Slingsby Cultivation and Nematicide Grower Collaboration Trials

Transcription

1 Final Report Slingsby Cultivation and Nematicide Grower Collaboration Trials Ref: Potato Council KT100 Reporting Period: 2013 Report Author: Matthew Smallwood, SAC Coulting Date report submitted: 18 th November 2013 The Potato Council is a division of the Agriculture and Horticulture Development Board.

2 While the Agriculture and Horticulture Development Board, operating through its Potato Council division, seeks to eure that the information contained within this document is accurate at the time of printing, no warranty is given in respect thereof and, to the maximum extent permitted by law the Agriculture and Horticulture Development Board accepts no liability for loss, damage or injury howsoever caused (including that caused by negligence) or suffered directly or indirectly in relation to information and opinio contained in or omitted from this document. Copyright, Agriculture and Horticulture Development Board No part of this publication may be reproduced in any material form (including by photocopy or storage in any medium by electronic mea) or any copy or adaptation stored, published or distributed (by physical, electronic or other mea) without the prior permission in writing of the Agriculture and Horticulture Development Board, other than by reproduction in an unmodified form for the sole purpose of use as an information resource when the Agriculture and Horticulture Development Board is clearly acknowledged as the source, or in accordance with the provisio of the Copyright, Desig and Patents Act All rights reserved. is a registered trademark of the Agriculture and Horticulture Development Board. is a registered trademark of the Agriculture and Horticulture Development Board, for use by its Potato Council division. All other trademarks, logos and brand names contained in this publication are the trademarks of their respective holders. No rights are granted without the prior written permission of the relevant owners. Additional copies of this report and a list of other publicatio can be obtained from: Publicatio Potato Council Agriculture & Horticulture Development Board Stoneleigh Park Kenilworth Warwickshire CV8 2TL Tel: Fax: publicatio@potato.org.uk Our reports, and lists of publicatio, are also available at 2

3 CONTENTS 1. SUMMARY Aim Methodology Key findings... 4 Practical recommendatio INTRODUCTION Aim 6 3. MATERIALS AND METHODS Cultivation Trials Nematicide trials RESULTS Primary cultivation trial Secondary Cultivatio trial Bed preparation trials Nematicide and in-furrow fungicide interaction trial Nematicide application trial DISCUSSION Cultivatio Primary Cultivatio Secondary cultivatio Bed Preparation Nematicide and in-furrow fungicide interaction Nematicide Application CONCLUSIONS Cultivatio Primary and secondary cultivation Bed Preparation Nematicide trials Nematicide In-furrow fungicide interaction trials Nematicide incorporation trial REFERENCES ACKNOWLEDGEMENTS APPENDICES Field Record Sheepwalk Field Grower Cultivation costings This work has been carried out as part of the Potato Council Knowledge Trafer programme in order to aid levy payer understanding of Potato Council research and other funded R&D. It may include references to data from demotration plots and other media, such as video. The data should be replicated and robust enough to help levy payers with decision making. 3

4 1. SUMMARY 1.1. Aim The Slingsby Potato Collaboration trials aims were: 1. To evaluate and demotrate range of primary, secondary and bed preparation cultivation techniques available to growers prior to planting potatoes in order to increase grower awareness of cultivation issues and enable them to make informed decisio. 2. To further investigate the impact of nematicide and in-furrow fungicides when used alone and in combination, where PCN infestatio are low. 3. To demotrate best practice for application of nematicide to potatoes for PCN control. 4. To generate data to support Potato Council cultivation projects (R444 and R459) and the new industry group, (the Soil Pest management initiative) Methodology Three cultivation trials were established to examine primary, secondary and tertiary (bed preparation) cultivatio on crop growth and development, soil structure, yield and tuber numbers. The cost of the various cultivation treatments applied was also evaluated. Two further trials involving the use of nematicides were designed to examine best practice for application and the interaction between nematicide use and in-furrow fungicide treatment. Effects on crop growth and development, yield and tuber numbers were also assessed. The field used had a quantified level of PCN. All trials were located in two fields, both of a sandy clay loam over limestone soil type. The trials were carried out under commercial conditio and treatments (appendix 9.1) represented those available to growers in NE England Key findings Practical recommendatio Cultivation treatments should be carried out at a depth where the soil is not plastic (i.e. too wet). Thus in the primary cultivation trial, because of wet conditio below the soil surface, shallow ploughing at 23-25cm proved the best treatment, preventing creation of a compaction pan and preventing formation of clods that subsequent passes had to break down. Shallow ploughing was also a lower cost option. Use of min-till, either deep leg/ tine (represented by Shakaerator) or disc and tine (represented by the Sumo Trio) was comparable to ploughing. There was no advantage to a second pass with the Sumo Trio with no yield benefit and the extra cost of the pass not being offset by enough cost saving in subsequent bed preparation. As a second cultivation treatment, use of a Shakaerator deep ridger following a Shakaerator min-till primary cultivation was most cost effective when cultivation cost and yield were taken into account. Using a Tillerstar at this site was more effective where it followed a primary cultivation treatment (ploughing) than used directly into the stubble. Production of a coarser ped size (50mm Unistar destoner) rather than a fine ped size (35mm Uniweb destoner) was more advantageous. The depth of free-working soil under the seed tuber appeared to be a major factor in yield potential and bed preparation to 35cm either by destoning or bed tilling produced the best yields. 4

5 The combination of bed tilling and destoning at 35cm produced a significant pan which reduced yield. Destoning at a shallower depth prevented the pan and increased yield. The nematicide incorporation trial demotrated the benefit in using a nematicide bed tiller for the incorporation of Nematicide (to 15cm depth) compared to incorporation with a conventional bed tiller (to 35cm depth) The nematicide/in-furrow fungicide trial demotrated the potential of the combination to increase marketable tuber number. 5

6 2. INTRODUCTION 2.1. Aim The Slingsby Potato Collaboration trials aims were: 1. To evaluate a demotrate range of primary, secondary and bed preparation cultivation techniques available to growers prior to planting potatoes in order to increase grower awareness of cultivation issues and enable them to make informed decisio. 2. To further investigate the impact of nematicide and in-furrow fungicides when used alone and in combination, where PCN infestatio are low. 3. To demotrate best practice for application of nematicide to potatoes for PCN control. 4. To generate data to support Potato Council cultivation projects (R444 and R459) and the new industry group, (the Soil Pest management initiative). To achieve this, all trials were carried out with commercially available equipment and in commercial potato crops. The trials were designed such that growers could put into practice any of the treatments showing benefit in All the trials at the Slingsby site were replicated so that data from them could be used to support Potato Council cultivation projects (R444 and R459) and the new industry group, (the Soil Pest management initiative). The Trials contained the same treatments that were in the core projects together with other treatments designed to expand knowledge and understanding and identify new areas for future research. Cultivation trials Objectives To evaluate a range of primary cultivation. This includes ploughing, mini-till optio and the George Moate Tillerstar optio available to growers using commercially available machinery To evaluate secondary cultivation optio and deep ridging practices with commercially available machinery. To evaluate bed preparation cultivation. This included evaluating the effects of bed tiller, lifting soil prior to bed tiller use, destoning and clod separation depth and the use of coarse and fine soil finishes with commercially available equipment. Nematicide trials Objectives To demotrate best practice for nematicide application To further investigate the impact of nematicide and in-furrow fungicides when used alone and in combination. 6

7 3. MATERIALS AND METHODS The three cultivation trials set out to examine primary, secondary or tertiary (bed preparation) cultivatio on crop growth and development, soil structure, yield and tuber numbers. The cost of the various cultivation treatments applied was also evaluated. Two trials involving the use of nematicides were designed to examine best practice in application and the interaction between nematicide use and in-furrow fungicide treatment. Effects on crop growth and development, yield and tuber numbers were assessed. The field used had a quantified level of PCN. The trials were located on a block of land rented from Castle Howard by Andrew Wilson and were in two fields, Bakers West and Sheep Walk. (Introduction and trial background Potato Council cultivation and nematicide demotration, Slingsby video 2013) The soil type was a sandy clay loam over limestone with progressively greater clay content at increasing depth. The Bakers West field was generally flat and Sheep Walk field gently sloping. The previous crop was winter wheat from which the straw had been baled. The fields were EC scanned using electromagnetic conductivity by Soil Quest, for soil texture and deep compaction. Mapping identified two main zones and the trials were located in the lighter zone. Fields were PCN mapped using GPS grid sampling by NDSM Ltd Cultivation Trials Cultivation investigatio were split into three trials, relating to primary, secondary and bed preparation (tertiary) cultivation. Primary and secondary cultivation trials were carried out in Bakers West field and the bed preparation trial in the Sheep Walk field. Plots were marked with canes on the stubble using RTK GPS according to the statistical design for the trial. In each trial, three replicate blocks of treatments ran down the field with 12m discard areas between blocks to enabled machinery to move without affecting plots Primary cultivation trial Primary cultivation treatments were designed to investigate some of the optio potato growers experienced when dealing with land which was unploughed in Spring 2013 (Table 3.1). (Primary cultivatio Potato Council demotration, Slingsby Video 2013) Table 3.1. Primary cultivation treatment summary Treatment Cultivation 1 Deep Plough - 13 inch deep (32.5cm) 2 Shallow Plough - 10 inch deep (25cm) 3 McConnel Shakaerator (Close spaced tined subsoiler) (33cm deep) 4 Sumo Trio (subsoiler disc and packer combination) x 1 (33cm deep ) 5 Sumo Trio (subsoiler disc and packer combination) x 2 (33cm deep) 6 George Moate Tillerstar (single bed, 2011/12 model) The trial was laid out in a randomised block design. Plots size was 3 beds (6 drills) wide by 25m long. 7

8 Deep and shallow plough plots were ploughed using a 5 furrow plough set on 14inch (35cm furrow width) using a 200 HP tractor on the 24 th April. The McConnel Shakaerator and Sumo Trio plots were cultivated on 25 th April using the same tractor as for ploughing. The soil was wetter at depth than anticipated, which mirrored the situation in many fields in the Spring of Land was left to dry. On the 1 st May the remaining Tillerstar plots were cultivated directly into stubble using a 2011/12 model single-bed George Moate Tillerstar with approximately 40-50% rotor ware. Apart from Tillerstar treatment (6), all plots were uniformly bed-tiller deep-ridged and de-stoned using a Reekie Speedstar, as per standard farm practice for the field. The field was uniformly planted using seed of the variety Innovator on 3 rd May Secondary cultivation trial This trial set out to examine the effect of secondary cultivation treatments. The trial was laid out in a randomised split-plot design with thee replicate blocks. Primary cultivatio were mainplots and secondary cultivatio sub-plots. (Secondary cultivation Potato Council demotration Slingsby video 2013) Table 3.2. Secondary cultivation trial treatment summary Treatment Primary Cultivation Secondary cultivation 1a Plough Deep ridger 1b McConnel Shakaerator Deep ridger 2a Plough Bed tiller deep ridge combination 2b McConnel Shakaerator Bed tiller deep ridge combination 3a Plough Shakaerator deep ridge combination 3b McConnel Shakaerator Shakaerator deep ridge combination 4a Plough George Moate Tillerstar 4b McConnel Shakaerator George Moate Tillerstar Primary cultivatio created mainplots of 6 beds (12 drills) wide by 25m long. Half of each mainplot received a primary cultivation of deep ploughing and the other half a primary cultivation using a McConnel Shakaerator (as per primary cultivation trial). The ploughing and Shakaerator were thus subplots. This was achieved on the 24 th and 25 th April. On the 1 st May the secondary cultivation treatments were carried out to the whole of a mainplot. These were i). Deep ridging using a ScanStone single-bed deep ridger, ii). a Standen Pearson bed tiller with ScanStone deep ridger combination iii). a Shakaerator and deep ridger combination,iv). the George Moate Tillerstar (as used in the primary cultivation trial). All main plots, except the Tillerstar, were stone and clod separated with a Reekie Speedstar and the whole trial planted as per the primary cultivation trial on 3 rd May Bed preparation trial The whole field was ploughed and cultivated with a McConnel Shakaerator at 45 degrees to the direction of ploughing, prior to deep ridging. The trial was a randomised split plot design with main plots as bed preparation treatments and the sub-plots as course or fine clod/ped size. Main plots were four beds wide by 25m long. These were split into two subplots two beds wide by 25m long. 8

9 All bed preparation treatments were carried out on the 26 th April. Bed tiller plots were tilled with a single bed machine, using a 150 HP tractor with narrow wheels, to a depth of 35cm. The clod and stone separation (destoning) was carried out by either a Uniweb or Unistar clod and stone separator supplied by Standen Pearson pulled by a 200 HP Fendt tractor on narrow wheels. The Uniweb (3 web machine) was set to produce a fine clod size set on 35mm size grading. The Unistar (star separator with underneath web) was set to create a coarse finish being set on 50mm size grade. Thus there were eight sub-plot treatments (Table 3.3). (Bed preparation Potato Council demotration Slingsby video 2013) Depth of the share was set at either 25cm or 35cm. The field was uniformly planted with the variety Innovator on 26 th April according to farm practice. Table 3.3. Bed preparation trial summary Clod and stone separation Treatment Bed tiller Share depth Clods size 1a Yes 35cm Fine 1 1b Yes 35cm Course 2 2a Yes 25cm Fine 1 2b Yes 25cm Course 2 3a No 35cm Fine 1 3b No 35cm Course 2 4a No 25cm Fine 1 4b No 25cm Course 2 1.Clod and stone separation carried out using a Uniweb (35mm size grade) 2.Clod and stone separation carried out using a Unistar (50mm size grade) Cultivation assessments Cultivation costs The cost of each treatment was calculated by taking into account the work rate, man hours, fuel use, depreciation and running costs of the tractor and implement combination used. (Appendix 9.2) Work rates were recorded for each operation in order that if primary and secondary cultivation impacted on the speed of clod and stone separation this would be taken into account. Results were expressed as total cost per hectare and acre for a treatment up to planting. The costs quoted will not be comparable to PCL Benchmark costs Activity related does not cover down time costs Canopy assessments All assessments were made from the centre two ridges of each plot to avoid edge effects. Emergence was scored twice on a weekly basis (as % plants emerged) based on 4 1.5m ridge counts per plot. Canopy cover was assessed every 2-3 weeks as % canopy cover using a grid square held over a representative area of the plot Penetrometer readings & compaction pan Four Penetrometer readings were taken and averaged per plot prior to any irrigation being applied. A Penetrologger was used to record soil resistance values in 9

10 MegaPascals (one recording for each 1cm of depth). Results per plot were then averaged to produce graphs of soil resistance with increasing depth for each treatment. One soil profile pit per plot was dug. Compaction pan depth and rooting depth were assessed visually Yield assessments A 3m test dig was taken from the centre two rows of each plot after desiccation. The yield was size graded as per commercial specification into three size fractio (<45mm, 45-90mm and >90mm) and weight and number of tubers in each size grade were recorded. Results were converted to tonnes per hectare and tubers per hectare. The tuber dry matter of each plot was assessed using a Zeal hydrometer Nematicide trials An area of the Sheep Walk field was selected for Nematicide trials from the GPS PCN testing. The nematicide and in-furrow fungicide interaction trials were located in an area that coistently showed 2 eggs/g for PCN. The nematicide application technique trial was located in the centre of a hot spot with eggs/g of PCN Nematicide and in-furrow fungicide interaction trial Cultivatio were carried out as per the rest of the field. Plots were marked out after destoning and clod separation. The trial was of a split plot design with four replicate blocks. In-furrow fungicide treatments were main plots with nematicide treatments (+/- ) as sub-plots. Main plots were 2 beds (4 drills wide by 30m long). (Fungicide Potato Council demotration Slingsby video 2013) These were split into two 15m long subplots and blocks ran up the field. On the 26 th April Nemathorin 10G 30kg/Ha was applied to nematicide treatment plots as per commercial practice for the field. Nematicide was applied to a depth of 15cm, by the farm nematicide bed tiller. Table 3.4. Nematicide and in-furrow fungicide interaction trial summary Treatment Nematicide In furrow fungicide 1 Untreated Untreated 2 30kg/Ha Untreated 3 Untreated 3.0 l/ha 4 30kg/Ha 3.0 l/ha 5 Untreated 1.5 l/ha 6 30kg/Ha 1.5 l/ha 7 Untreated fluoxastrobin l/ha 8 30kg/Ha fluoxastrobin l/ha The in-furrow fungicide application was carried out at planting on 26 th April with a Techneat applicator with a water volume of 50 l/ha mounted on the farm planter. Nozzles were configured according to industry best practice, onespraying the bottom of the furrow in front of the opener and a second spraying into the rear bow wave of soil without chemical contacting the tuber. 10

11 Nematicide application technique trial After deep ridging,plots were marked out in a randomised block design with a plot size of 15m by four drills (two beds) wide. Blocks ran up the field (Nematicides Potato Council demotration Slingsby video 2013). On the 26 th April 30kg/Ha was applied either using the farms Nematicide bed tiller, after stone and clod separation, or using a single row bed tiller with deep ridging bodies, prior to stone and clod separation. Table 3.5. Nematicide application technique trial summary Treat. Incorporation method Timing Depth Speed Rotor:forward motion A No nematicide B Nematicide bed tiller Prior to destoning 35cm Commercial C Nematicide bed tiller After destoning 15cm 1.5:1.0 D Nematicide bed tiller After destoning 15cm Faster E Nematicide bed tiller After destoning 20cm 1.5:1.0 F Nematicide bed tiller After destoning 20cm Faster Depth and Rotor speed to forward speed ratios were adjusted in treatments C to F. The recommended ratio of 1.5:1.0 was increased to 2.0:1.0 for the faster speed. The different Rotor to forward speed ratios were tested at the recommend depth of 15cm and at 20cm. The Trial was planted on the 26 th April with the variety Innovator as per farm practice Nematicide trial assessments Canopy assessments All assessments were made from the centre two ridges of each plot to avoid any edge effects. Emergence was scored twice on a weekly basis (as % plants emerged) based on 4 1.5m ridge counts per plot. Canopy cover was assessed every 2-3 weeks as % canopy cover assessed using a grid square held over a representative area of the plot Yield assessments A 3m test dig was taken from the centre of each plot after desiccation. Yield was size graded as per commercial specification (<45mm, 45-90mm and >90mm. Weight and number of tubers in each size grade were recorded. Results were converted to tonnes per hectare and tubers per hectare. The tuber dry matter of each plot was assessed using a Zeal hydrometer. 11

12 4. RESULTS Primary cultivation trial Primary cultivation costs Shallow ploughing produced the lowest cultivation costs being 15/Ha less than deep ploughing (Table 4.1). This resulted in reduced ploughing costs but mostly from a reduction in the cost of destoning due to the increased forward speed possible due to a reduction of clod within the bed. Table 4.1 Primary cultivation trial: detail and costs Primary Cultivation Bed till / Deep ridge Stone and clod separation speed Cultivatio Cost ( /ha) Cost ( /acre) Shallow Plough (23-25cm 10inch) 24 th April 1 st May 2.40 kph Plough Bedtill deep ridge Destoner Total Deep Plough (30-32cm 13inch) 24 th April 1 st May 2.00 kph Plough Bed till deep ridge Destoner Total Shakaerator (32-35cm 13-14inch) April 25 th 1 st May 1.90 kph Shakaerator Bed till deep ridge Destoner Total Sumo Trio x 1 (35cm 14inch) 25 th April 1 st May 2.25 kph Sumo Bed till deep ridge Destoner Total Sumo Trio x 2 (35cm 14inch) 25 th April 1 st May 2.60 kph Sumo x 2 Bed till deep ridge Destoner Total George Moate Tillerstar (2012 single bed) 1 st May N/a (Tillerstar 0.70 kph) Tillerstar Total

13 Deep ploughing and Shakaerator resulted in identical cultivation costs, with the saving of the Shakaerator compared to the plough cancelled out by increased destoning costs due to the slower forward speed necessitated by more clods in the bed. The single pass with the Sumo Trio produced fewer clods in the ridge so producing lower costs than the deep plough or the Shakaerator due to the reduced destoner costs. While the second pass with Sumo Trio resulted in a further reduction in clods in the ridge and reduced destoner costs, this did not offset the cost of the extra pass. The Tillerstar, although a one pass operation, did not produce a saving over the deep plough due to the slow work rate of the operation. We should be careful not to quote Tillerstar data out of context, this soil type is probably not suited to the one pass system Canopy development There was no significant difference in emergence between primary cultivation treatments (Fig. 4.1). All treatments reached 100% emergence by the 20 th June. Fig Primary cultivation trial: percentage emergence 12 th and 20 th June 120% 100% 80% 60% 40% 20% 12-Jun 20-Jun 0% There were no significant differences in canopy development in the first 2 weeks between primary cultivation treatments. On the 4 th July the single pass with the Sumo Trio and shallow ploughing had significantly more canopy development than the George Moate Tillerstar into stubble (Fig. 4.2). 13

14 Soil resistance (Megapascals) 20-Jun 27-Jun 04-Jul 11-Jul 18-Jul 25-Jul 01-Aug 08-Aug 15-Aug 22-Aug 29-Aug 05-Sep Fig. 4.2 Primary cultivation trial: canopy development Canopy (%) Shallow Plough Deep Plough Shakaerator Sumo x 1 Sumo x 2 Tillerstar By the 11 th July all cultivatio, except deep ploughing, had developed significantly more canopy than the Tillerstar and all treatments except the Tillerstar had reached full canopy by the end of July. Deep and shallow ploughing plots senesced at the slowest rate. However, this was not significantly different from any other cultivation Primary cultivation penetrometer & compaction pan The Penetrometer data displayed at the demotration event (Fig. 4.3) showed that the soil resistance increased earlier for both the Tillerstar and shallow ploughing. Fig. 4.3 Primary cultivation trial: soil resistance unadjusted Tiller Star Shakaerator Sumo x 2 Sumo x1 Plough Deep Plough shallow soil depth (cm) 14

15 Soil resistance (Megapascals) While poor canopy development and evidence from soil profile pits supported the penetrometer data for the Tillerstar, for shallow ploughing this was not the case. Shallow ploughing had both good canopy development and an absence of obvious compaction pan. Mark Stalham of NIAB recommended that the data was re-examined after the demotration. This was carried out and, in two of the replicates, one out of the 4 readings for each plot was found to have a very early rise in resistance compared to the other 3 readings which were very similar for the shallow plough. This anomaly did not seem to have occurred in other treatments. When these readings were removed from the analysis (Fig. 4.4) the shallow ploughing had the least resistance and this seems to be reflected in both the subsequent compaction pan visual assessments and yield results. Fig. 4.4 Primary cultivation trial: soil resistance adjusted 5.00 Primary Cultivaton Penetrometer Readings Tiller Star Shakaerator Sumo x 2 Sumo x1 Plough Deep Plough shallow soil depth (cm) Visual assessment of the compaction pan (Fig. 4.5) indicated that the Tillerstar had a significantly shallower pan, starting at approx. 25cm, compared to all other cultivatio. This impacted on the rooting depth. The shallow ploughing did not result in a plough pan. In the soil profile pit there was evidence of a potential pan that could have been caused by the tractor wheel running in the furrow bottom but this did not impact on rooting depth. The shallow ploughing produced a significantly greater depth of uncompacted soil than the Shakaerator. However, this was not significantly 15

16 different to the deep ploughing or Sumo Trio plots. As in the case of the Shakaerator, where the tine ran in the soil the compaction pan had been broken and roots did penetrate down into subsoil. However, there were zones in between the tines where the pan was not broken sufficiently to allow rooting to depth. In the case of Sumo Trio both one and two passes resulted in soil being moved and all panning removed to the depth of cultivation thus allowing rooting into the subsoil. There was some visible evidence also in the penetrometer results that a second pass with the Sumo may have marginally increased the soil resistance and reduced rooting deity at a shallower depth. The deep ploughing had resulted in a visible pan in most replicates but there was free rooting to the depth of ploughing. Fig. 4.5 Primary cultivation trial: soil compaction pan depth (cm) LSD (5%) Primary cultivation trial yield and tuber number Shallow ploughing produced the highest marketable yield which was significantly more (12.5 t/ha) than the Tillerstar, which was the lowest yielding treatment (Table 4.2). Other cultivatio were not significantly different to either shallow ploughing or the Tillerstar. There was a trend for shallow ploughing to have more of the premium >90mm yield but this was not significant. There were no other significant differences in yield. There were no significant differences in marketable tuber number (Table 4.3). There was however a trend for shallow ploughing to produce more >90mm tubers although this was not significant. 16

17 Table 4.2. Primary cultivation trial: yield Cultivation treatment <45mm (t/ha) 45-90mm (t/ha) >90mm (t/ha) Marketable (t/ha) Marketable (% of total) Shallow Plough a 95.3 Deep Plough ab 93.2 Shakerator ab 94.9 Sumo Trio x ab 94.1 Sumo Trio x ab 94.7 Tillerstar b 92.6 LSD (5%) Table 4.3. Primary cultivation trial: tuber number Cultivation treatment <45mm (No /Ha) 45-90mm (No /Ha) >90mm (No /Ha) Marketable (No /Ha) Marketable (% total) Shallow 66, ,396 25, , Plough Deep Plough 84, ,084 7, , Shakerator 68, ,812 10, , Sumo Trio x 1 69, ,864 9, , Sumo Trio x 2 65, ,327 17, , Tillerstar 90, ,471 8, , LSD (5%) 32,821 66,557 20,615 58,617 There were no significant differences in dry matter between cultivatio Secondary Cultivatio trial Secondary Cultivation costs The deep ridge only following ploughing and the Tillerstar following the Shakerator produced the lowest cultivation costs (Table 4.4). The slower forward speed of the destoner after Shakaerator compared to the plough, followed by deep ridging, only marginally increased the cultivation cost. Shakaerator deep ridging reduced clods in the bed for both ploughing and Shakaerator primary cultivatio resulting in the same destoner forward speed. This resulted in the Shakaerator having lower costs than after ploughing. The bed tiller deep ridging had the highest cultivation costs. The bed tiller deep ridging enabled the fastest destoning speed which was the same following the plough and Shakaerator but this was iufficient to offset the extra cost of the bed tilling operation. 17

18 Table 4.4. Secondary cultivation trial: details and costs Primary & Secondary Cultivatio Stone and clod separation speed Cultivatio Cost ( /ha) Cost ( /acre) Plough Deep ridge only 1.9 kph Plough Deep ridge Destoner Total Shakaerator Deep ridge only 1.75 kph Shakaerator Deep ridge Destoner Total Plough Shakaerator deep ridge 2.0 kph Plough Shakaerator deep ridge Destoner Total Shakaerator Shakaerator deep ridge 2.0 kph Shakaerator Shakaerator ridge Destoner Total deep Plough Bed till deep ridge 2.4 kph Plough Bed till deep ridge Destoner Total Shakaerator Bed till deep ridge 2.4 kph Shakaerator Bed till deep ridge Destoner Total Plough Tillerstar Tillerstar 1.1 kph Plough Tillerstar Total Shakaerator Tillerstar Tillerstar 1.1 kph Shakaerator Tillerstar Total Canopy Development The crop planted into the bed tiller deep ridge treatments and Shakaerator deep ridge only treatment emerged the fastest and significantly faster than the Tillerstar following the Shakaerator treatment on the 12 th June (Fig. 4.6). There was no significant difference in emergence from ploughing or Shakerator mainplots overall or secondary cultivation treatments. 18

19 Fig. 4.6 Secondary cultivation trial: emergence 12 th June % 60% 50% 40% 30% Plough Shakerator 20% 10% 0% Bed ridge D ridge Sh ridge Tillerstar LSD (5%) = 13% By the 20 th June all treatments had fully emerged. There was no significant difference in canopy development up to 27 th June. On the 4 th July bed tiller deep ridging and Shakaerator deep ridging following both the plough (Fig. 4.7a) and Shakaerator (Fig. 4.7b) had significantly more canopy development than the deep ridge only and Tillerstar following the plough or Shakaerator. By the 11 th July all cultivation treatments, except the Shakaerator followed by deep ridge only, had significantly more canopy than the Tillerstar treatments. The Shakaerator followed by Shakaerator deep ridge and bed tiller deep ridge had significantly more canopy than the Shakaerator followed by deep ridging only. All treatments reached full canopy except for the Tillerstar by the end of July. The deep ridge only combined treatments senesced significantly less on the 13 th August and 6 th September than the bed tiller deep ridge combined treatments. However this was not significantly different from any other treatment. On the 13 th August the bed tiller deep ridge following the plough and Shakaerator had senesced significantly more than deep ridging only following the plough. On the 6 th September bed tiller deep ridging following the Shakaerator had senesced significantly more than the deep ridge only following the plough but was not significantly different to any other treatment. Fig Secondary cultivation trial: canopy development a. Following ploughing 19

20 Canopy (%) P D ridge P Sh ridge P B ridge P Tillerstar 20

21 Canopy (%) b. Following Shakaerator S D ridge S Sh ridge S B ridge S Tillerstar LSD 5% 4 th July 11 th July 13 th Aug 6 th Sept Primary cult Secondary cult Primary x secondary cult Secondary cultivation trial penetrometer and compaction pan results The soil resistance increased slightly faster with depth following the Shakaerator than the plough; reaching 2 Mpa at a 3-5cm shallower depth (Fig. 4.8a & 4.8b). After the Shakaerator (Fig. 4.8a) the Shakaerator deep ridging combination (Sh ridge) produced the lowest soil resistance. The Tillerstar produced the highest levels of resistance with very little difference between the deep ridge only (D ridge) and bed tiller deep ridging combination (B ridge). The Tillerstar reached 2 Mpa resistance on average, 10cm shallower than the Shakaerator deep ridging combination. After ploughing (Fig. 4.8b), increasing the movement of top soil compared to Shakaerator, Shakaerator deep ridging and deep ridging only produced the lowest levels of soil resistance. The rotary cultivation with both bed tiller deep ridging and the Tillerstar resulted in highest level of soil resistance at shallower depths. The bed tiller deep ridging reached 2.5 Mpa, 10cm to 20cm shallower than other treatments. There was no significant difference in visual compaction pan depth when all secondary cultivatio after the plough were compared to those after the Shakaerator (Fig. 4.9). Where treatments following plough and Shakaerator were combined the Shakaerator deep ridged treatment produced a pan starting at a significantly deeper depth than the bed tiller deep ridging treatment. Overall the deep ridging only after ploughing produced the pan starting at the deepest depth. This was significantly deeper than deep ridging only, bed tiller deep ridging and the Tillerstar following the Shakaerator. As with the primary cultivatio, roots were able to penetrate the pan where the Shakaerator tines had run but there were still compacted zones in between the tines. The lack of soil movement also created more clods which were thrown into the trough by the destoner, particularly in the case of deep ridging only. This resulted 21

22 soil resistance (Mpa) soil resistance (Mpa) in a reduction the depth of soil in the bed. The Shakaerator deep ridging combination succeeded in breaking the pan thereby enabling rooting to access the subsoil effectively. It also reduced the amount of clods in the bed, thus increasing final bed depth. After ploughing the bed tiller deep ridging treatment produced a compaction pan at a significantly shallower depth than the Shakaerator deep ridging treatment. Fig Secondary cultivation trial: treatment effect on soil resistance a. After Shakaerator S D ridge S Sh ridge S tillerstar S B ridge soil depth (cm) b. After ploughing P D ridge P Sh ridge P tillerstar P B ridge soil depth (cm) 22

23 Fig Secondary cultivation trial: effect on compaction pan depth (cm) Plough Shakaerator 10 0 B ridge D ridge Sh ridge Tillerstar LSD (5%) Pan depth (cm) Primary cult 5.7 Secondary cult 8.1 Primary x secondary cult Secondary cultivation trial; yield and tuber number When mainplot treatments of plough or Shakaerator were compared, there was no significant difference for marketable yield or yield in any size fraction (Table 4.5). When comparing individual secondary cultivation treatments, the Shakaerator deep ridging following the Shakaerator treatment produced the highest marketable yield, which was significantly more than the Tillerstar following the Shakaerator but was not significantly different to any other treatment. Table 4.5. Secondary cultivation trial: yield Cultivation treatment <45mm (t/ha) 45-90mm (t/ha) >90mm (t/ha) Marketable (t/ha) P D ridge abc 57.3 ab 94.1 S D ridge ab 61.0 ab 94.9 P B ridge bc 57.3 ab 95.1 S B ridge a 63.4 ab 94.4 P Sh ridge ab 58.2 ab 95.0 S Sh ridge abc 64.8 a 95.2 P Tillerstar abc 58.4 ab 94.6 S Tillerstar c 54.9 b 93.4 LSD (5%) Secondary x Primary Secondary Primary Marketable (% of total) 23

24 The Shakaerator followed by bed tiller deep ridge treatment produced the most premium grade yield over 90mm and was significantly more than Shakaerator followed by Tillerstar treatment and the ploughing followed by bed tiller deep ridge treatment. Ploughing followed by Shakaerator deep ridging and Shakaerator followed by deep ridge only, also produced significantly more >90mm yield than Shakaerator followed by Tillerstar. There were no other significant differences in yield in any other size fraction. There was no significant difference in marketable or any size fraction tuber number where the mainplot Shakaerator and plough treatments were compared (Table 4.6). The bed tiller deep ridge (B ridge) and Shakaerator deep ridge (Sh ridge) treatments produced significantly more marketable tubers than deep ridge (D ridge) only but were not significantly different to the Tillerstar treatment. The Shakaerator followed by Shakaerator deep ridging treatment produce the highest number of marketable tubers being significantly more than Shakaerator followed by deep ridge only and also ploughing followed by bed tilling but not significantly different to any other treatments. Plough followed by bed tiller deep ridge had significantly more marketable tubers than the Shakaerator, followed by deep ridging only, but was not significantly different to any other treatment. Table 4.6. Secondary cultivation trial: tuber number Cultivation <45mm (No/Ha) 45-90mm (No/Ha) >90mm (No/Ha) Marketable (No/Ha) P D ridge 75, ,396 ab 17,088 abc 257,228 abc 77.3 S D ridge 74, ,078 b 20,747 ab 253,569 c 77.3 P B ridge 75, ,402 a 9,770 bc 295,281 ab 79.6 S B ridge 101, ,789 ab 23,161 a 282,840 abc 73.6 P Sh ridge 65, ,373 ab 23,161 a 274,425 abc 80.6 S Sh ridge 86, ,645 ab 18,295 abc 298,940 a 77.5 P Tillerstar 77, ,592 ab 15,843 abc 258,691 bc 76.8 S Tillerstar 83, ,084 ab 6,111 c 284,304 abc 77.4 LSD (5%) Secondary x Primary Secondary Primary 39,042 27,589 19,502 45,701 32,309 22,869 12,997 9,188 6,498 39,737 28,101 19,868 Marketable (% of total) The Shakaerator deep ridge treatments had significantly more >90mm tubers than the Tillerstar treatments. The Shakaerator followed by bed tiller deep ridge and plough followed by Shakaerator deep ridge treatments had the highest number of >90mm tubers, being significantly more than plough bed tiller deep ridge and Shakaerator followed by Tillerstar treatments - but they were not significantly different to any other treatment. The Shakaerator followed by deep ridge treatment had significantly more >90mm tubers than Shakaerator followed by Tillerstar treatment. Ploughing followed by bed tiller deep ridge had the highest number of 45-90mm tubers, being significantly more than the Shakaerator, followed by deep ridge only, although this treatment was not significantly different to any other treatment. There was no significant difference between any of the cultivation treatment for tubers <45mm. 24

25 Bed preparation trials Bed preparation cultivation costs There was a 172/ha cost difference between the most expeive bed cultivation treatment (bed tiller followed by 35cm deep fine stone and clod separation), compared to the lowest cost treatment (25cm deep course stone and clod separation) (Table 4.7). In all cases, the coarse stone and clod separation enabled twice the forward speed for any given depth than the fine treatment and therefore had the biggest reduction in total costs. Bed tilling prior to course destoning did not increase destoning speed or reduce the cost of the destoning operation but it increased total costs. Increase in bed preparation depth had a smaller effect on forward speed of the destoner and cost compared to moving from course to fine destoning. The bed tiller did speed up destoning to achieve a fine seed-bed and reduce cost but not sufficiently to offset the cost of the extra operation. Table 4.7. Bed preparation details and operation costs Bed preparation treatments Bed till Course 25cm Bed till Fine 25cm Bed till Course 35cm Bed till Fine 35cm Stone and clod separation speed Total Bed preparation 6.0 kph Bed till Destoner Total 3.0 kph Bed till Destoner Total 5.0 kph Bed till Destoner Total 2.5 kph Bed till Destoner Total Cost ( /ha) Cost ( /acre) Course 25cm 6.0 kph Destoner Fine 25cm 2.5 kph Destoner Course 35cm 4.0 kph Destoner Fine 35cm 2.0 kph Destoner Bed preparation canopy development There were no significant differences in emergence from any of the bed preparation treatments on 3 rd June Fig All treatments had reached full emergence by the 11 th June. 25

26 During early canopy development (20 th June) all the fine clod and stone separated treatments resulted in the canopy expanding slightly (and significantly) faster than the coarse clod and stone separated treatments (Fig. 4.11). These differences had disappeared by the 4 th July and all treatments reached full canopy at the same time after the 11 th July. There was a trend for all the 35cm destoning treatments to senesce faster than the 25cm destoning treatments but this was not significant, due to the variability of senescence (Fig. 4.12). Fig Bed preparation trial: emergence 3 rd June % 60% 50% 40% 30% Course Fine 20% 10% 0% Bed till 25cm Bed till 35cm None 25cm None 35cm LSD (5%) 9.3% Fig Bed preparation trial: canopy cover 20 th June Canopy (%) Course Fine 5 0 LSD (5%) = 1.4% Bed till 25cm Bed till 35cm None 25cm None 35cm 26

27 Canopy (%) Secondary cultivation trial penetrometer and compaction pan results All the treatments had very low levels of soil resistance, Mpa above 30cm (Fig. 4.13). The bed tiller treatments, particularly with 35cm destoner depth, seemed to increase in soil resistance rapidly around 35cm whereas most of destoner only treatments maintained a soil resistance of less than 2.5 Mpa. Where no bed tiller was used and the bed was de-stoned to 35cm there was no visible pan in the cultivation zone with free rooting (Fig. 4.14). This was significantly better than any other treatment. Where bed tilling was combined with destoning at 35cm this resulted in a significant pan at this depth, which did impede rooting. The shallower destoning after bed tilling significantly increased the depth of soil before the cultivation compaction pan was reached. Fig Bed preparation trial: canopy development Bedtill 25 C Bedtill 25 F Bedtill 35 C Bedtill 35 F None 25 C None 25 F None 35 C None 35 F 0 Where the bed tiller was not used, shallower destoning resulted in a pan at a significantly shallower depth than 35cm destoning. There was no significant difference between course and fine destoning treatments. While there were compaction pa present in all cases some rooting was present below the compaction pan with the bed tilling followed by 35cm destoning showing the most reduction in rooting. 27

28 soil resistance (Mpa) Fig Bed preparation trial: soil resistance with depth Bed preparation Penetrometer readings Bedtill 25cmC Bedtill 25cmF Bedtill 35cmC Bedtill 35cmF None 25cmC None 25cmF None 35cmC None 35cmF soil depth (cm) Fig Bed preparation trial: compaction pan depth (cm) Course Fine 10 0 Bed till 25cm Bed till 35cm None 25cm None 35cm LSD (5%) bed preparation x texture = 4.65, bed preparation

29 Bed preparation trial yield and tuber number There was no significant difference between coarse and fine destoning treatments overall either in marketable yield or yield in any size fraction. Where bed tilling was followed by destoning, destoning at 25cm produced significantly more marketable yield than 35cm. However, there was no significant difference between either depths where no bed tilling took place (Table 4.7). Overall, bed tilling followed by destoning to produce a fine texture at 35cm deep produced significantly less (11.3 t/ha) marketable yield than bed tilling followed by destoning at 25cm to produce a course texture. There were no significant differences in yield from any other bed preparation or course or fine destoning treatment. Table 4.7. Bed preparation trial: yield Bed preparation <45mm (t/ha) 45-90mm (t/ha) >90mm (t/ha) Marketable (t/ha) Bed till 35cm Fine b 47.0 b 93.1 Bed till 35cm Course ab 52.2 ab 94.4 Bed till 25cm Fine ab 57.7 ab 94.7 Bed till 25cm Course a 58.3 a 95.7 None 35cm Fine ab 51.3 ab 93.3 None 35cm Course ab 56.0 ab 94.5 None 25cm Fine ab 49.9 ab 93.7 None 25cm Course ab 56.4 ab 93.8 LSD (5%) Bed prep x texture Bed prep Texture Marketable (% of total) Differences in marketable yield could be accounted for by significantly more >90mm yield for the bed tilling and course destoning at 25cm treatment compared with fine destoning at 35cm. There was no significant difference to any other treatment or significant differences in size fraction. There was also no significant difference in marketable tuber numbers between any of the treatments (Table 4.8). In common with yield, bed tilling followed by course destoning at 25cm produced significantly more >90mm tubers than bed tilling followed by fine destoning at 35cm. The increase in >90mm tubers was reflected in significantly less 45-90mm tubers for the bed tilling followed by course destoning at 25cm when compared to no bed tilling and coarse destoning at 35cm; and not significantly different to all other treatments. 29

30 Table 4.8. Bed preparation trial: tuber number Bed preparation <45mm (No/Ha) 45-90mm (No/Ha) >90mm (No/Ha) Marketable (No/Ha) Bed till 35cm Fine 75, ,546 ab 0 b 264, Bed till 35cm Course 73, ,933 ab 13,429 a 252, Bed till 25cm Fine 70, ,864 ab 9,770 ab 281, Bed till 25cm Course 58, ,517 b 15,843 a 246, None 35cm Fine 73, ,766 ab 3,659 ab 274, None 35cm Course 63, ,425 a 6,111 ab 280, None 25cm Fine 72, ,789 ab 4,866 ab 264, None 25cm Course 79, ,130 ab 12,184 ab 268, LSD (5%) Bed prep x texture Bed prep Texture 37,285 26,381 18,661 41,822 29,565 20,929 12,788 9,041 6,392 40,688 28,760 20, Nematicide and in-furrow fungicide interaction trial Nematicide and in furrow fungicide canopy development The 3.0 l/ha with Nemathorin treatment had emerged significantly more on the 3 rd June than the fluoxastrobin + pencycuron treatment (with or without Nemathorin), the 1.5 l/ha rate of Amistar with Nemathorin and the untreated (Fig. 4.15). Fig Nematicide and in-furrow fungicide interaction trial: emergence (%) Marketable (% of total) Jun 11-Jun LSD (5%) fungicide = 5.49 fungicide x nematicide = 7.76 Any initial differences in emergence were small and by the 11 th June all treatments had fully emerged (Fig. 4.16). There was no significant difference in canopy development, or senescence, between any of the treatments. 30