Results from the Scottish Survey of Agricultural Production Methods, 2010

3 Commentary

3.1 Tillage Methods (Table 1)

More intensive tillage systems, such as conventional ploughing, leave low levels of crop residue cover, whereas reduced tillage methods leave about 30 per cent or more residue cover. These reduce the amount of soil erosion, soil compaction and fuel consumption. Reduced tillage or no-till systems will increase levels of soil organic carbon, and may result in lower direct carbon emissions from the soil.

In 2010 about 960,000hectares of land was cultivated, excluding permanent crops, grassland and crops under cover. The survey asked whether respondents had used inversion tillage or reduced tillage on the area of land sown/cultivated in the twelve months up to March 2010, with data being received for just over 50 per cent of this land. It is not known how much of the remainder used zero tillage rather than providing an incomplete response. From the data provided, just under 90 per cent of land tilled was done so using inversion tillage. The remainder (11 per cent) underwent reduced tillage.

Inversion tillage appeared to be used more on larger holdings (or on larger areas within holdings), being employed at an average of 53.2 hectares per holding compared to 38.9 hectares for reduced tillage.

Chart 1: Area of arable land by tillage method during the past 12 months

Note: Figures are based on a total of 514,347 hectares. Arable land excludes glasshouse crops, permanent crops and permanent grass. More than one form of tillage may be undertaken on a given holding.

3.2 Soil Conservation (Tables 2-3)

Maintaining soil cover over the winter is a practice aimed at reducing soil erosion and the loss of particulate pollutants (e.g. plant protection products and faecal microbes), in addition to contributing to the amount of organic matter in the soil.

The survey asked about coverage of land sown/cultivated over Winter 2009/10, including if the soil had been left bare. Responses accounted for just under half of the potential 960,000hectares of land. Chart 2 provides a breakdown of the reported soil cover methods used. The most widespread cover on cultivable land was autumn/winter crops, which were used on just over half of the area of land employing soil conservation methods, with 15 per cent of land reported as being left bare. Autumn/winter crop coverage was also used most on larger holdings or areas within holdings, averaging at 53.0 hectares per holding.

Chart 2: Area of land sown or cultivated over winter 2009/10 by soil cover method

Note: Figures are based on a total of 463,044 hectares. Excludes glasshouse crops and permanent crops and permanent grass. More than one form of cover may be undertaken on a given holding.

Crop rotation is the practice of alternating annual crops grown on a specific field in a planned pattern or sequence. The proportion of arable land not included in a holding's crop rotation is intended to give an indication of the degree to which monoculture is undertaken. The use of monoculture is also linked to environmental disadvantages and can have adverse effects on the productive capacity of the land.

Chart 3 details the proportions of holdings farming agricultural land which took a share of their agricultural land out of crop rotation. The majority (79.5 per cent) did not take any land out of general crop rotation, and of those that did, about three quarters did so with only 0-25 per cent of their arable land.

Chart 3: Distribution of holdings by percentage of arable land taken out of general crop rotation

Base: 15,595 holdings
Note: Excludes glasshouse crops, permanent crops and grass

3.3 Manure and Slurry (Tables 4-9)

Immediate incorporation of manure and slurry, following application onto fields, can reduce environmentally harmful ammonia emissions and odours and preserves nitrogen in the soil. A threshold of four hours from the time of application to manure and slurry being ploughed in, along with immediate injection of slurry, is used to define immediate incorporation.

Chart 4: Percentage of holdings applying manure and slurry, and on what percentage of their holding.

Base: 33,243 holdings

37.2 per cent of holdings applied manure or slurry to part or all of their land. Almost three times as many holdings applied manure as applied slurry on their holding, although most of those applying slurry also applied manure. Only a small proportion of holdings incorporated some or all of it immediately (14.5 per cent of manure users and 8.6 per cent of slurry users).

Covered storage facilities also reduce ammonia emissions, as well as protecting manure from rainfall. 23.1 per cent of all holdings had storage facilities for solid manure, and about one in ten of these had covered storage. 11.9 per cent of all holdings had storage facilities for slurry, with about half of these having covered storage.

Chart 5: Prevalence of storage methods

Base: 12,130 holdings

64.6 per cent of holdings in the survey had the capacity to produce manure. Table 9 details the distribution of exported manure among these holdings. 5.7 per cent of those holdings with the capacity to produce manure exported some quantity off the holding. In turn, the majority of these holdings (749 or 60.4 per cent) exported over half of their manure.

3.4 Irrigation (Tables 10-12)

Finding suitable sources of water for irrigation is a major problem in many countries in the EU, and is becoming more of an issue in Scotland in some eastern areas. Additionally, inefficient and unplanned use of irrigation can lead to over-wet soils which can affect yields and lead to leaching of nutrients.

Only 1.8 per cent of holdings had undertaken irrigation in the three years up to March 2010. This amounted to 622 holdings irrigating 18,435 hectares of land (an average of 30 hectares for each holding which irrigated its land in the 3 years up to March 2010).

501 holdings (1.5 per cent of all holdings) had undertaken irrigation in the twelve months up to March 2010. This amounts to 8,400 hectares of irrigated land (an average of 17 hectares for each holding which irrigated its land in the twelve months up to March 2010). Information was requested on the types of crops irrigated, water sources used and irrigation methods employed over the previous twelve months. The chart below demonstrates how this area was distributed among various crop types. The majority of irrigated crops were potatoes (74.1 per cent).

Chart 6: Irrigated area (in last twelve months) by type of crop

Base: 501 holdings

Responses were sought on the use of surface (flooding and/or furrows) and sprinkler irrigation methods. Holdings solely irrigating glasshouse crops and crops grown in accessible cover were excluded. 28 per cent of holdings undertaking irrigation employed surface irrigation, while the remaining 72 per cent employed sprinkler irrigation. No holdings reported using both of these methods.

Responses were also sought on the sources of water used for irrigation purposes. Please note that respondents were asked for the main source of irrigation, though some holdings reported more than one source. Holdings solely irrigating glasshouse crops and crops grown in accessible cover were excluded.

Of those who stated the source of their irrigation supply, the majority (52.5 per cent) sourced their water from off-farm surface water. On-farm ground water was the second most prevalent source (20.7 per cent) followed by on-farm surface water (18.4 per cent). The chart below details the use of irrigation sources among holdings.

Chart 7: Number of holdings by source of irrigation water

Base: 501 holdings, but with some holdings reporting more than one source

2.6 per cent of holdings reported the volume of water used on their holding for irrigation purposes (this percentage is larger than that given earlier as it also includes holdings irrigating glasshouse crops and crops grown under accessible cover). 14.1 million m³ were used to irrigate 897 holdings: an average of 15,762m³ per holding per year.

3.5 Landscape Features (Table 13)

The establishment and maintenance of boundaries, particularly trees and hedges, is important for providing a habitat for beneficial wildlife as well as providing shelter and shade for livestock. There are bio-security benefits of having a barrier between fields, and established field boundaries can provide a physical barrier to water movement and leaching from soil and provide a wind barrier to reduce soil erosion of bare soils.

5,616 holdings established some form of boundary on their holding during the preceding three years. Tree lines were the most commonly newly established boundary with 9.6 per cent of holdings establishing tree lines on their holding over the preceding three year period.

Overall 18,183 holdings carried out maintenance on some form of boundary in the preceding three years. Hedges were the most common form of boundary undergoing maintenance, with 37.8 per cent of all holdings maintaining (trimming, replanting, etc.) such features on their holdings over the three year period to March 2010. Data are not available on the proportion of holdings which have such features.

Chart 8: Holdings establishing or maintaining landscape features

3.6 Grazing Livestock (Table 14)

One of the risks to both the sustainability of agriculture and the environment in general in some areas of the EU is that of over-grazing. Under-grazing can also be an issue in Scotland on certain land types where a minimum level of grazing is needed to sustain the habitat for wildlife. Respondents were asked to state the area and the total amount of time cattle and sheep grazed on the holding. Just over 3 million hectares were reported as used for grazing cattle and sheep in the twelve months to March 2010, 70 per cent of all the available grazing land. Table 14 also shows that on average sheep were grazed for 9.9 months whereas cattle were grazed for 7.5 months.

3.7 Cattle Housing (Table 15)

The nature and quality of livestock housing is known to affect productivity, as well as having important animal welfare issues. The type of housing and slurry system used is also very important for determining methane and ammonia emissions.

The chart below covers cattle aged six months and over housed over winter 2009/10. 35.7 per cent of holdings had some form of housing for cattle. The most commonly found system was straw yards with solid manure, with 860,000 places in 9,551 holdings. However these recorded an average of 89.8 places per holding, compared to those holdings with slurry based systems which tended to utilise them on a larger scale, with an average of 144.6 places available for each holding.

Chart 9: Cattle housing places by housing type

Base: 12,022 holdings
Note: Cattle aged 6 months or less are excluded

3.8 Pig Housing (Table 16)

The chart below relates to places for pigs older than four weeks. 3.5 per cent of holdings had housing for such pigs. Straw yards were the most commonplace form of housing, constituting around half of all pig housing places. Though fully slatted floor systems were only found in 83 holdings, these holdings tended to hold more places (1,385 per holding).

Chart 10: Pig housing places by housing type

Base: 1,189

3.9 Poultry Housing (Table 17)

Holdings were asked for the number of laying hens kept in various housing systems. The EU Directive 1999/74/EC on laying hens stated that cage systems must have at least 750cm² of cage area per hen (known as enriched cages). They must also provide a nest, perching space of 15cm per hen, litter to allow pecking and scratching and unrestricted access to a feed trough measuring at least 12cm per hen in the cage. This directive came into force in January 2012. The survey did not request information to distinguish the number of places using enriched cage systems, and it is expected that some producers would have already sought to comply with the directive prior to the 2012 ban. Since the time of this survey in 2010, all cages would now have been converted, though it is likely that the overall total kept in cages has also reduced.

The total number of housing places for laying hens (6.8 million) exceeded the number of laying hens counted in the June 2010 Census (4.6 million). This difference may be due to:-

• respondents possibly supplying the number of housing places for laying hens as opposed to the number of birds.
• respondents possibly supplying data for all poultry as opposed to just those for laying hens.
• the degree of short-term variability in the poultry population, due both to market conditions or particularly where large poultry units reduce the numbers of birds on their holdings for operational reasons such as the cleaning of premises.

9.9% of holdings held housing for poultry. Cages with manure belts for collecting and transporting droppings were the most commonly reported form of housing, with 47.4 per cent of places being this type. Cage systems, specifically those with manure belts, were also the most populous housing systems, with an average of 50,000 poultry held per holding with these systems.

Chart 11: Poultry housing places by housing type

Base: 3,326
Note: Cage figures include both enriched cage systems and those types now banned. Other includes free range and barn/perchery.