Production of potatoes and forage plants

Name: Production of potatoes and forage plants
Topic: Agriculture, forestry, hunting and fishing

Division for Housing, Property, Spatial and Agricultural Statistics

County.

Annual. Preliminary figures will be published in February/March of the year following the crop year, together with final figures for the previous crop year.

Eurostat, FAO.

A data file with anonymous individual data is stored at Statistics Norway.

The purpose of the statistics is to estimate the yield of potatoes, meadows for mowing and coarse fodder in Norway.

The statistics will benefit the industry organizations, the Ministry of Agriculture and Food and various research institutions such as the Norwegian Institute for Agricultural Economic Research.

No external users have access to the statistics and analyses before they are published and accessible simultaneously for all users on ssb.no at 8 am. Prior to this, a minimum of three months' advance notice is given inthe Statistics Release Calendar. This is one of Statistics Norway’s key principles for ensuring that all users are treated equally.

Statistics Act § 10-1.

Agricultural crops include cereal-, potato-, and forage crops. The statistics on cereal crops are based on information from the Delivery Register for cereals and oilseeds in the Norwegian Directorate of Agriculture, and are mentioned on Statistics Norway's website under Cereals and oilseeds - area and crops.

Statistics on yield of potatoes and forage plants are based on information on the yield of these crops obtained by a form-based sample survey. The target population of this survey is holdings referring to these crops when applying for governmental grants on 1 October of the year to which the statistics refer. Agricultural holdings with at least one of the following productions that are part of the population:

• Meadow for mowing and grazing
• Other forage crops
• Potato

Crops from grazing meadows are not included in the statistics, while grazing crops from other fodder are included.

Every year, a sample is drawn from those who apply for production subsidies in agriculture.

From the register of applications for production subsidies in agriculture, information on agricultural holdings will be useful, such as the name and address of the applicant and the area distribution of the various crops. Information on autumn area, crop level and methods for harvesting comes directly from the respondents.

The sample comprises about 2,300 agricultural holdings with one or more of the productions mentioned. The sample is stratified by county, what is grown and the size of the area.

Elecronical forms are sent out in Altinn to the agricultural companies that have been selected to participate in the survey. The survey will be sent out in December, and information will be provided on the crop last growing season. The person who applies for production subsidies on agricultural holdings must report.

A number of controls and corrections are done to ensure consistency both within a single form and between forms and available register information.

On the form, the area is distributed according to the harvestmethod with the stated yield for first mowing and for second mowing and later mowing. The percentage of dry matter in the grass varies over districts and years. In the calculations that are made from reported figures for dry matter, the average dry matter from samples from Tine for the current year and region is used. The dry matter content is registered for grass in round bales, tower silos and flat silos for first and second mowing respectively. The region has 20 divisions that correspond to the county divisions before 2017.

For estimating totals, each unit in the sample gets calculated a weight based on the percentage of units in each stratum in the sample

Figures based on few units (holdings) are not published if this causes risk for identifying any of the units concerned.

The statistics before 2021 are mostly comparable back to 1970. The exception is the yield of meadows for mowing converted into hay , which before 1995 was converted on energy basis to hay, but which since 1995 has been converted via dry matter to hay.

From 2021, yield of meadows for mowing converted to hay have been calculated as kilos dry matter with dry matter percentages (average) taken from feed samples for the relevant year and region. In addition, from 2021, a new method for sampling and weighting for estimating totals have been used. Figures before 2021 are thus not directly comparable with figures from 2021 onwards for yield of meadows for mowing potatoes or other fodder crops.

The new method has resulted in evenly over somewhat higher yields than previous years.

Primary data are obtained from the forms filled in by the respondents. They may contain errors made by the individual respondents when filling in the form. ie the person reporting does not know the exact value that has been asked, the question is misunderstood or the wrong number has been entered. Many of the errors are discovered and corrected in the review in Statistics Norway. The control plan also reveals logical errors in the form. Errors during the collection and processing of the data are unavoidable and include errors that occur during revision, data processing etc. Extensive work has been carried out to reduce these errors as much as possible.

Non-response in the survey is due to the failure of individual respondents to deliver questionnaires or that a property has been sold or is no longer farmed as an independent unit. Normally, the response rate is around 98 percent. There may also be a partial non-response where parts of the form have not been filled in.

Uncertainty from sampling is an expression of the uncertainty one gets because numbers are based on information from a representative sample of agricultural holdings. By calculating a quantity called standard error (s), one gets a measure of how large the uncertainty is. If the standard error is known, one can find an interval that with a certain probability contains the true value of an estimated quantity (the value one would have received if one had made a total count instead of a sample survey). This interval is called the confidence interval. If one calls the estimated value M, for example, the interval with the outer limits M ± 2s with 95 percent probability will contain the true value of the estimate. To get an impression of how large such a 95 percent confidence interval is, one can look at the interval M ± 2s.

It may be expedient to express the standard deviation as part of the estimate itself. The estimate of this part is called the coefficient of variation, and is given as a percentage. The coefficients of variation for 2021 are between 1.1 and 5.5 per cent for national figures that are published. For county numbers, the uncertainty is generally higher and at high values ​​for the uncertain, the numbers are not published.

Table 1: Calculated uncertainties with coefficient of variation, standard error and error margin in a 95 per cent confidence interval for estimated values for country numbers of selected variables in 2021

The scheme for calculating and estimating totals was changed from the crop year 2021.