Summer Fallow: Seed Mixtures for Manuka Burns

New Zealand Journal of Agriculture, Volume 87, Issue 6, 15 December 1953, Page 541

Summer Fallow: Seed Mixtures for Manuka Burns

Seasonal Notes by the Extension Division

CULTIVATION

CUMMER fallowing before autumn sowing of pastures is now a fairly common practice, as it enables the seeds mixture to be sown on a firm, moist, and warm seed-bed. Early autumn sowing allows quick establishment of grasses and clovers and the first feeding off of the pasture to be carried out before the land becomes really wet in the winter.

A fundamental principle to observe in summer fallowing is to complete all deep working as early in the season as

possible while soil moisture is plentiful. Subsequent cultivation should be confined to surface working with roller and harrows, a loose tilth being left at all times on the top inch or so to prevent excessive moisture loss. A rolled surface will lose more moisture than a harrowed one. Obviously it is impossible to eliminate all weeds to the full depth of the plough sole, so efforts should be directed toward destroying those likely to compete with the subsequent pasture, namely, those in the top 2in. The aim should be to provide a seed-bed in which they can germinate and then to kill each successive strike with a timely stroke of the harrows. A cultivation programme based on these principles will result in an effective fallow.

TWITCH CONTROL

In direct contrast to a fallow before pasture establishment, a twitch control fallow Should aim at drying out the soil as thoroughly as possible. Repeated exposure to sun and wind

is the only effective means of achieving this. If the ground is rough and lumpy, a greater area is exposed than if it is fine and compact. The problem is therefore to work the ground often and yet keep it rough. The plough is the one implement capable of doing this and is therefore the most suitable for twitch control. The recommended practice is to plough as often as possible, the previous finishes being struck down each time. In this way the furrow is rolled back and forth, first one side and then the other being exposed to the sun. The first. ploughing should be comparatively shallow, as each subsequent ploughing inevitably goes a little deeper. Repeated working is necessary before the furrow is thoroughly dried. M. S. FOREMAN [A description of. the chemical control of twitch is given on page 520.]

* SEED MIXTURES FOR MANUKA BURNS

* * WITH the more general use of phosphatic fertilisers on hill country more reliance is now being placed on regrassing

manuka burns with perennial ryegrass and clovers. Manuka burns should be sown immediately after the burn with a suitable seed mixture, together with 3cwt. of phosphatic fertiliser. The phosphate topdressing is just as important as sowing the seed, because usually manuka initially enters the sward because of lack of phosphate, a lack which manifests itself in a weak and open pasture which offers little resistance to the ingress of manuka. If a liberal dressing of phosphate is not applied, it is reasonably certain that the burn will go back into manuka after a few seasons. In selection of the seed mixture attention should be paid first to species of grasses and clovers that are most suitable to the location and second to the quality of the seed. The emphasis in sowing manuka burns should be on the clover, and a very liberal sowing of the clover species should always be made. White clover is the best of the clovers and where conditions suit it this should be made the dominant clover in the mixture. The grasses, particularly browntop and danthonia, re-establish to some extent after the burn because the fire is seldom hot enough to kill them. On light manuka burns where danthonia and browntop are present it is unnecessary to sow further seed of these species.

LOTUS MAJOR

In the higher-rainfall areas Lotus major should be relied on as the main legume in the seeds mixture. A suitable mixture

WHITE AND SUBTERRANEAN CLOVERS

is Permanent Pasture perennial ryegrass 101 b., crested dogstail 41b., Yorkshire fog 21b., Lotus major 11b., and Permanent Pasture white clover 11b. . -

Over most of the North Island hill country white clover can be relied on to provide a good cover if it is regularly topdressed. A suitable mixture

is Permanent Pasture perennial ryegrass 101 b., crested dogstail 41b., Yorkshire fog 21b., and Permanent Pasture white clover 31b. On hill country where conditions are too dry for perennial clover subterranean clover should be used as the main legume, and even on the wetter country it is often advisable to include it in the mixture. A suitable mixture for drier country is: Permanent Pasture perennial ryegrass 51b., Danthonia pilosa 41b., Permanent Pasture cocksfoot 61b., subterranean clover 41b., and suckling clover lib. The Permanent Pasture grade of Certified seed is quite satisfactory for sowing on burns. A. A. DUNCAN

HARVESTING SUBTERRANEAN CLOVER SEED

SUBTERRANEAN CLOVER is not an easy crop to harvest, for it either buries its seed burrs in the soil or covers them completely with a mass of herbage. Harvesting is simplified

if a heavy growth of pure clover herbage is present, as most of the burrs are then held above ground level. Whether or not all burrs remain above ground level, they are always well under cover, and if adverse weather prevails after . maturity is reached, the seed is kept moist and germinates readily. A normally dry summer and early autumn ensure reasonable chances of success. The most common method of harvesting subterranean clover seed is by use of the dump-type hay rake without any prior mowing. This method can be used under most circumstances, though it is unsuited to paddocks where surface stones would be dislodged by the rake. The implement used is the old type of dump rake with stiff tines. The clover is allowed to become dead ripe and harvesting is normally carried out in January or February before the onset of the autumn rains. Best results are obtained from raking when the herbage is moist with dew or light rain. This temporarily toughens the fragile stems bearing the seed heads and any burrs having a loose hold on the soil are dragged out. The material is raked into windrows and is then allowed to dry out thoroughly before being threshed with the header harvester or clover huller. As the seed is fairly difficult to dislodge from the burrs, a period in stack facilitates threshing. >

The correct degree of moisture to have in the herbage before raking can be judged only from experience. Just sufficient to toughen the stems is required. If the herbage is excessively moist when it is raked, a protracted drying period in the windrow is necessary. Some farmers carry out the operation when the crop is quite dry, and though seed losses are greater under these circumstances, yields can still be quite satisfactory. When herbage growth is very heavy the crop may be cut with an ordinary mower with or without lifting fingers attached. Use of these fingers results in fewer burrs being detached from the stems. Dew or other light moisture on the herbage at cutting time strengthens the tiny stems bearing, the burrs and so prevents , loss of seed. The crop may be threshed either from the swath or after stacking. A header harvester or clover huller is used, the material normally being put through twice. Direct heading is feasible when a good heavy mat of herbage is present and if the crop is dead ripe and dry and the passage of the header harvester very slow. Lifting fingers are attached to the cutter bar and the herbage is drawn into the drum in a continuous mat.

—J. P. BEGGS