2 SITE SELECTION AND FIELD ACTIVITY, MARCH – OCTOBER 2000
In this section, we report field activity during March – September 2000. This included the following elements:
- Fieldwork on pilot sites
- Site selection
- Monitoring biodiversity
- Collating crop management data
2.1 Fieldwork on pilot study sites
During the period March to September 2000, botanical fieldwork on pilot study sites consisted (a) of first-season sampling of winter OSR and (b) follow-up sampling of sites that had been used for the trial in the previous season. Because the results were not intended for analysis but for protocol development, the emphasis of this effort was on logistics and timing.
There were three pilot study sites of winter oil seed rape that were being used for protocol development. There was a paired field site and a split-field site in Lincolnshire and a paired field site at Hertfordshire. All three sites were sampled for seedlings in the spring (2nd seedling count – post-herbicide). Here we give a summary of the observations that were taken at each. These data are used only to assist in the development and testing of the protocols.
2.1.1 Lincolnshire - Spital-in-the-Street
This was a paired field site. The weed flora, which was assessed on 3rd November, revealed that had been patchy establishment of the GM crop was noted. The conventional crop was treated with a graminicide on 5th October, while Liberty herbicide was applied to the GM crop on 3rd November.
Seedling counts 1 - 3/11/99
Post herbicide 1 veg survey - 26/4/00
Bee + Butterfly - 27/4/00
Gastropod searches - 27/4/00
Gastropod refuge traps - 27/4/00
Vortis - 10/4/00
Pitfall traps - autumn 99, 10-26/4/00, 30/6-14/7/002.1.2 Lincolnshire – Croxby
This was a split-field site. Both the GM and conventional crops were treated with herbicide in November. Vegetation sampling in October showed that there was some slug damage in the GM crop.
Vegetation –29/10/99, (post herbicide veg. Survey) 11/4/00
Pitfall traps – 15/10/99, 11/4/00-26/4/00 1/7/00-16/7/00
Gastropod margin searches 11/4/00
Slug refuge traps 11/4/00
Vortis 15/10/992.1.3Hertfordshire - Hemel Hempstead
This was a paired field site. The conventional crop was treated with a graminicide on 26th November and Liberty herbicide was applied to the GM crop in early February. There was very poor establishment of the GM crop, and the non-GM field was very weedy. Herbage biomass was sampled at the Hemel Hempstead site in July 2000. It was clear that the time of sampling was somewhat too late; many of the weeds had shrivelled and shed their seeds.
Seedling 1 counts 1/11/99
Post herbicide counts
Gastropod refuge traps - 7/6/00, and 23/6/00
Bee + Butterfly - 22/5/00, and 23/6/00
Pitfall traps - autumn 99, 17/5 - 6/6/00, and 6-23/6/0019992.1.4 spring sown sites
Follow-up sampling (weed counts) took place at 3 maize sites, 3 spring oil seed rape sites and one beet site.
We contacted the farmer at Lyng about his two maize fields (the trial on his farm used the two-field design that has now been abandoned in favour of split fields). He told us that the fields had now been put down to grass. We decided that this was such an untypical case that sampling it would serve little purpose in determining the best timing for follow-up sampling. Accordingly, his fields were not revisited.
2.2 Site selection
The objectives for 2000 were to include in the experiment between 12 (a minimum) and 25 (an ideal figure) sites for winter oil seed rape, spring oil seed rape and maize, and an ideal of 30 sites for sugar / fodder beet. These sites needed to represent the diversity of geography, farming intensity and biodiversity resources that should prove typical of any commercial growing of GMHT crops.
Table 2.1 Numbers of field sites, 2000
Maize
Beet
Spring OSR
Winter OSR
Sites considered by SCIMAC
24
60
29
35
Sites entered into the field work programme
16
24
16
25
Sites at harvest time
12
24
12
In general, the site selection process has worked well, and has provided with an appropriate range of geography (Fig 2.1) and farming intensities (Fig 2.2) for our purposes. However, there were fewer sites in the south-west than would have been appropriate for maize, and the numbers of maize and spring rape sites were less than desired.
The distribution of GM field sites for each of the four crops 
Fig 2.1 The distribution of GM field sites for each of the four crops. Red points indicate those sites that were selected to enter the fieldwork programme but subsequently did not take part in the study. The shaded areas indicate the areas where the crops were most frequently grown (data source Countryside Survey 1990, indicates sugar beet, not fodder, and oil seed rape as a single crop).
Data on the properties of the field sites that took part in the study during 2000, as provided by the farmers 
Fig 2.2 Data on the properties of the field sites that took part in the study during 2000, as provided by the farmers. Field size data will be updated using more accurate records, while the biodiversity and intensity self-assessments will be re-appraised in comparison with recorded biodiversity and crop management data.
The programme of field sampling has been presented in previous reports. Each field site is visited on at least one occasion for each of the sampling protocols.
The actual field programme corresponded well with the plans for survey (Table 2.2). However, there were some deviations. There were several reasons:
- different times of sowing and harvest between crops, as they affect the frequency with which bees and butterflies, carabids and seed rain estimates can be collected during the sampling season
- different crop management practices, which particularly affect the need for second and third seedling surveys to investigate weed abundances between and following herbicide treatments
- lost survey opportunities due to inappropriate weather (especially Vortis suction samples, bees and butterflies and gastropods)
Table 2.2. Provisional details of field surveys undertaken on beet, spring oil seed rape (osr) and maize sites during the summer of 2000. Those marked * were not anticipated for all sites. Seedling 2 counts (1) were expected to be more appropriate for beet than other crops.
Protocol
beet
spring osr
maize
Splitting
24
14
15
Layout & context
24
13
14
Margin attributes
24
12
13
Soil seedbank
24
13
14
Gastropod verges 1
24
12
11
Gastropod verges 2
21
11
11
*Gastropod verges 3
1
4
Gastropod crop 1 recover
24
12
12
Gastropod crop 2 recover
24
12
12
Gastropod crop 3 recover
22
11
11
*Gastropod crop 4 recover
15
6
5
*Gastropod crop 5 recover
4
2
2
Seedling 1
24
12
12
1Seedling 2
23
na
na
Seedling 3
19
11
12
Bee & butterfly 1
24
10
11
Bee & butterfly 2
24
12
12
Bee & butterfly 3
24
11
11
Bee & butterfly 4
19
10
7
Bee & butterfly 5
18
6
6
Bee & butterfly 6
18
6
5
Bee & butterfly 7
3
Crop pest 1
24
12
12
Crop pest 2
22
12
12
Crop pest 3
17
10
9
Vortis 1
24
12
12
Vortis 2
19
11
9
Vortis 3
16
9
7
Margins 1
24
12
12
Margins 2
23
12
11
Margins 3
17
10
7
Biomass
24
12
9
Seed rain 1 recover
23
12
10
Seed rain 2 recover
20
9
8
Seed rain 3 recover
19
8
7
Seed rain 4 recover
6
3
2
Seed rain 5 recover
4
0
1
Carabids 1 recover
24
12
11
Carabids 2 recover
24
12
12
Carabids 3 recover
24
12
12
Carabids 4 recover
24
9
10
Carabids 5 recover
2
1
2
2.4 Changes to protocols during the season
The issue of changes to protocols is discussed below. Here we simply note those changes that took place during the season.
2.4.1 Crop assessment
Crop assessments were simplified so that initial density is measured along drill lines and thereafter using quadrats.2.4.2 Margin attributes
Small changes were made to the list of features to be noted at each sampling station. The aim was to ensure that they could be coded up uniformly for entry to the database.2.4.3 Weed seedling counts
The area counted in each quadrat was reduced from 0.25 m² (the area sampled in 1999) to 0.125 m²; crop sampling and cover estimates continued to be for the full 0.25m². This change had already been notified to the SSC. Where weed densities exceed 100 individuals per 0.125 m², surveyors are permitted to make estimates based on one-half or one-quarter of this area.2.4.4 Weed biomass
The main change to weed biomass sampling is that weeds are counted in a standard 0.125 m² quadrat at the same time. It has been found logistically more efficient to sort the vegetation fresh and to freeze plant material only in emergency. Where biomass of weeds is very large, so that the sample from each 1 m² quadrat cannot fit into a single medium-sized bag, surveyors are permitted to sample a smaller area, down to 0.25 m². The need for this is exceptional, but occasional very weedy fields are encountered.2.4.5 Edge vegetation
Sampling intensity for edge vegetation was increased in 2000 to provide estimates of flower availability, presence of seeds and herbicide spray damage. Flowers and herbicide damage were sampled on 3 occasions at each of 9 stations beside each half-field, with separate records for a 10x1m strip in the boundary feature, the verge and the crop margin. Seed presence (3 occasions) and full species enumerations (1 occasion) were made at 3 stations round the field, also recording boundary, verge and crop margin.Crop pests
Crop pests were initially sampled on the basis of presence / absence on 90 plants per half field; this was changed to sampling on a count basis on 45 plants per half-field.2.5 Collecting crop management data
Management data has been collected throughout the season using pro forma recording sheets that rely on farmers sending the appropriate information as necessary. This has been successful in that we obtain the information we need, but not always in a timely way (Section 4.6.15).
2.6 Progress in data collation and validation
Because of the time required to establish data management systems, and delays due to post-sampling processing, such as invertebrate identification, most of the data collected during 2000 have not yet been entered or validated. Priority is being given to the seedling data and seed bank data. These data help describe the initial conditions on the different sites, and to provide data to support re-assessments of protocols. Priority is also being given to beet data, investigating whether there are distinctions between sugar and fodder beet cropping, and any implications for future seasons. We will shift to an ongoing process of data entry and validation, to enable a more rapid analysis of results that can be achieved at the moment.
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Published 2 January 2001
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