Fallow Land Research Articles

Land use & land cover dynamics and its relationship with nitrate pollution in groundwater around inactive mine areas using geospatial techniques, SW part of Cuddapah basin, Southern India

Geospatial maps can show how the ineffective operations of inactive mines affect water and aquifer quality. As such, the purpose of this study is to assess the impact of mining and irrigation on the aquifer ecosystem through the evaluation of LULC and slope maps through the application of Landsat 8 OLI/TIRS and DEM data. A total of 50 groundwater samples were prepared from villages in the close proximity to inactive mines during pre and post monsoon periods in 2021. The results of the analysis revealed alarming statistics, that 14% of groundwater samples exceeded the WHO nitrate limit in pre & post monsoon season, indicating a high-risk in the study area. According to guidelines (USEPA, 2014), 34% in pre-monsoon and 26% post-monsoon of samples exceeded the THI levels for adults and children respectively, indicating non-carcinogenic health risks. In addition, 80% of the samples in both seasons exhibited high NPI values, indicating nitrate contamination associated with blue baby syndrome. From the Geospatial analysis the findings from the LULC classification indicate that there has been a significant increase in cropland area from 2016 to 2021 due to changes in forest land, fallow land, and water resources. These problems have been exacerbated by the expansion of cultivated land, which has increased from 71.1 square kilometers in 2016 to 118 square kilometers in 2021, accounting for 13.1% of the total area. This expansion, coupled with elevated water body resource availability, has compounded the nitrate pollution including in intensely irrigated regions. The slope map analysis revealed that the inactive mines occur at low slope, high rainfall areas and these are compounded by runoff from other sources such as domestic and agricultural wastes. For these matters, sealing and remediating these inactive mines is essential so as to prevent further nitrate leakage.

Leveraging machine learning for analyzing the nexus between land use and land cover change, land surface temperature and biophysical indices in an eco-sensitive region of Brahmani-Dwarka interfluve

This present study aims to evaluate land use and land cover changes using five machine-learning algorithms in Google Earth Engine. The performance of these machine learning algorithms was evaluated using user accuracy, producer accuracy, overall accuracy, and kappa coefficient. Additionally, it seeks to understand the evolving pattern of land surface temperature and its correlation with biophysical characteristics in the Brahmani-Dwarka interfluve region from 1991 to 2021. The results demonstrate that RF algorithms outperform other algorithms in terms of performance, with RF algorithms averaging an 86 % overall accuracy and a Kappa coefficient of 0.82, while GTB comes in second with an 85 % overall accuracy and a Kappa value of 0.81. SVM performed moderately, while CART and MD algorithms struggled to perform in this study. The analysis of land transformation from 1991 to 2021 indicates that the stone crushing industry, built-up, and waterbodies have shown an upward trend, while vegetation and fallow land have decreased in their geographical extent. The results of the LST analysis indicated the study area had an LST rise of 8.72 °C over the last 30 years, or 0.29 °C per year, with the stone crushing and mining activities exhibiting the highest increase of 11.67 °C. Further, correlation analysis reveals LST has a highly significant positive correlation with NDBI and NDBaI and a very significant negative correlation with NDVI, MNDWI, and NDLI throughout the study period. The findings emphasize the importance of long-term planning and environmentally friendly development, ensuring responsible stone crushing activities, sustainable techniques, biodiversity conservation, and sustainable utilization of natural resources.

Stability and heavy metals accumulation of soil aggregates under different land uses in the southwest coastal Bangladesh

Agricultural soil contamination is increasing day-by-day and becoming a major problem over the globe. Trace elements accumulation in the bulk soil is frequently documented, however, there is no precise mechanism of their distribution in the different soil aggregates level. We collected twelve composite soil samples from banana fields, fallow land, rice cultivated with pond water (rice field-I), and rice cultivated with rain water (rice field-II). We separated soil samples into four different size of aggregates (4-2, 2–0.25, 0.25–0.053, <0.053-mm) and then, aggregate stability (MWD), soil organic carbon (SOC), and heavy metals content (Pb, Cd, Cr, As, Fe, Mn, Zn, Ni, Co, Cu) in the soil samples were measured with different techniques. Results showed that MWD was higher in the rice-based land use, which was significantly contributed by SOC (p < 0.001). The concentration of Pb, As, Cd, Fe, and Mn were increased, while Cu and Zn concentration were reduced with increasing aggregate size (p < 0.05). In contrast, aggregate size did not influence on Ni and Co accumulation (p > 0.05). Moreover, macroaggregate acted as an accumulator for Fe, Mn, and As, while all the aggregate fractions acted as accumulators for Cu and Zn. Our study indicated that MWD, SOC, aggregate size and composition, and metal species were the controlling factors of trace elements accumulation and distribution in the various sizes of soil aggregates.

Assessment of Landscape Change and its Relationships with Surface Temperature and Geo-spatial Indices during 1992 - 2022 at Haldia Industrial Region, West Bengal, India

Unplanned local development and alterations in Land Use and Land Cover (LULC) are an early alert for towns and cities around the world. The population pressure has resulted in the conversion of natural land into impermeable areas, which has altered the surface energy budget and created microclimatic differences locally. The main objective of the present study is to estimate LULC changes and its relation to increases Land Surface Temperature (LST) in the Haldia Industrial Region (HIR) of West Bengal using multi-temporal Landsat 5 Thematic Mapper (TM) of 1992 and Landsat 8 Operational Land Imager (OLI) of 2022 with 30-m spatial resolution images were obtained from the USGS website. The supervised classification method was applied by using Maximum Likelihood classification (MLC) to classify the satellite images into various LULC classes such as settlement, waterbody, vegetation, agriculture land, and fallow land, respectively. The result suggested an overall increase of settlement area from 13.49 km2 in 1992 to 44.54 km2 in 2022. On the other hand, the agriculture land decreased from 214.26 km2 to 152.34 km2 due to fast urbanization, decline green lands, and expansion of barren lands. The outcome result from LST was exhibited that the LST value has increased 3.77°C during 1992 to 2022 in this study area. The Normalized Difference Vegetation Index (NDVI) was showed a strong negative relationship with LST with a determination coefficient (R2) values found as 0.491 (1992) and 0.356 (2022). The positive determination coefficient between LST with Normalized Difference Water Index (NDWI) was found as 0.0002 (1992), and 0.0417 (2022). R2 values were estimated as 0.174 (1992), and 0.0347 (2022) between LST with Normalized Difference Built-up Index (NDBI) that indicated a positive determination coefficient. The findings enhanced understanding of the relationship between urban LST and LULC in developing an inclusive climate resilience policy and making the HIR more sustainable to the effects of climate change.

Evaluation of Alternative Break Crops in Rotation with Bread Wheat (triticum aestivum l.) in South-Eastern Ethiopia

Crop rotation could be a possible intervention to resolve multifaceted problems of monoculture. In recent years, there is a concern about soil depletion caused by intensive farming. In crop rotation legume crops, which capture atmospheric nitrogen and “fix” it into forms available to plants will increase soil fertility. Faba bean (Vicia faba L.), rapeseed (Brassica napus L.), oat (Avena sativum L.) and vicia (Vicia dasycarpa Ten.) forage mixture were considered as a break/precursor crops. The result showed that most profitable cropping sequence was faba bean grown in a 3 year cycle with 2 crops of wheat (Amanuel et al., 1994). Thus, searching for promising and alternative break crops for wheat based rotation could increase productivity and maximize profit. Adaptaion trial around Bekoji showed that sweet lupine seems an option in tolerating acidity where faba bean is found susceptible. Thus, the objectives of this study was to evaluate alternative break crops on yield and yield components of the succeeding wheat and soil fertility maintenance in the rotation scheme. Thus, this study was executed for three consecutive years from 2017- 2019 main cropping seasons at Kulumsa, Bekoji and Asasa Arsi zone, South-Eastern Ethiopia to evaluate advantage of alternative break crops on yield and yield components of the succeeding wheat and its effect on soil fertility maintenance in the rotation scheme. The experiment was laid out in randomized block design with five replications. The treatment include: wheat-sweet lupine-wheat-wheatwheat in year one (2017), sweet lupine-wheat-wheat faba bean-Ethiopian mustard in year two (2018) and wheat-wheat-wheat-wheat-wheat in the third year (2019). These leguminous crops have improved physico-chemical properties of soil. Plant nutrients of soil on which legumes were grown were increased. This improvement of soil properties by leguminous crops has resulted in higher yield of wheat than plots on which wheat was grown after wheat. Although non-significant, the third year Bekoji and Asasa combined analysis of variance revealed that the highest wheat grain yield (4197kg/ha) was obtained at sweet lupine-wheat-wheat followed by wheat-faba bean-wheat (4003kg/ha). However, plant height was significantly (P&lt;0.05) affected by rotational crops effect. The tallest plant height of wheat (105.0cm) was recoded from wheat-Ethioian mustard-wheat treatment. From this study, sweet lupine-wheat-wheat followed by wheat-faba bean-wheat with proper agronomic packages could be forwarded as a temporary recommendation in Asasa, Bokoji and Kulumsa areas and in areas with similar agro ecologies.

Testing the hydrological performance of live pole drains (LPD) for mitigation of slope instability

Nature-based solutions (NbS) and soil bioengineering techniques have gained considerable attention due to their relevant hydrological functions and ability to mitigate slope instability. Live pole drains (LPD), a lesser-known NbS, have traditionally been deployed on slopes to drain the excess surface water and regulate the soil's water budget, making it a suitable technique for stormwater management and landslide prevention. However, neither the LPD performance as a plant-based drainage system nor its potential to regulate the soil-water budget through hydrological processes have been thoroughly studied. This paper presents a novel pilot, lab-based approach for testing the hydrological performance of LPD under different soil hydrological conditions. We built three different treatments and investigated their hydrological performance under multiple storm events. We explored how LPD regulate the soil-water budget by partitioning the water inputs (i.e., rainfall precipitation) into water outputs (i.e., surface runoff, subsurface flow, and percolation). The study revealed that LPD can effectively manage stormwater by draining excess runoff and buffering water in the soil, outperforming fallow soil. Subsurface flow and percolation were significantly higher under LPD treatments when compared to fallow ground, suggesting that the presence of an enhanced structure in the soil results in high soil hydrological performance. The presence of a secondary species with the LPD showed a more efficient hydrological performance than an LPD alone, which aligns with the current implementation of NbS fostering biodiversity. Antecedent soil moisture impacted the hydrological performance of LPD by altering the relative infiltration capacity of the soil and by potentially modifying the availability of channels for preferential flow. Our findings provide a sound basis for future research to improve our understanding of the hydrological performance of LPD for slope instability mitigation and encourage their reproduction and upscaling.

Changes in the physical properties of fallow lands during their regeneration

The change of physical and mechanical properties of soil depending on the methods of its cultivation has been studied. The experiments were carried out in the Novosibirsk region from April to September 2023. To study the structure of the soil, a soil section was made to a depth of 0.7 meters. It was determined that the soil at the experiment plots was gray forest, the thickness of the turf layer was on average 10 cm, the depth of the humus horizon 25–27 cm, a layer of sandy loam was observed under the humus layer. Fallow land cultivation was carried out by the tillage combine AKP-2.5N with MTР-80L tractor and the working width of 1.8 meters. The working body of the AKP-2.5N was made in a form of a straight rack with a blade measuring 410 mm, in addition, a small screen was installed on the rack. The unit provides for the installation of the rollers with a size of 600 mm. To determine the operating modes of the unit, studies were carried out in the soil channel. It was found that the operating speed of the unit with installed screen should be no more than 2.22 m/s or 8 km/h. The conditions of the experiment: gray forest soil, air temperature not lower than 10 0C; air humidity no more than 70%; relative humidity of at least 18%, wind speed not higher than 2 m/s; the average length of the rut is not less than 70 m and without stones on the field. It has been concluded that the most rational way to introduce fallow gray forest soils into agricultural circulation is to treat them with AKP-2.5N units with working bodies equipped with blades. After three treatments, the content of soil particles less than 10 mm is up to 93.1%, the soil absorbs moisture faster and reduces the hardness to 15 kg/cm2, which corresponds to the hardness of the soil of the field in rotation. Equations of regularity of changes in the fractional composition of soil with a size of less than 10 mm and more than 50 mm depending on the timing and number of treatments have been obtained.

The green conundrum: Navigating the paradox of buffer farmlands of a mangrove forest landscape

Farmlands, positioned at the interface of mangrove forestlands and urban centers, serve as critical buffer zones. These areas play a pivotal role in determining the ecological fate of mangrove forests, acting as a cushion against mangrove deforestation. This study aims to study the spatiotemporal data from Landsat imagery whilst considering the geo-political and scocio-economic transformations of such a buffer region adjoining the Sunderban mangrove forest to understand the surreptitious reason for such expansive nature of the farmlands. Results indicate that these buffer farmlands are in a constant tug-of-war between the urban and forest ecosystems. The built up area adjoining the cities increases at a much higher pace than the areas adjoining the forest lands. Quite contrary to the popular belief, it is seen that the majority of cropland expansion in the mangrove adjoining regions arises from the use of fallow land rather than the clearing of vegetation. The study shows that the changes need to be addressed through the government’s policies and a restructure of governance is required. In policymaking, the collaborative action of scientists, governments, and local people should be involved. The lack of sustainable development and targeted improvement can increase the threat and risk nearby the mangrove farmlands.

Land use conversion to uplands significantly increased the risk of antibiotic resistance genes in estuary area

Land use conversion in estuary wetlands may affect the transmission of antibiotic resistance genes (ARGs), while the risk rank of the ARGs and the change of clinically relevant ARGs under various land-use types are not well understood. This study used metagenomics to reveal the diversity and abundance of ARGs across five distinct land uses: reed wetland, tidal flat, grassland, agricultural land and fallow land, as well as their distribution and potential health risks. Results showed that high numbers of ARG subtypes and classes were detected irrespective of land-use types, notably higher in agricultural land (144 ARG subtypes). The most shared ARG subtypes were multidrug resistance genes across all the land uses (29 subtypes, 4.7 × 10−2-1.5 × 10−1 copies per 16S rRNA gene copy). Proteobacteria and Actinobacteria were primary ARG hosts, with 18 and 15 ARGs were found in both of them, respectively. The ARG subtype mdtB was the most dominant clinical ARG detected with 90 % amino acid identity. The change of ARGs exhibited a consistent trend across land uses in terms of health risk ranks, with the highest observed in fallow land and the lowest in reed wetland. This study reveals the distribution pattern of ARGs across various land-use types, and enhances our understanding of the potential health risks associated with ARGs in the context of coastal wetland conversion in estuary areas.

High Impacts of Invasive Weed Lantana camara on Plant Community and Soil Physico-Chemical Properties across Habitat Types in Central Nepal

Although the effects of invasive alien plants on natural ecosystems are well known, the effects of specific plant species can vary across habitat types and disturbance intensity. This study was carried out to analyze the effects of Lantana camara on associated vegetation and soil physico-chemical properties at invaded and non-invaded sites across three different habitat types (forest edge, fallow land, and roadside) in central Nepal. We sampled 50 pairs of 5 m × 5 m (for shrub species) and 1 m × 1 m (for herbs species) plots at invaded and non-invaded sites in each habitat and recorded community variables for each species within the sampling plots for both wet (monsoon) and dry (pre-monsoon) seasons. Further, we collected soil samples from each quadrat and determined the soil physico-chemical properties. We recorded 137 species of flowering plants (119 from non-invaded and 97 from invaded plots) and classified them in accordance with life form/habit. In invaded sites, we found a significant decline in species diversity as indicated by the Simpson and Shannon diversity indices. Specifically, L. camara reduced the species richness, Simpson index, and Shannon diversity index by 36.84%, 11.84%, and 40.21%, respectively. Soil nutrients such as total nitrogen, soil organic carbon, and available phosphorus were significantly higher in invaded sites than non-invaded ones except for available potassium and soil pH. This study provided evidence that Lantana L. camara has a substantial impact on the understory plant community assemblage and the physico-chemical properties of soil. The results suggest that the protection of native plant community requires management of L. camara by implementing appropriate measures.

Geospatial AI solution to monitor and mitigate increasing adverse ecological and hydrological impacts of climate change in Uttarakhand Himalaya (India).

Though climate change and its adverse ecological and geohydrological impacts are being experienced across the world in all types of ecosystems but as far as the Himalaya mountain ecosystem is concerned, the rate of climate change and subsequent impacts have reached an alarming stage due to anthropogenic and technogenic intervention on natural process and now need most effective and less time taking management strategy. Addressing this burning environmental problem, a geospatial artificial intelligence (GeoAI) technique-based case study is presented here from one of the most densely populated and urbanized regions of Himalaya mountain, viz Uttarakhand Himalaya, which is also called central Himalaya. The results of the study suggest that due to quite a high rate of climate change, the climatic zones shifting towards higher altitudes at the average rate of 5.6 2m/year, causing several adverse ecological impacts in terms of decreasing quality dense temperate forest cover (0.05%/year), snow cover (0.02%/year), water bodies (0.01%/year), agricultural land (0.31%/year), and horticultural land (0.01%/year). Conversion of these eco-friendly land use land cover into barren land, fallow land, and built-up land causes geohydrological consequences of climate change in terms of decreasing rainy days (1%/year), drying perennial springs (0.20%/year), perennial streams (0.11%/year), decreasing spring and stream discharge during non-monsoon season, increased extreme rainfall events (6-8%/year), and subsequent surface runoff during monsoon season. Further, the study advocates that the degraded geohydrological process has resulted in an increased frequency of disaster events (floods, cloudbursts, landslides. etc.) with a 3% (12 events) annual rate, causing great loss of environment, infrastructure, lives, and economy each year. Therefore, it has been very urgent to mitigate climate change and increase geohydrological disaster events through an integrated approach. Keep in view this, the present study proposed an integrated watershed management plan which is equally useful to be implemented across the Himalaya region and other similar ecosystems across the world.

Annual time-series 1 km maps of crop area and types in the conterminous US (CropAT-US): cropping diversity changes during 1850–2021

Abstract. Agricultural activities have been recognized as an important driver of land cover and land use change (LCLUC) and have significantly impacted the ecosystem feedback to climate by altering land surface properties. A reliable historical cropland distribution dataset is crucial for understanding and quantifying the legacy effects of agriculture-related LCLUC. While several LCLUC datasets have the potential to depict cropland patterns in the conterminous US, there remains a dearth of a relatively high-resolution datasets with crop type details over a long period. To address this gap, we reconstructed historical cropland density and crop type maps from 1850 to 2021 at a resolution of 1 km × 1 km by integrating county-level crop-specific inventory datasets, census data, and gridded LCLUC products. Different from other databases, we tracked the planting area dynamics of all crops in the US, excluding idle and fallow farm land and cropland pasture. The results showed that the crop acreages for nine major crops derived from our map products are highly consistent with the county-level inventory data, with a residual less than 0.2×103 ha (0.2 kha) in most counties (&gt;75 %) during the entire study period. Temporally, the US total crop acreage has increased by 118×106 ha (118 Mha) from 1850 to 2021, primarily driven by corn (30 Mha) and soybean (35 Mha). Spatially, the hot spots of cropland distribution shifted from the Eastern US to the Midwest and the Great Plains, and the dominant crop types (corn and soybean) expanded northwestward. Moreover, we found that the US cropping diversity experienced a significant increase from the 1850s to the 1960s, followed by a dramatic decline in the recent 6 decades under intensified agriculture. Generally, this newly developed dataset could facilitate spatial data development, with respect to delineating crop-specific management practices, and enable the quantification of cropland change impacts on the environment. Annual cropland density and crop type maps are available at https://doi.org/10.6084/m9.figshare.22822838.v2 (Ye et al., 2023).

Geospatial Analysis of Lumpy Skin Disease Outbreaks among Cattle in Uttar Pradesh, India, 2021-2022.

The emergence of lumpy skin disease (LSD) among cattle in India is concerning. District-level data on LSD cases in Uttar Pradesh between 2021 and 2022 were analyzed. A stepwise spatial analytical approach was followed by first constructing yearly and monthly disease maps for LSD incidence rates (IRs), then spatially interpolating the LSD IRs, followed by evaluating the global and local clustering of LSD IRs and finally conducting spatial regression modeling. Overall, 5784 LSD cases from 6 districts and 112,226 cases from 33 districts were detected in 2021 and 2022, respectively. In the incremental spatial autocorrelation analysis, the highest global clustering of LSD IRs for the 2022 outbreak was detected at 196.49 km. For the 2021 LSD outbreak, one district with high-low and nine districts with low-high LSD IRs were identified in the eastern region of the state. For the 2022 LSD outbreak, 13 districts with high-high and 7 districts with low-high LSD IRs were identified in the western part of the state. A geographically weighted regression model identified the impact of climate (temperature and humidity) and land cover (pasture, fallow, and non-agricultural land) on LSD IRs. The study results can aid animal health authorities in developing LSD prevention and control programs.

Assessment of land use transformations and its impact on fluctuations in groundwater quality in Chengalpattu district, Tamil Nadu

ABSTRACT This study examines land use transformations and their impact on groundwater quality fluctuations in Chengalpattu district, Tamil Nadu. Chengalpattu is a rapidly urbanizing coastal region in South India. Landsat 5 and 9 satellite imagery were utilized to create land use land cover (LULC) maps for 2011 and 2021, with overall accuracies of 82.20% and 85.71%, respectively. The analysis showed significant growth in built-up and fallow lands due to urbanization, which has altered LULC. Groundwater Quality Index (GQI) was generated using seven groundwater quality parameters, adhering to World Health Organization (WHO) standards. The mean GQI showed slight fluctuations during pre- and post-monsoon periods, with a declining trend in pre-monsoon seasons. The study area predominantly experiences moderate groundwater quality, with fewer areas of low and high quality. The findings indicate that land use transformation significantly impacts groundwater quality, emphasizing the need for sustainable urban planning and water resource management in the region.

Trade-off between the future water resource utilization and grain production in a water-deficient region from the perspective of the Water−Land−Grain nexus

The utilization and future evolution of water resources in water-deficient regions will have a significant impact on sustainable agricultural development. The trade-off between water resource utilization and grain production in the Daqing River Basin (DRB) was explored, and the characteristics of the future evolution of the water − land − grain system was analyzed. The main planting patterns of farmland in the DRB are winter wheat, spring maize, summer maize, or a winter wheat − summer maize rotation. The total water consumption and supply are 61.6 × 108 and 54.4 × 108 m3, respectively. The water supply gap is approximately 7.2 × 108 m3, which is mainly supplemented by the overexploitation of groundwater. Under the current land use structure, grain production in the DRB has achieved self-sufficiency, but excessive water consumption in agricultural production has led to severe groundwater overexploitation. Despite the exploration and implementation of a fallow land policy in the DRB, the quantity of water resources conserved currently falls significantly short in comparison to the extent of groundwater overexploitation. From the trade-off between water resource utilization and grain production, if winter wheat areas were left completely fallow, or winter wheat planting regions establish three crops in two years or a single crop in a year, the total amount of irrigation water that could be saved was 18.4 × 108, 7.5 × 108, and 15.2 × 108 m3, although the grain production capacity would be reduced by 31 %, 12 %, and 24 %, respectively. This study proposes prioritizing fallow areas in the winter wheat planting regions with high water demand located in the Diandong Plain, and changing the current system of two crops a year to three crops in two years or a single crop a year. The implementation of this approach is anticipated to alleviate the strain on water resources. To achieve the control of groundwater overexploitation and balance the supply and demand of water resources, it is necessary to continue to expand the fallow area of winter wheat in the eastern and southern plains of Baiyangdian by approximately 25.3 × 104 hm2, or increase the amount of water diverted from outside the basin by approximately 7.20 × 108 m3. By 2030, the DRB will face the dual pressures of both water and grain security, with a water resource gap of 13.8 × 108 m3. It is therefore necessary to increase inter-basin water transfer or continue to expand the fallow area of winter wheat in the future.

Performance of co-designed diversified Mediterranean cropping systems: Hybridizing stakeholders' knowledge and modelling data

Mediterranean cropping systems, characterised by continuous cereal cropping, are largely dependent on synthetic inputs, such as N fertilisers. On the other hand, they face difficult pedoclimatic conditions, exacerbated by climate change. Diversification is seen as a way to increase cropping systems resilience. The aim of this study was to co-design diversified cropping systems based on the expertise of local stakeholders and co-assess their performance, using modelling data. Our case study is the Ebro valley in Spain, a Mediterranean area with great potential for diversification, particularly where irrigation is available. Two workshops were organized to i) define the reference system in the study area and its limitations ii) co-design diversified systems to overcome these limitations and iii) co-assess reference and diversified systems. Between the two workshops, the STICS soil-crop model was calibrated with local experimental data, enabling to simulate the inter-annual (2000–2021) agronomic and environmental performance of the reference and diversified systems. An economic analysis was conducted. Stakeholders evaluated all economic, agronomic and environmental aspects. The reference system was a continuous winter cereal crop based on synthetic N fertilisation and intensive tillage. The four diversified co-designed systems consisted in introducing pea and/or rapeseed every 2 or 4 years, reducing tillage and partially replacing synthetic N fertilisation with locally sourced livestock manure. Simulation results showed that wheat and barley grain yields remained stable with diversification. Pea and rapeseed yields were lower in rotations where both were introduced compared to when each was the only break crop over 4 years. At the system level, protein yield remained stable with diversification, however, energy yield decreased by 20 % when break crops were introduced twice and by 10 % when introduced once. Gross margins improved with diversification only when pea was introduced once (12 %), mainly due to reduced expenses (-31 %), while incomes remained stable compared to RCS. However, incomes decreased by 5 % when rapeseed was introduced once, and by 10 % when both break crops were introduced. Unexpectedly, environmental performance deteriorated with diversification, with increased N losses through ammonia volatilisation and nitrate leaching in the years following pea and rapeseed cropping, due to greater N availability in the soil. An increased use of pesticides was predicted by the stakeholders in diversified systems, where the environmental impacts were exacerbated with the higher presence of break crops. The reference system presented slightly lower N availability and increased soil organic carbon storage. Overall, the approach proved useful in identifying a diversification strategy that improved agronomic and economic performance, with the system including pea once every four years being the most efficient. However, the environmental trade-offs associated with the increased presence of pea and rapeseed in the crop rotation must be considered in order to mitigate the environmental risks.

Changes to soil profile carbon and nutrient distribution following pasture renewal with full inversion tillage

ABSTRACT Full inversion tillage (FIT) at pasture renewal is a management option aiming to increase carbon stocks in long-term pasture, to achieve carbon neutrality. This study investigated the effects of FIT on carbon and nutrient distribution in the soil profile (0–7.5, 7.5–15, 15–22.5 and 22.5–30 cm depths) as well as nutrient uptake, and subsequent fodder crop and/or pasture yields across three pasture renewal trials (Trials 1 and 3: Alfisol; Trial 2: Andisol). These effects of FIT were assessed against standard tillage treatments (no till, shallow till), and non-renewed pasture within 8–18 months post-tillage. FIT changed soil carbon stratification, causing 16%–46% reduction in topsoil (0–7.5 cm) cation exchange capacity across the three trials. However, nutrient levels after FIT remained within recommended ranges for crop and/or pasture growth, avoiding any yield reductions. Topsoil fertility post-FIT depended on original degree of nutrient stratification in the soil profile. At Trial 1, temporary deficiencies caused by low subsoil P and K soil tests pre-FIT were anticipated and corrected with fertiliser nutrients for the following break crop and resown pasture. We conclude that soil testing the cultivation depth prior to FIT at pasture renewal provides the necessary soil test information to manage yield expectations.

ТРАНСФОРМАЦИЯ ПЛОДОРОДИЯ ПОЧВ ЗАЛЕЖЕЙ ЛЕСОСТЕПНОЙ ЗОНЫ ПРИ РАЗЛИЧНОМ НАПРАВЛЕНИИ ИХ ИСПОЛЬЗОВАНИЯ

The purpose of research is to provide a comprehensive comparative assessment of the fertility of gray fallow soils in the forest-steppe zone of the Krasnoyarsk Region, overgrown with forest, used for hayma-king and re-developed into arable land. The studies were conducted in 2007–2020 in the Krasnoyarsk and Achinsk-Bogotol forest-steppe on gray soils of fallow lands no longer used for agricultural purposes. Stu-dies were carried out to assess the indicators of the potential and effective fertility of gray soils of fallow lands of the Krasnoyarsk and Achinsk-Bogotol forest-steppe with their various post-agrogenic use. It has been established that forests regenerated on fallow lands do not lead to degradation of soil fertility, especially in terms of the content of humus and agronomically valuable aggregates. The emerging forest litter and tree litter accelerate the accumulation of organic matter, a source of humus. There is weak spatial va¬riation in most indicators of effective and potential fertility in soils under regenerating forest compared to pure fallow lands. With the re-involvement of fallow land into arable land, nitrification somewhat increases, spatial variation in soil properties decreases, and the content of humus and absorbed bases decreases. The structural composition of the soils of all study objects is characterized as excellent (ACF 88–77 %) with an insignificant value of the coefficient of variation of fractions (4–7 %). When reclaiming fallow lands into arable land, the proportion of the blocky fraction is significantly reduced. The spatial variability of the structural composition of soils in fallow lands and hayfields is higher than on arable land, which is asso¬ciated with the “clumpiness” of the ground cover and root system of plants on uncultivated soils. In terms of fertility, post-agrogenic gray soils used for haymaking occupy an intermediate position between clean fallow lands and those overgrown with forest. The productivity of the phytomass of fallow lands, arable land and hayfields in the Krasnoyarsk and Achinsk-Bogotol forest-steppe is more closely correlated with the indicators of the potential fertility of post-agrogenic gray soils. In most cases, the values of the correlation coefficients are closer between phytomass reserves and indicators of effective fertility in the Achinsk-Bogotol forest-steppe, which is associated with more favorable hydrothermal conditions in this research area and optimal water-physical properties.

ОСОБЕННОСТИ ГУМУСНОГО СОСТОЯНИЯ ЧЕРНОЗЕМОВ ПРИ ОСВОЕНИИ ЗАЛЕЖИ

The purpose of the study is to determine the direction of change in the humus state of fallow soils in the forest-steppe zone when they are re-involved in arable land. The studies were carried out in the Kras-noyarsk forest-steppe during three growing seasons of 2015–2017 when the forb-grass deposit is replaced at the turf stage by agrocenosis of wheat and then by agrocenosis of pea-oat grass mixture. A distinctive feature of the process of involving fallow land in arable land was the chemical treatment of plants before plowing. Research has established that when the fallow is treated with herbicides and subsequent plowing, the sod horizon disappears, the amount of plant residues decreases sharply, the humus horizon differen¬tiates into arable and subarable with different densities, and blocky and dusty aggregates appear. The humus content under the long-term fallow land and during its plowing was high and amounted to 9.4–9.3 %; no decrease in humus was detected in the first two years after plowing, but the enrichment of humus with nitrogen decreased from an average to a very low level. The content of mobile humus in the soil under the long-term fallow land was 951 mg/100 g; when the fallow was plowed, it decreased to 346 mg/100 g. At the same time, the potential emission of carbon dioxide from agrochernozem increa¬sed – from 5.5 to 18.5 mg CO2 /10 g, which had an average inverse relationship with the SpO content (r = 0.56). It has been established that with intensive agrotechnical influence with the use of chemicals to destroy the turf horizon, the share of SPOs from Shumus decreases by more than 2.8 times due to its mineralization.

Features of the introduced species composition and state in the arboreta of Dzhanybek research station in the Northern Pre-Caspian Semi-Desert

The results of studying introduced species diversity and state under rainfed conditions at the Research station of the Institute of Forest Science of the Russian Academy of Sciences have been presented. The station is located in the clay semi-desert of the Northern Pre-Caspian region between the Volga and Ural rivers. The collections of two arboreta were examined. The first arboretum was established in 1953 on hydromorphic meadow-chestnut soils of large mesodepressions, and the second – in 1974 on solonetzic automorphic soils. The arboreta were originally established with an idea of complete elimination of irrigation. In recent decades, tending and silvicultural treatments were discontinued for a number of reasons. An annotated list of tree and shrub species includes 77 species belonging to 25 families and 44 genus. In the arboretum on the large mesodepression, the number of species surviving for more than half a century is 35% in relation to the number of “core” introduced species. Mostly, the species are represented by the families Rosaceae, Caprifoliaceae, Elaeagnaceae, Fagaceae, Fabacea, Oleaceae, Salicaceae, Sapindaceae, Ulmaceae. Some specimens older than 70 years are in satisfactory condition and produce viable volunteer regrowth. The main stages of their acclimatization, in relation to age, and changes in growing conditions, as affected by plants themselves as well as climate, are distinguished. In arboretum on solonetzic soils, the survival of species is 50%. The composition of tree and shrub vegetation of an unused pond, where spontaneous vegetation formed an intrazonal willow-oleaster-poplar community of quasi-riparian type, and of the overgrowing fallow land, where a specific “savannah-like” landscape was formed, have been studied. This allowed to identify the species whose life strategy contributes to their successful colonization of human-disturbed habitats and, in some cases, manifestation of the features of naturalization and invasiveness. The most promising species for landscaping, parks and other plantings in such harsh natural and climatic conditions were also determined.