Impact Of Agricultural Land Use Research Articles

The impact of multiple agricultural land uses in sustaining earthworm communities in agroecosystems - A global meta-analysis

The impact of agricultural land use on biodiversity has been extensively examined through efforts to synthesize available data. Nevertheless, there is still a lack of a thorough synthesis describing the earthworm response to agricultural land-use Our meta-analysis compared undisturbed ecosystems (i.e., undisturbed grassland, primary forest) as controls against agricultural land-use treatments, with data extracted from 113 publications across 44 countries, yielding 1040 pairwise comparisons of earthworm density and biomass, and 536 pairwise comparisons of earthworm diversity. We also evaluated how agricultural land use effects on earthworms depend on soil, climate, and management practices reported in the studies. Arable cropland had significantly lower earthworm density (-18%), biomass (-15%), and species richness (-27%) compared to undisturbed sites. Conversely, higher earthworm density, biomass and species richness were observed in pastures, sites under agroforestry, crop management with fallow periods and crop-livestock integration. In regions with continental climates characterized by cool summers, agricultural land use exhibited positive effects on earthworm density and biomass. In sites with higher soil bulk density and lower organic matter content the adverse effects of agricultural land use are exacerbated. However, highly heterogeneous earthworm responses cannot be explained by the individual evaluation of climatic, soil-related, or management factors. Our results guide future efforts to address the data limitations that enable us to enhance our understanding of the interactive effects of various factors on earthworm responses to agricultural land use, as well as evidence-based and management strategies targeted at promoting sustainable agricultural systems while preserving soil biodiversity.

Impact of agricultural land-use on functional feeding groups of Afrotropical Ephemeroptera, Plecoptera and Trichoptera in the Kat River, Eastern Cape, South Africa

Despite Africa experiencing a substantial rise in inadequately managed agricultural practices, studies examining the effects of these activities on the functional organisation of macroinvertebrates in tropical streams are underdeveloped. The responses of Ephemeroptera, Plecoptera and Trichoptera (EPTs) functional feeding groups (FFGs) to agricultural pollution were investigated in the Kat River, Eastern Cape, South Africa, to identify potential FFG indicators. Physicochemical parameters and macroinvertebrates were sampled from eight sites delineated into four land-use impact categories (highly impacted, HIC; impacted category, IC; moderately impacted, MIC; and least impacted, LIC) based on the percentage of agricultural land cover. The Permutational multivariate analyses of variance (PERMANOVA) results revealed land use (F = 4.2, 3.62; p < 0.05) and season (F = 2.89, p < 0.03) influenced FFGs in the river, with shredder abundances decreasing with increasing agricultural stress. Conversely, collectors, predators and scrapers were tolerant of agricultural disturbance. Nutrient variables (NO3-N, NO2-N and NH4-N), canopy and depth were the critical variables that affected FFG structure in the river. Our findings provided more understanding and insights into the functional structure of EPT in relation to agricultural pollution and can contribute to developing trait-based biomonitoring tools in Africa.

Habitat quality in farmland influences the activity patterns of giant Galapagos tortoises

Many Galapagos giant tortoises make seasonal migrations from arid lowlands in the wet season, to humid highlands in the dry season. However, for critically endangered Western Santa Cruz giant tortoises (Chelonoidis porteri), at least 88% of the habitat in the highlands is now used for agriculture. To understand the impact of agricultural land use on tortoise behavior, we conducted 242 30-minute observations of tortoises on farms. We (1) recorded the time tortoises spent eating, walking, and resting in three different land-use types, (2) measured their temperature, and (3) quantified their selection of fine-scale vegetation characteristics. We found that tortoises rest for significantly longer periods when they are in abandoned land, compared to livestock, grazing, and touristic land. Generally, tortoises rested for longer when they were cooler. Time spent eating was increased by the density and proportion of ground vegetation, while time spent walking was reduced by tall vegetation. These findings suggest that the distribution of land-use types and the fine-scale composition of thermoregulatory and grazing resources within farmland have important implications for the behavior of tortoises while in human-modified land. Wildlife managers and landowners wishing to support tortoises on farms should focus on rehabilitating abandoned land and encouraging a heterogenous mix of sun and shade, and short ground vegetation across land-use types.

The impact of agricultural land use on the linkages between soil microbial communities and agroecosystem functioning is depth-dependent

Soil carbon (C) and nitrogen (N) mineralization rates are critical indicators of ecosystem functioning in agricultural land. However, the effects of agricultural land use on the interactions between soil C and N mineralization at different soil depths, especially in tropical regions, are poorly understood. Here, a longan orchard (LO) was converted to a conventional tea plantation (CTP) and an organic tea plantation (OTP) in the tropical region of China, and the responses of fungal and bacterial communities to these changes were assessed. The characteristics of the microbial communities, enzyme activities, and N and C mineralization rates were evaluated in response to the changes in land use. It was found that LO and OTP had faster N and C mineralization rates than CTP in surface soil. However, in subsurface soil, LO and OTP showed a faster C mineralization rate and a slower N mineralization rate than CTP. Structural equation modeling revealed that pH and C/N were the most crucial factors affecting N and C mineralization rates in surface soil. In contrast,soil bacterial and fungal community structures were the principal drivers of both the C and N mineralization in subsurface soil. Although soil C and net N mineralization were positively correlated in surface soil, this was not seen in subsurface soil. Collectively, this study demonstrated that differential drivers and their effects on the interactions between soil C and N mineralization at different soil depths should be considered for more accurate prediction of soil C and N dynamics under land-use changes.

Comprehensive monitoring of contamination and ecological-health risk assessment of potentially harmful elements in surface water of Maroon-Jarahi sub-basin of the Persian Gulf, Iran.

The increase in heavy metal concentration in water bodies due to rapid industrial and socio-economic development significantly threatens ecological and human health. This study evaluated metal pollution and related risks to ecology and human health in the Maroon-Jarahi river sub-basin in the Persian Gulf and Oman Sea basin, southwest Iran, using various indicators. A total of 70 water samples were taken from the sampling sites in the Maroon, Allah, and Jarahi sub-basins and analyzed for nine heavy metals. According to the results, the mean concentration of metals in the sampling locations across the entire sub-basin of Maroon-Jarahi was observed as follows Iron (528.22µg/L), zinc (292.62µg/L), manganese (56.47µg/L), copper (36.23µg/L), chromium (11.78µg/L), arsenic (7.09µg/L), lead (3.43µg/L), nickel (3.23µg/L), and cadmium (1.38µg/L). Most of the metals were detected at the highest concentration in the sub-basin of the Jarahi River. The Water Quality Index (WQI) index in the basin varied from 18.74 to 22.88, indicating well to excellent quality. However, the investigation of the pollution status at the monitoring stations, based on the classification of Degree of Contamination (CD) and Heavy Metal Pollution Index (HPI) indices, revealed that they are in the category of relatively high pollution (16 < CD < 32) to very high (32 ≤ CD), and in the low pollution category (HPI < 15) to high pollution (HPI < 30), respectively. According to the three sub-basins, the highest amount of WQI, HPI, and Cd was observed in the stations located in the sub-basins of the Jarahi River. The calculation of Heavy Metal Evaluation Index (HEI) also indicated that only 10% of the monitoring stations are in moderate pollution (10 < HEI < 20), while in other monitoring stations the HEI level is less than 10. The Potential ecological risk factors ( ) of an individual metal was obtained as follows: Cd (173.70) > As (131.99) > Zn (57.52) > Cu (55.39) > Ni (48.98) > Cr (21.57) > Pb (0.71), revealing that Cd and As are the main elements responsible for creating ecological risk in the studied area. The Maroon-Jarahi watershed included areas with ecological risks that ranged from low (PERI ≤ 150) to very high (PERI ≥ 600). HI and ILCR health indicators indicated that consumption and long-term contact with river water in the study area can cause potential risks to human health, especially children. Moreover, the findings, the highest level of pollution and health risk for both children and adults, considering both exposure routes, occurred in the Jarahi River sub-basin, suggesting that those who live in the vicinity of the Jarahi River are likely to face more adverse health effects. In addition, the findings of the evaluation of the relationship between land use patterns and water quality in the studied basin showed that agricultural lands acts as a main source of pollutants, but forest lands play an important role in the deposition of pollutants and the protection of water quality at the basin scale. In general, the results of pollution indicators, risk assessment, and statistical techniques suggest that the lower sub-basin, the Jarahi area, and the Shadegan wetland are the most polluted areas in the investigated sub-basin due to excessive discharge of agricultural runoff, industrialization, and rapid urbanization. Thus, special measures should be considered to reduce the risks of HMs pollution in the sub-basin of the Maroon-Jarahi watershed, especially its downstream and the impact of agricultural land use on water quality should be taken into consideration in basin management plans.

The Impact of Agricultural Land Use on Some Chemical Properties of Desert Soils in the Holy Karbala Governorate

The Impact of Agricultural Land Use on Some Chemical Properties of Desert Soils in the Holy Karbala Governorate

Climate mitigation technology for holistic resource management in sub-Saharan Africa: Impact on greenhouse gas emissions

This study investigates the impact of climate change mitigation technologies, specifically agricultural land management and renewable energy consumption and production, on greenhouse gas emissions (GHG) in sub-Saharan Africa (SSA) over the period of 1991 to 2015. Our analysis was conducted using an ARDL panel data model with data from 26 countries representing four sub-regions. The results demonstrated that an increase in renewable energy consumption is significantly associated with a decrease in GHG emissions, with a long-term coefficient of -0.422 and a short-term coefficient of -0.757. Additionally, natural resource rents, agricultural land use and population density have a positive impact on greenhouse gas emissions, with coefficients of 0.0605, 0.392 and 0.690, respectively. However, renewable energy production does not have a significant effect on greenhouse gas emissions. This suggests that promoting renewable energy consumption can be an effective way to combat greenhouse gas emissions in the region, and policymakers should implement policies and programs that encourage and facilitate the adoption of renewable energy whilst taking into consideration the impact of agricultural land use. Overall, this study emphasizes the importance of promoting renewable energy consumption and managing agricultural land use as a viable approach to combating greenhouse gas emissions in sub-Saharan Africa, and highlights the potential of climate mitigation technology as a tool for regulators to optimize policy development and counter climate change.

Association between early life exposure to agriculture, biodiversity, and green space and risk of inflammatory bowel disease: a population-based cohort study

Specific pollutants and environmental exposures are implicated in modulating inflammatory bowel disease (IBD) risk. However, the role of environmental exposures, particularly during the early life period, towards IBD risk, has not been systematically evaluated. We conducted a nationwide population-based cohort study during the study period extending from January 1, 1995, to September 1, 2020, using cross-linked Danish registers, maps, and inventories to ascertain the impact of agricultural land use, biodiversity, green space, urban space, blue space, and normalized difference vegetation index during pregnancy and the first two years of life on IBD, Crohn's disease (CD), and ulcerative colitis (UC) risk, using adjusted Cox proportional hazards regression analyses. We adjusted for covariates sex, maternal age at delivery, calendar year of birth, municipal-level socioeconomic status, and first-degree relative with IBD. Of 1,438,487 individuals included in the study who were followed from age 2 years until a median (IQR) age of 14 (8-20) years, 3768 individuals were diagnosed with IBD. Exposure to the second, third and highest quartiles of agriculture land use during early life, relative to the lowest quartile, were associated with increased CD risk (aHR 1.12, 95% CI 1.01, 1.26, 1.19, 95% CI 1.05, 1.34 and, 1.24 95% CI 1.06, 1.46, respectively). There was no association of agriculture land use with UC risk. Conversely, exposure to the third quartile of biodiversity in early life, compared to the lowest quartile, were associated with a lower CD risk (aHR 0.86, 95% CI 0.75, 0.98). A protective effect of greenspace was noted in the highest quartile for CD (aHR 0.87, 95% CI 0.78, 0.98). In a nationwide cohort with long-term follow up data, early life environmental exposures were associated with modulation of CD risk, with a harmful effect of agriculture land use and protective effect of biodiversity and green space. Danish National Research Foundation, the International Organization for the Study of Inflammatory Bowel Disease, the National Institute of Diabetes and Digestive and Kidney Diseases.

P1093 Early life exposure to agriculture and biodiversity influences Crohn’s disease risk in a population-based cohort study

Abstract Background Specific pollutants and environmental exposures are implicated in modulating inflammatory bowel disease (IBD) risk. Crohn’s disease (CD) clustering has been reported in agricultural areas. However, the role of environmental exposures, particularly in early life, towards IBD risk, has not been systematically evaluated. Methods We conducted a nationwide population-based cohort study during the study period extending from January 1, 1995, to September 1, 2020, using cross-linked Danish registers, maps, and inventories to ascertain the impact of agricultural land use, biodiversity, green space, urban space, blue space, and natural vegetation density index during pregnancy and the first two years of life on IBD, CD, and ulcerative colitis (UC) risk, using adjusted Cox proportional hazards regression analyses. We adjusted for the following covariates: sex, maternal age at delivery, calendar year of birth, municipal-level socioeconomic status, and first-degree relative with IBD. Results Of 1,438,487 individuals included in the study who were followed from age 2 years until a median (IQR) age of 14 (8-20) years, 3,768 individuals were diagnosed with IBD. Exposure to the highest and third quartiles of agriculture land use during early life, relative to the lowest quartile, were associated with increased IBD risk (aHR 1.16, 95% CI 1.02, 1.31 and 1.19, 95% CI 1.07, 1.32, respectively). Conversely, exposure to the highest and third quartiles of biodiversity in early life, compared to the lowest quartile, were associated with a lower IBD risk (aHR 0.90, 95% CI 0.82, 1.00 and 0.90, 95% CI 0.82, 0.99, respectively). These associations were driven by differences in CD risk (Figure), but there was no association with UC risk. Other environmental exposures were not associated with IBD risk. Conclusion In a nationwide cohort with long-term follow up data, early life exposure to agriculture land use was associated with an increase in CD risk, while higher biodiversity was protective.

Investigating the impacts of agricultural land use on soil earthworm communities: A case study of northern Zagros Mountains of Iran

Earthworms play a crucial role in the invertebrate community of soil by contributing to the belowground biomass and biogeochemical cycle. Environmental stresses, such as human activities and land use changes, have been found to negatively affect their abundance and diversity. To investigate the impact of agricultural land use and pastures on earthworms' genetic diversity in the Northern Zagros Mountains, we used COI molecular marker and DNA barcoding approaches. We collected earthworm specimens from four farmland sites and six pastures and assessed the abundance and species composition of earthworm communities across the two land uses using quadrat sampling. Using the barcoding method, we identified 13 molecular operational taxonomic units (MOTUs) among the captured earthworms. Our results showed that the number of total MOTUs, density, and earthworm communities differed significantly between the two land uses. We also found that pastures had more abundant earthworms, while farmlands had greater diversity. The diversity of OTUs in the Lumbricidae family was dominant in the agricultural system. Overall, the population of invasive earthworm species in cultivation systems is influenced by chemical inputs and organic materials from plant residues, cover crops, manure, or organic fertilizers. Given the rapid rate of land use change worldwide, especially in Iran, it is crucial to understand the impact of disturbances on earthworms.

Impact of Agricultural Land Use on Nematode Diversity and Soil Quality in Dalmada, South Africa

During a survey on soil nematode diversity, the soil samples were collected from Field-1 (3-months-not-used land), Field-2 (5-years-not-disturbed land), Field-3 (the rhizosphere of tomatoes), and Field-4 (natural land, not disturbed for 50 years), in Dalmada, Limpopo Province, South Africa. A total of 25 nematode genera were found to be associated with the surveyed plant species. The result showed Acrobeloides, Aphelenchus, Aporcella, Ditylenchus, Mesorhabditis, Pratylenchus, and Rotylenchus with a 100% frequency of occurrence. Meloidogyne was detected only in association with Field-3, with a low frequency of occurrence (25%). The study of the relationship between nematodes with physicochemical properties in the soil using Pearson correlation revealed that phosphate of the soil had a positive correlation (r = 0.977) with Bitylenchus and Pseudacrobeles species. In contrast, pH strongly correlated with Nanidorus (r = 0.928), Trypilina (r = 0.925), Xiphinema (r = 0.925), and Zeldia (r = 0.860). The principal component analysis placed Field-4 and Field-3 in two groups, indicating the biodiversity dynamics among the two locations. Soil texture showed that clay was correlated with Rotylenchulus. In contrast, soil texture had no effect on Meloidogyne. The Shannon index was the lowest (1.7) for Field-1 in Dalmada compared to the other Fields, indicating lower nematode diversity. The structure index showed that Field-2 was disturbed with a low C:N ratio. In contrast, Field-3 and Field-4 had suppressive soil but matured and fertile. The network analysis showed that Panagrolaimus was only found in Field-4 and was the most engaging genus describing soil quality in the soil system in Dalmada. In conclusion, Field-2 showed a high diversity of free-living nematodes than the disturbed land of tomatoes. Additionally, plant-parasitic nematodes numbered more in the rhizosphere of tomatoes. The results suggest that the soil nematodes, especially free-living bacterivores, may mediate the effects of ecosystem disturbance on soil health.

Impact of agricultural land use on distribution of microbial biomass and activity within soil aggregates

AbstractThe presence of aggregates of various sizes in the soil is an important condition for soil carbon sequestration. In this system, microbial biomass is a key link. This work was devoted to the study of the influence of land use systems on the distribution of SOС, MB‐SIR, microbial activity and eco‐physiological indices (qCO2, QR, MB‐SIR/SOС and qCO2/SOС) in relation to the size of soil aggregates. The distribution of SOС, MB‐SIR and mineralization activity among the aggregates was heterogeneous. In the soil of crop rotation, high mineralization activity and MB‐SIR were found in the aggregates 0.5–0.1 mm, in the monoculture soil in aggregates &lt;0.1 mm and in the control soil in the aggregates 1–0.25 mm. There was a general trend towards a decrease in microbial activity, MB‐SIR and SOС availability with an increase in aggregate size. In agricultural soils, microbial activity was determined by large aggregates (&gt;5 mm), while in the control soil, by the aggregates 5–1 mm. Depending on the type of site and the size of aggregates, the differences in microbial metabolism were revealed. The qCO2 and QR values decreased, and the MB‐SIR/SOС and qCO2/SOС increased in the series: control soil &gt; crop rotation &gt; monoculture. In the control soil, the values of the eco‐physiological indices decreased with decreasing aggregate size. And vice versa, in agricultural soils, these parameters were the highest in the microaggregates (&lt;0.25 mm). The monoculture soil, in contrast to the control soil and crop rotation soil, turned out to be more energy efficient.

Sustainable nutrition: a spatially explicit modeling approach for urban land use planning

Rapid urbanization has influenced the transformation of local and global food systems, altering the availability, access to, and distribution of healthy food. Micronutrient deficiency and hunger have been exacerbated worldwide. Balancing social, economic, and environmental needs and demands is complex, and often presents tradeoffs between nutritional security and sustainable practices. While various frameworks have been developed to support policy and decision makers in prioritizing tradeoffs that impact urbanization and food production, they are not easily operationalized due to complexities of implementation stemming from the availability of data, place-specific nuances, and methodological difficulties, among others. There is a need to develop analytical approaches to enable researchers, planners, and policymakers to better understand the impact of land use choices on sustainable local food production. The foodshed approach can be a powerful tool to improve the sustainability of regional and local food systems. This research proposes a simulation strategy to evaluate the impact of agricultural land use and crop choices on nutritional production in rapidly growing urban areas. The application of this framework for decision-making is exemplified in the Toluca Metropolitan Zone, Mexico by showing how tradeoffs between macronutrient and micronutrient daily requirements could be explored under a variety of land use scenarios. This analytical framework can be used to understand options for providing nutritional security to the local population.

The role of cover crops for cropland soil carbon, nitrogen leaching, and agricultural yields – a global simulation study with LPJmL (V. 5.0-tillage-cc)

Abstract. Land management practices can reduce the environmental impact of agricultural land use and production, improve productivity, and transform cropland into carbon sinks. In our study we assessed the biophysical and biogeochemical impacts and the potential contribution of cover crop practices to sustainable land use. We applied the process-based, global dynamic vegetation model LPJmL (Lund–Potsdam–Jena managed Land) V. 5.0-tillage-cc with a modified representation of cover crops to simulate the growth of grasses on cropland in periods between two consecutive main crops' growing seasons for near-past climate and land use conditions. We quantified simulated responses of agroecosystem components to cover crop cultivation in comparison to bare-soil fallowing practices on global cropland for a period of 50 years. For cover crops with tillage, we obtained annual global median soil carbon sequestration rates of 0.52 and 0.48 t C ha−1 yr−1 for the first and last decades of the entire simulation period, respectively. We found that cover crops with tillage reduced annual nitrogen leaching rates from cropland soils by medians of 39 % and 54 % but also the productivity of the following main crop by an average of 1.6 % and 2 % for the 2 analyzed decades. The largest reductions in productivity were found for rice and modestly lowered ones for maize and wheat, whereas the soybean yield revealed an almost homogenously positive response to cover crop practices replacing bare-soil fallow periods. The obtained simulation results of cover crop with tillage practices exhibit a good ability of the model version to reproduce observed effects reported in other studies. Further, the results suggest that having no tillage is a suitable complementary practice to cover crops, enhancing soil carbon sequestration and the reduction in nitrogen leaching, while reducing potential trade-offs with the main-crop productivity due to their impacts on soil nitrogen and water dynamics. The spatial heterogeneity of simulated impacts of cover crops on the variables assessed here was related to the time period since the introduction of the management practice as well as to environmental and agronomic conditions of the cropland. This study supports findings of other studies, highlighting the substantial potential contribution of cover crop practices to the sustainable development of arable production.

Changes in Selected Water Quality Parameters in the Utrata River as a Function of Catchment Area Land Use

Surface waters are very important for society, as they are a source of potable water, as well a water supply for agricultural, industrial and recreational purposes. This paper presents changes in the quality of the water in the Utrata River, along its entire length, as a function of the catchment area’s land use. Water-quality measurements were carried out once a month for a total period of one year (April 2019–March 2020) at 24 measurement points. The concentrations of the following compounds were measured: total phosphorus, ammonia nitrogen and nitrate nitrogen, dissolved oxygen, and chemical oxygen demand. The results were compared with the limit values specified in the Regulation of the Minister of Maritime Economy and Inland Navigation. In order to determine the impact of land use on water quality in the Utrata River, principal component analyses (PCA) were conducted. The research demonstrated a considerably negative impact of agricultural land use and the presence of urban areas on the water quality of the Utrata River, with elevated concentrations of total phosphorus, ammonia nitrogen, nitrate nitrogen and COD, and decreasing concentrations of dissolved oxygen. The presented results point to the need for effective strategies to mitigate the adverse impact of agriculture and urbanisation on the environment and surface waters.

The Effects of Land Use on Concentrations of Nutrients and Selected Metals in Bottom Sediments and the Risk Assessment for Rivers of the Warta River Catchment, Poland

Changes in the environment, aiming at agricultural intensification, progressive urbanisation and other forms of anthropopression, may cause an increase in soil erosion and a resulting increase in the pollution inflow to surface water. At the same time, this results in increased nutrient pollution of bottom sediments. In this study, the concentrations of total nitrogen (TN), total phosphorus (TP), total organic carbon (TOC), calcium (Ca), iron (Fe) and potassium (K) were analysed using bottom sediment samples collected at 39 sites located along the entire length of the Warta River and its tributaries. Agricultural use of land adjacent to rivers was found to significantly degrade sediment quality, while anthropogenic land use (as defined by Corine Land Cover classification—CLC), unlike previous studies, reduces the pollution loads in the bottom sediments. Forest use also contributes to the reduction of the pollution load in sediments. It was found that the significance of the relationship between pollutant concentrations and land use depends on the length of the river–land interface. According to the analyses, the level of correlation between the analysed constituents depends on the use of land adjacent to rivers. The impact of agricultural land use has the strongest effect in the 1 km zone and 5 km in the case of anthropogenic land use. The results showed that the variability of total phosphorus TP concentrations is strongly correlated with the variability of iron concentrations. SPI values indicate that the risk to sediment quality is low due to TOC and Fe concentrations. In contrast, the risk of sediment pollution by TN and TP shows greater differentiation. Although the risk is negligible for 40% of the samples, at the same time, for 33% of the samples, a very high risk of pollution with both TN and TP was found.

Soil microbial community, enzyme activity, C and N stocks and soil aggregation as affected by land use and soil depth in a tropical climate region of Brazil.

The impact of agricultural land-use on soil microbial community composition and enzyme activity has not been extensively investigated in Ultisols. We investigated soil health parameters by analyzing phospholipid fatty acids (PLFAs), extracellular enzyme activity, C and N stocks, and soil structure. Four land uses were established in a tropical climate region of Brazil: native Cerrado (savanna), monoculture pasture [Urochloa brizantha (Hochst. Ex A. Rich.) R. Webster 'Marandu'], an integrated crop-livestock system (ICLS), and maize (Zea mays)-fallow in a no-tillage system. Soil microbial biomass was 40% higher in the native Cerrado than in the monoculture pasture, ICLS, and no-tillage maize. Soil organic carbon was positively correlated with microbial community composition (MB; gram-; AC; AMF; Fungi; F: B ratio) and enzyme activity (bG, AP, NAG). Large macroaggregates were positively correlated with bG, AP, and AMF. In summary, the native Cerrado had a higher level of carbon at the soil surface and greater soil structure with increased microbial biomass, gram+ bacteria, AMF, fungi, and F:B ratio in a tropical region of Brazil. However, bG and AP enzyme activities were lower in the ICLS and no-till maize at the soil surface (0-5cm) compared to the native Cerrado. The conversion of native Cerrado to agricultural systems shifted the soil microbial community composition, enzyme activity, C and N, and soil structure of this sandy soil of the Brazilian Cerrado.

Impact of agricultural land use and economic growth on nitrous oxide emissions: Evidence from developed and developing countries

The environmental Kuznets curve (EKC) establishes a hypothetical link between economic growth and environmental degradation and has been tested empirically using various measures of pollution, including carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions. However, few studies have focused on N2O emissions, despite their projected lifetime of 114 years and 300 times greater warming potential than CO2. Employing panel data for the period 1980 to 2012, this study uses the EKC to investigate N2O emissions, including those resulting from agriculture, economic growth, agricultural land use, and exports. Two groups of data are extracted from the panel data: the first group contains the top 15 countries, ranked by N2O emissions, measured in thousand metric tons of CO2, while the second group contains the top 18 countries, ranked by share of agriculture in GDP. A pooled mean group approach developed by Pesaran et al. (1999) is used to determine whether long-run relationships exist between the variables after determined by the Hausman test. The results show that N2O emissions and economic growth are co-integrated in both panels, providing evidence in favour of the EKC. In addition, agricultural land use has a positive and significant effect on N2O emissions. That is, if countries wish to reduce their N2O emissions or agricultural N2O emissions, they should optimize or reduce the use of agricultural land.

Impact of agricultural land use on soil organic carbon sequestration at sub-catchment scale

Soil organic carbon (SOC) pool determines the potential of soil to perform ecosystem services and maintain climatic stability. Land use plays a significant role in determining the carbon (C) sequestration in soil. This study aimed to determine the impact of long-term agricultural land uses on SOC and other physico-chemical properties and to determine interrelationships between SOC stock and topographic variables at sub-catchment scale in upcountry of Sri Lanka. Soil samples were collected from surface (0-30 cm) and subsurface (30-60 cm) at 109 locations from vegetable (n = 42), tea (n = 44) and forest (n = 23) land uses in a sub-catchment (360 ha) in Nuwara Eliya. Average SOC in different land uses were compared by analysis of variance followed by Tukey post-hoc mean comparison. The largest surface SOC stock was observed in forested area (71.8 Mg/ha) followed by vegetable lands (61.8 Mg/ha) and it was significantly lesser in tea lands (50.7 Mg/ha). The forest soils showed the largest subsurface SOC stock (67.1 t/ha) as well, followed by tea (64.8 Mg/ha) and vegetable (57.9 Mg/ha) land uses. No significant relationship was observed between SOC stock and topographic variables, namely elevation, slope, wetness index and stream power index. This study concludes that the land use is a key determinant of the spatial heterogeneity of SOC and forest have the greater ability of sequestering C compared to vegetable and tea land uses in the studied sub-catchment area.

Impact of agricultural land use on physicochemical properties of soils derived from sedimentary rocks in Malaysia

ABSTRACT In Malaysia, soils derived from sedimentary rocks are extensively used for agricultural purposes with oil palm and rubber being the main dwellers. In order to understand the environmental impact of these perennial crops planting, the variability of physicochemical properties of 25 representative soils derived from sedimentary rocks under different ecosystems (agriculture land and natural forest) at six study sites spread across Malaysia was examined. Among the soil physicochemical properties, total soil organic carbon, total nitrogen, and fertility level were found to be generally higher in the forest ecosystems followed by rubber plantation and finally oil palm plantations. Likewise, projection of principal component analysis showed an associative relationship between soil physicochemical properties and microhabitats. Finally, this study showed that soils from different agricultural and natural sites, but derived from similar sedimentary rocks, had distinctive weathering conditions and soil properties. Therefore, site-specific field management according to soil type, soil management techniques as well as fertilizer strategies are required to maximize crop production and to sustain ecosystem services. The output of this study will enable farmers to improve their crop yield via the selection of suitable crops cultivation based on soil characteristics.