C. J. Baker

Comparison of tillage methods on red clover and ryegrass establishment and production under grazing in the establishment year

Abstract ‘Grasslands Pawera’ red clover (Trifolium pratense L.) was drilled into perennial ryegrass (Lolium perenne L.)-white clover (Trifolium repens L.)-dominant pasture in autumn and spring. A prototype drill equipped with a chisel coulter and band spray mechanism was used. At both dates Pawera was drilled into a cultivated seed bed, oversown or overdrilled into an undisturbed sward, and overdrilled into paraquat-sprayed bands. Effects of captan, phorate, methiocarb, and urea on red clover establishment were studied with autumn drilling. Spring drilling included blanket applications of paraquat and glyphosate and overdrilling of Pawera alone or with ‘Grasslands Nui’ perennial ryegrass. Sown plant survival and development, pasture production, and composition were evaluated under sheep grazing. After full cultivation, recovery of pasture production and red clover seedling development were more rapid for spring than autumn sowing. Compared to untreated pasture full cultivation reduced the establishment ye...

Some effects of cover, seed size, and soil moisture status on establishment of seedlings by direct drilling

Abstract The amount and nature of cover over seeds direct drilled into dead turf depends on the shape of the furrow openers or coulters, as well as the covering device. In a field experiment sown with hoe coulters the importance of bar harrowing to cover large seeds, such as maize and barley, was demonstrated in terms of seedling emergence, but little or no advantage was apparent from harrowing smaller, lucerne seeds. Coulters and covering devices were laboratory tested under continuous soil moisture stress using a tillage bin technique. This confirmed the advantage of bar harrowing after passage of both the hoe coulters and experimental chisel coulters.

Developments with seed drill coulters for direct drilling

Abstract When overdrilling into established pasture, the application of paraquat plus dicamba, or glyphosate, sprayed simultaneously in bands on the drilled rows, was both a feasible and an effective way of suppressing competition from resident plant species. Pilot experiments highlighted the need for precise control of nozzle height and suggested preferences for placement of the nozzles in relation to both chisel and triple disc coulter assemblies. Experiments in the Bay of Plenty, Waikato, and Manawatu on paspalum-, browntop-, and clover-dominant swards suggested that in all these pastures, paraquat + dicamba produced a more rapid and complete suppression of resident vegetation within the bands than did glyphosate. Both herbicides applied in bands were better than not spraying, but suffered in the longer term in comparison with blanket spraying. In the Waikato there was an advantage with paraquat using a chisel coulter assembly in comparison with a triple disc coulter assembly but no logical explanation...

A mechanism to regulate winged coulter depth and overdrilled seed spacing in field experiments

Abstract A mechanism capable of holding a coulter at specified depths in soil is described. Rolling, positive depth regulation is pivoted over the leading point of the lateral wings of the coulter on a common walking beam axle. This places depth sensing as close as possible to the point on the coulter most influencing groove depth, without interfering with groove formation or applied herbicide. The coulter is raised or lowered in a shaft to produce the desired depths. Results are presented illustrating the ability of this design to maintain groove depth despite changes in surface contour. A hand-loaded seeder which can be incorporated into the unit is also described and evaluated. Seed is released from regularly spaced holes in a slide immediately over the coulter seed tube, resulting in very low seed delivery error.

Comparisons of reduced time and energy seedbed preparation systems: year 1

Abstract Reduced time and energy seedbed preparation methods were compared with conventional ploughing methods. Maize was sown in the spring followed by winter oats. Cultivation techniques were studied by comparing crop yields from each treatment over identical growth periods. Systems of cultivation were also studied, comparing yields obtained for a full cycle of growth from sowing to sowing thereby allowing for any short fallow period which was an essential part of the conventional ploughing treatments. Total annual yields were also compared. Once-over, directdrilled, and conventional fallow tillage techniques gave similar maize dry matter yields, all significantly greater than minimum tillage or rotary cultivated techniques. Oats yields showed no difference. On comparing systems, the direct-drilled, once-over, and rotary-cultivated treatments gave highest maize yields. Highest oats yields were obtained from the once-over and minimum tillage systems. Fallow tillage systems gave least yields of both crops...

III. An improved chisel coulter with trash handling and fertiliser placement capabilities

Abstract A redeveloped direct drilling chisel coulter is described. The new version has retained the agronomically desirable features displayed by its original experimental counterpart, particularly when operating in dry soil or climatic conditions. In addition the new coulter has much better trash handling ability, separate seed and fertiliser placement, covering and depth control, wear characteristics, and maintenance. The device also operates well in cultivated soil and gives the impression that in these conditions, seed placement is little different from that commonly attributed to precision unit drills, particularly for depth control and the press wheel covering action/and soil-seed contact. Simultaneous band or blanket spraying are now more simple possibilities, as nozzles can be mounted immediately behind the press wheels. Draft requirements have been increased substantially compared with triple disc coulter assemblies and the original experimental chisel coulter assembly, and there is some doubt a...

Production from a drought-prone Northland pasture direct drilled with 3 grass cultivars

Abstract A ryegrass/white clover dairy pasture on a volcanic soil was direct drilled with ‘Grasslands Nui’ perennial ryegrass (Lolium perenne L.) (15 kg/ha), ‘Grasslands Matua’ prairie grass (Bromus catharticus Vahl.) (40 kg/ha), and ‘Grasslands Mara’ phalaris (Phalaris aquatica L.) (20 kg/ha) 3 days after the break of a 15-week drought. Seeds were drilled into 25 mm bands sprayed with either paraquat (0.22 kg a.i./ha) or glyphosate (2.88 kg a.i./ha), or into unsprayed pasture. Both herbicides reduced the growth of resident pasture within the sprayed bands, but Maru was the only sown species with a higher tiller density in sprayed than in unsprayed treatments after 28 days. Band sprayed herbicides had no effect on DM production of mown pasture in each of 2 years. Matua-sown pastures yielded 14% more DM than unsown control pasture, but Nui and Maru pastures had no significant effect on annual production.

I. Trash handling properties of coulters

Abstract To extend the range of surface conditions under which an experimental non-rolling direct drilling coulter could operate, several trash clearance modifications were evaluated. The emphasis of the modifications was on cutting, deflecting, and/or holding several different classes of trash. At the same time, the agronomically desirable characteristics of groove formation and seed placement were retained. Although all the modifications were of limited value by themselves, a number of important principles were demonstrated with regard to the interrelationship of rolling and non-rolling components. Trash could not be cleared with non-rolling components, spaced 150 mm apart, in a wide range of conditions unless these components were in at least partial and intimate contact with accompanying discs. Also discs could not be relied on to cut all trash, but a proportion of trash could be expected to deflected rather than cut. These principles suggested several avenues of development for future coulter designs...

Tractor fuel requirements of two tillage systems and zero-tillage

Abstract The relative amounts of fuel used in 3 seedbed preparation and crop establishment systems were measured over a spring-summer-autumn period on 2 trial sites. The 3 tillage systems studied were: (i) Traditional cultivation based on mouldboard ploughing, rolling, disc and tine harrowing, and “levelling”, (ii) Rotary cultivating, rolling, and “levelling”, (iii) Zero-tillage or direct-drilling. Data from the 2 trial sites showed that the net fuel consumption (excluding tractor rolling resistance) for zero-tilled treatments was consistently and significantly less (P = 0.01) than that of the rotary cultivated treatments, which themselves had a similar advantage over the traditional “ploughing etc.” treatments. Consumption did not include the fuel requirements of weed control, which varied between treatments, but which were in all treatments only small.

II. Wear characteristics of an experimental chisel coulter

Abstract The wear rate typical of soil engaging tools is especially pronounced in direct drill coulters. Several examples of an experimental non-rolling coulter which had shown agronomic promise (especially in dry untilled soils) were subjected to a range of arc welded hard facing treatments. Differences in measured wear rates between treatments were substantial in field operation, but few clear trends were apparent and correlation coefficients between wear rates and hardness values were surprisingly weak. Visual observations, however, suggested that wear patterns had occurred in a manner not easily characterised by weight measurements alone. Measured wear rates of coulters tracking in the tractor wheel marks and those not doing so were similar.