Farm Business Survey 2021-22: Farm level emissions and nitrogen usage: Methodology

The Farm Business Survey (FBS)

More detailed methodology and quality information about data collected in the FBS and its headline measure of income, namely Farm Business Income (FBI), is available in Scottish farm business income (FBI) - gov.scot (www.gov.scot).

The FBS results are obtained from a sample of farms that are stratified by farm type and economic size. The survey does not include farms predominantly engaged in horticulture, poultry, egg production or pig production. The coverage of the survey is restricted to farms with considerable economic activity (at least €25,000 of output, equivalent to approximately £20,000) that are not considered spare-time farms (have a Standard Labour Requirement [1] (SLR) of more than 0.5).

An important feature of the survey is the measurement of changes over time for particular types of farm. To achieve this, it is necessary to maintain farms in the sample surveyed over a number of years. The survey is effectively a panel survey with little change in the membership of the sample between years.

The survey is not carried out on a calendar-year basis but based on individual businesses’ accounting year ends which all centre on the same cropping period and on average roughly align with the financial accounting year. For example, 2021-22 data is for the 2021-22 accounting year and relates to the 2021 crop year.

Industry coverage and limitations for emission estimates

The FBS is designed to provide good coverage of the majority of economic output from supported sectors of agriculture.

The FBS is representative of around 11,000 farms in Scotland, which is around 21% of all farms included in the June Agricultural Census. These farms cover 64% of Scotland's agricultural land, employ 46% of those employed in Scottish farming, and produce 95% of standard output from the farming sectors that are included in the FBS.

Data from the June Agricultural Census are used to weight the farm business income estimates. A calibrated weighting method sums the following variables to equal the estimated population totals:

• type of farm
• tenure type of farm
• area of barley
• area of oats
• area of potatoes
• area of wheat
• rented area of land
• total area of farm
• number of dairy cows
• number of beef cows
• number of ewes

Classification of Farms

The classification is based on detailed sub-types as defined in the European Commission (EC) farm typology, which have been grouped together where required to give the types shown below.

The classification is based on the relative importance of the various crop and livestock enterprises on each farm assessed in terms of standard output. The method of classifying each farm is to multiply the area of each crop (other than forage) and the average number of each category of livestock by the appropriate standard output, with the largest source of output determining the type of farm. The table below defines the main types that are reported in the FBS and groupings applied to present emissions and nitrogen use data.

Table 1: Main farm types reported in the Farm Business Survey and groupings applied to present emissions and nitrogen use data