2007 Comparison of Disc & Tine Implements

• Summary
• Trial aims and design
• Results

Summary
This trial was designed to highlight some commonly asked questions involved in the disc versus tine debate.  It showed that the disc machine was more successful than the tine in getting seeds to germinate and establish, but the depth of sown seed was also important due to the drying conditions around sowing.  Measurements taken up to 35 days after sowing also demonstrated that seeds sown into moisture with good seed-soil contact had greater early vigour than those where moisture was more marginal.  However, drought conditions from mid-August resulted in no harvest data being collected.  The data contrasted to the results from 2006, highlighting the fact that machine set-up is as critical as teh type of machine being used.

Trial Aims and Design

The grain growing community in the central west of NSW is divided over whether disc sowing technology or tine sowing technology is the way of the future for the various soil types, sowing conditions, farming systems and rotations employed in the region.  Subtle differences exist between manufacturers of the two types of machinery.  The GRDC held a light-hearted debate at the Dubbo Update in 2007 to highlight the key issues.  A similar trial in 2006 suggested that the disc machine used was more successful than the tine in getting seeds to germinate and establish, but the depth of sown seed was also important due to the drying conditions around sowing

This project aimed to quantify the performance of the two sowing technologies under zero tillage farming systems. Performance criteria such as establishment percentage, and final yield were to be assessed.

The aim of the field trial was to demonstrate to growers the advantages and disadvantages of disc and tine sowing technologies and their impact on crop establishment and yield.

IMAG Home Page	Summary of IMAG-GRDC Projects	2007 Nitrogen Trial	2007 Disc versus Tine
2007 Precision Planting for Disease Management	2007 Raxil & Dividend Trial	2007 Rust Management Trial	2007 Establishment Trials

The site chosen for the trial was at "Almirica", owned by the Tink family, 25km east of Narromine.  Due to delays in planting the commercial parts of the property (late break), this trial was planted slightly later than desired on the 19th July.

A summary of the main aspects of the trial are as follows:

Sowing Depth
The results of the depth of sowing were as follows (average readings of all counts in both replicates):

        Disc Rep 1:        23mm
        Disc Rep 2:        30mm
        Tine Rep 1:        29mm
        Tine Rep 2:        33mm

These results are not statistically different, allowing direct comparison between the sowing techniques in subsequent analyses.

However, there was a difference in the establishment of plants under each system as well.  The results were as follows:

        Disc Rep 1:        38 plants/m row    (115 plants/m²)
        Disc Rep 2:        42 plants/m row    (127 plants/m²)
        Tine Rep 1:        42 plants/m row    (141 plants/m²)
        Tine Rep 2:        42 plants/m row    (142 plants/m²)

This difference is significant at the 95% level, indicating that the tine machine gave a better plant establishment (in contrast to last years results which showed the disc to be the superior machine at establishing seeds, click here for more details).  This is highlighted when examining the results in the field, with Figure 1 demonstrating the more even establishment under the tine sowing.  Closer examination reveals that the difference appears to be due to some individual disc assemblies not giving consistent establishment along the furrow, leading to gaps in the row (Figure 2).  Other assemblies are giving excellent germination, indicating some inherent differences between the assemblies that needs further investigation.