Soil Physical Degradation Research Articles

PENGARUH AMELIORAN ORGANIK TERHADAP SIFAT KIMIA TANAH DAN PERTUMBUHAN CABAI RAWIT (Capsicum annum L.) PADA TANAH BEKAS TAMBANG NIKEL

Nickel mining activities in Southeast Sulawesi have triggered the physical, chemical and biological degradation of soil. Therefore, the application of organic amendment was an alternative solution to restore the degraded soil. This research aimed to study the effect of ameliorant on soil chemical properties and the effect of ameliorant on yield of cayenne pepper on ex-nickel mining soil. This research was conducted on Field Experimentation Station. Faculty of Agriculture Halu Oleo University, from January to April 2021. This study was carried out using a Randomized Block Design (RBD), which consists of 4 treatments namely without ameliorant (B0), cow manure 60 (B1), biochar husk 60 (B2), cow manure + biochar husk (1:1) 60 (B3) with 4 replications. The results showed that overall ameliorant had an effect on increasing soil pH, Organic-C, available-P, available-K, and Cation Exchange Capacity. Soil pH increased from 4.32 to 6.1, C-organic increased from 0.78% to 1.89%, available-P increased from 3.87ppm to 16.87ppm, available-K increased from 10 mg 100g-1 to 40 mg 100g-1, Cation Exchange Capacity increased from 0.1 me 100g-1 to 75.11 me 100g-1, while total-N increased from 0.21% to 0,38%. Application of 60 (B1) of cow manure increased the plant height and the number of leaves by 29.65 cm and 51,25 respectively.

Soil physical change and sugarcane stalk yield induced by cover crop and soil tillage

Conventional tillage and intensive machinery traffic are the major causes of physical soil degradation in sugarcane fields. This study evaluates the impact of adopting conservation management practices during sugarcane planting on soil physical properties and stalk yield of sugarcane in the municipality of Ibitinga, state of São Paulo, Brazil. The experimental design (split-block) included four cover crops and three soil tillage systems, with three repetitions. For comparison purposes, a control treatment was also included (without cover crop and under [...]

Technical and technological foundations of soil cultivation in conditions of climate change

Purpose. To determine promising directions for the development of the technical and technological foundations of soil cultivation in the conditions of climate change. Methods. Monographic, abstract-logical, graph-analytical, induction and deduction, regression analysis of results. Results. Modern soil cultivation technologies are considered, their advantages and disadvantages, development trends are defined. It has been established that climate change will significantly affect the terms of execution of works, the conditions of interaction of working bodies of technical means with the soil environment. The parabolic relationship between traction resistance and soil moisture means that climate change will increase fuel costs for tillage. Therefore, the further search for new technical and technological solutions should be aimed at reducing energy consumption and preventing physical degradation of soils, substantiating structural and functional schemes of technical means for soil cultivation, parameters of working bodies and modes of operation, under which the number of dust particles in the surface layer of the soil will be minimal. Conclusions. The main direction of the development of the technical and technological base for the production of plant products in the conditions of climate change is the harmonization of the interaction of the working bodies of tillage machines with the soil, which will ensure the reduction of physical soil degradation and energy consumption to create a favorable environment for plant development and crop formation. In the conditions of global climate change, agricultural production is being reoriented towards precision farming systems, therefore, crop production technologies should be based on targeted tillage with the simultaneous introduction of a full dose of mineral nutrition into the seed sowing area for the planned harvest, sowing of seeds and preservation of plant residues on the surface of the soil for protection it from overheating and loss of moisture. Keywords: technical means, soil cultivation technologies, interaction of working bodies with the soil, soil moisture, soil resistance, energy consumption, physical soil degradation.

Просторово-часова трансформація якості поливних вод на Південнобузькій та Кам’янській зрошувальних системах

Much of Ukraine is located in areas of insufficient moisture, and therefore the food supply and export potential of the state largely depends on the availability, condition and efficiency of irrigated land use. A factor that significantly affects the development of irrigation in the South of Ukraine is the quality of irrigation water. The aim of the article is to highlight the results of the study of spatial-temporal aspects of various indicators of agronomic quality of irrigation waters of the South Bug Irrigation System (SBIS) and Kamianska Irrigation System (KIS). The task of the research was to determine the degree of danger of salinization of soils, the hazard of physical degradation of soils, the danger of toxic effects on the plant of certain toxic anions and cations and the pH value. In terms of the risk of soil salinization, these waters have a medium level of hazard. Such irrigation water has certain limitations in use. If there is no noticeable reduction in the yield of the main crops at the SBIS, then watering with this water will lead to a noticeable loss of yield at the KIS for the most sensitive to salinity crops. KIS and SBIS irrigation water have medium risks of potential salinization of soils, which makes the application of gypsum a mandatory technological measure in the process of growing crops. Regarding the impact of sodium cations on agricultural plants, the quality of irrigation water on the lands of SBIS is low and medium, and on the lands of KIS – average. But at the end of the irrigation season under the influence of temperature and probable inflow into reservoirs along the route of transportation of mineralized groundwater, the use of such water on KIS lands requires significant restrictions due to the high risk of injury to plants with excess sodium cations. The low initial content of chlorine anions in the Southern Bug River, which does not change significantly in the process of water transportation, does not lead to toxic effects on plants in all lands of both irrigation systems hydrocarbonates dominate among all anions in irrigation water, both on SBIS and on KIS, but the content of bicarbonates does not exceed the normative indicators inherent in "average danger of influence on soil solution". At the same time, the presence of large relative amounts of hydrocarbonate anions and sodium cations leads to high values of the "residual sodium carbonate index" (RSCI), especially in the KIS, which indicates the potential danger of rising sodium in water, which can have negative consequences for soil and for the plant. The pH values of irrigation water on the entire transport route in all terms of measurement often fall into the range of values acceptable for agricultural plants. Thus, the assessment of water used in SBIS and KIS, for most parameters shows an average and low agronomic quality, and therefore only limited use of this water for irrigation is possible. This is especially true of KIS lands.

Capacity and Intensity Indicators to evaluate the effect of different crop sequences and cover crops on soil physical quality of two different textured soils from Pampas Region

Soil physical degradation is a current problem in Molisols of the Pampas Region under no-tillage (NT), that has been related to over-simplified agricultural systems with scarce or no rotations and long winter bare fallows. Soil physical quality (SPQ) is a key factor of soil health and productivity, as it controls root development and air and water fluxes and storage in the soil, which in turn affect nutrient uptake and plant growth. Cover crops have been proposed as a companion agricultural practice to improve NT performance and SPQ. The aim of this study was to evaluate the effect of the inclusion of winter cover crops in different cropping sequences on capacity and intensity indicators of SPQ in two soils of different texture under NT and to compare it with different traditional crop sequences, including non-agricultural plots. SPQ was evaluated at two different sites, one with a silty loam Argiudoll and the other with a sandy loam Hapludoll. Treatments included plots with and without cover crops, with different summer crop sequences (continuous soybean and corn – soybean rotations). Also, a corn – wheat/soybean rotation with and without pastures was evaluated. All treatments had more than 15 years under the same management. We measured soil organic carbon (SOC), and capacity SPQ indicators (bulk density, total porosity, pore size distribution, air capacity, plant available water, relative field capacity and S index). We also measured dynamic SPQ indicators derived from field infiltration tests (saturated and near saturation hydraulic conductivity, effective macro and mesoporosity, and porosity connectivity indexes for different pore families). On the silty loam Argiudoll, cover crops increased SOC but failed to improve SPQ. This was related to soil physical degradation and the low ability of these soils for structure regeneration. On the sandy loam Hapludoll, cover crops had mixed effects on SOC and pore size distribution, but increased near saturation hydraulic conductivity, in the case of the corn – soybean rotation with cover crops, reaching values similar to those of a natural grassland.

Mapping of soil degradation potential in Nguntoronadi District Wonogiri Regency

Soil is the most important component in agriculture. Soil degradation is caused by improper soil management, unpatterned planting, and homogeneous rainfall. Mapping of potential soil degradation was a process of identifying initial conditions to determine areas that have the potential in soil physical, chemical, and biological degradation. The purpose of this study was to create a map of Soil Degradation Potency (SDP). The research was conducted in Nguntoronadi district, Wonogiri. The mapping used a guided-qualification method and was assisted by ArcGIS application for overlaying the maps according to standard procedures, and the resulting value of soil degradation potency. The results showed the soil degradation potency was slightly in 454 hectares, moderate in 5,186 hectares, and high in 192 hectares. The research area was dominated by moderate to high degradation. Land management requires more attention according to soil conservation and sustainability. Further research is needed to determine the actual level of soil degradation to obtain recommendations for sustainable land management.

Закономірності прояву фізичної деградації в орних ґрунтах України та регіони підвищеного її ризику

Goal. To study the patterns of physical degradation in arable soils of Ukraine, and identify its features in different climatic zones, as well as to identify regions of increased risk of its manifestation and propose efficient anti-degradation measures. Methods. Information-analytical — to analyze the literature on physical degradation of arable soils; mathematical and statistical — to identify the reliability of the results and calculate the area of soils at risk of physical degradation; cartographic — to create cartographic materials to identify problem areas of physical degradation. Results. The main reasons for the spread of physical degradation of arable soils were identified: the increased tendency of humus to mineralization and mobility, over compaction and destructurization, increase in the number of large and small pores in macroaggregates. The peculiarities of the manifestation of physical degradation of soils depending on the natural and climatic zone of their location are characterized. Based on the creation and analysis of cartographic materials, problem areas with physical soil degradation were identified and their areas were calculated by administrative regions of Ukraine. It is established that the soils of the Kherson region are characterized by the greatest tendency to the manifestation of physical degradation. Also, regions with an increased risk of physical degradation in soils are Zaporizhzhia, Poltava and Kyiv. The principles of overcoming physical degradation are determined, effective anti-degradation measures are proposed, the main ones of which are minimization of mechanical impact on the soil, observance of the deficit-free balance of organic matter and preservation of the agronomically useful structure. Conclusions. The causes and consequences of the physical degradation of arable soils are outlined. The urgency of identifying areas of soil susceptibility to physical degradation is proved, the peculiarities of its manifestation in different climatic zones of the country are analyzed. The main means and principles for overcoming the physical degradation of soils are proposed.

Approbation of various approaches to environmental and economic assessment of soil and land degradation

The paper reveals three different approaches to measuring the depth of soil degradation and possible efficiency of its improvement on agricultural lands of two Russian regions. The methods include the evaluation of land productivity and land degradation, then the assessment of the amount of damage to the soil caused by current agricultural practices, and finally the assessment of the cost of inaction compared to the cost of action towards degraded soils using the economics of land degradation framework (ELD). Finding the connection among these methods for establishing an integrative approach is a key goal of this research. First, the main land productivity changes during 2001–2015 period was analyzed and the land degradation neutrality (LDN) indicator was estimated. Secondly, the physical soil degradation was measured, particularly soil erosion, soil nutrients balance, and changes in acidity and salinity of the soils. Finally, the ratio of the cost of inaction compared to the cost of action against land degradation was evaluated. The paper reveals all three methods on the examples of Volgograd oblast’ and Belgorod oblast’. These estimates using the economics of land degradation framework showed that only in the Belgorod region the cost of action against land degradation is economically efficient on a 20-year horizon.

Effects of land use, tillage management, and crop diversification on soil physical quality in Cerrado agricultural systems

AbstractSustainable agricultural intensificationhas been considered one of the solutions for increasing food production and mitigating climate changes. Nevertheless, soil physical degradation induced by intense mechanization may threaten those benefits in large‐scale agricultural regions such as the Brazilian Cerrado. Thus, our study aimed to assess the effects of land use, tillage management, and crop diversification on soil physical quality of two long‐term experiments in Cerrado through on‐farm visual evaluation of soil structure (VESS) and soil physical parameters. Soil sampling was performed in 0‐to‐10‐ and 10‐to‐20‐cm layers of four agricultural systems: soybean [Glycine max(L.) Merr.]–fallow under conventional tillage (SF); soybean–fallow under no‐till (SN); soybean–maize (Zea maysL.) succession under no‐till (SM); and crop rotation under no‐till including soybean, maize, grasses, and legumes (CR). An additional area of native Cerrado vegetation (NV) was included as reference. Land transition from Cerrado to agricultural systems declined the soil physical quality, detected by VESS assessment and physical parameters in both layers. Tillage management did not alter soil physical parameters, which was likely associated with the medium time adoption in the experiments (9 yr) and high resilience capacity of clayey Oxisols. Unexpectedly, SM and CR negatively affected the porosity‐ and water‐associated soil parameters in the 10‐to‐20‐cm layer compared with SN. It suggests that the soil physical damage induced by higher frequency of machinery operations required to manage a more diverse crop sequence may prevail over the benefits provided by crop diversification. Finally, this study highlights that intensified agricultural systems need to be coupled with strategies to reduce and/or control intensive machinery traffic.

Soil physical degradation and rill detachment by raindrop impact in semi-arid region

Tillage along slopes creates furrows similar to rills which exposes the soil surface directly to raindrop impact (RI) especially in semi-arid regions. In order to quantify the effect of RI on soil physical degradation and rill detachment we determined the change of soil aggregate stability, bulk density, surface resistance and rill detachment in semi-arid soils. Toward these some dominant soils including silt, silty clay, clay, sandy clay and loamy sand were exposed under rainfall impact at four slope gradients (5, 10, 15 and 20%). The laboratory experiments were set up at two soil surface conditions: with and without RI in a flume under simulated rainfalls with an intensity of 90 mm h−1. Four rills with parabolic cross sections, 10 cm width and 4 m length were installed along the flume. Results indicated that the soils are physically degraded (aggregate breakdown, soil compaction and surface resistance) by RI. The rate of physical degradation processes was significantly influenced by the soil type and slope gradient. The soils with higher water-stable aggregates such as sandy clay showed lower physical degradation symptoms. The susceptibility of these soils to physical degradation processes increased with increasing slope gradient. Soil detachment through concentrated flow under RI was affected by the soil physical degradation rate, which in turn was controlled by the two variables i.e. soil type and slope gradient. However the direct effect of RI act in rill detachment (rainfall-driven force) increased rill detachment. As a conclusion, the rill detachment showed higher dependency to RI than soil physical degradation processes. This study revealed that the importance of maintaining the soil surface cover for controlling the negative effects of RI in the soil physical degradation as well as rill detachment especially in semi-arid soils with lower aggregate stability and under steep slopes.

PGPR in Agriculture: A Sustainable Approach to Increasing Climate Change Resilience

Growing environmental concerns are potentially narrowing global yield capacity of agricultural systems. Climate change is the most significant problem the world is currently facing. To meet global food demand, food production must be doubled by 2050; over exploitation of arable lands using unsustainable techniques might resolve food demand issues, but they have negative environmental effects. Current crop production systems are a major reason for changing global climate through diminishing biodiversity, physical and chemical soil degradation, and water pollution. The over application of fertilizers and pesticides contribute to climate change through greenhouse gas emissions (GHG) and toxic soil depositions. At this crucial time, there is a pressing need to transition to more sustainable crop production practices, ones that concentrate more on promoting sustainable mechanisms, which enable crops to grow well in resource limited and environmentally challenging environments, and also develop crops with greater resource use efficiency that have optimum sustainable yields across a wider array of environmental conditions. The phytomicrobiome is considered as one of the best strategies; a better alternative for sustainable agriculture, and a viable solution to meet the twin challenges of global food security and environmental stability. Use of the phytomicrobiome, due to its sustainable and environmentally friendly mechanisms of plant growth promotion, is becoming more widespread in the agricultural industry. Therefore, in this review, we emphasize the contribution of beneficial phytomicrobiome members, particularly plant growth promoting rhizobacteria (PGPR), as a strategy to sustainable improvement of plant growth and production in the face of climate change. Also, the roles of soil dwelling microbes in stress amelioration, nutrient supply (nitrogen fixation, phosphorus solubilization), and phytohormone production along with the factors that could potentially affect their efficiency have been discussed extensively. Lastly, limitations to expansion and use of biobased techniques, for instance, the perspective of crop producers, indigenous microbial competition and regulatory approval are discussed. This review largely focusses on the importance and need of sustainable and environmentally friendly approaches such as biobased/PGPR-based techniques in our agricultural systems, especially in the context of current climate change conditions, which are almost certain to worsen in near future.

Machinery traffic in sugarcane straw removal operation: Stress transmitted and soil compaction

Straw removal requires a complex set of mechanized operations, including machines for raking, baling, and transporting the straw, which may intensify soil physical degradation in sugarcane fields. A field experiment was conducted to estimate the stress transmitted caused by a set of machines used for sugarcane straw removal and to quantify the impact of these stresses on soil physical indicators. The treatments consisted of reproducing the field traffic of individual and sequential operations used for straw removal, including raking; raking + baling; and raking + baling + transporting operations. Soil bulk density (BD), soil penetration resistance (SPR), macroporosity (MaP) and microporosity (MiP) at the depths of 2.5, 5, 15, and 30 cm were measured before and after the field operations. Contact area of the tires and stress transmitted into the soil induced by the straw removal operations were simulated by SoilFlex model and then used to assess the magnitude of the changes in soil physical indicators. Results showed that baling operation transmitted the highest stress (∼400 kPa), followed by straw raking and transporting, whose transmitted stress level exceed 300 kPa near the soil surface. The sum of sequential operations (i.e., raking + bale + transporting) showed the highest negative impact on soil physical quality. The magnitude of the changes in soil physical indicators occurred according to initial conditions of BD and transmitted stress. Our results show that operations for straw removal intensify soil compaction, which can be detrimental to sustain soil health and plant growth. Therefore, we advocate that traffic control strategies should be adopted during the straw removal operations to improve soil quality towards greater sustainability of sugarcane production in Brazil.

Ecological intensification of cropping systems enhances soil functions, mitigates soil erosion, and promotes crop resilience to dry spells in the Brazilian Cerrado

Water scarcity threatens global food security and agricultural systems are challenged to achieve high yields while optimizing water usage. Water deficit can be accentuated by soil physical degradation, which also triggers water losses through runoff and consequently soil erosion. Although soil health in cropping systems within the Brazilian Cerrado biome have been surveyed throughout the years, information about soil erosion impacts and its mitigation are still not well understood; especially concerning the role of cropping system diversification and its effects on crop yield. Thus, the aim of this study was to assess whether ecological intensification of cropping systems –inclusion of a consorted perennial grass and crop rotation– could promote soil coverage and consequently decrease water erosion and soil, water, and nutrient losses. This work studied the effects of crop rotation and consorted Brachiaria, along with different levels of investment in fertilization on soil physical quality and on soil, water, and nutrient losses, and crop yields. Results proved that soybean monoculture (SS) is a system of low sustainability even under no-till in the Brazilian Cerrado conditions. It exhibited high susceptibility to soil, water, and nutrient losses, causing low crop yields. Our results showed that water losses in SS cropping system were approximately 10% of the total annual rainfall, and total K losses would require an additional 35% of K application. Conversely, ecological intensification of cropping systems resulted in enhanced soil environmental and agronomic functions, increased grain yield, and promoted soil and water conservation: high soil cover rate, and low soil, water and nutrient losses. Ecological intensification proved to be an adequate practice to boost crop resilience to water deficit in the Brazilian Cerrado.

Effects of long-term tillage systems on soil physical quality and crop yield in a Brazilian Ferralsol

Long-term soil tillage trials can provide important knowledge about sustainable changes in soil physical quality and crop yield. This study evaluated soil physical quality indicators under different long-term tillage systems and examined the relationships between quality indicators and crop yield. The study was carried out on a Rhodic Ferralsol with three tillage systems established in 1989: conventional tillage (CT), strategic tillage (ST), and no-tillage (NT). All treatments had long-term crop rotation. The soil parameters evaluated were total organic carbon (TOC), bulk density (ρs), macro and microporosity (Mac and Mic), relative gas diffusivity (D/D0), pore tortuosity (τ), relative field capacity (RFC), structural stability index (SSI), least-limiting water range (LLWR), and degree of compactness (DC, taking as reference the soil bulk density in which LLWR = 0). Soybean and maize yields in two consecutive summer seasons were measured. Conventional and strategic tillage provided higher ρs in the 0.15–0.30 m layer depth, leading to higher DC in CT. Using soil bulk density at LLWR = 0 as reference proved useful to assess soil DC and plant response. No-tillage provided lower DC in the 0–0.15 m (86 %) and 0.15–0.30 m (78 %) layers than CT (91 % and 94 %, respectively). The maize yield had a negative linear relationship to DC, with the lower values at DC > 87 %. All tillage systems affected D/D0, even at similar porosity values. The better soil physical quality under NT provided 1211 kg ha−1 higher maize yield compared with CT. The differences in soybean yield between treatments were not significant, but NT provided 381 kg ha−1 more than CT. These findings indicate that NT is the best system studied. Our results strongly suggest that ST does not improve physical properties of soils under NT with crop rotation, and that a diversified crop rotation in NT was efficient to avoid soil physical degradation.

ҐРУНТОВІ РЕСУРСИ УКРАЇНИ: СТАН, ПРОБЛЕМИ І СТРАТЕГІЯ СТАЛОГО УПРАВЛІННЯ

The purpose of this study is to propose the concept of a strategy for sustainable management of soil resources in Ukraine based on the analysis of the dynamics and current state of soils and their fertility. In this study, we used such main methods: analysis, synthesis, monographic, expert assessments, calculation-and-analytical, abstract-and-logic, cartographic. Despite the intensification of soil degradation (losses of humus and nutrients, especially phosphorus and potassium, erosional losses of the upper fertile layer, physical degradation of soils; acidification of soils, especially in the Polissya and in the Carpathian region; secondary alkalinization and salinization of irrigated soils), there is a reduction in funding for soil protection measures. The area of degraded and infertile soils in Ukraine is over 8 mln ha, and direct annual losses of income only from crop failure due to the main types of soil degradation reach about 33.6 bln UAH in the country as a whole. The novelty of the study is that the provisions on the strategy of sustainable management of soil resources of Ukraine were further developed, in particular, in terms of a holistic macroeconomic approach to the scale of soil degradation and its environmental-and-economic consequences, and a holistic solution through a set of strategic measures of soil fertility reproduction. One of the first attempts to substantiate the strategy of sustainable management of soil resources of Ukraine from the standpoint of an interdisciplinary approach, which provides for: improvement of legislative and regulatory support; improving information and institutional support; effective international cooperation; technological and financial support of sustainable soil management, as well as forecast economic, environmental and social effects of solving the problem of soil degradation. The practical value of the obtained results is that their application should help increase the efficiency and performance of sustainable management of soil resources and achieve land degradation neutrality in Ukraine.

Response of soil physical degradation and fine root growth on long-term film mulching in apple orchards on Loess Plateau

Response of soil physical degradation and fine root growth on long-term film mulching in apple orchards on Loess Plateau

Nutrient Stocks Study in Agroecosystems Located near the Steel Industry, Galati, Romania

It is well known the role of nutrients in growing crops and obtaining cost-effective production, but also to ensure a nutritious contribution to humans and animals alike, in food safety conditions. This study aims to evaluate both the supply of nutrients and the main parameters of agricultural soils, in 0-30 cm layer, under intensive agricultural practices pressure, undertaken in an agricultural area influenced by steel industry activities. The soil samples were collected from three sites and different plots grown with wheat, corn and sunflower, and subjected to analysis protocols within Galati County Soil Survey Office. Soil supply with the main macronutrients indicates imbalances in all studied sites, regardless of the cultivated plants. Overall, soils have a high nitrogen deficiency, correlated with the low level of soil organic matter supply. Total Kjeldahl nitrogen values are between 0.076-0.258 % for all surveyed plots. Mobile phosphorus is low to very high (8-276 ppm), while mobile potassium is low to very high (70-600 ppm). This is due on the one hand to the natural process of soil degradation through water and wind erosion, and on the other to anthropogenic activities. Most of the time, out of the desire to obtain large harvests, farmers apply non-compliant amounts of fertilizers, which translates into the physical and chemical degradation of agricultural soils and poor management of crop nutrition. Other investigated soil parameters were pH, particle size fractions, as they are related to the dynamics of chemical elements in soil. It could be concluded that, the studied agricultural soils are characterized by imbalances in terms of providing chemical elements accessible to plants, in relation to the main investigated physico-chemical parameters and environmental conditions.

Soil Physical Quality and Relationship to Changes in Termite Community in Northwestern Colombian Amazon

Conversion from Amazon forest to low-management pasture or agriculture causes not only degradation of aboveground vegetation but also negative changes in soil properties and ecosystem services. This study aimed to evaluate the impact of physical soil degradation on termite community changes in three contrasting land uses (natural regeneration, rubber plantations, and silvopastoral systems). Soil physical quality was assessed through a set of physical variables, such as bulk density, porosity, soil macro-aggregation state, Visual Evaluation of Soil Structure (VESS) and penetration resistance, which were summarized in an overall synthetic indicator of physical quality. Besides, transects of 20 × 2 m were established in each land use; each transect was divided into four sections of 5 m to search and collect termites during 1 hour in each section; likewise, termites were collected from blocks of soil 25 × 25 × 10 cm (length, width, and depth, respectively) adapted from the Tropical Soil Biology and Fertility (TSBF) method. In total, 60 transects were evaluated, 20 in each land use. A total of 41 species were collected across the three land uses evaluated: natural regeneration presented 60% of the collected species (25 species), silvopastoral systems 53% (22 species), and rubber plantations 39% (16 species). Additionally, composition species from the silvopastoral, agroforestry systems, and natural regeneration were different, and a close association between these last land uses was observed. Soil physical characteristics showed significant variations between land uses. The rubber plantations presented lowest values of soil physical quality, while the natural regeneration showed high soil physical quality. These changes affected termite community and lead to changes in its composition with disproportionate loss of some species; however, there are some that can acclimate well to the decline in the soil physical quality.

Physical properties and soil degradation of PLA/PBAT blends film reinforced with bamboo cellulose

Cellulose is known as the most abundant organic molecule that is renewable and suitable to replace synthetic polymers in the production of plastics with a formula of (C6H1005)n. Cellulose from plants is the most excellent material for reinforcing fillers. The percentage of cellulose in bamboo is range 45-55%. In this research cellulose from bamboo were incorporated with PLA and PBAT to produce cellulose film. The cellulose film produced with different amount of cellulose which are 0%, 3%, 6% and 9%. The findings showed that PLA/cellulose with 9% content of cellulose showed a higher mass loss with 12.39%, followed by the PLA/PBAT/cellulose 9%, which was 9.69%. Meanwhile, the cellulose film with 0% cellulose content for both types of plastic showed the lower biodegradability of 0.57% (PLA/cellulose bioplastic) and 0.44% (PLA/PBAT/cellulose bioplastic). It shows that biodegradability in the natural environment is the benefits of the film with a high content of cellulose. This analysis revealed the degradation of cellulose film in the soil. Usually, conventional plastic cannot easily be biodegraded by the organisms. Based on this study, it is showed that the increase of the cellulose content also encourages the film to degrade quickly. It is thus revealed that the study on bamboo’s cellulose, provides the scientific information for the application and implementation of bamboo cellulose as an effective biodegradable plastics.

Modelling Alternatives for Highland Soil Structural Degradation and Erodibility, Bui Plateau, Cameroon

Highland triggers of soil physical degradation through the fragilisation of soil aggregates are primarily factors of soil biochemistry and anthropogenic mishandling of land resources. Soil degradation forms are challenging the sustenance of human systems on earth. This study probes into soil physical degradation and exposure to external stressors using 60 soil samples collected and analysed for soil aggregate stability, vulnerability and erodibility to determine soil structural stability/resilient capacity. The soils were found to be stable in structure, but highly vulnerable to stress and erodible. Coarse-granitic sandy soils just as the less evolved erosion soils of the eastern slopes of the plateau were proven to be most erodible and vulnerable to physical degradation. Soil Structural Stability Index (ISS) was very low (≤ 4.3%: severe physical degradation) for disturbed soils under grazing with similar tendencies on cultivated humid volcanic soils. High erosion vulnerability/erodibility soils are indicative of low organic matter and organic carbon content issuant of heavy and uncontrolled grazing, annual biomass burning and long-term cropping without soil improvement schemes which calls for guided land use practices over the Bui Plateau.