Lower Soil Bulk Density Research Articles

Deep return of straw improves topsoil health and maize productivity more efficiently than shallow return

AbstractStraw return is an important nature‐based solution to identify optimal management practices to maintain cropland soil health and food security. However, there is still limited information available regarding the impacts of different straw return strategies on soil health, especially when considering a comprehensive assessment of soil physical, chemical and biological characteristics. Soil microorganisms are the core and key to maintaining soil health. The present research aims to determine the impact of straw return to different depths on soil health index (SHI) and crop productivity across different soil layers. We conducted a 3–year field experiment with four treatments: a blank control with no straw return (NR), straw return treatments with shallow return (SR), mulch return (MR) and deep return (DR), and the straw application rate was 10,500 kg/ha. The results showed that it was the microbial indicators that dominated the effects on soil health, rather than soil organic carbon (SOC). Specifically, we found that the SR treatment exhibited the highest extracellular enzyme activities of both hydrolases and oxidases in the subsoil, and the peroxidase (PEO) activity was 758.99 nmol/g/h. In addition, compared with MR and DR treatments, the abundance of symbiotroph fungi in SR treatment increased by 78.41% and 54.38%, releasing more nutrients to the soil. Hence, SR treatment increased SHI mainly by increasing the PEO activity and NO3−–N content, and SR treatment significantly increased SHI by 25.59% and 22.16% compared with MR and DR treatments. By contrast, the DR treatment greatly increased the topsoil SHI by 43.33% and 58.98% compared with SR and SM treatments, mainly due to the enhanced microbial biomass N (MBN) and dissolved organic nitrogen (DON). The DR treatment in topsoil had the lowest soil bulk density (BD) which enhanced Bacteroidota but decreased Methylomirabilota abundance, thus resulting in the accumulation of MBN. Moreover, DR treatment led the highest maize yield which increased with an increasing SHI. To conclude, DR treatment is an effective method to improve SHI and crop productivity in nutrient‐rich topsoil, while SR treatment has a much better effect in the subsoil. Our results will provide a theoretical paradigm for selecting straw return strategies, which is crucial for promoting soil health and food productivity, achieving high crop yields, and supporting sustainable agricultural development.

Sustainability of athletic field turf comparing organic and synthetic practices under two heights of cut

AbstractLong‐term comparisons over several years between organic and synthetic management are lacking in sports turf research. Our objective was to investigate playing surface qualities and soil properties over an 8‐year period. For this trial, Kentucky bluegrass (KBG, Poa pratensis L.) sod was established and annually inter‐seeded with perennial ryegrass (Lolium perenne L.) and KBG. Factors included height of cut (3.2 and 6.4 cm) and management systems (MSs; synthetic and organic) with three replicates. Synthetic practices included chemical fertilizers and pesticides, while the organic system used hand‐weeding and biological fertilizers (leaf compost and naturally derived organics) with biological controls. In all years, wear was simulated in the fall using a slip‐wear machine and evaluated for playing qualities including visual wear tolerance, ball bounce (BB), surface hardness, and traction. Soil properties were evaluated in some years including pH, soil organic matter (SOM), soil bulk density, soil aggregate stability (SAG), and soil available P. Both MS received the same total N of 196 kg ha−1 year−1 but P applied varied with the MS (synthetic, 7.6 kg ha−1 year−1; organic, 23.2 kg ha−1 year−1). Synthetic practices provided acceptable visual wear tolerance (1–9, ≥6 acceptable) in 4 of 8 years compared to only 1 year for organic practices. Shorter cut grass (3.2 cm) consistently provided better visual wear tolerance (average = 5.6), harder surfaces (average = 51 g), and higher BB (average = 35.8%) consistent with accepted player standards. Synthetic practices afforded better tolerance to wear compared to organic practices in 5 of 8 years but little difference was observed in the other surface properties. Organic practices were consistently above 6.0 in soil pH (higher by 12%), 20% higher in soil available P, 25% higher in SOM, and with lower soil bulk density. SAG was higher following 8 years of simulated traffic by the last year of the test under organic practices. Results suggest competing benefits with synthetic practices affording better wear tolerance while organic practices promote better soil health.

Functional traits and ecological niches as correlates of the interspecific growth–mortality trade‐off among seedlings of 14 tropical tree species

Abstract The interspecific trade‐off between growth versus mortality rates of tree species is thought to be driven by functional biology and to contribute to species ecological niche differentiation. Yet, functional trait variation is often not strongly correlated with growth and mortality, and few studies have investigated the relationships of both traits and niches, specifically encompassing above and belowground resources, to the trade‐off itself. These relationships are particularly relevant for seedlings, which must often survive resource limitation to reach larger size classes. We investigated the functional basis of the interspecific growth–mortality trade‐off and its relationship with ecological niches for seedlings of 14 tree species in a tropical forest in southwest China. We found evidence for an interspecific growth–mortality trade‐off at the seedling stage using 15 functional traits and 15 ecological niche variables. None of the organ‐level traits correlated with growth, mortality, nor the trade‐off, whereas specific stem length (SSL), a biomass allocation trait, was the only trait to have a significant correlation (positive). Moreover, light‐defined niches were not correlated with growth, mortality or the trade‐off, but soil‐defined niches did. Species at the faster growth/higher mortality end of the trade‐off were associated with higher fertility defined by lower soil bulk density and slope, and higher soil organic matter concentration and soil total nitrogen. Our findings indicate the importance of stem elongation and soil fertility for growth, mortality and their trade‐off at the seedling stage in this Asian tropical forest. Our findings contrast with analogous studies in neotropical forests showing the importance of photosynthesis‐related leaf traits related to insolation. Therefore, the functional drivers of demographic rates and trade‐offs, as well as their consequences for ecological niches, can vary among forests, likely owing to differences in biogeography, canopy disturbance rates, topography and soil properties. Moreover, the effects of functional trait variation on demographic rates and trade‐offs may be better revealed when biomass allocation is accounted for in a whole‐plant context. Read the free Plain Language Summary for this article on the Journal blog.

Hydrological Response of Bamboo Plantations on Soil–Water Dynamics in Humid and Semi-Arid Coastal Region of Kenya

Soils and water are major resources that drive a country’s economy, and therefore should be conserved and utilized sustainably. However, in Kenya, these two resources are facing huge depletion and degradation due to anthropogenic factors and climate change. Bamboo species, especially on large plantations, can significantly alter ecological, hydrological, and biogeochemical processes in the long term. This study aimed to evaluate the effects of different species of bamboo and tree plantations on important soil–water processes like infiltration, bulk density, runoff, and soil loss in Kenya. The research was conducted at two sites (Gede in Arabuko Sokoke forest and at Baolala, in Kilifi County) managed by the Kenya Forestry Research Institute (KEFRI). The Arabuko Sokoke forest has a hot–humid coastal climate, while Baolala is a hot semi-arid area with little precipitation. The study involved measurement of soil–water infiltration rates using infiltrometers, installing runoff plots to quantify surface runoff and sediment loss, and analyzing soil properties like bulk density for growing periods for different bamboo and tree species. At the Gede forest site, the 30-year-old Thyrsostachys siamensis and Bambusa bambos plantations recorded the highest infiltration rates. Mature bamboo plantations of T. siamensis and B. bambos recorded higher infiltration rates compared to mature plantations of E. camaldulensis and G. arborea. It was observed that the bamboo plantations manifested lower soil bulk density compared to bare land, which recorded the highest bulk density. At Boalala, infiltration rates were significantly higher in the bamboo species compared to grassland and bare land. The painted bamboo (B. vulgaris vittata) had a slightly higher water infiltration rate compared to B. vulgaris. Runoff and erosion patterns reinforced the benefits of more mature bamboo plantations as well. There was a significant correlation between amount of runoff and collected soil loss through erosion. The data showed reductions in surface runoff volumes and sediment loss as the bamboo plantations aged compared to younger species. Therefore, by enhancing infiltration and reducing runoff and erosion, well-managed bamboo plantations can protect valuable soil resources, improve water recharge, and support sustainable land use over the long term. In conclusion, this study showed the strong potential of bamboo as a soil and water conservation tool in Kenya.

Factors Affecting Soil Bulk Density: A Conceptual Model

Soil bulk density is an important aspect of soil properties, and it can affect agroecology as in diversity, synergies, efficiency, recycling, and resilience. Diversity as in soil low in bulk density allows greater penetration of plant roots allow better access of water and nutrients. The synergistic effect of adequate supply of soil moisture content in forming moderately low soil bulk density for deeper plant roots for better access to water and nutrients. Agroecology efficiency reduces the need of external inputs to reduce environmental impact related to the resulted excessive pollution and wastage. Ultimately, an improved soil bulk density may increase the overall agroecosystem resilience and output, thus, improving the efficiency. Recycling in agroecology involved mass recycling and heat circulation as in nutrient, water, and waste reduction. A high soil bulk density will impede the recycling process the soil. Resilience as in drought resistance is for soil not too loosely packed that cannot hold water or too compacted until flooding water occurs at the surface and too little water infiltrates the soil. In addition, soil bulk density can affect the estimation of soil moisture content and temperature distribution. The ability to understand the factors that influence changes in soil bulk density would improve the predictive ability of the current model. The current study conducts a review on factors affecting the soil bulk density that is divided into soil physical, chemical, biological, environmental, and management practices. A cumulative of more than 50 factors are discussed in the review on how it affects the change in soil bulk density. The current review illustrates the conceptual relation of these factors on soil bulk density. Also, the result of the current work can be used to support future endeavour by turning the conceptual relation into quantifiable predictive model.

Straw Use to Reducing Soil Compaction and Its Effect on the Biometric and Physiological Characteristics of Soybean and Maize Plants

ABSTRACT The objective of this study was to evaluate the straw to decrease the bulk density of sandy clay loam and clay soils and to determine the effect of this on the development of soybean and maize plants. The soils were compacted using Proctor test with different amounts of crushed straw on the soil surface corresponding to 0, 3, 6, 9 and 12 t ha−1. After this, the soils in pots were compacted with same levels of straw on its surface using the maximum bulk density each soil. Then, soybean and maize were sown and after 42 days, biometric characteristics and physiological parameters were evaluated. The results showed that the maximum bulk density and critical soil moisture for the sandy clay loam soil were 1.51 t m−3 and 0.15 kg kg−1, respectively, while those for the clay soil were 1.54 t m−3 and 0.19 kg kg−1. The straw reduced soil compaction for the two soils, resulting in lower soil bulk density with 9 and 8 t ha−1 of straw on the surface of sandy clay loam and clay soils, respectively. When evaluated the plant, the amounts 6 to 9 t ha−1 of straw promoted better initial development of soybean and maize plants. Thus, this study suggests that a minimum of 6 and 8 t ha−1 of straw be used on the surface of sandy clay loam and clay soils, respectively were efficient in promoting physical soil improvements and better plant development.

Integrated parasite management (IPM) and the pasture ecosystem: Optimizing outcomes for cattle, insect biodiversity, and soil health

Concerns over the negative environmental impacts of livestock parasiticide treatments and the widespread development of resistance has precipitated a move towards integrated parasite management (IPM). However, within the pasture ecosystem management strategies are likely to impact multiple processes in complex ways. This study investigates the impacts of IPM strategies on pest flies, gastrointestinal nematode (GIN) parasites, beneficial dung insects, and soil health. Twenty-nine grazing dairy farms participated in the study, representing different chemical and nonchemical parasite management and grazing strategies (continuous, rotational, or management intensive rotational (MIG)). Cattle managed using rotational grazing and MIG had significantly lower FEC than continuously grazed cattle. Farms using chemical parasiticides had significantly fewer pest flies, however farms releasing parasitoid wasps as biological control also had reduced abundances. Dung inhabiting beetle abundance was significantly correlated with reduced pest flies and GIN. Beneficial insects were negatively impacted on farms that used parasiticides. Continuously grazed pastures had higher beneficial insect abundances only on farms that did not use chemical parasiticides. Pastures managed under MIG had lower soil bulk density and higher active carbon compared to continuous grazing. There were positive associations between soil health and tunneling dung insects (Onthophagus spp. dung beetles). Finding optimal strategies will be context dependent, however the results of this study indicate that grazing strategies can control gastrointestinal parasites and improve soil health outcomes, natural enemies such as parasitoid wasps and dung inhabiting beetles can suppress pest fly populations, and the impacts of chemical control strategies may be mitigated through thoughtful implementation.

Effect of cover crops and tillage systems on soil quality and sugarcane yield

AbstractThe management adopted in the establishment and replanting of sugarcane fields, with conventional tillage followed by fallow, is one of the main causes of soil quality degradation. In this context, the soil quality index (SQI) is an important tool to guide the use of more sustainable practices and management. This study aimed to monitor the effect of different cover crops in association with different tillage systems on sugarcane yield based on key indicators and an SQI developed using the Soil Management Assessment Framework (SMAF). The experiment was carried out on a sugarcane expansion area located in the municipality of Ibitinga, São Paulo, Brazil. The following soil physical and chemical attributes were analyzed: soil bulk density, macroaggregates, available phosphorus and potassium. Soil carbon content was also analyzed and used to calculate the SQI. Productivity over the 4 years of sugarcane cultivation was also analyzed. The use of subsoilers for soil tillage proved efficient in managing compaction by providing lower soil bulk density values in the first years of cultivation (1.59 and 1.63 g cm−3); however, these effects occurred in the short term with a 10% increase in later years. The use of millet in association with subsoiling showed the best results for soil quality (0.59), reflected in the maintenance of yields at 100 Mg ha−1 over time. Thus, our study reinforces the importance of using soil conservation systems in sugarcane replanting areas to achieve production longevity.

Soil meso- and microfauna community acts as an environmental bioindicator in urban greenway landscapes

Urbanization accelerates habitat fragmentation and leads to the decline of biodiversity in cities. Urban greenway landscapes provide not only social functions but also important ecological services. In this study, taxonomic richness, abundance, diversity, and the distribution of soil meso- and microfauna were investigated in three different urban greenway landscapes to assess their environmental quality. Urban greenway landscapes that had a richer tree species composition, higher deciduous tree ratios, wider ecological greenspace, moderate soil temperature and moisture, and lower soil bulk density and less lead were conducive to the survival and development of the soil meso- and microfauna community. Different soil fauna groups had varied responses to different environmental conditions in urban greenway landscapes. Microarthropods were more sensitive to plant communities; in contrast, soil moisture was the most important abiotic driver for hygrophilous meso-micro fauna. Our study highlights the importance of deciduous trees for their rich litter input, and the wide ecological greenspace for its buffering effect on various disturbances, which promote the conservation of biodiversity in urban greenway landscapes.

Effects of Pieris japonica (Ericaceae) dominance on cool temperate forest altered-understory environments and soil microbiomes in Southern Japan.

The number of plants unpalatable to deer increases with increasing deer numbers. In the Kyushu Mountain area of Southern Japan, Pieris japonica (Ericaceae), an unpalatable shrub, has become the monodominant vegetation under evergreen conifer and deciduous broad-leaved tree stands. The monodominance of unpalatable plants in the understory has potential advantages and drawbacks; however, the effects of Pieris dominance are not well understood. To assess the effects of P. japonica dominances on forest environments and ecosystems, we investigated understory environments and soil microbiomes in Pieris-dominant sites. Under the deciduous broad-leaved trees, Pieris dominance leads to considerable Pieris leaf litter and humus weights and low soil bulk density and canopy openness. In the soil fungal community and fungal functional groups, the relative abundance of symbiotrophic fungi, particularly ectomycorrhizal fungi in Pieris-dominant sites were lower than in other-vegetation understory sites and saprotrophic fungi vice versa. Because few seedlings and saplings were found under Pieris shrubs, Pieris dominance in the understory might exclude other plant species. The results of this study will contribute to the Pieris population and forest management following deer overgrazing.

Soil Characteristics, Growth, Yield, Mineral Composition and Proximate Content of Soybeans Under Various Tillage Techniques

Different tillage methods can have varying effects on soil properties and crop quality. Therefore, field experiments were conducted at the Teaching and Research Farm of Landmark University, located in Omu‐Aran, Kwara State. The objectives were to investigate the impacts of various tillage methods on soil characteristics and the growth, yield, mineral and proximate content of soybean (Glycine max (L.) Merr.). Based on these objectives, it was hypothesized that soil properties, growth, yield, mineral and proximate contents of soybean would react differently to different tillage methods. Consequently, experiments were conducted to validate this hypothesis. The treatments were four tillage methods: manual clearing (MC), ploughing (P), ploughing plus harrowing (P + H) and manual ridging (MR), replicated three times in a randomized complete block design. Data on the initial soil properties (bulk density, particle size, pH, organic matter, N, P, K, Ca and Mg), along with the chemical properties of the soil on a per‐plot basis at the end of the experiment, were collected. Additionally, data on soil bulk density, porosity, moisture content and temperature were collected during the vegetative growth of the soybean. Soybean plant height and the number of branches were recorded at the midflowering stage, while grain yield and the number of pods were recorded at harvest. Soybean seeds were later analysed for their mineral and proximate contents using standard methods. P + H resulted in lower soil bulk density than other tillage methods and led to higher growth, yield, proximate and mineral contents of soybean. In MC, bulk density, soil moisture content, soil organic matter, N, P, K, Ca and Mg were significantly higher and temperature lower than in other tillage methods; yet, these advantages did not translate into increased yield and quality due to the higher bulk density. The growth, yield and quality of soybean were significantly influenced by soil bulk density rather than by soil chemical properties. Using the mean of the two sites, relative to MC, P and MR, P + H increased the grain yield of soybean by 41.3%, 24.4% and 13.7%, respectively. These findings underscore the importance of appropriate tillage practices for successful soybean cultivation in similar agroecological zones. For small‐scale operations, MR is suggested, while P + H is recommended for large‐scale soybean production in the studied area. Future studies could include additional variables, such as economic analysis, long‐term soil health impacts or the effects of tillage methods under varying climate conditions.

Biomass Storage Potential and Improvement in Soil Properties under Different Bamboo Plantations in the Terai Region of Central Himalaya

This study evaluates six bamboo species, i.e., Dendrocalamus hamiltonii, Bambusa nutans, Dendrocalamus asper, Bambusa bambos, Bambusa balcooa, and Dendrocalamus strictus, regarding their growth behavior, nutrient uptake, and effect on the soil properties of the Terai region. Various aboveground growth parameters exhibited significant variations with the maximum clump girth (8.60 m) and internodal length (35.37 cm) of B. nutans, which was also reported by the culm diameter (5.70 cm) of D. hamiltonii and the number of culms per clump (65) of D. strictus. The total aboveground biomass ranged from 51.14 Mg.ha-1 in D. asper to 362.56 Mg.ha-1 in D. hamiltonii. The most significant variation in soil properties was observed in the 0-40 cm soil layer. Under D. hamiltonii, the lowest soil bulk density (1.07 g.cm3; 1.21 g.cm3) and the maximum soil porosity (59.00%; 56.40%), soil organic carbon (1.54%; 0.72%), and available soil nitrogen (228.29 kg.ha-1; 173.73 kg.ha-1) were found the 0-40 and 40-80 cm soil layers. Furthermore, significant enhancements in soil microbial population were recorded. Thus, bamboo plantations have great potential to enhance the biomass generation and fertility quotient of fallow lands.

PENGGUNAAN MULSA PLASTIK SEBAGAI UPAYA KONSERVASI LAHAN UNTUK MENJAGA STABILITAS SIFAT FISIKA DAN KIMIA TANAH

Low nutrient availability and high soil bulk density are caused by the loss of fertile soil particles due to the kinetic energy of rain. Land management that does not apply conservation principles such as soil covering is one of the factors causing this to happen. This research was conducted to determine the impact of using plastic mulch as one of conservation actions. This research was conducted at the experimental field University of Siliwangi, Mugarsari. Soil samples were taken from mulched and without mulch lands as treatments. Soil samples were collected at 0-10 and 10-30 cm soil depths. Soil samples were taken to analyze the chemical properties of the soils (i.e., pH H2O, organic C, total N, available P, exchangeable K, Ca, Mg, Na) and physical properties (i.e., soil bulk density, porosity, water content, and texture). The results showed that the use of mulch had a significant effect (p<0.05) on pH H2O, organic C, total N, available P, exchangeable K, exchangeable Ca, bulk density, and water content. The results of the correlation showed that increasing organic C in mulched land had an effect on decreasing BD (r = -0.739). In addition, the organic C increased soil porosity (r = 0.612). Meanwhile, soil depth had no effect (p>0.05) on soil chemical and physical properties.

Lithology‐mediated soil erodibility characteristics after vegetation restoration in the karst region of Southwest China

AbstractEcological restoration projects have significantly increased global vegetation cover and reduced soil erosion. However, it is very challenging to clarify the complex soil erosion mechanisms of limestone and dolomite in the southwest karst region and to identify the key factors affecting erosion. The study site has a subtropical monsoon climate with precipitation concentrated during the rainy season from May to September. In this study, four plantation restoration measures with a recovery time of approximately 16 years were selected, which included arbor forest, orchard, grassland, and cropland (control). Soil physical–chemical properties and soil erodibility K values were used to evaluate the soil erosion characteristics. The results showed that both limestone and dolomite exhibited lower soil bulk density as well as higher capillary porosity, and soil water‐stable aggregates after revegetation. The limestone and dolomite K values were reduced by 12%–15% and 15%–17%, respectively. However, the K value of limestone was 17.9% higher than that of dolomite, indicating that dolomite exhibited a higher stability. Through redundancy analysis and structural equation modeling, revegetation was found to reduce soil erosion by influencing the soil particle composition. The silt was the key factor influencing soil erosion, accounting for 84.4% and 78.2% of the variation in the limestone and dolomite K values, respectively. These findings suggest that vegetation restoration enhances soil erosion resistance; however, the effectiveness of restoration is controlled by the lithology in the southwest karst region. These findings provide a reference for soil and water management and vegetation restoration.

Impact of soil structure and texture on occurrence of microplastics in agricultural soils of karst areas

The impact of microplastics (MPs) on soil ecosystems has attracted widespread attention; however, the effects of soil structure and texture on the occurrence of MPs are not fully understood. In this study, we investigated the effects of soil structure and texture on the abundance of MPs and their potential mechanisms in agricultural soils of karst areas in Guizhou, China. The results showed the average abundance of MPs was 2948 items/kg. The soil texture in the study area can be categorized into seven types such as powdered-light clay, the range of total soil porosity was 39.05–69.22 % and the range of soil bulk density was 0.66–1.51 g/cm3. Soils with a powdered-light clay, low soil porosity, and low soil bulk density showed higher MPs pollution. The percentage of pellet MPs in agricultural soils with a powdered-light clay was 84 %, which was higher than that of the other soil textures. The direct effects of soil texture, soil porosity, and soil bulk density on MPs abundance were much lower than the indirect effects, with soil texture having the highest effect on MPs abundance. We speculated that karst geology may affect the accumulation and distribution of MPs in soil by affecting soil texture and structure, which, in turn, affects the fragmentation and migration of MPs. These findings will help to better understand the mechanisms of soil MPs pollution and provide a scientific basis for the development of relevant control strategies.

Effects of biochar, compost, and composted biochar soil amendments on okra plant growth

Soil fertility can be improved by incorporating organic matter such as biochar and compost. The combined addition of biochar and compost effectively restores soil degradation by enhancing nutrient availability, soil aggregation, and porosity. Nonetheless, many studies mainly concentrated on a single application of biochar and compost as a soil amendment. In this work, the biochar samples were prepared from oil palm empty fruit bunch (OPEFB) material at the desired microwave power (450 W) under 1 L/min of N2 flow for 10 min. Then, sandy soil was amended with 5 g of sole biochar and compost, as well as a biochar-compost mixture at a ratio of 1:1 for 8-weeks polybag experiment of okra plants. At 4 weeks of the plantation, the physical and chemical soil properties were analyzed. The okra plant's growths were also measured weekly for 8 weeks of the plantation. The application of biochar and composts alone, and in combination significantly improved soil physicochemical properties and plant growth compared to control soil. The synergetic positive effect of biochar and compost combination resulting lowered soil bulk density with higher soil porosity, moisture content, and nutrients availability. The study showed that a biochar-compost mixture is more effective to enhance soil quality over individual treatments and unamended soil.

Distribution and Recurrence of Warming‐Induced Retrogressive Thaw Slumps on the Central Qinghai‐Tibet Plateau

AbstractRetrogressive thaw slumps (RTSs) have become a dominant geomorphic event in permafrost regions due to the modern climate change. However, the roles of topographic, vegetation, and soil factors in influencing the spatial distribution and recurrence of RTSs remain not fully understood. Here, we identified the formation and recurrence of 459 RTSs during 2008–2021 using satellite images of the central Qinghai‐Tibet Plateau (Northwest of the Beiluhe Basin, 239 km2). We found that the topographic and environmental attributes of the RTSs exhibited strong correlations with the variation in the RTS density. The RTS‐affected areas had a higher slope, elevation, relative slope position, normalized difference vegetation index, soil water content, and lower soil bulk density than other landscapes. Regarding the influence of topographic and environmental attributes on the activity status of RTSs during 2018–2020, we found that the higher slope, elevation, and soil water content were advantageous for the activity of the RTSs. The RTSs with larger sizes and presenting an elongated shape were more likely to be active. Additionally, we examined the variation of the headwall shape of RTSs based on the fractal dimension and UAV‐based orthophoto. We found that the headwall shape of RTSs becomes more complicated due to the small‐scale thawing of ice‐rich permafrost, which may further induce subsequent thaw slumping. Higher air temperature triggers new RTSs, and increased precipitation may be responsible for the further activity of RTSs. Our findings can enhance our understanding of the development pattern and mechanism of RTSs in permafrost regions.

Relationship between soil porosity and the apparent density of Astronium fraxinifolium (Anacardiaceae) wood

Summary Plants can modify their anatomy and physiology to improve their survival. Water stress is one of several factors that have been identified as potential wood modifiers. This study aimed to analyse whether soil physical properties and dioecy influence the wood density of Astronium fraxinifolium (Anacardiaceae). Samples of A. fraxinifolium trees were obtained from 20 male and 20 female individuals in two fields (an impacted area (IA) and a non-impacted area (NIA)) and the physical properties of soils from both areas were analysed. The apparent densities of the bark-to-bark wood samples were determined by X-ray densitometry. The apparent density values were calculated using QMS software. The IA soil showed lower porosity (macroporosity and microporosity) than the NIA soil. The wood densities of IA trees differed significantly, with IA trees having higher values than the NIA trees. The results indicated that trees growing in soils with low porosity and high soil bulk density had higher wood density. Based on the results of this study, which showed that species in areas with compacted soils had relatively high wood densities, it was concluded that A. fraxinifolium trees in environments with low water availability have dense wood with conducting vessels of large diameters. None of the wood features were influenced by the dioecy of A. fraxinifolium.

Weed infestation and productivity of wheat crop sown in various cropping systems under conventional and conservation tillage.

Climate change, pest infestation, and soil degradation are significantly reducing wheat (Triticum aestivum L.) yield. Wheat is cultivated in rice-wheat and cotton-wheat cropping systems and escalating global population is exerting substantial pressure on the efficiency of these systems. Conservation tillage and crop rotation could help in lowering soil degradation and pest infestation, and improving wheat yield. This three-year study evaluated soil properties, weed infestation and wheat yield under various tillage and cropping systems. Six different cropping systems, i.e., cotton-wheat, sorghum-wheat, mungbean-wheat, rice-wheat, sunflower-wheat, and fallow-wheat (control) and three tillage systems, i.e., conventional tillage (CT), zero-tillage (ZT) and minimum tillage (MT) were included in the study. The individual and interactive effects of tillage and cropping systems significantly affected soil properties, weed infestation and yield of wheat crop. Overall, CT resulted in lower soil bulk density and higher porosity, while ZT behaved oppositely at all locations in this regard. Similarly, mungbean-wheat cropping system resulted in lower bulk density and higher porosity and nitrogen (N) contents, while fallow-wheat cropping system resulted in higher bulk density, and lower soil porosity and N contents. Similarly, ZT and CT resulted in higher and lower weed infestation, respectively. Likewise, lower and higher weed density and biomass were recorded in wheat-sorghum and wheat-fallow cropping systems, respectively at all locations. In the same way higher number of productive tillers, number of grains per spike, 1000-grain weight, grain yield, and economic returns of wheat crop were recorded for CT, whereas ZT resulted in lower values of these traits. Regarding interactions, wheat-mungbean cropping system with CT resulted in lower bulk density and higher porosity and N contents, whereas wheat-fallow system with ZT behaved oppositely at all locations in this regard. Similarly, higher and lower values for yield-related traits and economic returns of wheat crop were noted for mungbean-wheat cropping system under CT and fallow-wheat and sorghum-wheat cropping systems under ZT, respectively. It is concluded that the mungbean-wheat cropping system improved wheat productivity and soil health and sorghum-wheat cropping system could lower weed infestation. Therefore, these cropping systems can be practiced to lower weed infestation and improve wheat yield and economic returns.

Improvement of the soil quality under intercropped conilon coffee (Coffea canephora P.) in the coastal tablelands of Southeast Brazil

The objective of this study was to evaluate the physical-hydrological and chemical properties and organic carbon stock of soil under intercropped conilon coffee (Coffea canephora P.) and in full sun in the coastal tablelands of Espírito Santo, Brazil. The treatments evaluated were coffee intercropped with rubber tree (CR) and in full sun (FS) in the area 1; coffee intercropped with papaya (CP) and in full sun (FS) in the area 2; coffee intercropped with coconut (CC), in full sun (FS), and an area of ​​native vegetation (NV) in the area 3. The physical and chemical properties of the soil and its organic carbon stocks were measured in layers of 0-0.4 m. In area 1, CR showed lower soil bulk density and temperature, and higher total porosity and macroporosity. In area 2, CP presented higher available water capacity and soil water content, better soil fertility, and lower soil temperature. In area 3, CC presented higher total porosity, available water capacity, and soil organic carbon stock. NV presented physical and chemical properties of soil that limit the agricultural development of the crops. Conilon coffee plantations can improve the physical-hydrological and chemical quality of soil compared to cultivation in full sun and native vegetation in the coastal tablelands, which varies according to the intercropped culture.