Soil Physical Properties Research Articles

Soil Physical and Chemical Properties under Shea Tree (Vitellaria paradoxa) at Different Stages of Growth

Shea tree (Vitellaria paradoxa), is one of the dominant agro-forestry species in Otuke district of Northern Uganda. Due to its economic importance and, in line with the numerous threats the tree is faced with, there is an urgent need for measures to conserve this species, for example, through incorporating annual food crops in the Shea tree parkland. This, however, requires a better understanding of tree-soil-food crop interactions. A number of studies of this aspect either considered only the mature Shea tree gardens or did not provide a clear distinction between the physiological states of the Shea tree. This was the motivation for this study where we compare variation in soil properties under mature and young Shea tree gardens with sites not having trees in Okwang sub-county, Otuke district. Five soil samples (up to 15 cm deep for top soil and 15-30 cm for sub-soil) were obtained per treatment using a soil auger. Our results show that in the top soil, only percent sand varied among the treatments, while, in the sub-soil, only percentage nitrogen and average phosphorus varied among the treatments. We also found that percentage top soil organic matter and percentage of sub-soil sand had negative strong correlations with maize and soybean yields, while percentage sub-soil clay had a strong positive correlation with maize and soybean yield. We conclude that variations in soil physical and chemical properties under Mature and Young Shea gardens only occur for those properties that have a direct link to tree residues

Best Combination of Liquid Organic Fertilizer with NPK Fertilizer for Cocoa Seedling Growth (Theobroma cacao L.)

One strategy for achieving sustainable agriculture is the reduction of inorganic fertilizers. Inorganic fertilizers are reduced by substituting them with organic fertilizers. This study aimed to identify the optimal combination of LOF with NPK fertilizers to promote the growth of cocoa seedlings in polybags. The study used completely randomize design. The treatment design, namely the combination of LOF with NPK fertilizers, consisted of five distinct combinations: control, 100% LOF, 100% NPK, 75% LOF +25% NPK, 50% LOF + 50% NPK, and 25% LOF + 75% NPK. The parameters observed were plant height, stem diameter, number of leaves, total leaf area, plant dry weight, shoot dry weight, root dry weight, soil physical properties, soil water content, soil analysis, and seedling quality index. The results showed that treatment 25% LOF + 75% NPK increased the percentage of plant height by 73.47%, stem diameter by 42.13%, number of leaves by 67.36%, total leaf area by 75.30%, plant dry weight by 45.70%, shoot dry weight by 24.81%, root dry weight by 95.54%, and seedling quality index by 90.65%. LOF can reduce the use of NPK fertilizer by 25% in cocoa seedling

Hydrological and pedological effects of combining Italian alder and blackberries in an agroforestry windbreak system in South Africa

Abstract. The Western Cape in South Africa is a water-scarce region which will likely receive less rainfall and higher air temperatures under projected climate change scenarios. The integration of trees within agricultural systems provides an effective measure for improving water retention on agricultural land. Studying an established and irrigated agroforestry system (AFS) combining alder (Alnus cordata (Loisel.) Duby) as a linear windbreak with a blackberry (Rubus fructicosus L.) crop, we explore the water use dynamics of the intercrop as influenced by the windbreak element by combining methods from hydrology, soil science and forestry disciplines. Our objective is to explore whether the AFS positively impacts the water balance by combining measurement campaigns to characterise the spatial variability of various key system properties with continuous monitoring. The campaigns encompassed extensive soil sampling to determine soil characteristics (nutrient concentrations, hydraulic conductivity, texture, water retention) in the laboratory as well as terrestrial laser scans of the field site, especially of the windbreaks. The continuous measurements covered meteorological, soil water content and soil water potential observations over a 6-month period (in summer). These were applied to understand soil water dynamics during rainstorms and dry spells, including root water uptake as well as soil water storage. We recorded a total of 13 rainfall events delivering 2.5–117.6 mm of rainfall with maximum intensities of 4.1 to 82.6 mm h−1. Further analyses showed that infiltration is likely dominated by preferential flow, with root water uptake potentially occurring in two depth zones corresponding to different plant communities. While soil water content varied by depth and was influenced by physical and environmental factors, it was generally higher in the intercrop zone than within the windbreak-influenced zone. During dry spells, soil water content did not drop below the water content of the permanent wilting point (<-1500 kPa). Values corresponding to soil water tensions above 1000 kPa were recorded on several occasions; these were mitigated by irrigation and, thus, did not result in water stress. Nutrient distribution and soil physical properties differed near the windbreak in comparison to the blackberry crop, and the carbon sequestration potential is great in comparison to monoculture farming. We could demonstrate positive effects of the windbreak on the water balance and dynamics in the blackberry field site, even though questions remain as to the extent of these benefits and how they compared to disadvantageous aspects brought about by the presence of the trees (e.g. increased water usage). Irrigation did, in fact, shift the AFS from a water-limited regime to an energy-limited one.

Continuous Monitoring of Vegetation and Soil Recovery After Eucalyptus grandis Removal in Dense Trees and Shrubs Areas

ABSTRACTInvasion by invasive alien plants is a global challenge and South Africa has invested billions of Rands to manage invaders through the Working for Water programme. However, regular monitoring after alien plant clearing is hardly done, yet it forms the basis for assessing clearing programme effectiveness, particularly ecosystem recovery trajectories. I monitored both vegetation and soil recovery 6 years after Eucalyptus grandis clearing by Working for Water at Zvakanaka Farm in Limpopo Province of South Africa. Vegetation diversity and soil physical properties were surveyed in 2019 and re‐surveyed in 2022 on fell‐and‐removal and fell‐and‐stackburn cleared treatments and compared to the nearby uninvaded treatment. Results show a significant increase in species richness in 2022 compared to 2019 in the fell‐and‐removal treatment. Cover of both native trees and shrubs as well as forbs was significantly higher in 2022 compared to 2019 in the fell‐and‐removal treatment compared to the fell‐and‐stackburn treatment. Most secondary invaders such as Acacia mearnsii, E. cloeziana, Lantana camara and Rubus rigidus that frequently occurred in 2019 showed decreased occurrence in 2022 on both cleared treatments. Between the two sampling years, soil compaction improved on the fell‐and‐removal treatment only, whereas hydraulic conductivity increased significantly in 2022 compared to 2019 in both the fell‐and‐removal and fell‐and‐stackburn treatments. Soils that were strongly and severely repellent in 2019 in the fell‐and‐stackburn treatment were becoming slightly repellent in 2022. These results show varied vegetation and soil improvements between 2019 and 2022 in both the fell‐and‐removal and fell‐and‐stackburn cleared treatments an indication that recovery is moving towards a positive vegetation and soil recovery trajectory in the direction of the uninvaded treatment. Recommendations for successful passive restoration such as secondary invasion follow‐up clearing are discussed.

Temperature and water content estimation in soils of the semi‐arid region of Brazil using finite difference and CFD

AbstractDetermining the temperature and water content of soil, at a given instant or along time, is fundamental to understand several soil‐related phenomena and processes. Evaporation, aeration, chemical‐reaction rates and types, biological processes such as germination and growth of seeds, root development, nutrient and water uptake by roots, and decomposition of organic matter by microbes, are all strongly influenced by soil temperature. On the other hand, infiltration of water through the soil surface allows soil to temporarily store water, making it available for uptake by plants and organisms living in soil. Furthermore, soil water content is closely related to physical and chemical properties of soil, such as oxygen content and demand, which impacts root breathing, microbial activity and soil chemical balance. The accurate evaluation of these two parameters and their interconnection is even relevant in semi‐arid regions, where climate conditions are particularly difficult, such as the north‐eastern zone of Brazil. Thus, the use of computational models and coupled approaches are imperative for rigorous descriptions. This work presents a contribution to estimate soil temperature and water content, by solving the heat transfer equation and the Richards equation, respectively, through finite differences. As input, the model uses the experimental material composition of the soil, the time‐dependent temperature profile at the surface and information about the regional rain regime. Three different numerical approaches were implemented: explicit, simple implicit and the Crank–Nicolson method. The calculations for temperature and water content of the soil obtained with these computational models were compared with the results from Computational Fluid Dynamics (CFD). The relative differences between the numerical methods were less than 0.006% by solving the heat transfer equation and less than 2.75% using the Richards equation. The maximum relative differences within the model, including both a constant and a variable water‐content profile, were 3.28%. The results from the computational model using the CFX tool have maximum relative differences of 0.6%, which contributes to verifying the accuracy of the implemented methods.

Efecto antrópico en propiedades del suelo en sistemas de producción agrícola en la granja Santa Inés

Soil is the main element for the health of agroecosystems; however, agricultural activities have altered the properties of the soil, affecting the quality of the non-renewable natural resource. The objective of the work was to determine the anthropogenic effect of agricultural management on the physical, chemical, and biological properties of the soil in production systems of the Santa Inés farm. For this, permanent sampling points were randomly selected in five agroecosystems (cocoa, banana, corn, pastures, and forest) belonging to the Santa Inés farm. The anthropogenic effect in agriculture has significantly transformed the properties of the soil, caused by the intensive use of agricultural tillage, fertilizers, and pesticides which have caused notable changes in apparent density, porosity, sand content, clay, and nutrients. The modifications that occurred in the physical, chemical, and biological properties of the Inceptisol soil reflect the direct influence of agricultural practices on soil degradation and its ability to maintain sustainable crops.

Greenhouse gas emissions during the rice season are reduced by a low soil C:N ratio using different upland-paddy rotation systems

ContextUpland-paddy rotation can improve multiple-cropping index and crop yields; however, the mechanisms underlying the effects of dry-season crop diversification on rice yields and greenhouse gas (GHG) emissions under multiple rotation systems remain unclear. ObjectiveHere, we aimed to clarify the intrinsic mechanisms whereby rice yields and GHG emissions respond to the diversification of dry-season crops and lay a theoretical foundation for developing agronomic measures that can stabilize yields and reduce GHG emissions. MethodsUsing a positioning experimental site for upland-paddy rotation, we measured rice-season CH4 and N2O emissions, crop yields, GHG-emission intensity (GHGI) levels, soil physical and chemical properties in garlic–rice (GR), wheat–rice (WR) systems for 3 years (2019–2020, and 2022), and in a rapeseed–rice (RR) system for 1 year (2022). The soil microbial dynamics of the three systems were only tested in 2022. ResultsThe WR system had the highest CO2 emission equivalent (CO2-eq), with a 3-year interval value of 1898.24–16794.30 kg·ha−1, the lowest yield (8490.10–9773.46 kg·ha−1), and the highest GHGI (0.22–1.83). The GR system had the highest rice yield (9718.91–10769.75 kg ha−1), a lower CO2-eq (1588.55–12567.51 kg·ha−1), and therefore a lower GHGI (0.16–1.24). The RR system had the lowest GHGI in 2022 (benefiting from the lowest CO2-eq) and a slightly higher yield than that of the WR system. CH4 contributed to >88 % of the CO2-eq under the three systems in 2020 and 2022. The higher soil C:N ratio of the WR system stimulated methanogenic microorganisms, coupled with higher microbial biomass C levels, and ultimately increased CH4 emissions substantially. The soil C:N ratios of the GR and RR systems were significantly lower than that of the WR system because the soil total nitrogen (TN) of both systems was higher and increased CH4 emissions were avoided. The higher levels of N nutrients (TN, NO3--N, and NH4+-N) in the GR and RR systems also enhanced rice yields, with respective increases of 10.37 % and 1.22 %, compared with that of the WR system. ConclusionsThe diversified cultivation of dry-season crops in upland-paddy rotation systems affected rice yields and GHG emissions by changing the ratios of C and N. ImplicationsOur findings highlight the importance of future research involving comprehensive agronomic measures to help reduce emissions, including fertilizer management, straw management, and tillage methods.

Effect of improving soil physical properties by aeration using compressed air

Effect of improving soil physical properties by aeration using compressed air

Impact of formulated organic fertilizers on soil physical and chemical properties in sandy loam soil of North-Eastern Nigeria

The excessive and sole use of inorganic fertilizers has led to soil nutrient depletion, acidification and loss of soil organic matter. Decreased organic matter content reduces the soil's ability to hold water and nutrients, which can lead to reduced crop yields. Organic fertilizers provide a slow release of nutrients to soil while at the same time improving soil health and reducing the risk of soil degradation. Hence, there is a need to investigate the impact of formulated organic fertilizers on soil physical and chemical properties in the study area. The study site is in the Teaching and Research Farm, Yobe State College of Agriculture, Science and Technology Gujba, Damaturu, Yobe State. Its geographic coordinates are 11.7461° N, 11.9608°. The study area is approximately twenty hectares while the size of land for the experiment was approximately two hectares. The soil analysis conducted revealed varying levels of nutrients. Nitrogen (N) ranged from 0.11 to 0.20 g/kg-1, indicating medium fertility. Phosphorus (P) levels ranged from 0.17 to 0.19 g/kg-1, indicating signifying low fertility, while potassium (K) varied from 0.46 to 0.89 g/kg-1, indicating high fertility. Copper (Cu) levels ranged from 0.67 to 0.85 g/kg-1, suggesting medium fertility. Zinc (Zn) ranged from 0.55 to 0.38 g/kg-1, indicating medium to low fertility, particularly in deeper soil layers. Iron (Fe) ranged from 0.53 to 0.01 g/kg-1, categorized as medium to low fertility. Manganese (Mn) ranged from 0.11 to 0.04 g/kg-1, showing low fertility levels insufficient for optimal agricultural production. Despite minor improvements post-application of organic fertilizer, overall fertility ratings remained largely unchanged. The study highlights the heterogeneous distribution of nutrients in the study area, emphasizing both strengths and deficiencies crucial for agricultural productivity.

Assessment of nutrient status, macro faunal diversity and microbial isolates in date palm plantation in Damaturu Yobe State, Nigeria

This research assessed nutrient status, macro-faunal diversity and microbial isolates in the soil of date palm plantation in Mai Sandari Damaturu, Yobe State. Parameters evaluated include; data on nutrient status of soils, assemblage and diversity of soil macro invertebrates and assemblage of microbial isolates based on growth performances of the date palm. The plantation was divided according to growth variabilities. Eighteen (18) auger points were taken, six (6) in each performance site based on the corresponding variability as observed. Soil samples were collected within same points for physicochemical analysis, microbial isolates and for soil macro-invertebrates ‘identification and enumeration. One-way Analysis of Variance (ANOVA) was used to compare results of nutrient status of soils and to test for significant differences in nutrient concentration of the soils samples, mean separation was done using Least Significant Difference (LSD). Soil macro-invertebrate assemblage was analyzed for diversity indices of species using relevant formulae. Nutrient agar medium at 105 dilutions inoculated in a petri-dishes and incubated at 30±10°C for 2-5 days for bacteria colonies, while for fungi and actinomycetes, sabaurond dextrose agar was used at 25°C for 5-7 days and afterward microorganisms per colony forming units (Cfu) were counted. Analysis of variance for the soil parameters tested at p≤ 0.05 level of significance showed no significant differences in all the parameters of soil physical properties based on growth performance sites. However, organic carbon, organic matter and TN vary significantly after the post-hoc tests across growth performance sites in chemical properties (p ≤ 0.05). Results showed a total of 2646 macro fauna scattered within the study area. Eleven (11) families of macro fauna were also identified in the study. Results from the study area showed that the area is highly rich in microorganisms. A total of 5096 colonies were scattered within 10 families in the study area. The finding of this study revealed that there was no significant difference among the physical properties across the study site leading to the conclusion that soil physical properties may not have been responsible for the observed differences in the growth of the Date Palm Plantation. A different pattern was however observed in the values of the chemical properties of the plantation where significant differences exist in organic carbon, organic matter and total nitrogen across these sites. Based on the findings of the study it is recommended that all application of agrochemicals except fertilizers in the plantation should be suspended until evidence of their efficiency on the palm trees is shown.

Effect of Tillage, Crops Residues and Crops Management Practices on Runoff Erosion, Soil Loss and Soil Properties in Ethiopa: Review

The conducted investigations showed that tillage practices with crop residue and proper cropping systems protect loss of soil from runoff erosion which depletes soil nutrients and affects soil physical and chemical properties. The review was conducted with aim of reviewing the effect of tillage, crops residues and crops management practices on runoff, soil loss and soil properties in Ethiopia. The three years study conducted in the Upper Blue Nile basin of Northwestern Ethiopia showed that reduced tillage reduced soil loss over conventional tillage, row planting reduced soil loss over broadcast planting, without trampling reduced soil loss over with trampling planting, and the sediment concentration was ranged from 0.01 to 5.37g/L and total soil loss was 0.20 to 0.50t/ha. The study conducted in the humid highlands of Ethiopia showed that the lower average soil loss was 16 t/ha.yr under zero tillage with crop residue and maximum was 30 t/ha.yr in conventional tillage without crop residue. The investigation indicated that zero tillage with maize soya bean intercrop, maize rotation, continuous maize and continuous soya bean improved soil properties than conventional tillage system. The investigation which was carried out to evaluate the effects of tillage and cropping system on soil properties showed that enrichment ratio ≤1 under no tillage with intercropping and no tillage with mulch reduce nutrient losses and enrichment ratio. The study conducted at Derashe and Arba Minch Zuriya in Ethiopia showed that some selected properties were statistically significant (P<0.05) and conservation tillage is favored for soil management relative to conventional tillage. Therefore, tillage practices like zero tillage and minimum tillage with crop residue management like mulching and crop management such as intercropping and crop rotation reduce surface runoff erosion, soil loss and soil fertility depletion, but additional continual research is needed to reveal trends in tillage, crops residues and crops management.

Effects of soil heating changes on soil hydraulic properties in Central Chile

Wildfires are natural phenomena for most ecosystems on Earth. Many soil properties are impacted by fire, including soil hydraulic properties. We used a laboratory experiment to replicate the temperatures reached by a natural wildfire and documented the effects on soil hydraulic properties. This study hypothesizes that the impact of heating on soil hydrological properties can be explained by the interaction of a number of variables especially organic matter content (OM), cation exchange capacity (CEC), texture, pH, and electrical conductivity (EC). The main objective of this study is to explore the interconnections between soil hydraulic, chemical, and physical properties, focusing on understanding how these relationships change across different ecoregions and temperatures. Sixteen soils were collected across 16 sites susceptible to forest fires in the Central Zone of Chile and heated to 100 °C and 300 °C for two hours. These sites were representative of two distinct ecoregions: the Chilean Matorral (CM) and the Valdivian Temperate Forests (VTF). Chemical, physical, and hydraulic soil properties were measured before and after heating. At 100 °C, there were no significant changes in chemical, physical, or hydraulic soil properties. At 300 °C, significant changes were observed in most soil properties in soils from both ecoregions. The OM content and CEC decreased, whereas pH and electrical conductivity increased. In addition, clay content and water aggregate stability (WSA) decreased, while all hydraulic properties increased their values. The aforementioned results demonstrate that infiltration increased after the soil was heated. This can be attributed primarily to decreases in clay content. At the same time, the water repellency (R) index decreased, allowing water to more easily wet the soil particles. Correlations revealed that CEC and clay are the main factors ruling soil hydraulic properties at all temperatures. Clay mineralogy also contributes to the soil hydraulic behavior observed. Nonlinear models were developed to estimate hydraulic properties at 100 °C and 300 °C, using the main soil properties. The models illustrated that the soils of the CM ecoregion, which are characterized by lower OM and influence of clay/CEC ratio, would be less affected by fire compared to the soils of VTF. The water holding capacity would decrease in both ecoregions. However, due to the greater changes in OM and clay in VTF, the impact would be greater than in CM.11Ca2+ = Calcium cations (meq/ 100g); CEC = Cation exchange capacity (meq/ 100g); CM = Chilean Matorral; EC = Electrical conductivity (μS/cm); I = Cumulative infiltration (cm); K = Unsaturated hydraulic conductivity (mm/h); K+ = Potassium cations (meq/ 100g); Ks = Saturated hydraulic conductivity (mm/h); Mg2+ = Magnesium cations (meq/100g); Na+ = Sodium cations (meq/100g); OM = Organic matter (g/100g); R index = Water repellency index; Se = Ethanol sorptivity (cm/s05); Sw = Water sorptivity (cm/s05); VTF = Valdivian Temperate Forest; WSA = Water-stable aggregates (%).

Using Gliricidia sepium prunings as green manure in a degraded ultisol ; effect on soil physical properties and yield of okra (Abelmuschus esculentus) in Abakaliki, southeast Nigeria

ABSTRACT Okra (Abelmoschus esculentus) is an important vegetable crop in southeast Nigeria, though at present there are only limited data available on the production in this area. A two-year field experiment was carried out in 2019 and 2020 cropping seasons to determine the effects of soil incorporation of different rates of Gliricidia sepium prunings (GS) as a green manure on soil consistency limits and physical properties, and yield of okra. The experiment was arranged as a randomised complete block design with four treatments and five replications. The treatments were as follows: control (C, no amendment); application of GS at 3 t ha−1 (3 GS), GS at 6 t ha−1 (6 GS); and GS at 8 t ha−1 (8 GS). The results showed significant increases (p < 0.05) in soil consistency limits in soil amended with GS relative to the control. The result also showed significant decrease in soil bulk density and increase in total porosity in soil amended with GS green manure. Soil water retention was significantly higher in Gliricidia sepium–amended plots. The dry pod yield of the okra increased significantly with the incorporation of the Gliricidia sepium green manure, though the differences in the yield between treatments with 6 and 8 t ha−1 rates of incorporation were not significant. Using GS as a green manure improved the consistency limits and physical properties of the soil and resulted in enhanced okra yields.

Spent coffee waste-derived biochar improves physical properties, water retention, and maize (Zea mays L.) growth in sandy soil

Adding organic soil amendments can improve the physical and hydrological properties of soil, subsequently enhancing fertility for better crop production. In this study, spent Arabica and Columbian coffee wastes and their respective biochars were evaluated as soil amendments to improve the physical and hydrological properties of loamy sand soil and enhance maize (Zea mays L.) crop growth. Spent Arabica coffee (AC) and Columbian coffee (CC) wastes were collected and transformed into biochar through pyrolysis process at 550 °C with a residence time of 3 h and pyrolysis rate of 5 °C per minute. The AC and CC derived biochar were termed as ABC and CBC, respectively. The produced soil amendments were applied to soil at 0% (control), 1%, 3%, and 5% in a column setup. The moisture characteristics, including water infiltration, evaporation, and water retention, were investigated. Thereafter, the prepared amendments were applied to loamy sand soils at 0% (control), 1%, 3%, and 5% (w/w) application rates. Maize growth was then observed for a period of 30 days under greenhouse conditions. Results of the column trials showed that ABC and CBC applied at 5% reduced the cumulative water evaporation by 57%–66% and cumulative infiltration by 124%–181% compared to control. Likewise, 5% application of ABC and CBC resulted in 101 to 130% higher water retention in loamy sand soil. Results of the greenhouse experiment showed that 5% application of ABC and CBC amendments resulted in root biomass of 2.12 and 2.38 g, respectively, as compared to 0.51 g in control treatment. Similar treatments resulted in shoot biomass of 9.70 and 9.93 g respectively, as compared to 7.37 g in control. Likewise, 5% application of CBC and ABC increase plant height from 15.71 to 30.94 cm in ABC and 33.23 cm in CBC. Overall, 5% application of coffee waste-derived biochars significantly reduced water evaporation and infiltration, while increasing soil water retention and maize plant height, root biomass, and shoot biomass. Therefore, spent coffee waste-derived biochar could effectively be employed to improve physical and hydrological properties of loamy sand soils for better crop productivity.

Gypsum and organic materials improved soil quality and crop production in saline-alkali on the loess plateau of China

Arable soil and crop productivity are severely affected by salinization. Therefore, soil amendments are an important measure for improving saline-alkali soil for agricultural development. Desulfurized gypsum is a common soil amendment that has been used repeatedly alongside organic materials to improve the biological, physical, and chemical properties of saline soil. This study takes the typical saline-alkali farmland soil in Yulin as the research object, and five treatments were established: a blank treatment (CK), a single application 2.5 t ha−1 of desulfurized gypsum (T), 2.5 t ha−1 of desulfurized gypsum and 1.5 t ha−1 of green manure (TL), application 2.5 t ha−1 of desulfurized gypsum and 1.5 t ha−1 of straw (TS), and 2.5 t ha−1 of desulfurized gypsum and 1.5 t ha−1 of organic fertilizer (TV). The results show that the TV treatment achieved a significant improvement in soil nutrients, organic carbon, enzyme activity, and maize yield. In 2022 (2023), the compared of organic matter, TN, TP, TK, AP, and AK increased significantly compared with the CK treatment when the TV treatment was applied. Soil phosphatase activity (SPA), soil urease activity (SUA) and soil sucrase activity (SSA) significantly higher in the TV treatment compared with the other treatments and increased significantly over the two-year period. Furthermore, soil organic carbon (SOC), easily oxidizable organic carbon (EOC), dissolved organic carbon (DOC) and microbial biomass carbon (MBC) also significantly increased with the 2022 and 2023 TV treatments. Correlation analysis revealed a positive relationship between maize yield and soil nutrients, organic carbon, and enzyme activity (P &amp;lt; 0.05). Thus, the TV treatment was determined to be the optimal treatment for soil improvement. This conclusion was supported by analyses performed using membership function analysis, gray correlation analysis, and entropy TOPSIS model evaluation. Therefore, this method increases soil quality, improves soil fertility, achieves high maize yields, and provides a scientific basis for enhancing and utilizing saline-alkali soil in the Loess Plateau.

Nitrates and Microbiome Components Engaged in Denitrification within Soil Regulate Morchella spp. Growth

Morels (Morchella spp.) are a kind of rare and precious edible fungus and have been successfully cultivated in many places. Currently, the widespread cultivation of morels poses a significant challenge owing to their demanding environmental requirements. Soil properties and the soil microbiome are thought to play pivotal roles in morel growth. However, it remains unknown what factors exert a decisive influence on morel growth. In this study, soils with different morel yields were studied in nine sites from four locations. The basic soil physical and chemical properties were measured. In addition, the soil microbiome was analyzed using high-throughput metagenomic sequencing. We found that soil pH, nitrogen, carbon and conductivity were key indicators for the impact on microbial communities in soil for cultivating morels. Among these, nitrate was more positively associated with morel yield. The soil microbial diversity was more abundant in the soil with a high morel yield. Moreover, certain unknown archaea might be unfavorable to morel growth. The microbes that perform incomplete denitrification (no step of N2O reduction to N2) and nitrogen fixation were positively and negatively correlated with morel growth, respectively. In summary, morels prefer to live in nutrient-rich soils with a variety of microbes and are supported by nitrate and microbiome components involved in denitrification. The findings elucidate a pivotal mechanism in eliciting morel fructification and provide valuable insights for guiding production practices.

Trade-Offs in Plant Functional Traits Driven by Soil Changes under Urban Hardened Surfaces

The large-scale surface hardening has changed the urban environment and affected the normal growth of urban plants. However, it is still unclear how the urban hardened surface affects the functional urban plant traits. To explore whether the urban hardened surface affects the ecological strategies of plants by changing the urban soil properties and reflecting them on the plant traits, we studied the physical and chemical properties and plant functional traits of three different types of hardened surface in Shandong Province, China. Our results showed that the physical and chemical properties (soil bulk density, soil total porosity, capillary porosity, non-capillary porosity, soil moisture content, pH, organic carbon, total nitrogen, total phosphorus, total potassium, available phosphorus, and available potassium) of urban soils showed obvious differences with the increase of hardening strength. In this case, the plant functional traits (branch diameter, branch length, leaf thickness, branch weight, internode length, leaf dry weight, leafing intensity, leaf area, specific leaf area, and leaf dry matter content) were also differentiated to varying degrees. Meanwhile, there was a strong correlation among plant functional traits. Nevertheless, hardened surfaces break the quantitative relationship among functional traits of urban trees. They do not affect their stable correlation: as the hardening intensity gradually increases, its correlation weakens. In addition, plant functional traits have a significant response mechanism to soil physicochemical properties. There was a transformation of plant resource utilization strategy by changing plant functional traits to adapt to the hardened environment. Urban trees exhibit strong and rapid resource-allocation strategies. They are mainly reflected in the reduction of branch diameter, branch weight, leaf dry matter content, leaf area, mass ratio of branches and leaves, and the improvement of leafing intensity and leaf thickness. Overall, there were tight connections among urban soil properties, plant branches, and leaves functional properties. This finding reveals that urban trees can change their functional traits and the plasticity of their trait combinations under the background of hardened urban surface expansion, which is conducive to survival and growth.

Effect of Streptomyces costaricanus Strain A-m1 as a Bioinoculant on Tea Garden Soil and Tea Quality

Chemical fertilization is usually associated with some unreasonable problems that affect the sustainable production of tea gardens. The micro-organism fertilizer created from plant growth-promoting microbes (PGPM) integrates the beneficial properties of functional micro-organisms and bioinoculants. Application of PGPM can activate soil nutrients, prevent soil-borne diseases, and promote crop growth, thus improving crop quality and yield. In this study, the effects of bioinoculants composed of Streptomyces costaricanus strain A-m1 on the properties, enzyme activity, and micro-organisms of soil in a tea garden and on the chemical composition and production of tea were investigated. The present results showed that the application of A-m1 bioinoculant could increase the activities of urease, protease and catalase, the content of alkali-hydrolyzable nitrogen, and the number of bacteria, fungi, and actinomycetes in tea garden soil. After application, the free amino acid content, 100-bud weight, and bud density of spring tea were also elevated. In the year of fertilization, the treatment composed of 70% bioinoculant + 30% chemical fertilizer showed the best effects on soil physical and chemical properties, enzyme activity, culturable microbial counts, and tea quality. A high ratio of organic to chemical fertilizer coapplication can significantly improve the growing conditions for tea plants, reduce the use of chemical fertilizers, improve the efficiency of nutrient utilization, and enhance both the yield and quality of tea. One year after fertilization, the 50% bioinoculant + 50% chemical fertilizer was more conducive to enhancing the quality of tea, while the 30% bioinoculant + 70% chemical fertilizer was more beneficial for improving the production of tea. A high ratio of chemical to bioinoculant coapplication is more favorable for maintaining high yield and quality in tea production, achieving healthy and sustainable tea garden management. The application of A-m1 bioinoculant will reduce the use of chemical fertilizers, improve the utilization efficiency of soil nutrients, and increase the production and quality of tea, contributing to the sustainable production of tea gardens.

Modeling the spatial distribution of soil physical properties in a semiarid tropical region

In semiarid regions, sustainably managing the limited available water resources is critical for food, water, and economic security. An important aspect of water management is monitoring, analyzing, and predicting soil moisture and hydrologic fluxes, especially under the threats of climate change. Unfortunately, since monitoring of soil moisture and water fluxes is often sparse in these regions, one needs to rely on hydrological modeling. The latter requires accurate knowledge of soil properties (e.g., texture, porosity, hydraulic conductivity), which in semiarid regions is also complicated by high level of spatial heterogeneity that is not captured by the low density of soil sampling efforts as well as by globally gridded soil databases. Using 300 monitoring sites across the Semiarid region of NE Brazil and a soil moisture model, this study aims to estimate soil properties at the sites through inverse-modeling and then spatially interpolation these properties via geostatistics. Inverse modeling with the Levenberg–Marquardt algorithm accurately captured soil properties across the sites, while clear spatial patterns in these properties allowed us to confidently interpolation them across the region. Comparing our results with a global soil dataset shows that the latter does not capture spatial variability in the region, underlining the need to leverage small scale information. The derived soil property datasets may then particularly be valuable for regional water and ecosystem management applications.

Impact of forest fire severity on soil physical and chemical properties in pine and scrub forests in high Andean zones of Peru

Forest fires are the main threat to ecosystems and human life. The frequency, seasonality, extent and severity of fires affect ecosystems and the physical and chemical properties of the soil by direct (heating) and indirect (ash) effects. This could affect biodiversity and forest residency in the face of climate change. In this study, we evaluated the impact of fire severity on soil physical and chemical properties caused by forest fires in a high Andean area of Peru. For this purpose, the severity levels, the degree of hydrophobicity, and the physical and chemical properties of the soil were analyzed by sampling in affected areas (Pinus radiata D. Don plantation and shrubland) and unaffected areas. The results showed a very low severity in soil components, with a strong hydrophobicity, more persistent in the forest plantation area than in the shrubland. The physical properties of the soil did not show variations; however, in the Pinus plantations they showed variations in their chemical properties such as pH, electrical conductivity, organic matter, nitrogen and cation exchange capacity compared to areas not affected by the forest fires. Likewise, in the study area an adequate regeneration process was evidenced; in fact, it is important to apply mechanisms to accelerate the restoration of the vegetation cover and the physical and chemical quality of the vegetation.