site, was similar to or less than that from inoculated-only seed. There was a consistent trend for all pelleting treatments to give a lower degree of establishment than did gum arabic adhesive alone. Lotus dry matter production in the second growing season was measured on one site and the importance of maximizing establishment was demonstrated by the marked treatment effects on lotus yield.
ALMOST all the discussions on forest farming to date have centred on the tree establishment stage, or at least the very early years of the stand. This being so new a concept, and with few forests planted on farmed grassland, such emphasis is understandable. However, although tree establishment is an important phase, in the end the system must stand or fall agriculturally by the pastoral production obtained among stands for older, say, 4 years plus, trees. The trees will then be beyond browsing damage and the underlying pastures could supply substantial grazing until canopy closure. How much grazing and for how long are major questions to be answered.
The agronomic performance of the traditional New Zealand herbage cultivars in several overseas countries is reviewed. Preliminary information is also presented on six new cultivars. In comparison with some locally bred cultivars New Zealand types tend to lack winter hardiness and drought tolerance and are more susceptible to some diseases. As more countries develop their own plant breeding programmes, it is likely that New Zealand cultivars will be most useful in areas which have a similar climatic and agricultural pattern to New Zealand. The importance of Plant Breeders Rights legislation in protecting the new cultivars overseas is stressed.
Soldier fly, Inopus rubriceps (Macquart), larvae suck nutrients from the roots of ryegrass, ‘reducing root growth, tiller and foliage production, and probably plant survival. Accurate placement of insecticide with the seed killed larvae, and en’hanced establishment of the seedlings. The use of minimum cultivation, paraquat, and fertilizer sown with the seed, all made larvae move on to the rows of new seedlings thereby improving the efficiency of the insecticide and establishment of the seedlings. This was associated with increased root weights and pasture production. These techniques warrant consideration as alternatives to full surface cultivation and should readily fit into farm undersowing programmes.
It is suggested that methods of stock and pasture management integrated with the farm management programme could reduce both pasture pest populations and their effect on farm stock production.
Farming in Hawke’s Bay is very versatile because of its favourable climate and soils for pasture and horticultural production - hence this paper is rather general. Discussion covers some early history and a brief description of the district, land utilization and production, followed by some brief discussion on developments since the last conference in Hawke’s Bay in 1955, illustrated by titles where applicable. Finally, a brief comment on the future of Hawke’s Bay Cor a farming and horticultural industry.
THE PHOSPHATE CYCLE under grazing and the practical significance of phosphate fixaltion are briefly discussed, as are maintenance requirements of fertilizers, effects on pasture production when fertilizers are not used for one or two years, and finally, liming.
The history and development of Pouto Forest Farm Ltd are outlined. Pouto Forest Farm is a forest farm project on the Pouto Peninsula, which has been in operation for five years on 3200 ha of land, of wh’ich 1890 ha are now planted in radiata pine. Brief consideration is given to the philosophy associated with the setting up of the project and to its prime stated objective, one of environmental betterment. Research and development work being undertaken at Pouto are also briefly outlined.
White clover (Trifolium repens), red clover (T. pratense), subtcrrnnean clover (T. subterraneum) and alsike clover (T. hybridum) were sown singly or in combinations at three sites in Otago. Ryegrass (Lolium perenne) was included in all clover treatments and was also sown alone. Lucerne (Medicago sativa) was sown alone at two sites. Herbage dry matter production was measured over a three-year period. At the high fertility lnvermay site, white and red clovers gave similar total and legume dry matter production and were markedly superior to alsike and subterranean clovers. White and nlsike clovers were most productive at the higher altitude, low fertility Berwick site, and at the dry, medium fertility Dunback site red clover produced the highest yields. Lucerne greatly outyielded all other species in the second and third years at Invermay and in the third year at Dunback.
The need to spell lucerne adequately between cutting or grazing has been clearly demonstrated by numerous workers.
Detailed recordings have been taken at four climate stations within the forest farm plantation at Pouto to study the influence of young Pinus radiuta on the microclimate. This paper gives a brief summary of the results from daily recordings from July 1972 to July 1973, and from June 1974 to June 1975 of wind speed, soil moisture, relative humidity, precipitation, air temperat,ure, and soil temperature. Note is made of the importance of the lowest 2 m of the atmosphere, the zone in which most plants and animals liye. Finally it is pointed out that, by planting trees, the forest farmer is altering his environment and that he must consider the consequent effects.
The problems of managing pasture while establishing a stand of trees in both developed and developing sward are outlined. In particular, the two basic means of pasture control-animals and machines-are examined. Examples of pasture management control and utilization cover the planting, releasing, early thinning and pruning phases up to year 5 at Pouto. Particular reference is made to fertilizing practices, the problems of Kikuyu grass pasture and summer drought conditions.
THE UTILIZATION of plant resistance against insect pests is not a new phenomenon in New Zealand, but until the present decade it has been largely concerned with resistance in horticultural (Lamb, 1953a; Smith et al., 1960; Colttier, 1948), cereal (Marrisen, 1938) and fodder crops(Lamb, 1953b; Palmer, 1956, 1965; Palmer and Smith, 1967).
Spaced plant data on rust and heading are summarized, comparing overseas ryegrass cultivars with those of New Zealand. Relative to ‘Grasslands Ruanui’ perennial ryegrass, most overseas cultivars were equally or more resistant to field infections of rust, and tended to be later heading. Overseas cultivars of annual ryegrasses tended to be earlier heading than ‘Grasslands Paroa’ Italian ryegrass.
Studies were made of the effects of barley grass on young sheep. Up to 8 kg per lamb loss of weight gain during summer has been shown to be due (to barley grass seed damage. Seed in the eyes caused the most rapid growth check but irritation to nostrils, mouth, and skin all contributed. Lambs were affected far more than adult sheep and differences between breeds of sheep were sufficient to consider change of breed where barley grass was troublesome. The beneficial effects and disadvantages of herbicide conmtrol are discussed in relation to density of barley grass infestation.
THE EFFECTS of wind velocity on Trifolium repens L. cv. ‘Grasslands Huia’ white clover seedlings were examined in a wind tunnel. Three experiments were conducted, each at a different wind velocity, in which wind was applied to seedlings at three distinct stages of growth (cotyledons, unifoliate leaf and trifoliate Icaf) for three periods of time (two, four and six days). The wind velocities were 5.0, 7.5 and 10.0 m/s. In all experiments total plant, shoot and root dry weights and shoot/root ratios were determined after 28 days.
The success of grazing within 3 years of planting radiata pine seedlings in pasture is affected by early tree growth rate, class of livestock used, type of pasture available, season, and topography. This early grazing should be with sheep, restricted to autumn and winter in the first 2 years after planting, and must always be associated with cautious stock management. Trials in the central North Island have shown that, during the 3 years after planting, 20, 40, and 80%, respectively, of the full grazing potential can be achieved, with adequate development of the tree crop. Inter-row cropping of hay or silage has been demonstrated with a production loss (in area) of about 8% during the first 3 years rifler planting.
An experiment was conducted within the confines of a practical farming situation. Two treatments were compared: “Control”, where the normal stocking rate was imposed without fertilizer nitrogen, and “Nitrogen”, where a single dressing of urea was combined with a 10% increase in the normal stocking rate. Urea was applied when ewes were set-stocked for lambing, in late winter 1970. Pasture production and animal liveweights were recorded over the ensuing three to four months. Measurements under cage exclosures in the grazed paddocks indicated an overall yield response of 1 820 kg DM/ha (+36%) to the single dressing of 58 kg N/ha. A greater response was recorded from grasses other than ryegrass, than from ryegrass, which constituted 50% of control yield. The N effect declined with time. Responses occurred irrespective of aspect or slope. Similar measurements under cages, where herbage was repeatedly cut and discarded, indicated a smaller response and failed to show residual effects of N. Ewe liveweights showed a greater increase in the Nitrogen group, and lamb liveweights were almost identical between treatments. These results indicate that urea application stimulated pasture growth sufftciently to more than meet the requirements of the additional stock
Studies of the plant-insect relationship of grass grub larvae have highlighted the sensitivity of this insect to changes in the botanical composition of existing pastures, the effect of resistant plants sown as pure species or in mixtures wtih susceptible species, and the intensity of defoliation through the summer months. From these findings it is concluded that agronomic practices offer considerable scope as a component of a pest management programme for grass grub control.
An attempt is made to establish a relationship between herbage utilization, pasture production, and animal performance per unit area. When pastures are rotationally grazed, it appears that the highest pasture yield and animal production per unit area will result only if feed demand is closely matched with supply so that little stubble is left after grazing. Experimental data indicate that the aim should be to achieve at least 60% single grazing utilization of the total herbage on offer as long as in so doing overgrazing does not occur. Future work is likely to show the need for an even greater degree of utilization if per-hectare production is to be maximized. Limited data suggest that overgrazing of ryegrass pastures commences when they are grazed below 2 cm, while with more upright grass species this starts when defoliation is closer than 10 cm.
Historical data on stocking rates and supplementary feed used on the 321 ha farm are given for the years 1970 to,l975. During this period major changes in winter grazing management practices were adopted. Management changes and reasons for thim are described and cost of and labour advantages of these changes; associated with a reduction of supplementary feed, are outlined: It is concluded that increases in stocking rates do not necessarily increase profit since in some instances they cause an increase in supplememary feeding. It is also concluded that the farm could winter l8 stock units/ha provided buying and selling policies were correctly timed and management systems used that can control intakes to the level desired.