Afforestation Of Land Research Articles

Afforestation of common land in the Classical Karst: relations between the authorities, the local population, and the economic consequences of afforestation

The findings of environmental history are in the service of ecology and represent an important contribution to the understanding of the sustainable management of land. The aim of this article is to shed light on the relations between the local population and the authorities regarding the afforestation of common land in Komen in the second half of the 19th century and the beginning of the 20th century, placing them in a broader Mediterranean context. The local population was not opposed to afforestation per se, but to the prohibition of usufruct on afforested land, which had major economic consequences for the local population. Authorities did not always take into consideration the annual agricultural processes, local customs, and natural resource needs in their afforestation decisions. The prohibition of usufruct was followed by a shortage of fodder and firewood, which led to forest violations to satisfy demands. Thus, afforestation has undermined the basis of agriculture. In addition, already afforested land remained under common ownership for a relatively long time.

Organic matter accumulation encouraged K-strategy bacteria increase and metabolism variation in karst vegetation restoration

Vegetation restoration plays a critical role in terrestrial carbon sink increase, especially in subtropic Southwest China which has been the hotspot of vegetation restoration areas in recent decades. However, the variations in microbial community diversity resulting from this intervention remain unclear, and further research is needed to elucidate the complex interactions between microorganisms and soil nutrient elements. Soil samples were collected from three vegetation restoration stages in a karst rocky desertification (KRD) valley of Southwest China, which were named dry cropland (CL), 3–8 years grassland (WL), and afforestation land that recovered more than 20 years (AL), to investigate the soil nutrient and bacterial diversity variation during vegetation restoration course. The soil organic carbon (SOC) and total nitrogen (TN) contents are significantly higher in the afforestation land soil compared to the cropland and grassland soils, while the available nutrient contents decrease during the vegetation restoration course. The soil dominant bacteria genus shifts from R-strategy bacteria in cropland to K-strategy bacteria in afforestation land, and the relative abundances of R-strategy genera remain similar in the grassland and cropland soil. The dual-relative bacteria network evaluates from simple correlation net to very complex ones during the vegetation restoration, of which the core influenced factor alters from available nutrients to organic matter. The results of this study suggest that it will take a relatively longer period for the soil nutrient conditions and bacterial community to recover fully, although vegetation restoration could reduce the impacts of agricultural activities. This study refers to the ecological preservation and restoration strategies under the global climate change background, elucidating the nutrient metabolism variation induced by the accordance variation of organic matter accumulation and soil bacterial life strategy during the ecosystem restoration course.

Declining interest in afforestation under the common agricultural policy. Evidence from Poland and Lithuania

Land afforestation is an important aspect of forested land development. Increasing the area of forest areas through the reforestation of uncultivated, abandoned or agriculturally unsuitable land is considered an important way to diversify economic activities in order to reduce dependence on agricultural activities and improve environmental conditions in rural areas. The main objective of the study is to identify the factors affecting the afforestation of agricultural land carried out in the years 2004–2020 by farmers under the individual financial perspectives of the Rural Development Programme (RDP) in Poland and Lithuania. The study included a review of Polish and Lithuanian regulations aimed at providing financial support for afforestation under the RDP. Moreover, a comparative analysis of the rules and criteria for financial support for afforestation in relation to selected socio-economic indicators of the two countries was carried out. Based on the study results, it can be clearly stated that in both Poland and Lithuania, the support for afforestation under the RDP fails to meet the beneficiaries’ expectations. It would, therefore, be advisable to adapt the Programme to the changing economic conditions and keep the afforested land under the RDP under technical supervision. Support for afforestation should be continued to ensure the improvement in land use and the enhancement of the prospects for long-term economic activity in rural areas as well as to implement the assumptions of the green economy.

Reduced ligninase‐cellulase ratio enhances soil carbon sequestration following afforestation of agricultural land

AbstractIntroductionAfforestation of agricultural land is one of the most essential approaches to mitigate climate change by enhancing the sequestration of atmospheric carbon (C) into the soil. C‐degrading extracellular enzymes produced by soil microbes regulated the decomposition and fate of sequestrated soil organic carbon (SOC), with potential divergent variations following afforestation across different ecosystem scales. However, the feedbacks of different C‐degrading enzymes and their relationships with SOC following afforestation of agricultural land remain unclear.Materials and MethodsWe investigated the changes in enzyme activity and their relationships with SOC in soil aggregates across two typical climatic vegetation restoration regions in China, and explored the mechanisms through which changes in enzyme activity contribute to SOC sequestration following afforestation of agricultural land.ResultsAfforestation of agricultural land generally decreased ligninase activity and increased cellulase activity across various aggregate fractions, compared to the adjacent croplands in both subtropic (Danjiangkou Reservoir, DJK) and temperate (Maoershan, MES) region. Additionally, the ratio of ligninase to cellulase (L:C) was lower in afforested lands than in the croplands, with L:C as the major factor explaining the variations of SOC sequestration following afforestation. Specifically, ligninase and L:C were negatively correlated with SOC, whereas cellulase showed positive correlations with SOC. Further analyses suggested that microbial biomass C and nitrogen (MBC and MBN) and the ratio of SOC and total nitrogen (SOC:TN) were important factors influencing L:C and subsequently regulating SOC. These results suggest that shifts in microbial enzyme production from ligninase to cellulase following afforestation, reduced the decomposition of recalcitrant C, thus contributing to SOC sequestration.ConclusionOur work underscores the critical role of reduced L:C in enhancing SOC sequestration following the restoration of croplands to afforested lands. These findings advance the understanding of the influence of microbial community physiological adaptations on C sequestration across different land use types.

Estimation of Spatial–Temporal Dynamic Evolution of Potential Afforestation Land and Its Carbon Sequestration Capacity in China

Estimation of Spatial–Temporal Dynamic Evolution of Potential Afforestation Land and Its Carbon Sequestration Capacity in China

Wood Quality of Pendulate Oak on Post-Agricultural Land: A Case Study Based on Physico-Mechanical and Anatomical Properties

Oak is one of the most economically important hardwood tree species in Europe, and its prevalence will increase due to progressing global climate change, according to predictive models. With the increasing demand for timber and with the need for a balance between carbon emissions and sequestration, it is essential to address the afforestation of agricultural land. Therefore, this research aimed to investigate the physico-mechanical properties and anatomical structure of pendulate oak (Quercus robur L.) wood—specifically focusing on the trunk’s cross-section—in post-agricultural areas compared with the forest land in the western part of Poland. Wood density, bending strength, modulus of elasticity, and other parameters were analyzed from 1626 wood samples. The analysis of physico-mechanical properties reveals that, historically, agricultural land use has an almost negligible impact on wood quality. Despite significant differences in small vessel diameter and fiber length favoring trees from post-agricultural land, the physico-mechanical properties remain consistent. Large vessel measurements show comparable diameter and length in both land types. These findings suggest that post-agricultural land can serve as an effective alternative for high-quality pendulate oak wood production for industrial purposes. However, wood from post-agricultural land may exhibit a decrease in modulus of rupture by over 30% and potentially lower density above the trunk’s halfway point. This observation hints at the fact that oak trees in post-agricultural areas could be cultivated in shorter rotation periods compared to forest land.

Coupling Coordination of Multi-Dimensional Urbanization and Ecological Security in Karst Landscapes: A Case Study of the Yunnan–Guizhou Region, China

Globally, karst regions face the dual challenges of urbanization and ecological protection, with the coupling coordination of multi-dimensional urbanization (MDU) and ecological security (ECS) being a necessary condition for achieving sustainable development. This study, based on statistical data on MDU and ECS in the Yunnan–Guizhou Region (the YGR) in China, employs the entropy weight TOPSIS model, degree of coupling coordination (CCD) model, and panel Tobit regression model to explore the coupling relationship between MDU and ECS. The main conclusions are as follows. (1) MDU in the YGR increased from 0.299 to 0.305, indicating low-level and sluggish development. Spatially, it is characterized by a “dual-core” structure centered on Kunming and Guiyang. (2) ECS decreased from 0.456 to 0.423, with a spatial pattern of “high in the east, low in the west”. The impact of human activities on ECS increased from 0.579 to 0.631 due to the increase in social and economic activities. (3) CCD increased to 0.579, achieving moderate coordination. The spatial feature evolved into a tri-cluster pattern of “high–low–high” across the “eastern–central–northwestern” regions. (4) Regression results indicate that annual average precipitation has a “both promoting and limiting” dual effect on CCD. The coefficient for the proportion of afforested land area is 0.205, with a significance level of 5%, suggesting that increasing forest cover is a key measure for improving CCD. The study reveals the factors influencing the evolution of MDU and ECS from a negative to a positive correlation, providing a basis for decisions related to sustainable development for urban and ecological management in karst landscapes globally.

Conversion of farmland to forest or grassland improves soil carbon, nitrogen, and ecosystem multi-functionality in a subtropical karst region of southwest China

The conversion of farmland to forest in China has been recognized for its positive impact on above-ground vegetation and carbon sequestration. However, the impact on soil quality during land conversion, particularly in vulnerable karst areas, has received less attention. In this study conducted in a karst area of southwest China, eight different farmland conversion strategies were investigated to assess improvements in surface soil carbon, nitrogen, and ecosystem multi-functionality (EMF). Our results showed that farmland converted to afforestation areas or farmland that was abandoned contained higher amounts of carbon (total, organic, active) and ammonium nitrogen (NH4+-N) in the soil compared to farmland converted to grassland or maize crop. Soluble organic carbon levels were higher in afforestation and grassland areas compared to maize crop controls. By contrast, soil from grassland and abandoned land exhibited higher levels of nitrate nitrogen (NO3--N) compared to afforestation land or maize crop controls. There were no differences in NH4+-N content between any condition, except for afforestation land that specifically contained the Zenia insignis plant species. Afforestation land consistently exhibited higher EMF values than grassland. Pearson correlation analysis revealed positive relationships between soil indices and EMF scores, except for NO3--N.Random forest analysis explained 95% of the variation in soil EMF and identified specific soil factors: total carbon, organic carbon, active labile organic carbon, total nitrogen, and ammonium nitrogen, as the main drivers of soil multi-functionality. Our studies show how various reforestation strategies can enhance soil nutrient sequestration and improve soil multi-functionality of farmland in the karst areas.These findings provide insight into sustainable soil management practices for converting farmland into natural areas.

Response of soil moisture to rainfall following deep soil drying in China's hilly loess lands

Deep soil drying is a physical soil phenomenon that has become increasingly characteristic to artificial afforestation on China's Loess Plateau. Current research is largely short of conclusive reports on soil moisture recovery following deep soil drying in afforested lands. In this study, a 10-m deep underground column was constructed at Pengyang Experimental Station in Ningxia. The CS650-CR1000 automatic soil moisture monitoring system and BLJW-4 small meteorological observation stations were used to respectively monitor soil moisture and meteorological conditions in the study area for the period 2014–2019. The local rainfall was classified and the characteristics of soil infiltration analyzed at both monthly and annual scales. The results showed that: i) Deep soil moisture recovery in the semi-arid Loess Plateau region depended mainly on 25–49.9 mm and >50 mm types of rainfall; together accounting for 35.44 % of the precipitation. ii) Deep soil moisture replenishment occurred mainly for the period from April to October. While this accounted for 30.13 % of the precipitation, evaporation loss accounted for 69.87 % of it. With increasing monthly rainfall (Pm), the variation in monthly infiltration depth (Zm) was quadratic in shape — where Zm = −0.0094 Pm2 + 3.7702 Pm (R2 = 0.9577). iii) At the annual scale, deep soil moisture replenishment was mainly driven by year-on-year infiltration water accumulation. This is because a single year precipitation infiltration was not enough to replenish deep soil moisture. The cumulative infiltration depth for 2014–2019 was 180, 260, 400, 700, 1000 > 1000 cm. It suggested that soil water infiltration and deep dry soil recovery occurred at different times under rainfed conditions in the semi-arid loess hills in China. This is key for in-depth studies of the hydrological process in dry soil regions.

Restoration of vegetation in the Yellow River Basin of Inner Mongolia is limited by geographic factors

Studying the relationships between vegetation cover and geography in the Mongolian region of the Yellow River Basin will help to optimize local vegetation recovery strategies and achieve harmonious human relations. Based on MOD13Q1 data, the spatial and temporal variations in fractional vegetation cover (FVC) in the Mongolian Yellow River Basin during 2000–2020 were investigated via trend and correlative analysis. The results are as follows: (1) From 2000 to 2020, the vegetation cover in the Mongolian section of the Yellow River Basin recovered well, the mean increase in the FVC was 0.001/a, the distribution of vegetation showed high coverage in the southeast and low coverage in the northwest, and 31.19% of the total area showed an extremely significant and significant increase in vegetation cover. (2) The explanatory power of each geographic factor significantly differed. Precipitation, soil type, air temperature, land use type and slope were the main driving factors influencing the spatial distribution of the vegetation cover, and for each factor, the explanatory power of its interaction with other factors was greater than that of the single factor. (3) The correlation coefficients between FVC and temperature and precipitation are mainly positive. The mean value of the FVC and its variation trend are characterized by differences in terrain and soil characteristics, population density and land use. Land use conversion can reflect the characteristics of human activities, and positive effects, such as returning farmland to forest and grassland and afforestation of unused land, promote the significant improvement of regional vegetation, while negative effects, such as urban expansion, inhibit the growth of vegetation.

The Long-Term Effects of Barren Land Afforestation on Plant Productivity, Soil Fertility, and Soil Moisture in China: A Meta-Analysis.

As global ecological degradation intensifies, the long-term impacts of afforestation on productivity and soil fertility in barren lands have become critical in improving global ecological security and productivity. Through meta-analysis, this study integrates data from 109 barren land afforestation sites across China, aiming to comprehensively analyze the effects on plant productivity and soil fertility while identifying the key environmental drivers of these changes. We found that afforestation consistently enhances plant productivity across 60 years. However, soil fertility and moisture initially surged significantly after afforestation but gradually declined after the first decade, indicating the limited long-term benefits. Climatic factors, namely precipitation and humidity index, are crucial in enhancing plant productivity, while geographic factors, specifically lower elevations and gentler slopes, are associated with greater increases in soil fertility. Elevation and slope are two key factors that influence soil moisture after afforestation. These findings highlight the need for ongoing soil management and ecological maintenance in afforestation projects to sustain the soil fertility benefits. Our study provides a robust scientific foundation for afforestation strategies aimed at barren land restoration and offers valuable insights for policy formulation in barren land afforestation.

Spatial adequacy of afforestation in Poland: do afforestation needs and environmental preferences matter?

The article concerns the afforestation of agricultural land, especially soils of low quality classes with little suitability for agriculture. The assumption was made that in order to effectively implement afforestation and optimize spatial structures, these lands should be analyzed from the point of view of environmental and spatial conditions (including the quality of the land and its suitability for field crops, cohesion of the forest ecosystem, the presence of naturally valuable areas), according to the potential of a given area. Land that is ineffective in cultivation and does not improve the cohesion of the ecosystem should be treated as preferred for afforestation. The assessment of the spatial adequacy (optimization) of afforestation in the context of afforestation needs and predispositions was carried out for Poland in terms of municipalities using the spatial autocorrelation model and methods. The research results indicate the need to strengthen the effectiveness of solutions that take into account the endogenous potential of municipalities.

Planning of rational use of forest resources in Ukraine based on the improvement of ecosystem services

The study of land conservation methods for forest conservation and restoration is important and relevant from the standpoint of balanced use of natural resources and biodiversity conservation. The purpose of the study was to investigate effective strategies for the exploitation of land with self-forested areas to meet the needs of the agricultural sector of the Zolochiv District of the Lviv Oblast. In the course of the study, the following methods were used: analysis; geographical method; statistical method; cartographic method; geoinformation method. It is worth noting that for the land plot No. 1 within the Buska territorial community of Lviv Oblast, it was recommended to conserve the land, with its subsequent renaturalisation. According to the results of the analysis, it is shown that in 2011 the processes of independent afforestation of agricultural land within the Busk territorial community were insignificant. In 2023, the situation improved, as the area of afforded land increased significantly. To the soils of the land plot No. 2, which was part of the Brody urban community, it was advisable to use conservation and transformation. In the Zolochiv community, 14.2 hectares of land should be rehabilitated, 27.3 hectares should be transformed into pasture, and 3.5 hectares should be alkalised. The paper suggests the introduction of innovative approaches for integrated planning of the use of forest resources: creation of forest farms, development of forest tourism, creation of special forest stands for air filtration, application of bio-refining technology, etc. The findings can be used by local communities to develop and implement a draft of measures for the comprehensive development plan of the territory of the Lviv Oblast to improve forest ecosystem services

Optimizing China’s Afforestation Strategy: Biophysical Impacts of Afforestation with Five Locally Adapted Forest Types

Recent research has mapped potential afforestation land to support China’s goal of achieving “carbon neutrality” and has proposed tree species selection to maximize carbon uptake. However, it overlooked biophysical climatic effects, which have a more significant impact on local temperature than CO2 reduction. This study aims to present a comprehensive understanding of how afforestation in China affects local and regional climates through biophysical processes. It focuses on the latitudinal patterns of land surface temperature differences (ΔLST) between five locally adapted forest types and adjacent grasslands using satellite-based observations. Our key findings are as follows: Firstly, broadleaf forests and mixed forests exhibit a stronger cooling effect than coniferous forests due to differences in canopy structure and distribution. Specifically, the net cooling effects of evergreen broadleaf forests (EBFs), deciduous broadleaf forests (DBFs), and mixed forests (MFs) compared to grasslands are −0.50 ± 0.10 °C (mean ± 95% confidence interval), −0.33 ± 0.05 °C, and −0.36 ± 0.06 °C, respectively, while evergreen needleleaf forests (ENFs) compared to grasslands are −0.22 ± 0.11 °C. Deciduous needleleaf forests (DNFs) exhibit warming effects, with a value of 0.69 ± 0.24 °C. In regions suitable for diverse forest types planting, the selection of broadleaf and mixed forests is advisable due to their enhanced local cooling impact. Secondly, temperate forests have a net cooling effect to the south of 43° N, but they have a net warming effect to the north of 48° N compared to grasslands. We recommend caution when planting DNFs, DBFs, and MFs in northeastern China, due to the potential for local warming. Thirdly, in the mountainous areas of southwestern China, especially when planting ENFs and MFs, tree planting may lead to local warming. Overall, our study provides valuable supplementary insights to China’s existing afforestation roadmap, offering policy support for the country’s climate adaptation and mitigation efforts.

Assessing whether peri-urban agricultural land or plantation forest is a better green infrastructure for ground arthropods at local and landscape scales

City agencies across multiple continents have invested millions of funds in ambitious afforestation projects in urban and peri-urban areas to enhance the city green infrastructure. One example is the Beijing One Million Mu Plain Afforestation Project, which has established 146,000 ha of plantation forests, mainly on arable lands. This contradicts the national arable land conserving policies and has dramatically changed local habitat types and landscape context. However, the impact of these processes on biodiversity is not well understood. To investigate this impact at local and landscape scales, we explored a space-for-time approach. We selected 12 plantation forests and their nearby arable lands along a gradient of plantation forest cover in the surrounding landscapes. We surveyed ground spiders and carabids and analyzed their responses to local habitat type, landscape context, and their interaction. In the sampled landscapes, plantation forest cover increased (12.0%–35.9%), while arable land cover decreased (58.3%–31.8%). 96.3% of the new plantation forests were established on arable lands. Intensive afforestation on arable lands did not increase local ground arthropod diversity. In fact, ground arthropod abundance and species richness in plantation forests were significantly lower than in arable lands when the surrounding arable land cover was relatively high. With surrounding arable land cover decreasing, ground arthropod abundance and species richness in plantation forests increased but did not exceed those in nearby arable lands. Hence, the overall ground arthropod diversity at landscape scale was not improved. These findings suggest that, from a biodiversity conservation perspective, plantation forests did not surpass peri-urban agricultural lands as a better green infrastructure . However, ground arthropods benefit from rich local non-crop herb communities. Conserving peri-urban agricultural lands and implementing extensive management regimes for agricultural lands and existing plantation forests are more effective tools than ambitious afforestation of agricultural land in peri-urban areas of Beijing and other metropolises.

Simulating impacts on UK air quality from net-zero forest planting scenarios

Abstract. The UK proposes additional bioenergy plantations and afforestation as part of measures to meet net-zero greenhouse gas emissions, but species and locations are not yet decided. Different tree species emit varying amounts of isoprene and monoterpene volatile organic compounds that are precursors to ozone and secondary organic aerosol (SOA) formation, the latter of which is a component of PM2.5. The forest canopy also acts as a depositional sink for air pollutants. All these processes are meteorologically influenced. We present here a first step in coupling information on tree species planting suitability and other planting constraints with data on UK-specific BVOC emission rates and tree canopy data to simulate, via the WRF-EMEP4UK high spatial-resolution atmospheric chemistry transport model, the impact on UK air quality of four potential scenarios. Our “maximum planting” scenarios are based on planting areas where yields are predicted to be ≥ 50 % of the maximum from the Ecological Site Classification decision support system (ESC DSS) for Eucalyptus gunnii, hybrid aspen (Populus tremula), Italian alder (Alnus cordata) and Sitka spruce (Picea sitchensis). The additional areas of forest in our scenarios are 2.0 to 2.7 times the current suggestions for new bioenergy and afforestation land cover in the UK. Our planting scenarios increase UK annual mean surface ozone concentrations by 1.0 ppb or 3 % relative to the baseline land cover for the highest BVOC-emitting species (e.g. E. gunnii). Increases in ozone reach 2 ppb in summer when BVOC emissions are greatest. In contrast, all the additional planting scenarios lead to reductions in UK annual mean PM2.5 – ranging from −0.2 µg m−3 (−3 %) for Sitka spruce to −0.5 µg m−3 (−7 %) for aspen – revealing that PM2.5 deposition to the additional forest canopy area more than offsets additional SOA formation. Relative decreases in annual mean PM2.5 are greater than the relative increases in annual mean ozone. Reductions in PM2.5 are least in summer, coinciding with the period of maximum monoterpene emissions. Although only a first step in evaluating the impact of increased forest plantation on UK air quality, our study demonstrates the need for locally relevant data on land cover suitability, emissions and meteorology in model simulations.

Monetary Valuation of Ecosystem Services Provided by Protective Forest Plantations in the Agroforestry System in the South of the Volga Upland

The purpose of the study is an economic assessment of the effectiveness of agroforestry based on determining the value of ecosystem services of an afforested model land object and extrapolating the data obtained to the territory of the south of the Volga upland with identical natural and economic conditions to the model. The study presents a methodology for the economic assessment of ecosystem goods and services of forested agricultural landscapes based on the modern classification of ecosystem services: CICES. It is established that the economic value of the regional ecosystem product provided by forested lands in the dry steppe is USD 1323 per 1 ha of agroforest landscape per year (price for 2021 on average for 30 years). Of these, regulatory and maintenance services account for 52% of the total economic value, security services—45%, and cultural services—3%. The projected economic value of ecosystem services that will be provided by afforested lands in the south of the Volga upland, the price for 2025, taking into account inflation, is estimated at almost USD 20 million. This value is a sufficient justification for conducting forest reclamation works in the region and providing recommendations for their necessity for small enterprises and farms.

Shyshatska sand arena: History, current state, and prospects of afforestation

Non-afforested lands in Ukraine are the primary instrument for increasing the forest cover of the territory The issue of sand afforestation is relevant in the context of climate change. Treeless sand arenas are a source of dust storms, and deflationary processes that occur lead to negative consequences that are quite difficult to correct in the future. The purpose of this study was to summarise the experience and achievements of the branch “Myrhorod Forest Enterprise” of the State Specialised Commercial Enterprise “Forests of Ukraine” in afforestation of mobile sands in the conditions of the Forest-Steppe of Ukraine. Forest stands are established using one-year-old Scots pine seedlings on sandy soils to achieve the set goal. Testing is conducted using planting material grown under various conditions – in the open ground and in a greenhouse. Extended periods for establishing forest stands beyond agrotechnical terms are examined during the late spring and summer periods using rejuvenated planting material with partially damaged root systems. The current state of plantings within the Shyshatska sand arena is analysed. It is established that in general, the territory of the arena is represented by the entire range of types of forest conditions ranging from bors to mixed broad-leaved forests. The prevailing types of forest-growing conditions are given, among which dry and fresh forests are distinguished. Subors and su-deciduous forests are represented on small areas. Deciduous types of conditions are located mainly in the drained areas of the Psel River floodplain. The main forest-forming species on the territory of the arena is Scots pine, which occupies more than 60% of the territory. Also in the lowlands and floodplains of the Psel River stands of Black Alder and Common Oak grow. In the conditions of bors, Scots pine grows in III – Va bonitet class. In richer conditions, subor and su-deciduous forest cultures have better indicators and have a class I-II bonitet, but there are not many of them. The results of this study can be used in the afforestation of sandy lands in the Forest-Steppe of Ukraine and adjacent regions

The increased soil aggregate stability and aggregate-associated carbon by farmland use change in a karst region of Southwest China

Land use change can significantly alter the distribution of different soil aggregates, thereby influencing aggregate stability and aggregate-associated organic carbon (OC). However, there is minimal research on the variations in the distribution of soil aggregates, aggregate stability, and aggregate-associated OC following land use change from farmland to afforested land in the karst regions of Southwest China. Undisturbed soil samples were collected from farmland (FL) and three afforestation patterns (bamboo forest: BA; landscape tree planting: LAT; and orange orchards: ORO) converted from farmland in a karst region of Southwest China. These four land uses have similar geographical characteristics (e.g., elevation and slope aspects) and previous framing practices. The distribution of macroaggregate (>0.25 mm), microaggregate (0.053–0.25 mm) and silt + clay fractions (<0.053 mm) and the aggregate-associated OC contents under the four land uses were measured at the 0–10 cm and 10–20 cm depths. The results showed that afforestation converted from FL significantly increased the macroaggregate and microaggregate contents, geometric mean diameter (GMD), and structural stability index (SSI) but decreased the silt + clay fraction content. Compared with FL, the values at the 0–20 cm depth under BA, LAT and ORO increased by 108.79%, 34.89% and 36.56%, respectively, for GMD and by 239.84%, 94.05%, and 123.41%, respectively, for SSI. Land use change and soil aggregate size had obvious influences on soil organic carbon (SOC) content. The SOC content in the bulk soil, macroaggregate, microaggregate, and silt + clay fraction at the 0–20 cm depth after afforestation increased by 26.83%, 45.57%, 27.14%, and 13.80%, respectively, compared to FL. The contributions of macro- and microaggregates to the increase in SOC content in bulk soil were 146% and 78%, respectively, while the silt + clay fractions had a negative effect with a value of 125% after afforestation. The GMD and SSI were positively correlated with the macroaggregate content and SOC content in the bulk soil and different soil aggregates. Although the increase in SOC content in bulk soil and soil aggregates under BA and ORO was significantly higher than that for LAT, the soil aggregate stability under ORO was lower than that under BA. These findings suggest that afforestation increases aggregate ability, SOC content in bulk soil and aggregate-associated OC and that BA might be the optimum choice among the three afforested lands compared for soil sustainability from the perspective of improving carbon sequestration and soil erosion.

Legacy of Prior Management of Cropland after Afforestation with Populus x euroamericana (Dode) Guinier: Effects on Soil Respiration

Afforestation is a good strategy for climate change mitigation through increasing carbon stocks. This study determined changes in soil respiration (SR) brought about by the afforestation of high quality agricultural land in a temperate-humid region (Galicia, NW Spain), identified the variables that explain the observed changes and determined the main factors regulating SR temporal variation. Paired plots of fertile soils (cropped vs. afforested plots) were established in two similar areas (Pontevea and Laraño) where afforestation with Populus x euroamericana (Dode) Guinier was carried out in the same year. Different management practices and crop rotations were used (maize–pasture, Laraño and maize–fallow, Pontevea). The SR was measured in situ with a CO2 static chamber every 15 days (every month in winter) for 16 months; soil temperature (Ts) and soil moisture content (W) were also measured. In both areas, significant differences (p &lt; 0.05) in SR between paired plots were related to soil organic C content and SR was mainly influenced by Ts, except during the summer period where SR fluctuations were accompanied by W fluctuations. These findings show that growing pasture crops on high quality land can prevent the loss of soil N and C and probably improve the greenhouse gas balance in the system.