Descriptive statistics and description of the drought risk survey
Supplement paper: Evaluation of socio-economic factors that determine adoption of climate compatible freshwater supply measures at farm level: a case study in the southwest Netherlands
Jeroen A. Veraart 1,*, Rianne van Duinen 2,3, Jan Vreke1
Representativeness of the sample
To check the representativeness of the sample (141 respondents), the age, education, farm size, farm type and access to an external water supply were compared to those of the population using data from CBS Statistics Netherlands (see figure below). On average, farmers in the sample were slightly younger and better educated than the overall population they represented. Further, farmers above 65 years of age and/or with a low level of professional education are more under-represented in the online survey than in the paper questionnaire. Nevertheless, the differences between the population and the overall sample are small.
In the survey arable farmers (81% compared to 70%) and those who cultivated fruit and flowers were over-represented compared to farmers who cultivate grass and corn (12% compared to 26% of the actual population). The reply rate was thus higher for farm types that are more susceptible for drought (target group GO-FRESH experiments).
In the southwest Netherlands there are about 5500-6000 farms of which 50% arable farming, 12% horticulture and 6% greenhouse horticulture(CBS and LEI 2014) with a total turnover of 1.3 billion euros in 2012 (Visser and Van Tuinen 2012).
Summary survey questions
1: Survey item on protection motivation
This part of the survey is about several measures against water shortage and salinization caused by droughts. We are interested which of the measure you have already adopted and which ones you consider to implement in the future.For each of the adaptation measures, please indicate which statement is applicable to your situation:
- I have already implemented this measure
- I am planning to take this measure within five years
- I have thought about implementing this measure
- I am familiar with this measure
- I am not familiar with this measure
- This measure is not implementable on my farm
2: Descriptive statistics
Variable / Description / Min / Max / Mean / S.D.Level of adaptation motivation / Number of implemented adaptation measures / 0 / 6 / 1.42 / 1.17
Field-scale measures / Adoption of field-scale measures (1 = yes; 0 = otherwise) / 0 / 1 / 0.61 / 0.49
Farm-level measures / Adoption of farm-level measures (1 = yes; 0 = otherwise / 0 / 1 / 0.46 / 0.50
Joint measures / Adoption of joint measures (1 = yes; 0 = otherwise / 0 / 1 / 0.12 / 0.33
Perceived probability / Average chance on a ‘dry year’ and an ‘extreme dry year’ / 2.50 / 58.33 / 22.94 / 11.26
Perceived severity / Average estimate of financial damage due to a ‘dry year’ and an ‘extreme dry’ year (x €100,000) / 0 / 8.5 / 0.54 / 1.01
Perceived control efficacy / Average effectiveness of all adaptation measures / 1 / 7 / 4.28 / 1.41
Perceived control field-scale measures / Average effectiveness of field-scale measures / 1 / 7 / 4.19 / 1.69
Perceived control farm-level measures / Average effectiveness of farm-level measures / 1 / 7 / 4.44 / 1.53
Perceived control joint measures / Average effectiveness of joint measures / 1 / 7 / 4.35 / 1.96
Perceived cost / Average costs of all adaptation measures / 1 / 7 / 4.86 / 1.25
Perceived cost field-scale measures / Average costs of field-scale measures / 1 / 7 / 4.75 / 1.43
Perceived cost farm-level measures / Average costs of farm-level measures / 1 / 7 / 4.94 / 1.52
Perceived cost joint measures / Average costs joint measures / 1 / 7 / 5.04 / 1.76
Perceived self-efficacy / Average of four 7-point items on self-efficacy / 1 / 7 / 3.84 / 1.39
3: Survey items on perceived probability and perceived severity
In a normal year the precipitation deficit during the growing season is approximately 110 mm.1. Imagine an extreme dry year occurs, in which the precipitation deficit is 360 mm at the moment in the growing season crucial for your main crop / 2. Imagine a dry year occurs, in which the precipitation deficit is 220 mm at the moment in the growing season crucial for your main crop.
- How often (once in how many years) do you expect your farm to be exposed to an extreme dry / a dry year?
- In an extreme dry year / a dry year, how much financial damage do you expect for your farm?
4: Survey items on perceived control efficacy and perceived costs
This part of the survey is about several measures against water shortage and salinization caused by droughts. We are interested which of the measure you have already adopted and which ones you consider to implement in the future.Thinking about protecting your farm against drought,
1.How effective do you consider each of the following adaptation measures?
2.How costly do you consider each of the following adaptation measures in terms of time/effort/money?
5: Survey items on perceived self-efficacy and Principle Component Analysis results
To what extent do you trust yourself to be capable to:- Protect the farm against the consequences of drought
- Act correctly the moment a drought occurs
- Take suitable measures
- For farmers like me, it easy to protect my farm against the consequences of water shortage and salinization
6: Details on the adoption of drought adaptation measures
Descriptive statistics of the number of adopted measures show that the majority (75.9%) of farmers has adopted at least one adaptation measure. 0.7% of farmers have adopted more than 4 measures, see table below. The most common adaptation practice among farmers is optimizing the height and distance of drainage which is adopted by 51.1% of farmers, followed by irrigation with 39% adopters. Freshwater injection into deep aquifers and desalination of brackish water has not been adopted by any of the farmers in the sample. These two technologies are in the first place intended for glasshouse horticulture farming and there are very few glasshouse horticulture farmers in the south-west Netherlands. Only two farmers (1.4%) in our sample indicated growing crops in glasshouses, compared to 2.5% of the total population. Furthermore, these farmers both indicated that glasshouse horticulture is not their main activity and that they dedicate only a small percentage of their total area to glasshouse horticulture. Therefore, the probability that one of the respondents would choose this strategy was small and it is not surprising that not one farmer in our sample has adopted this technique.
Adoption of drought risk mitigating strategies
Dependent variable / Categories / Adopted (%)Adaptation motivation / Adopted 0 measures / 24.1
Adopted 1 measure / 33.3
Adopted 2 measures / 24.8
Adopted 3 measures / 13.5
Adopted 4 measures / 3.5
Adopted > 4 measures / 0.7
Adoption of field-scale measures / Optimizing height and distance drainage / 51.1
Automatic water level operated drainage / 2.1
Regulate water level in ditches / 12.8
Drain off brackish percolation water with a deep drain / 2.8
Freshwater storage in basin on parcel / 5.7
Adopted at least one field-scale measure / 61.0
Adoption of farm-level measures / Irrigation / 39.0
Switch to more salt/drought resistant crops / 4.3
Weather insurance / 10.6
Desalinate brackish water / 0.0
Adopted at least one farm-level measures / 46.1
Adoption of joint measures / Freshwater extraction from creek or sand-ridges / 5.0
Freshwater extraction from phreatic aquifers / 8.5
Freshwater injection into deep aquifers / 0.0
Adopted at least one joint measure / 12.1
Additional information:
Duinen Rv, Filatova T, Geurts P, Veen Avd (2015) Empirical Analysis of Farmers' Drought Risk Perception: Objective Factors, Personal Circumstances, and Social Influence. Risk Analysis 35 (4):741-755. doi:10.1111/risa.12299
The Dutch version of the survey is available on request. Contact Rianne van Duinen.
Email:
We have elaborated on the descriptive statistics in the paper In addition we refer to a paper with more descriptive information and we have developed a supplement.
Concerned paper: