Trends of soil degradation: Does the socio-economic status of land owners and land users matter?

Highlights

• Influence of land owner and user characteristics on soil degradation is tested.

• Land user characteristics are more significant than land owner characteristics.

• Large farm size and non-family character of user promote soil degradation.

• Older owners without post-secondary education renting out land promote degradation.

Abstract

Land degradation results from natural and from socio-economic factors. However, the socio-economic factors are less adequately understood than the natural factors. In this study, we focus on the impact of the socio-economic status of land owners and land users on soil degradation trends in the Czech Republic over a period of 14–20 years. The trends were monitored using several indicators: soil porosity, cation exchange capacity (CEC), base saturation (BS), and Cu + Zn levels. We have focused on those characteristics of land owners and land users (76% of the land owners included in the study rent out their land) which can be determined without conducting labour-intensive and relatively expensive demographic surveys, therefore, can be used quite easily in subsequent evaluations, e.g. by land conservation authorities. Generally, the influence of land user characteristics has been shown to be more significant than the influence of land owner characteristics. The most significant degradation-promoting characteristics of land users are large farm size and non-family character of the farm. Degradation-promoting characteristics of land owners include older age, absence of post-secondary education, and renting out of their land. The probability of soil degradation is also marginally increased by the owner’s gender (male) and by greater distance of the owner’s place of residence from the plots studied here.

Introduction

What explains two agricultural areas with very similar natural conditions, yet in one area the soil is degrading, while in the other it is improving? While there is increasing research on land and soil conservation evidenced in recent literature (Collard-Dutilleul and Breger, 2014; Malucelli et al., 2014; Trolard et al., 2016) and in policy (European Commission, 2011; Decoville and Schneider, 2016), many of the processes leading to soil degradation are not yet fully understood. And the extent of soil degradation is influenced not only by the natural (i.e. environmental, biophysical) characteristics of a locality, but also by a number of factors that can collectively be referred to as socio-economic (Lambin et al., 2001; Boardman et al., 2003).

Research has shown the motivation of land owners and land users to promote sustainable use of their land can be affected by a number of socio-economic factors. For example, the effect of individual characteristics of land owners and land ownership on soil degradation has been examined in several studies. Petrzelka et al. (2013) found absentee landowners are less likely than resident owners to be engaged in active management, conservation practices, and decision making on their land. Sklenicka et al. (2015) found tenants (those renting from the landowner) apply erosion control measures on land they rent from absentee owners to a much lesser extent than do those farming their own land. A greater responsibility to the land by operating land owners in comparison with tenant farmers has been confirmed by other studies (e.g. Nowak and Korsching, 1983; Gillis et al., 1992; Hu, 1997; Praneetvatakul et al., 2001). This study takes place in the Czech Republic, where almost 80% of agricultural land in the Czech Republic is farmed by tenants. In this respect, the Czech and Slovak Republics have the highest level among the EU Member States (Eurostat) of alienation of land owners from their land (Sklenicka et al., 2014).

Another factor co-determining farming sustainability is land ownership fragmentation, which, in its extreme form, has been identified as an underlying cause of soil degradation (Sklenicka et al., 2014; Sklenicka, 2016). Other authors explain the sustainability of land owners' behaviour by socio-economic indicators such as occupation, age, income and education (Barbier, 1997; Salmon et al., 2006; Côté et al., 2015), by lifestyle indicators such as habits and personal and family values (Côté et al., 2015; Song et al., 2014), and by social norms or community knowledge (Hoffman and Todd, 2000; Taddese, 2001).

A separate group of studies has focused on the effect of the characteristics of land users on the sustainability of farming practices. Most of these studies have focused on farm characteristics, such as size or income. Tavernier and Tolomeo (2004) found that the operators of farms in lower income brackets (defined by annual sales), valued sustainable farming practices that contribute to soil conservation, such as agroforestry or crop diversification. Similarly, D’Souza and Ikerd (1996); Thompson (1986); Krojerova-Prokesova et al. (2008) and Novotný et al. (2017) have argued that the operators of smaller farms are better stewards of the environment, and use their land less intensively than farmers on a larger scale. However, Liu et al. (2007) found that smaller farm size in Kenya led to maize being grown in rainy seasons in order to maintain sufficient production for the land user’s family, and this in turn led to soil degradation.

When examining various demographic characteristics, researchers suggest a tendency towards sustainable lifestyle/farming by those with a higher education (e.g. Ervin and Ervin, 1982; Skaloš et al., 2015). The authors of these studies consider the main causes behind this phenomenon to be a higher level of consciousness and personal responsibility among more educated people, resulting both from more advanced environmental education and from other influences of further education on their social responsibility and critical thinking. When examining other demographics, Sidibé (2005) found no relationship between the age or wealth of land users and their use of soil conservation practices, while Temesgen et al. (2008) noted that repeated ploughing and cross ploughing, leading to soil degradation, were more frequently practised by more experienced, thus older, farmers. Finally, Boserup (2017) has emphasized that family farms have strong motivation to protect soil in order to pass it on to the next generations in good condition.

The brief discussion above shows some studies have linked selected characteristics of land owners or land users to their preference for, or use of, sustainable farming practices. However, to the best of our knowledge, no previous studies have linked these characteristics to directly-monitored soil degradation or soil conservation trends. Our study is an attempt to start filling this critical gap in the research, with a focus on rented lands.

Soil degradation is defined as a change in the soil health status, resulting in a diminished capacity of the ecosystem to provide goods and services for its beneficiaries (FAO, 2018).

The process of soil degradation is associated with the loss of various aspects of soil quality and soil function - physical, physico-chemical, chemical and biological - which are generally closely connected to each other; a decrease in one function usually affects other characteristics of the soil (Sklenicka et al., 2004). However, the indicators respond differently to different agricultural practices and on different time scales. It is therefore important to select a number of indicators to be able to estimate the full extent of soil degradation (Walmsley and Sklenička, 2017).

Soil porosity is one important indicator of soil quality as it relates to soil structure and of the level of soil compaction. Reduced soil porosity indicates increased compaction, which can be avoided by good timing of operations (i.e. not putting heavy equipment in the field when the ground is wet) and by investing in modern farm equipment, or by remediation operations (direct drilling, subsoil ripping). Soil compaction may also be alleviated by high organic matter content (SOM; Capowiez et al., 2012; Arthur et al., 2013; Défossez et al., 2014). SOM is connected to cation exchange capacity (CEC) – the ability of the soil to bind nutrients. Loss of organic matter generally results in a decrease in negatively-charged binding sites, which will show as a decrease in CEC (Tiessen et al., 1994; MacHmuller et al., 2015). Decreasing CEC may also be related to the loss of clay particles from soils, most often caused by erosion or weathering during intensive agriculture (Jackson and Sherman, 1953; Chichester and Richardson, 1992).

Soil acidification is a second important indicator of soil quality, and a common type of soil degradation in the Czech Republic. In addition to naturally occurring acidification resulting from the leaching of alkalis from the soil by rain, several anthropogenic factors contribute to this process, including; acid rains; acid production by crops due to the use of ammonia-rich fertilizers; use of grain crops (which produce low amounts of basic cations); reduced CEC and washing-out of clay particles from the soil (resulting in reduced buffering capacity of the soil-- (Rowell and Wild, 1985; Helyar and Porter, 1989; Guo et al., 2010)). One indicator of soil acidification is soil pH or base saturation (BS), which expresses how many binding sites of the soil complex are taken up by basic cations, as opposed to acidic cations (mainly H⁺).

Related to soil acidification is presence of Zinc (Zn) and Copper (Cu), important micronutrients in soil. However, the concentration of these metals in soil has been increasing above levels that are useful to plants, as a result of pollution from industry, inorganic fertilizer use, sewage sludge application and the use of animal waste as a fertilizer (Cu and Zn are present in the mineral salts fed to animals (Mantovi et al., 2003; Micó et al., 2006)). Cu is also present in many pesticides (Trewavas, 2001). High concentrations of these metals may negatively affect some soil organisms and in that way have an indirect effect on soil function (Giller et al., 1998; Ciarkowska et al., 2014).

Soil porosity and acidification are affected by both long-term and short-term land management practices (ISPRA, 2018), and are amongst the soil properties that are most strongly detrimentally affected with soil degradation in Europe (Pražan and Dumbrovský, 2010). Using these soil quality indicators, we test selected characteristics of land owners and land users on soil degradation trends, expressed by changes in the indicators. We aim to determine whether it is possible to define two basic archetypes of land owners and land users, with regard to specific characteristics: (1) owners or users whose land follows a degradation trend during the observed period; and (2) owners or users whose land follows a sustainable or improving trend over the observed period.