Major Agricultural Land Research Articles

Recent increase in sediment dry matter, carbon, and phosphorus accumulation in small boreal lakes with clayey catchments

This study estimated the mass accumulation rates of sediment (MAR), carbon (CMAR), and phosphorus (PMAR) in small Finnish lakes with agricultural clayey catchments over a 25-year period (1986–2011) and compared these with the conditions before major agricultural land use. Twenty-two lakes were cored for recent and reference (pre-disturbance) sediments. The recent sediment section was selected based on the 1986 137Cs fallout peak (TOP), whereas the pre-disturbance section (REF) was selected immediately below the first signs of human-induced erosion. The 50-cm reference section was dated with 14C at both ends. The mass accumulation rates were estimated based on dating, weighing, and chemical analysis for both sediment sections. Furthermore, sediment-penetrating echo soundings were used to estimate the amount of sediment in the whole lake basins. These data were used to examine area-specific loading from clay-rich catchments. The average whole-basin pre-disturbance MAR, PMAR, and CMAR were 62 g m−2 a−1, 0.06 g m−2 a−1, and 4.7 g m−2 a−1, respectively. The corresponding recent rates were 11, 13, and 8-fold (693 g m−2 a−1, 0.79 g m−2 a−1, and 37 g m−2 a−1). In the recent conditions, sediments were generally more minerogenic and MAR, PMAR, and CMAR were higher in lakes with more arable fields in their catchments. Average area-specific suspended sediment load from the catchment for the region (∼39% clayey soils) was approximately 69–137 kg ha−1 a−1 in the undisturbed state and 767–1534 kg ha−1 a−1 in recent conditions based on 100–50% retention. The results demonstrate that the increases in sediment, nutrient, and organic matter accumulation due to agriculture can be several fold over undisturbed state.

Associational susceptibility of crop plants caused by the invasive weed Canadian goldenrod, Solidago canadensis, via local aphid species

In the present study, field surveys were conducted to detect potential associational susceptibility of crop plants (potato, alfalfa and maize) caused by Canadian goldenrod, Solidago canadensis (L.), one of the most common invasive weeds in Central and Eastern Europe, via plant associated virus vectoring aphids. Assessments were made in two major agricultural land types: crops grown under high input vs. low-input (LIF) conditions, with and without fertilizers and pesticides. The two most frequent aphid species, found both on Canadian goldenrod and crop plants, were the leaf-curling plum aphid, Brachycaudus helichrysi Kaltenbach and the glasshouse-potato aphid, Aulacorthum solani (Kaltenbach). Plant viruses in both weed and crop plants were identified using high-throughput sequencing of small RNAs. Peroxidase (POD) enzyme activity was tested in weed and crop plants to connect aphids feeding processes in weeds and crops. In addition, conceptual modeling was used to detect direct relationships between viruses and other crops. The Canadian goldenrod density was only relevant in the LIF regime. Furthermore, its association with B. helichrysi and associational susceptibility was detected only in LIF. In total, 18 viruses comprising 17 plant and one insect virus were detected in Canadian goldenrod, of which 11 were also detected in potato and alfalfa crops. POD activity was high and correlated with high aphid density in both weed and crop plants, suggesting a direct associational susceptibility between these plants through aphid infestation and viral transmission.

Agricultural landscape change impact on the quality of land: An African continent-wide assessment in gained and displaced agricultural lands

Agricultural land area is increasing globally despite the loss of productive agricultural lands in some world regions. We examine the case of Africa where the knowledge about major agricultural land transitions and the impacts on the quality of land is still very limited. A comprehensive assessment of change in agricultural landscapes was conducted at the African continental scale. We identify influencing factors and model the quality of land associated with agricultural land gains and losses between 2000 and 2018. Land quality was established based on spatially-explicit analysis of varying Net Primary Productivity, soil organic carbon content, crop suitability and percent yield change for major crops of global importance grown across Africa such as maize, rice, soybean, wheat, and alfalfa. Distance to settlements was important in explaining agricultural land dynamics. Most land areas that transitioned to cropland in Africa were associated with large distances away from major roads. Poor access to major roads suggests the remoteness of gained croplands. Land quality was better in gained croplands than in those lost, whereas gained grasslands were of lesser quality compared to areas of grassland loss. Five typologies of African countries were developed based on net yield and amount of land cultivated per crop in cropland change areas. Type 1 typifies net yield increase and cultivated land decrease, while type 2 is characterized by yield increase consequent upon cropland expansion. Net yield and land remain unchanged in type 3, while in type 4 cultivated land increased but yield decreased as in 40% of African countries for maize, and in type 5, both yield and land area decreased. This study thus provides evidence about the quality of land in gained and lost agricultural areas and generalizable insights on their dynamics across Africa.

Examining the carbon emissions and climate impacts on main agricultural crops production and land use: updated evidence from Pakistan.

One of the major challenges to the survival of life on earth is the increasingly evolving climate change. The key source of environmental pollution is global warming. With the combustion of fossil fuels, greenhouse gas (GHG), which is generated in the external environment, is increased and air pollutant as well. The present analysis key intention was to examine the CO2 emission and climatic effects on major agricultural crop production and land use in Pakistan. The study used time span annual data varies from 1970 to 2019, and data stationarity was rectify by utilizing the unit root tests. A generalized method of moments with two-stage least squares technique was applied to expose the variables' association with CO2 emission. The study consequences uncover that the wheat, maize, sugarcane, cotton, bajra, gram, sesamum crops, and land use have constructive association with CO2 emission having positive coefficients with probability values (0.3762), (0.0435), (0.2287), (0.2303), (0.2272), (0.0192), (0.4535), and (0.0017) correspondingly, while rainfall, temperature, rice, jowar, and barley uncovered an adversative linkage to CO2 emission in Pakistan. As Pakistan is an emerging country, potential constructive measures must be introduced in directive to reduce CO2 emissions to improve the agricultural productivity.

Monitoring of Atrazine Pollution and its Spatial-Seasonal Variation on Surface Water Sources of an Agricultural River Basin.

Surface water sources are greatly impacted in areas with major agricultural land use. The atrazine quantification in surface waters as well as the spatial-temporal patterns of this herbicide was studied to detect pollution hotspots and to understand the putative factors responsible of its occurrence at the Ctalamochita river basin. The samples were collected on the aeolian fluvial plain of the river basin during five consecutive years. The results showed the high ubiquity of this compound and several sites with hazardous concentration (exceeding 0.1µg/L international guidelines). The frequencies of quantification range from 67 to 100% in spring and 33%-67% in autumn. The atrazine content in surface water increased during the warm-rainy season, as consequence of atrazine application events (coinciding to the prevalent crop type). Overall, the study highlights the factors that could have favored atrazine pollution in the river basin such as land use, transport by runoff processes and atmospheric deposition.

Ecosystem services from (pre-)Alpine grasslands: Matches and mismatches between citizens’ perceived suitability and farmers’ management considerations

The integration of socio-cultural assessments in ecosystem services research has increased steadily over the last years. However, the stakeholders’ perception of ecosystem services from grasslands, a major agricultural land cover in (pre-)Alpine landscapes, has received only limited attention. Furthermore, studying the heterogeneity of perceptions within stakeholder groups is a major scientific need. In this study, we examined the perceptions of farmers and citizens regarding grassland ecosystem services, specifically the matches and mismatches between perceived suitability of grasslands and importance assigned by farmers in their management considerations. We conducted surveys in a study area in southern Bavaria, Germany, in 2018. Overall, ecosystem services that citizens perceived as very suitable to be provided by grasslands aligned well with the ecosystem services that are highly important to farmers in their management considerations, but significant mismatches also existed among all categories of ecosystem services. Clustering and dimension reduction revealed two clusters of farmers and three clusters of citizens depending on farm characteristics and environmental attitudes, respectively. Redundancy analysis showed a strong influence of the stakeholder cluster on the perception of the services assessed. Furthermore, age and gender influenced the perceptions attached to grassland ecosystem services.

Effects of Replanting and Retention of Mature Oil Palm Riparian Buffers on Ecosystem Functioning in Oil Palm Plantations

Oil palm plantations are a major agricultural land use in Southeast Asia. In the coming decades large areas of mature oil palm will be cleared and replanted. To inform more sustainable long-term production in this globally important crop, it is crucial we understand how replanting impacts ecosystem functions and services. We investigated whether several production-relevant ecosystems functions (dung removal, soil mesofauna feeding activity, herbivory, herbivore predation, and seed predation), and the simultaneous delivery of all functions (ecosystem multifunctionality), vary between recently-replanted oil palm (1-4 yr) and mature oil palm (23-30 yr) areas. Following new in-country and Roundtable on Sustainable Palm Oil (RSPO) guidelines, riparian buffers of mature oil palm, in which subsequent natural regrowth is allowed, are being preserved during the replanting cycle in plantations that lack natural forest reserves. We investigated whether or not mature oil palm riparian buffers maintain levels of ecosystem functioning beneficial for palm oil production. Only one function (herbivory) differed between mature and replanted areas, with higher levels of herbivory found in recently replanted oil palm. There was no difference in ecosystem multifunctionality between mature and recently-replanted oil palm. Mature oil palm riparian buffers were found to be valuable for maintaining lower levels of herbivory than recently-replanted oil palm. However, no other functions, nor ecosystem multifunctionality, differed between the mature oil palm riparian buffers and recently-replanted oil palm. The results of this study suggest that replanting has limited impacts on the ecosystem functions we considered. Furthermore, they suggest mature oil palm riparian buffers do not have negative impacts on production-relevant ecosystem functions in oil palm landscapes.

IDENTIFICATION OF RIVER BANK EROSION AND INUNDATION HAZARD ZONES USING GEOSPATIAL TECHNIQUES – A CASE STUDY OF INDUS RIVER NEAR LAYYAH DISTRICT, PUNJAB, PAKISTAN

This study aims to assess an area of about 70 km along Indus River in Layyah and Muzaffargarh districts of Punjab, Pakistan, which is highly vulnerable to erosion. Actual erosion and deposition has been quantified for each of left and right bank of river over a period of 2002 to 2016. Open source data product of Landsat is used to identify the spatio-temporal changes of Indus River. A model has been developed that extracted the water from satellite images using NDWI. River path of Indus has been mapped for 2002, 2009 and 2016 during high and low flow seasons which not only signifies the channel shifting and river morphology, but also highlights the zones where water over run into land. It has been observed from the study that river is shifting more towards its left bank and the area is highly vulnerable to erosion. In 2009, river eroded 24.3 km2 from right bank while it eroded 100 km2 from left bank. Similarly, in 2016, 12.5 km2 and 71.9 km2 eroded from right and left bank respectively. The river inundation eroded the major agricultural land and affected the life of people and infrastructure. Results provide the latest and reliable information on the dynamics of Indus River in the study area which can be utilized to develop erosion control program and taking practical measures to ensure the safety of life and infrastructure.

Monitoring of 45 pesticides in Lebanese surface water using Polar Organic Chemical Integrative Sampler (POCIS)

The aim of this study is to assess the dissolved concentration of 45 pesticides in the surface waters of the Lebanese Republic using Polar Organic Chemical Integrative Sampler "POCIS". All of the sampling sites are located in the major agricultural land areas in Lebanon. POCIS (n = 3) were deployed at Ibrahim River, Qaraoun Lake and Hasbani River for a duration of 14 days. The total concentration of pesticides ranged from not detected (nd) to 137.66 ng.L-1. Chlorpyrifos, DDE-pp, diazinon and Fenpropathrin were the most abundant compounds. Qaraoun Lake and Hasbani River were found to be more polluted than Ibrahim River, since they receive large amounts of waste water derived from nearby agricultural lands and they had the lowest dilution factor. The aqueous average concentration of the target compounds were estimated using sampling rates obtained from the literature. Comparison between Time Weighed Average concentrations "TWA" using POCIS and spot sampling is presented. Results showed that POCIS TWA concentrations are in agreement with spot sampling concentrations for Ibrahim and Hasbani Rivers. The toxicity of the major detected pesticides on three representative aquatic species (Daphnia magna, Scenedesmus quadricauda and Oncorhynchus mykiss) is also reported.

Characterizing major agricultural land change trends in the Western Corn Belt

In this study we developed annual corn/soybean maps for the Western Corn Belt within the United States using multi-temporal MODIS NDVI products from 2001 to 2015 to support long-term cropland change analysis. Based on the availability of training data (cropland data layer from the USDA-NASS), we designed a cross-validation scheme for 2006–2015 MODIS data to examine the spatial generalization capability of a neural network classifier. Training data points were derived from a three-state sub-region consisting of North Dakota, Nebraska, and Iowa. Trained neural networks were applied to the testing sub-region (South Dakota, Kansas, Minnesota, and Missouri) to generate corn/soybean maps. Using a default threshold value (neural network output signal⩾0.5), the neural networks performed well for South Dakota and Minnesota. Overall accuracy was higher than 80% (kappa>0.55) for all testing years from 2006 to 2015. However, we observed high variation of classification performance for Kansas (overall accuracy: 0.71–0.82) and Missouri (overall accuracy: 0.65–0.77) for various testing years. We developed a threshold-moving method that decreases/increases threshold values of neural network output signals to match MODIS-derived corn/soybean acreage with the NASS acreage statistics. Over 70% of testing states and years showed improved classification performance compared to the use of a default 0.5 threshold. The largest improvement of kappa value was about 0.08. This threshold-moving method was used to generate MODIS-based annual corn/soybean map products for 2001–2015. A non-parametric Mann-Kendall test was then used to identify areas that showed significant (p<0.05) upward/downward trends. Areas showing fast increase of corn/soybean intensities were mainly located in North Dakota, South Dakota, and the west portion of Minnesota. The highest annual increase rate for a 5-km moving window was about 6.8%.

Spatial distribution of triazine residues in a shallow alluvial aquifer linked to groundwater residence time

At present, some triazine herbicides occurrence in European groundwater, 13years after their use ban in the European Union, remains of great concern and raises the question of their persistence in groundwater systems due to several factors such as storage and remobilization from soil and unsaturated zone, limited or absence of degradation, sorption in saturated zones, or to continuing illegal applications. In order to address this problem and to determine triazine distribution in the saturated zone, their occurrence is investigated in the light of the aquifer hydrodynamic on the basis of a geochemical approach using groundwater dating tracers (3H/3He). In this study, atrazine, simazine, terbuthylazine, deethylatrazine, deisopropylatrazine, and deethylterbuthylazine are measured in 66 samples collected between 2011 and 2013 from 21 sampling points, on the Vistrenque shallow alluvial aquifer (southern France), covered by a major agricultural land use. The frequencies of quantification range from 100 to 56% for simazine and atrazine, respectively (LQ=1ngL-1). Total triazine concentrations vary between 15 and 350ngL-1 and show three different patterns with depth below the water table: (1) low concentrations independent of depth but related to water origin, (2) an increase in concentrations with depth in the aquifer related to groundwater residence time and triazine use prior to their ban, and (3) relatively high concentrations at low depths in the saturated zone more likely related to a slow desorption of these compounds from the soil and unsaturated zone. The triazine attenuation rate varies between 0.3 for waters influenced by surface water infiltration and 4.8 for water showing longer residence times in the aquifer, suggesting an increase in these rates with water residence time in the saturated zone. Increasing triazine concentrations with depth is consistent with a significant decrease in the use of these pesticides for the last 10years on this area and highlights the efficiency of their ban.

English

The current agriculture land uses around Kibale National Park forest have been expanding towards the forest area threatening its conservation efforts and this has contributed to crop raiding and destruction to the neighbouring agricultural communities. This study was conducted to identify and assess the suitability of major agricultural land uses around Kibale National Park. The major agricultural land uses included; Banana (Musa spp), Maize (Zea mays) and Tea production (Camellia sinensis) and these were identified using three randomly selected transects of 5 km per transect, and obtaining information using a structured questionnaire administered to 30 key farming households near Kibale National Park. Soil samples were also taken within the identified major agricultural land uses at the depths of 0-15 and 15-30 cm. Physical suitability of the major agricultural land-uses was assessed by matching their requirements with existing land qualities extracted from the Uganda soil memoires. Results showed that, western part of Kabarole District is highly suitable for tea production, the southern part is highly suitable for maize and the northern part is highly suitable for banana. The central part of Kabarole was found to be highly suitable for both banana and maize. The study finally recommended a buffer zone of 3.5 km from the national park planted with tea and eucalyptus around the national park boundary for crop defense separating agricultural communities and Kibale National Park since there not affected by animal raids and destruction. Key words: Major agricultural land use, land qualities, land suitability.

Chemical and physical amelioration of subsoils has limited production benefits for perennial pastures in two contrasting soils

While broad acre grazing is the major agricultural land use in Southern Australia, there has been comparatively little research on the effect of alleviating subsoil limitations on pasture production under field conditions. The effect of modifying the physical and chemical properties of soil on perennial pasture production and root distribution was studied on 2 major soil types in two regions of Southern Victoria, Australia. Soil treatments included the deep placement of fertilisers, lime and organic matter, and soil disturbance to a range of depths. The Ellinbank field site on a Ferrasol was monitored for 2 years, while the Curdievale site on a Sodosol was monitored for 1 year. There were substantial changes in soil physical and chemical characteristics as a result of the soil treatment. Soils were softer, less acidic and had increased nutrient availability within the profile. However, these changes did not result in consistent gains in pasture productivity, over-and-above the normal practice of surface applied nutrients and lime. The deep placement of organic matter at the Ellinbank site resulted in an initial increase in pasture production, but this effect declined with time. The perennial ryegrass (Lolium perenne L.) based pasture was shallow-rooted and substantial modifications to the soil profile did not result in significant changes to root distribution. It appears that the productivity of perennial ryegrass pasture in high rainfall regions can be maintained at a productive level, with a localised nutrient and water supply.

Agricultural land use dynamics in the Brazilian Amazon based on remote sensing and census data

The potential impact of deforestation in the Brazilian Amazon on greenhouse gas emissions to the atmosphere calls for policies that take account of changes in forest cover. Although much research has focused on the location and effects of deforestation, little is known about the distribution and reasons for the agricultural uses that replace forest cover. We used Landsat TM-based deforestation and agricultural census data to generate maps of the distribution and proportion of four major agricultural land uses throughout the Brazilian Amazon in 1997 and 2007. We built linear and spatial regression models to assess the determinant factors of deforestation and those major agricultural land uses – pasture, temporary agriculture and permanent agriculture – for the states of Pará, Rondônia, and Mato Grosso. The data include 30 determinant factors that were grouped into two years (1996 and 2006) and in four categories: accessibility to markets, public policies, agrarian structure, and environment. We found an overall expansion of the total agricultural area between 1997 and 2007, and notable differences between the states of Pará, Rondônia, and Mato Grosso in land use changes during this period. Regression models for deforestation and pasture indicated that determinant factors such as distance to roads were more influential in 1997 than in 2007. The number of settled families played an important role in the deforestation and pasture, the effect was stronger in 2007 than 1997. Indigenous lands were significant in preventing deforestation in high-pressure areas in 2007. For temporary and permanent agricultures, our results show that in 1997 the effect of small farms was stronger than in 2007. The mapped land use time series and the models explain empirically the effects of land use changes across the region over one decade.

Nitrous oxide emissions from a legume pasture and the influences of liming and urine addition

Nitrous oxide (N 2O) is a potent greenhouse gas contributing to global radiative forcing. Grazed legume pasture is one of the major agricultural land uses in southern Australia and no N 2O emission studies have been undertaken previously on this system. A study over 1 year has been undertaken measuring N 2O emissions from legume pasture at Wagga Wagga, Australia. The study was embedded within a larger on-farm study of the management of acid soils. Sampling involved simultaneous N 2O emission measurements on two paddocks each of: acidic soil with pH 4.0; limed soil with soil pH 5.5, and limed soil with addition of 20 g N m −2 of animal urine. The average emission of N 2O from the acidic legume pasture was 0.35 kg N ha −1 y −1 with a standard error of 0.03 kg N ha −1 y −1. Isotope measurements indicated that in aerobic conditions the ratio of N 2O emissions to gross mineralisation was 0.01–0.05%. Liming did not make a significant change to the average N 2O emissions. The average of daily N 2O emissions are: for the acidic plots 0.96 ± 0.07 mg N m −2 d −1 and for the limed plots 0.88 ± 0.04 mg N m −2 d −1. We conclude that under the conditions experienced at Wagga Wagga, which are typical of many Australian pastures, liming does not change the N 2O emissions. Measurements from the urine-treated soil showed that between 0.1 and 0.2% of the nitrogen in the urine was released as N 2O. These and a compilation of other emission factors for N 2O emissions from urine addition to pasture give a median emission factor of 0.7%, significantly smaller than the two default values of 2% and 1% recommended by the Revised 1996 and the 2006 IPCC Guidelines for National Greenhouse Gas Inventories.

Using the NZ–DNDC model to estimate agricultural N2O emissions in the Manawatu–Wanganui region

Nitrous oxide (N2O) emissions are difficult to quantify at regional and national scales. There is considerable spatial and temporal variability in N2O emissions from soil, partly because of variability in the underlying biogenic processes responsible for soil N2O production. The process-based NZ–DNDC (New Zealand Denitrification-Decomposition) model was used, with georeferenced input data on soils, climate and land use, to map and predict net N2O emissions from farming in the Manawatu–Wanganui region. The Manawatu–Wanganui region has a temperate, maritime climate and the major agricultural land use is pastoral grazing. We created databases of regional soil, climate and farm management information from various available data sources including national databases of climate, soil type and land use, and national agricultural production statistics. The error introduced by upscaling the model was assessed by comparing results using measured site data with the corresponding predictions using the regional approximations. We also examined the effect of climate conditions by rerunning the 2003 simulation using the climate data for the years ended June 1990 and 2004. The modelled net N2O emissions for this region for the year ended June 2003 were 4.6 ± 1.5 Gg N2O–N per year. The total fertiliser and excretal N inputs for the region were approximately 224,140 tonnes, so the percentage emitted as N2O was 2.0 ± 0.7%. The modelled net N2O emissions for the region for the year ended June 1990 were 3.8 ± 2.1 Gg N2O–N per year, indicating annual net N2O emissions in the Manawatu–Wanganui region between 1990 and 2003 had increased by 0.8 ± 0.6 Gg N2O–N (an increase of about 20%). This change can be attributed to both changes in weather conditions and land use and farm management between 1990 and 2003.

Eco-balance analysis of six agricultural land uses in the Ikushunbetsu watershed

This study quantified and evaluated the greenhouse gas emissions of farmland soils at a watershed scale using parameters available at a regional scale. The estimation was based on field monitoring data in the Ikushunbetsu River Watershed, Hokkaido, Japan. Simple regression models were created for carbon dioxide, nitrous oxide and methane emissions associated with six major agricultural land uses, and forest as an alternative land use to farmland. An eco-balance method involves conducting an analysis on the basis of farmland surplus nitrogen (N) and global warming potential (GWP). Uncertainties associating the estimations were estimated using Mote Carlo simulation. The eco-balance is the analysis of the relationship between production and environmental load. In this study, production and environmental load were compared by changing each of the land use combinations by 10%. Farmland surplus N was lowest for soybean with 8.2 kg N ha−1 year−1, followed by paddy rice. The highest value was recorded for vegetables with 99.8 kg N ha−1 year−1. The weighted mean of total farmland based on the land use proportion was 44 ± 33.8 kg N ha−1 year−1. The calculated GWP was 7.3 Mg CO2 eq ha−1 year−1 for paddy rice and 0.1 to 6.8 Mg CO2 eq ha−1 year−1 for upland crops. The weighted mean of the total farmland area was 4.0 ± 3.4 Mg CO2 eq ha−1 year−1. The eco-balance analysis showed that there were 59 combinations out of 8008 combinations able to reduce GWP more than 6%, but less than 7%, than the value in 2005. Among them, in 30 combinations, farmland surplus N became less than the value in 2005; production was reduced compared with the value in 2005 in 27 combinations. Soybean occupied 20–80% in the seven combinations where production was increased compared with 2005, while keeping farmland surplus N below the value in 2005. The estimation of greenhouse gases in this study exhibited high uncertainty because of variability in management and errors in evaluation procedures. Quantification of the data variability is set at maximum, which comprises the measured values in this area. Based on the quantification of the uncertainty, more efficient quantification methods can be established to clarify mitigation potential. This type of quantification and comparison between production and emission enables decision makers to set some threshold values that allow a compromise between production and environmental load.

Agricultural land-use change in Brazilian Amazônia between 1980 and 1995: Evidence from integrated satellite and census data

As cropland and pasture have replaced forest and cerrado in Brazilian Amazônia, concern has mounted over the effects of changing the biogeochemical and hydrological properties of one of the world's great storehouses of biomass and biodiversity. Although much recent effort has focused on the location, effects, and causes of deforestation and cerrado conversion, much less is known about the basin-wide spatial distribution and density of the land use following conversion for crops or pasture. In this paper, we use census and satellite records to develop maps of the distribution and abundance of major agricultural land uses across 4.5×10 8 ha of Brazilian Amazônia in 1980 and 1995. Results indicate an overall expansion of 7.0×10 6 ha in total agricultural area in Brazilian Amazônia between 1980 and 1995. The net change during this period is estimated for three different land-use types: croplands (an increase of 0.8×10 6 ha), natural pastures (a decrease of 8.4×10 6 ha), and planted pastures (an increase of 14.7×10 6 ha). These estimates, the first spatially explicit quantifications of agricultural land-use activities in 1980 and 1995 across Brazilian Amazônia, are shown to be consistent with the results of applying a land use change and secondary regrowth model to published deforestation rates for the period. The resulting time slices, presented for each land-use category at 5-min (∼9 km) spatial resolution, allow for the quantification of land-use changes in this region for biogeochemical, demographic and economic models. Several foci of agricultural change existed within Brazilian Amazônia during this period: in the state of Pará, cropland was lost and planted pasture increased markedly; in Mato Grosso, both cropland and planted pasture increased; in Rondônia, planted pasture replacing forest was the primary route to agricultural expansion.

The impact of climate change on the soil/moisture regime of Scottish mineral soils

The likely impact of climate change on the moisture regime of Scottish soils and consequently on agriculture and land use has been addressed using a novel Geographic Information Systems (GIS) approach. Current estimates of changes in summer precipitation by the year 2030 are 0% with an associated uncertainty of ±11%. This study considers the worst case scenario of a decrease in rainfall by 11% which will lead to some low rainfall areas experiencing an increased drought risk, particularly on lighter soils. Wet areas with heavy soils could benefit from an increase in the accessibility period for machinery. As the major agricultural land in Scotland is located on the relatively dry east coast where localised problems due to drought are not uncommon even under the present climate, the detrimental effects of a decrease in rainfall for the whole of Scotland are therefore likely to outweigh the benefits. Approximately 8% of Scotland has been identified in this study as soil/climate combinations which will be susceptible to drought should summer rainfall decrease by 11% and summer temperature increase by 1·4° C.