Afforestation Of Arable Land Research Articles

Integrated assessment of the impact of land use changes on groundwater recharge and groundwater level in the Drava floodplain, Hungary

Land-use/land-cover (LULC) change is considered a key human factor influencing groundwater recharge in floodplains. Without accurate estimations, the impact of LULC change on water balance components may be either significantly understated or exaggerated. This paper assesses the impacts of LULC changes from 1990 to 2018 on water balance components and groundwater levels of the Drava floodplain, Hungary, where human interference has led to a critical environmental situation. In this study, a spatially-distributed water balance model (WetSpass-M), and a groundwater flow model (MODFLOW-NWT) were integrated to assess the impacts of LULC changes. The moderate expansion of built-up areas increased surface runoff, while the afforestation of arable land and meadows and the overgrowth of bare mudflats with willow shrubs increased evapotranspiration. As a consequence, total annual groundwater recharge decreased by 5.3 × 107 m3 in the floodplain with an average of 335 mm year−1 and 317 mm year−1 in 2012 and 2018, respectively. Moreover, an average groundwater level decline by 0.1 m is observed in the same period. Declined groundwater recharge, increased runoff, and evapotranspiration exerted a negative effect on water resources in the Drava basin. The approach tested in this paper allows temporal and spatial estimation of hydrological components under the changes of LULC, providing quantitative information for decision-makers and stakeholders to implement efficient and sustainable management of water resources in the Drava floodplain. The provided integrated model is also applicable to regionally.

Soil carbon stock assessment using depth and spatial models on afforested arable lands

The change from grasslands and natural shrubs to afforested arable land has a major impact on soil organic carbon (SOC) stocks. Grasslands are known to be SOC sinks as seen in the Chernozems of North America, Eurasia and South Africa. However, determining the SOC stocks of soils can be financially costly as each location must be sampled in depth increments. This study aimed to estimate the SOC stocks for the Mvoti catchment (30° 48′ E and 29° 18′ S) in Kwa-Zulu Natal, South Africa by developing depth functions on a limited number of soil samples and expanding these functions to known land-uses and soil types. The results showed that splines captured the short-term vertical distribution of SOC better than exponential decay functions, which has major implications on arable lands. Long-term forest plantations showed a positive correlation with SOC stocks (32.7 kg m−2), while annual crop cultivation (27.0 kg m−2) showed a negative correlation when compared to natural grasslands (28.8 kg m−2). The Cubist algorithm predicted the total SOC stock of the catchment area at between 12 248 and 17 624 Mg depending on the depth function used. Soils with yellow-brown subsoils tend to have higher SOC stocks and the lowest degree of uncertainty.

Temperature sensitivity of soil carbon decomposition due to shifts in soil extracellular enzymes after afforestation

Afforestation of arable land has been proposed as one of the most effective strategies for climate change mitigation. However, the effects of afforestation on soil CO2 emissions have not been well investigated due to a lack of information on the capacity of carbon pools to sequester CO2 over the long term. In this study, we conducted a 414-day incubation experiment to monitor changes in CO2 emission, soil extracellular enzymes, and microbial biomass at soils collected from a site afforested with R. pseudoacacia L and an adjacent cropland system under 15 °C and 25 °C constant temperatures. The study was to reveal how soil organic carbon decomposed under different temperatures during incubation along an afforestation gradient. Our results showed that: 1) after warming, active pool respiration increased from 0.64% to 12.57%, passive pool respiration increased from 20.62% to 46.77%, and slow pool respiration decreased from 21.27% to 59.35% for cropland to afforested land; 2) active and slow carbon pool increased in young and middle-aged afforested lands while the passive carbon pool increased in the late stage; and 3) microbial biomass and enzyme activities affected the respiration rate and the fraction of respiration during warming, especially enzyme affected active and slow pools. Our findings indicate that the temperature sensitivity of soil organic carbon decomposition changed mainly due to shifts of soil extracellular enzymes after afforestation, and provides insight into how SOC decomposition in afforested ecosystems may respond to future changes in climate.

Understanding soil carbon sequestration following the afforestation of former arable land by physical fractionation

To determine soil organic carbon (SOC) sequestration and storage mechanisms following the afforestation of arable land, soil samples were collected from a depth of 0–100cm from cropland as well as six hippophae (Hippophae rhamnoides) and robinia (Robinia pseudoacacia) stands, which represented two afforestation chronosequences that were converted from arable land 13 and 39yrs ago, respectively, in the Loess Hilly Region of China. The SOC in the whole soil profile was separated into four specific size/density fractions: coarse free (cf) particulate organic carbon (POC) inter-macroaggregates (>250μm), fine free POC (ffPOC) inter-microaggregates ?thyc=5?> (53–250μm), intra–microaggregate POC (iPOC) and mineral–associated organic carbon (MOC) in silt+clay (<53μm). The concentrations of SOC in the whole soil profile and its fractions under robinia stands were generally on the order of 39yrs>25yrs>13yrs, whereas under the hippophae stands, the order was 38yrs=28yrs>13yrs. The concentrations of SOC in all of the fractions in each soil layer were significantly higher under afforested stands relative to cropland, especially in the topsoil layer (0–10cm). At a soil depth of 0–100cm, the SOC sequestration rates in the fractions under robinia over 39yrs were ranked on the order of MOC (0.94MgCha−1yr−1)>iPOC (0.41MgCha−1yr−1)>cfPOC (0.35MgCha−1yr−1)>ffPOC (0.12MgCha−1yr−1), whereas the order under hippophae over 38yrs was MOC (0.27MgCha−1yr−1)>cfPOC (0.18MgCha−1yr−1)>ffPOC (0.09MgCha−1yr−1)=iPOC (0.07MgCha−1yr−1). Furthermore, MOC accounted for 47.0% and 52.1% of SOC sequestration under hippophae 38yrs after afforestation and under robinia 39yrs after afforestation, respectively. Our results indicate that the afforestation of former arable land with robinia and hippophae in the loess hilly gully region could greatly increase SOC sequestration in all four fractions, especially the MOC.

Afforestation of rural land in greece: a multinomial logistic regression analysis of driving factors

This article deals with the importance of European Agricultural Fund for Rural Development through the implementation of afforestation schemes in rural communities. The main aim of the article is to investigate the spatial patterns of afforestation in Greece, the driving factors behind these patterns as well as the degree of the success of the EU policy for forest expansion through afforestation of arable land. Therefore, the focus is on providing a concrete appraisal regarding the contribution of EU 2080/92 and 1257/99 Regulations to the improvement of regional forest status by means of increasing forest areas and improving the local people's standard of living. The study area covers the entire Greek territory which consists of 51 administrative prefectures. Methodologically speaking, the empirical analysis is based on a multinomial logistic regression model targeted at providing a thorough understanding of the major driving factors that influence rural communities' response to the regulations. The environmental importance of arable land afforestation is highlighted as well as the extent to which the regulations has met the initial expectations. Keywords: afforestation, EU Regulation 2080/92, EU Regulation 1257/99, forest resources, Greece, multifunctional agriculture, multinomial logistic regression, rural development, rural land, spatial analysis. In recent decades, land use patterns have undergone tremendous transformations of such a magnitude that have attracted considerable attention within the scientific community. At present, an international multidisciplinary debate is in progress among scientists, experts, policy makers, non-governmental organisations and various economic and institutional players with some interest at or involvement in land use allocation. In some respects, this is due to the fact that the magnitude and pace of land change have risen considerably, affecting almost all fundamental components of the system created from both natural and anthropogenic communities. The most affected uses of land seem to be agricultural and forest uses. Rural areas in the EU make up 80% of the territory and have approximately 25% of the population. These areas have undergone major adjustments resulting from agricultural policies and other driving forces such as policy decisions about tourism, transportation networks and forestry. Implications have been great and pressuring, especially those concerning forests and soil, ranging from biotic diversity threats, desertification and forest and open land 'squeeze' to increased vulnerability to human settlements as well as local water and food shortage. Therefore, there is a pressuring need for designing and applying integrated, sustainable and realistic forest policies tightly connected to the requirements for improving the local people's quality of life. The declining economic viability of rural areas not only in Greece but also in other Mediterranean countries has forced the decision makers to develop policies targeted at delivering support to the rural communities to invert the current situation. Multifunctional forestry is perceived as a means of rural development. It is also considered to be an important vehicle for diversifying the countryside through the restoration of existing woodlands and the establishment of new forests on suitable land including former agricultural land (1, 2). In this way, it is possible to strengthen the livelihood base and the quality of life in rural areas. Afforestation of marginal agricultural land through the EU Regulations 2080/92 and 1257/99 is a Common Agricultural Policy (CAP) target focused on (a) decreasing agricultural goods production

Soil–water content and air-filled porosity affect height growth of Scots pine in afforested arable land in Finland

We examined the soil–water content (SWC) and air-filled porosity (AFP) of afforested arable land in situ and related them with tree growth, which was expressed as the total length of 5-year-height growth above 2.5 m stem height. A total of 34 randomly selected sites in western Finland afforested with Scots pine ( Pinus sylvestris L.) were sampled and SWC was measured using time domain reflectometry (TDR). Increasing AFP up to 30% and correspondingly decreasing SWC significantly increased tree growth while concentrations of foliar nutrients and contents of soil nutrients had no effect. Increasing organic matter content (OMC) and decreasing bulk density (BD) were accompanied by increasing SWC and decreasing AFP in the 0–10 cm soil layer. SWC values above 70% indicated critical AFP below 10%. It was found that 44% of the studied sites had mean AFP lower than 10%. The results obtained indicate that the afforested Finnish arable land with high soil OMC is commonly characterized by high SWC and low soil aeration, which can limit tree growth.

Farmer-specific relationships between land use change and landscape factors: Introducing agents in empirical land use modelling

Traditional empirical land use change models generally assume one average land use decision-maker. Multi-Agent System (MAS) models, on the other hand, acknowledge existence of different types of agents, but their poor empirical embedding remains a serious handicap. This paper demonstrates how agent information can also be incorporated into empirical, biophysical land use models. Agent (farmer) information was captured in four farmer types by means of cluster analysis. The types were distinguished by age, education, property size, distance from residence, and the number of animals owned. This information was made spatially explicit as each field in the study area is related to a farmer, based on cadastral information. Statistical interaction terms between farmer type and landscape factors such as remoteness, soil quality, slope and aspect, were tested for significance in describing the observed occurrence of three land use changes: afforestation of arable land, abandonment of arable land, and restoration of the traditional Montado system. Results showed that each farmer type uses different criteria for selecting land for a certain land use change. For example, absentee farmers abandon the most remote areas while other farmer types do not use remoteness as a criterion for abandonment; active farmers select the most accessible fields for afforestation while other farmer types do not; absentee farmers select their best soils for restoration of the traditional Montado system, while active farmers tend to select poor soils. It is demonstrated that each farmer type shows a different relationship between landscape factors and land use changes. Hence, farmer-specific relationships between landscape and land use contribute significantly to the explanation of land use change.

Carbon mineralization and properties of water-extractable organic carbon in soils of the south Loess Plateau in China

Addition of organic manure over thousands of years has resulted in the development of very fertile soils in parts of the Loess Plateau in Northwest China. This region also suffers from serious soil erosion. For that reason, afforestation of arable soils has taken place. The dynamics of soil organic matter in these soils affected by a very specific management and by land use changes is largely unknown. Therefore, we measured C mineralization in a 35-days incubation experiment and analyzed amounts and properties of water-extractable organic carbon (WEOC) in 12 topsoils of this region. The soils differed in land use (arable vs. forest) and in amounts of added organic manure. Afforestation of arable soils resulted in a distinct stabilization of organic C as indicated by the smallest C mineralization (0.48 mg C g −1 C d −1) and the highest C content (2.3%) of the studied soils. In the soils exposed to intensive crop production without regular addition of organic manure we found the largest C mineralization (0.85 mg C g −1 C d −1) and the lowest contents of organic C (0.9%). Addition of organic manure over a time scale of millennia resulted in high organic C contents (1.8%) and small C mineralization (0.55 mg C g −1 C d −1). The content of WEOC reflected differences in C mineralization between the soils quite well and the two variables correlated significantly. Water-extractable organic C decreased during C mineralization from the soil illustrating its mainly labile character. Carbon mineralization from soils was particularly large in soils with small specific UV absorbance of WEOC. We conclude that amounts and properties of WEOC reflected differences in the stability of soil organic C. Both afforestation of arable land and the long-term addition of organic manure may contribute to C accumulation and stabilization in these soils.

The destination of arable land in a marginal agricultural landscape in South Portugal: an exploration of land use change determinants

This research attempts to investigate what drives three conversions of arable land during the period 1985–2000 in a marginal agricultural landscape in Southern Portugal: afforestation of arable land, abandonment of arable land and regeneration of the agro-silvo-pastoral system. This was done by exploring the associations between these changes and a selection of both biophysical and socio-economic variables in a study area of 44 square km. For each conversion of arable land into one of the three other land use types the descriptive power of the various independent variables were evaluated using logistic regression. By comparing different statistical models (one containing only the biophysical attributes, another model containing only the socio-economic variables and finally a model containing both types of variables) the relative importance of socio-economic and biophysical variables was evaluated. The results show that both the biophysical and socio-economic variables were significantly associated with the occurrences of the land use changes. However, the models containing only the socio-economic variables were stronger related to occurrences of afforestation and regeneration of the montado, whereas the biophysical variables were more related to land abandonment. The landowner type was a significant descriptive variable across all land use change models. The results suggest that local socio-economic factors are significant in explaining the pattern of the conversion of arable land in the study area and for this reason the variety of landowners’ response to the physical conditions deserves more attention in land use change modelling.

Site classification of afforested arable land based on soil properties for forest production

We used discriminant analysis to identify the key soil properties that discriminate among 30 forest sites representing a floristic site-type fertility gradient. Thereafter we classified 24 sites on afforested arable land into forest site types using these discriminant functions. The most important soil properties of the E horizon separating different forest site types were pH and the densities of Ca, P, and silt. Using properties of soil from the 0–10 cm depth to represent the current level of site productivity, we classified all soils from afforested arable land into forest site types of high productivity. Among these soils, the most fertile were those with high clay and silt densities. Again, using properties of soil from the 30–40 cm depth to emulate the site productivity that prevailed before soil-formation processes and agricultural land use altered the upper soil horizon, we classified most of the soils from afforested arable land into forest site types of medium productivity. This implies that agricultural land use had increased the densities of basic elements at the 0–10 cm soil depth and, consequently, site productivity. The high productivity of former arable lands was attributed to their previous agricultural use and to the inherent properties of fine-grained soils.

Soil fertility of afforested arable land compared to continuously

In Finland, over 220,000 ha of arable land has been afforested in recent decades. To meet the goals of forest management on afforested fields, information on the effects of former agricultural land use on soil fertility is needed. In this study, we examine the soil fertility of 12 former arable fields afforested either 10 or 60–70 years ago with Norway spruce (Picea abies (L.) Karst.) and adjacent sites that have been forested continuously. Volumetric soil samples were collected from the organic soil layer and from mineral soil to a depth of 40 cm. Soil samples were analyzed for pH, bulk density, organic matter content and amounts of nutrients (Kjeldahl N, extractable P, K, Ca, Mg, Zn and B). On afforested fields, amounts of nutrients in the mineral soil, especially in 10-year-old afforestations, were higher than on continuously forested sites. In the organic layer plus the 0–40 cm soil layer, the 10-year-old afforestations had 68% more N, 41% more P, 83% more K, 252% more Ca, 6% more Mg, 61% more Zn and 33% more B than the continuously forested sites at a comparable soil depth. In the 60–70-year-old afforestations, the differences were significant only for N, Ca and Zn (20% more N, 121% more Ca and 115% more Zn than on the continuously forested sites). The effects of agriculture on amounts of nutrients were most clearly detected in the former plough layer (0–20 cm) of the 10-year-old afforestations and in the top layer (0–10 cm) of the older afforestations. Amounts of nutrients in the organic layer of the afforested sites were lower, but their concentrations were higher than in the continuously forested sites. On the 10-year-old afforestations, the bulk density of the mineral soil tended to be lower and the organic matter content higher than on the continuously forested sites. On both young and old afforestations, soil pH was higher than on the continuously forest sites. According to these results, changes in soil properties caused by agriculture have increased the soil fertility and therefore probably also the site index. The results also suggest that changes in soil properties due to agricultural land use are quite long lasting.

Soil water-retention characteristics and fertility of afforested arable land

From the standpoint of evaluating site quality for growing forest trees, the soil chemical and physical properties of cultivated arable land are poorly known. Therefore, soil matrix, water-retention characteristics and fertility of afforested arable land were studied. Subsequently, the implications of these soil characteristics for productivity of tree stands were assessed. The results indicated that the soil properties of afforested arable land differ markedly from those of forest soils. The changes in the composition of the soil matrix due to former agricultural land use manifested as increased organic matter content in mineral soils and, in contrast, as increased mineral matter content in peat soils. In general, afforested arable lands were characterized by soils having high contents of nutrients, high content of organic matter, high pH, and low air-filled porosity at field capacity, which resulted from the predominance of small pores. In all investigated soils, the air-filled porosity was less than 20% in the topmost soil layer and decreased significantly with increasing soil depth. The results suggested that soils of afforested arable land commonly have critically low aeration for tree growth. It appears that due to management history, afforested arable lands have a higher level of soil fertility compared to their inherent soil fertility. The high soil fertility of former arable land was, however, also attributed to the inherent properties of fine-grained soils. Consequently, based on of densities of Ca, P, silt and pH in the 0-10 cm soil depth, derived discriminant functions classified all sites from afforested arable land into forest site types of high productivity. Among these soils, those with high clay and silt content were the most fertile. The changes in the physical and chemical properties of soils due to former agricultural land use seem to be significant and long lasting to such a degree that afforested arable land is very unlikely to regain its inherent soil fertility even over an extended period of time.

Carbon and Nitrogen in Danish Forest Soils—Contents and Distribution Determined by Soil Order

Increasing atmospheric CO2 concentrations, and widespread deposition of N to terrestrial ecosystems has increased the focus on soil C and N pools. The aim of this study was to estimate the size and distribution of organic C and N pools in well-drained Danish forest soils. We examined 140 forest soil profiles from pedological surveys of Danish forest soils. We calculated total C and N pools in organic layers and mineral soils to a depth of 1 m. The profiles represent variations in texture (sandy to loamy), and soil order (USDA soil taxonomy Spodosols, Alfisols, Entisols, and Inceptisols). The average total organic C and N contents were 12.5 and 0.61 kg m−2 respectively. There were large differences in total C and N among soil orders. Spodosols had the greatest C content (14.6 kg m−2), and Alfisols the least (8.8 kg m−2), while the N content was highest in Alfisols (0.75 kg m−2) and least in Spodosols (0.51 kg m−2). The main contributor to the high C content in Spodosols is the spodic horizons containing illuvial humus, and thick organic horizons. Carbon and N concentrations decreased with soil depth. Soil clay content was negatively correlated to C content and positively correlated to N content. Soil order and horizon designations may be useful in predicting the total C and N content of Danish forest soils, and may also predict potential for C sequestration following afforestation of arable land.

Carbon and Nitrogen in Danish Forest Soils—Contents and Distribution Determined by Soil Order

Increasing atmospheric CO2 concentrations, and widespread deposition of N to terrestrial ecosystems has increased the focus on soil C and N pools. The aim of this study was to estimate the size and distribution of organic C and N pools in well‐drained Danish forest soils. We examined 140 forest soil profiles from pedological surveys of Danish forest soils. We calculated total C and N pools in organic layers and mineral soils to a depth of 1 m. The profiles represent variations in texture (sandy to loamy), and soil order (USDA soil taxonomy Spodosols, Alfisols, Entisols, and Inceptisols). The average total organic C and N contents were 12.5 and 0.61 kg m−2 respectively. There were large differences in total C and N among soil orders. Spodosols had the greatest C content (14.6 kg m−2), and Alfisols the least (8.8 kg m−2), while the N content was highest in Alfisols (0.75 kg m−2) and least in Spodosols (0.51 kg m−2). The main contributor to the high C content in Spodosols is the spodic horizons containing illuvial humus, and thick organic horizons. Carbon and N concentrations decreased with soil depth. Soil clay content was negatively correlated to C content and positively correlated to N content. Soil order and horizon designations may be useful in predicting the total C and N content of Danish forest soils, and may also predict potential for C sequestration following afforestation of arable land.

Nitrate concentrations in soil solutions below Danish forests

Nitrate in the soil water below the root zone is a pre-condition for nitrate leaching, and it indicates loss of nutrients from the forest ecosystem. Nitrate leaching may potentially cause eutrophication of surface water and contamination of ground water. In order to evaluate the extent of nitrate leaching in relation to land-use, a national monitoring programme has established sampling routines in a 7×7 km grid including 111 points in forests. During winters of 1986–1993, soil samples were obtained from a depth of 0–25, 25–50, 50–75 and 75–100 cm. Nitrate concentrations in soil solutions were determined by means of a 1 M KCl extraction. The influence of forest size, forest-type, soil-type, tree species and sampling time on the nitrate concentrations was analysed in a statistical model. The analysis focused on data from depth 75–100 cm, as nitrate is considered potentially lost from the ecosystem at this depth. The range of nitrate concentrations was 0–141 mg NO − 3–N dm −3 and the estimated mean value was 1.51 mg NO − 3–N dm −3. The concentration was influenced by (1) forest size (concentrations in forests <10 ha were higher than concentrations in forests >50 ha), (2) forest-type (afforested arable land had higher concentrations than forest-type `other woodland'), (3) soil-type (humus soils showed above average concentrations, and fine textured soils had higher concentrations than coarse textured soils), and (4) sampling time. Unlike other investigations, there was no significant effect of tree species. A few sites deviated radically from the general pattern of low concentrations. The elevated concentrations recorded there were probably caused by high levels of N deposition due to emission from local sources or temporal disruptions of the N cycle. The nitrate concentration in the soil solution below the root zone was mostly rather low, indicating that, generally, N saturation has not yet occurred in Danish forest ecosystems. However, median concentrations exceeding drinking water standards (11.3 mg NO − 3–N dm −3) were found at 7% of the sites. Furthermore, 30% of the sites had median concentrations above 2 mg NO − 3–N dm −3, suggested as an elevated level for Danish forest ecosystems, equalling annual N losses of more than 2–6 kg ha −1 year −1.

Afforestation and sediment yields in British fresh waters

Abstract. This paper reviews research on sediment yields in British fresh waters affected by afforestation in their catchments. Soil erosion and sedimentation in fresh waters increase after afforestation in the uplands. In the long term a three‐to tour‐fold increase appears to be common in established upland forests, but much larger increases, some amounting to 50 times that before afforestation, have been recorded soon after ploughing, draining, roadmaking and harvesting. Some of the erosion has been exacerbated by environmental conditions such as steep slopes and storms. Improved silvicultural practices should reduce sediment output to fresh waters, but they might not prevent serious sedimentation following afforestation in the uplands. In contrast, afforestation of arable land under the Farm Woodland Scheme should result in decreased rates of erosion in the lowlands.

Skogsplantering på marginaljord—miljö och ekonomi

Olsson, Mats: Skogsplantering pa marginaljord—miljo och ekonomi. Geografisk Tidsskrift 89:14–18. Kobenhavn 1989. The paper aims at dicussing forest production potential and impact of forest ecosystems on soil properties at afforestation of arable land. It is shown that forest ecosystems improve soils of arable land by increasing the organic contents, increasing the contents of plant available nutrients and by improving the soil structure.