Soil Physico-Chemical Properties and Different Altitudes Affect Arbuscular Mycorrhizal Fungi Abundance and Colonization in Cacao Plantations of Cameroon

This study aims to investigate the abundance of AMF according to soil properties and altitudes in different cacao plantations of Cameroon. Physico-chemical analyses were made on soil samples collected from three agro-ecological zones. Soil samples were also used to evaluate directly the AMF abundance following the various altitudes and after trapping by sorghum plant. The results showed that soil properties, AMF spore abundances and colonization fluctuated significantly at different altitudes. The most represented texture was sandy loam. The bimodal zone presented a homogeneous texture (sandy loam) in all its localities. Cacao soil chemical characteristics showed that, the highest nitrogen rate (0.47%;p 0.05, Scott-Knott test) was recorded at Melong in a monomodal zone while Tonga in the Western highlands displayed the lowest rate (0.13%). Soil P concentration was significantly high in monomodal zones (Mbanga and Melong). Soil pH level indicated that the soil from Tonga in the Western highlands was neutral (pH = 6.67), and soils of other localities under study were acidic with the lowest (4.75) pH level recorded at Melong in a monomodal zone. In soil samples, the highest spore density (1.03 spores/g soil) was observed at Ntui in Bimodal zone, while the lowest spore density (0.26 spores/g soil) was observed at Bafang in the Western highlands. Root colonization showed that the sample from Bokito in a bimodal zone displayed the best frequency of mycorrhization (86.11%) while the sample from Bafang in the Western highlands recorded the lowest (27.11%). The PCA analysis highlighted that available phosphorus, pH and altitude all strongly correlated with AMF root colonization ability and can be used as a predictor of AMF colonization ability in cacao rhizosphere.

Soil Physico-Chemical Properties and Microflora as Influenced by Bispyribac Sodium 10% SC in Transplanted Kharif Rice

The effects of bispyribac sodium 10% SC and butachlor 50% SC on soil physico-chemical properties and microflora in transplanted kharifrice were investigated over two seasons （2010 and 2011 ） Effects of the herbicide on bulk density, water holding capacity, moisture content, soil pH, organic matter content, electrical conductivity, as well as total nitrogen, available phosphorus and available potassium contents were analyzed along with microflora population （total bacteria, actinomycetes and fungi）. No significant changes in soil physico-chemical properties were observed. Herbicide treatments resulted in decreases in microbial counts initially. With the degradation of applied herbicides within a considerable time, the microflora populations even exceeded the initial count at 60 d after application of the herbicide.

Comparison of soil physico-chemical properties under different land-use and cover types in northeastern China's Horqin Sandy Land

The Horqin Sandy Land of northeastern China was originally a grassland with plenty of water and lush vegetation dominated by palatable grass species along with sparsely scattered woody species. However, it has experienced severe desertification in recent decades due to its fragile ecology together with inappropriate human activities. Currently, the landscape of the Horqin Sandy Land is dominated by irrigated croplands and sand dunes with different degrees of vegetation cover, as the region has become the most important part of the semiarid agro-pastoral ecotone of northern China. In this study, we compared soil physical and chemical properties under different land-use and cover types （irrigated cropland, rainfed cropland, sandy grassland, fixed dunes, and mobile dunes）. We found that soil particle size distribution; organic C, total N, and total mineral element, microelement, and available microelement and nutrient contents; pH; CEC; and bulk density differed significantly among the land-use and cover types. In general, soil quality was highest in the cropland, intermediate in the sandy grassland, and lowest in the dunes. The most important soil quality attribute, soil organic carbon （SOC） storage, decreased in the fol-lowing order： irrigated cropland （5,699 g/m^2） 〉 sandy grassland （3,390 g/m^2） 〉 rainfed cropland （2,411 g/m^2） 〉 fixed dunes （821 g/m^2） 〉 mobile dunes （463 g/m^2）. SOC was significantly positively correlated with a large proportion of the other soil physico-chemical parameters. Our results suggest that the key issue in restoration of the degraded soils will be to increase SOC storage, which would also create a high potential for sequestering soil C in desertified areas of the Horqin Sandy Land.

Cokriging of Soil Cation Exchange Capacity Using the First Principal Component Derived from Soil Physico-Chemical Properties

As soil cation exchange capacity （CEC） is a vital indicator of soil quality and pollutant sequestration capacity,a study was conducted to evaluate cokriging of CEC with the principal components derived from soil physico-chemical properties.In Qingdao,China,107 soil samples were collected.Soil CEC was estimated by using 86 soil samples for prediction and 21 soil samples for test.The first two principal components （PC1 and PC2） together explained 60.2% of the total variance of soil physico-chemical properties.The PC1 was highly correlated with CEC （r=0.76,P0.01）,whereas there was no significant correlation between CEC and PC2 （r=0.03）.The PC1 was then used as an auxiliary variable for the prediction of soil CEC.Mean error （ME） and root mean square error （RMSE） of kriging for the test dataset were-1.76 and 3.67 cmolc kg-1,and ME and RMSE of cokriging for the test dataset were-1.47 and 2.95 cmolc kg-1,respectively.The cross-validation R2 for the prediction dataset was 0.24 for kriging and 0.39 for cokriging.The results show that cokriging with PC1 is more reliable than kriging for spatial interpolation.In addition,principal components have the highest potential for cokriging predictions when the principal components have good correlations with the primary variables.

Impacts of Four Invasive Asteraceae on Soil Physico-Chemical Properties and AM Fungi Community

Invasive Asteraceae are an important group of plants and might have universal impacts on invaded ecosystems. However, research data on the ecological impacts of specific plants are still lacking. Chromolaena odorata, Ageratina adenophora, Flaveria bidentis, and Mikania micrantha are four typical alien Asteraceae in China. The involvement of soil biota, in particular, the community structure of arbuscular mycorrhizal (AM) fungi in their invasion process was tested in present research. It was found that invasion by the four Asteraceae changed, to different extents, the nutrient levels in soils. Invasion by C. odorata, A. adenophora, and F. bidentis followed common patterns: 1) decreasing pH value;2) increasing the soil AM fungal diversity and species richness. Invasion by all four Asteraceae tested increased nitrogen pools and accelerated nitrogen fluxes with a decrease in the phosphorus pool, especially available phosphorus. It was suggested that mycorrhizal symbiosis might partially promote successful invasion of these Asteraceae by affecting the metabolism of phosphorus in soil. The impacts on soil ecosystems of these Asteraceae tested were also species-specific, and different invasion strategies were exhibited.

Relationship between Selected Soil Physico-Chemical Characteristics and Mycorrhizal Status under <i>Triumfetta cordifolia</i>in the Cameroon Western Highlands

There is limited information on the pedological requirements of Triumfetta cordifolia. A starting point for establishing such information requires knowledge on the growing environment of the species. The aim of this study was to assess the physicochemical properties and mycorrhizal status in the rhizosphere of Triumeffa cordifolia. Soil and root samples from the rhizosphere of T. cordifolia were collected from three localities (Santchou, Bandjoun, and Balatchi) in the West Region of Cameroon. The results show that the soils are dominated by a loamy texture and have a mean porosity > 50%. Mean bulk density ranges from 0.91 ± 0.02 to 1.26 ± 0.04 g⋅cm−3. The sum of exchangeable cations ranges from medium (6.45 ± 1.02) to high (11.21 ± 1.35) and are evident of the satisfactory soil organic matter (OM) content in the various localities (5.90% ± 0.42% to 10.65% ± 0.73%). Total nitrogen (TN) content of the soils ranged from low (0.10%) to very high (0.41%). Biological activity is low due to very poor OM quality (mean C/N > 20). The average available phosphorus status ranged from medium (18.32 ± 3.91 ppm) to very high (69.39 ± 26.09 ppm). The Cationic Exchange Capacity (CEC) was moderate (19.28 - 29.28 cmol⋅kg−1) and was mainly contributed by soil organic matter. Base saturation ranged from low (28.0%) to medium (48.83%). Assessment of endomycorrhizal colonization showed that the intensity (I), frequency (Fr) and specific density of spores (Ds) were not significantly different among sites. A high level of available P in the Santchou soils appears to be the major cause for the lowest values of Fr, I, and Ds observed. These results reaffirm the link between soil physicochemical properties and endomycorrhizal infection in T. cordifolia. Site characteristics and soil OM quality are factors to be considered in promoting the establishment of mycorrhizal symbiosis for profitable and sustainable cultivation of T. cordifolia.

Impact of Seasons on Soil Physico-Chemical Properties and Tea Yields Based on Enriched Sheep Manure Used in Kericho, Kenya

Tea (Camellia sinensis (L) O. Kuntze) is a perennial crop grown for beverage consumption. Its production is the leading foreign exchange earner in Kenya contributing about 26% foreign exchange and 4% GDP. Nitrogen (N), Phosphorus (P) and potassium (K) are the recommended nutrients for tea production. However, their continuous use has been reported to have negative effect on soil physico-chemical properties and health. Sheep manure has been recommended in tea production for its soil pH buffering effect and increased tea yields. However, effects of sheep manure enriched with inorganic fertilizer on tea soils and yield have not been conclusively investigated. This study was established at KALRO—Tea Research Institute Kericho in Timbilil estate to determine the impact of seasonal variation on soil pysico-chemical properties and yields on enriched sheep manure used. Randomized complete block design (RCBD) experimental design was adopted with 14 treatments replicated thrice. The treatments were: control with no fertilizer use, NPK at 180 Kgs N/ha/yr, sheep manure only and two enriched sheep manure ratios of 4:1 and 8:1 which translates to a mixture of (4:1) 4 parts of sheep manure and 1 part of D.A.P inorganic fertilizer. Same applied to 8:1 ratio, respectively at rates of 60, 120, 180 and 240 Kgs N/ha once per year. Data were subjected to ANOVA in GenStat statistical package and means separated by Duncan’s multiple range tests at P ≤ 0.05 significance level. Results obtained showed that soil physico-chemical properties and tea yields were influenced significantly (P ≤ 0.05) by treatments applied. Soil available water and organic matter were higher on enriched sheep manure 4:1 at 240 rate used while soil porosity and bulk density were not significantly affected. Total N and P, increased with enriched sheep manure ratio of 4:1 at 240 rate while K+, Ca2+, Mg2+, Mn and pH increased with sole application of sheep manure at rate 180 and enriched sheep manure 8:1 at 180 rate. Tea yields increased with enriched sheep manure 4:1 ratios at the rates of 240. The findings recommend enriched sheep manure 4:1 ratio at 240 rates to be adopted by tea farmers within Kericho region. Further studies involving different geographical locations are proposed.

Variations in Soil Physico-Chemical Properties as Influenced by Landuse in a Toposequence

Soil, water and air work interchangeably for optimum growth and productivity. Soil as a resource provides crops with essential nutrients necessary for growth and human consumption. With the insurgence of high population growth leading to pressure on lands, poor land management etc., this tendency of the soil as a nutrient pool is seen to be dwindling. It is therefore prudent to investigate and understand the dynamism of soil properties to inform proper management. Understanding topography effects and assessing soil properties on different slope positions is a first-hand step in ensuring proper soil management practices. This paper considers the assessment of physico-chemical properties of soils located on different slope gradients and land use types on the Wamaso research site in Ghana made principally of cape coast granite. In all, eighteen samples were collected from identified horizons of five distinctive subsections of the slope were delineated as follows, summit (PP1), shoulder (PP2), middle (PP3), foot slope (PP4) and toe slope (PP5) respectively. Remarkable variations were observed within PP1 to PP3 and then PP5. Pearson’s correlation index revealed that the associations between most of the soil physico-chemical were not consistent across the identified slope positions. The biplot of the first two principal components together is 68.3% of the total variation and might be interpreted as change in Cation exchange capacity, sodium, sand and clay. On the first axis highlights the influence of sand and clay on soil fertility, also the relationship between pH and Na. Organic carbon derived from organic matter contributes to the availability of the basic soil cations and therefore enhances ECEC of the soils and hence the relationship obtained from the biplot. In sum, this research achieved the objective which sought to substantiate indeed the impact topography has on soil physico-chemical properties thereby serving as a reference for the classification of the soils identified.

Physico-Chemical Analysis of Soils Used for Pineapple Cultivation in the Sub-Prefectures of Maferinyah and Friguiagbé (Prefectures of Forécariah and Kindia) Republic of Guinea

Over the years, pineapple production in the Republic of Guinea has become less competitive in the West African sub-region, with a world ranking of 144th. It is therefore only natural to review certain parameters in order to improve this ranking. To do this, certain physico-chemical parameters of soil samples from Friguiagbé and Maferinyah (in the Kindia and Forécariah prefectures) were taken and analysed using the following techniques: Pipette de Robinson, Anne, Bray II, Kapen HICDVITZ, Mc. Lead (1982). The analytical results show that the soils at Friguiagbé in Kindia and Maferinyah in Forécariah are acidic, with pH values of 4.4 and 4.7 (fields I and II) and 4.8 and 4.7 (fields I and II) respectively. The soils have a silty-sandy texture. This study could therefore serve as a guide for the Ministry of Agriculture of the Republic of Guinea.

Physico-Chemical Properties of Soils from Diguel and Koudalwa Tchad,and Phytoremediation Potentials of Acasia and Kinkeliba Plants in Removing Cr and Cu from These Soils

The aim of this study to investigate the physico-chemical properties of soils from Diguel and Koudalwa Tchad,and phytoremediation potentials of acasia and kinkeliba plants in removing Cr and Cu from these soils.Soil was sampled from the tannery plant in Diguel and agricultural land around crude oil activities in Koudalwa.Soils were characterized by the following properties:pH,(Electrical Conductivity),TDS(Total Dissolved Solids),salinity,bulk density,OM(Organic Matter),nitrate,phosphate,clay,silt,sand,and textural class.The acasia and kinkeliba plants were used to decontaminate Cu and Cr from sample soils for 30 days period.The bulk density of all the soil samples from Kouldawa was higher compared to Diguil,ranging from 1.421 to 1.64 g/cm^(3)compared to 1.21 to 1.51 g/cm^(3)for Diguel.Most of the soils in Kouldawa are mineral soils,while those of Diguel are mostly mineral soil with some organics.Diguel soils are richer in nitrate(577.9 to 2,687.32 mg/kg in Diguel and 33.64 to 197.64 mg/kg in Kouldawa)and phosphate than soils from Kouldawa.Soils from the studied areas are not saline except for a subsurface soil in Diguel(salinity,4.21;EC,4.280 dS/m;TDS,3,040 mg/L).The highest amount of Cr and Cu removed by acasia is 78%and 53.12%compared to 73.8%and 52.21%by kinkeliba.Diguel soil can be very suitable for agriculture and Kouldawa soils for construction.Acasia and kinkeliba can be effectively used to decontaminate the studied soils from heavy metal pollution.

Physico-chemical properties and macrofauna of soils under various farming systems of cold arid region in Balochistan,Pakistan

Barshore is a small village in the Pishin District,Balochistan,Pakistan,with dry summers and cold rainy winters.This is an agrarian region,mostly with orchards of various fruit trees.This study investigated the physico-chemical properties and macrofauna of soils under various agricultural management practices of this region.The concentrations of soil organic matter(SOM),soil organic carbon(SOC),nutrients,pH,electrical conductivity,soil texture,and the abundance and number of species of soil macrofauna of the agricultural fields were measured.Fifteen agricultural fields were sampled.Fourteen fields were orchards of apple,apricot or the mixture of apple and apricot trees and one field was a cropland,cultivated with wheat as a monocrop.The orchards were under conservation agricultural practices;whereas,the cropland was under conventional management.These agricultural lands were 2-26 years old.The concentration of soil organic matter(SOM)in the upper 0-10 cm depth of these field sites ranged from 11.6 g kg^(-1)to 32.8 g kg^(-1)soil.As compared to cropland,orchards had significantly higher concentration of SOM and SOC.A total of 18 soil macrofauna species were found and the most common and abundant were ants(Monomorium minimum,Camponotus pennsylvanicus,Solenopsis invicta,and Lasius niger)followed by Arion ssp.(Brown Slug)and earthworm Lumbricus terrestris.Regression analysis revealed non-significant relationship of the age and the concentration of SOM with the number of macrofauna species and with the concentrations of total mineral nitrogen,bioavailable phosphorus and clay.The existence of ants had no relationship with the concentration of SOM;whereas,existence of Lumbricus terrestris tended to had a positive relationship with the concentration of SOM.The field of tree-based intercropping system was 2 years of age since the land was converted from rangeland to a cropland,had two ant species coexisting.This indicates the positive influence of crop diversification on soil macrofauna.

Physico-Chemical and Nutritional Properties of a Food Broth Based on Nere (Parkia biglobosa)

Purpose: Diet and eating habits are major risk factors for the health and the development of disease, such as, for example, metabolic disorder leading to cardiovascular pathology and cancer, decreased immunity exposing to infections. This study of the physico-chemical and nutritional properties of a soumara-based food broth was carried out with the aim of promoting the consumption of organic broth made from nere seeds (soumara). That is to alleviate certain metabolic diseases, which is a matter of food safety, and also to limit the risk for the health about the consumption of some cooking stocks on the market. Methods: Several natural ingredients such as nere seeds (soumara), ginger, black pepper, parsley and garlic were used to create a nere-based stock. All these ingredients were freeze-dried and the powder obtained was used to make the broth, regarding their physical and chemical properties. Results: The broth had a good protein content of 17.41 ± 0.367 g/100g, a lipid content of 16.80 ± 0.08 g/100g and a fiber content of 8.66 ± 0.04 g/100g. In terms of nutritional values, the broth showed good levels of calcium 184.21 ± 0.09 mg/100g, potassium 50.04 ± 1.45 mg/100g and iron and zinc. In terms of antioxidant activity, the broth also showed good antioxidant activity. Conclusion: Regarding the properties of our food broth, whose composition is based on natural ingredients, could be recommended for consumption and, its properties, could play an important role in preventing and combating certain metabolic diseases.

Physico-Chemical and Structural Assessment of Akono Riparian Forest Watershed, Tributary of the Nyong Basin (Centre-Cameroon) at Different Stages of Degradation

Freshwater bodies are natural resources that should be exploited to the fullest, while maintaining the sustainability of ecosystems and ecosystem services which they support. Riparian forests are more important as they contain rivers which are vital sources of fresh water for local populations. However, the quality and quantity of water issued from the watershed depend on the structural state of these forests. The aim of this work was to assess the physico-chemical and structural state of the Akono gallery forest. To achieve this, fieldwork consisted of selecting six major streams of the watershed including Ndjolong, Menyeng adzap, Emomodo, Mvila, Negbe and Ossoé kobok. On each of these, two stations, one intact and one degraded, were marked by transects. The method involved measuring Hydrometric parameters (depth, length, width) of the stream and Physico-chemical parameters of water in the streams while dendrometric parameters were measured along 100 m-transects laid using the point-centred quarter method modified for water bodies to collect tree, shrub and palm variables such as trunk diameter, crown diameter and height. Macrophytes and species identification were carried out using standard botanical procedures. Results showed that, the majority of physico-chemical parameters measured differed significantly between intact and degraded stations (P Pentachletra mancrophylla, whereas on degraded sites, this index was low and characterized by the relative dominance of species Piptadeniastrum africanum. Sorensen’s index (0.56) and CFA showed that the different stands were homogeneous. We can affirm that the riparian forests of Akono watershed are towards a state of stability notwithstanding the perpetuation of anthropological actions.

Assessment of Groundwater Physico-Chemical Quality in the Ouémé Delta (Southern-Benin)

Groundwater resources are the main sources of water used to supply drinking water to the population of the Ouémé Delta via the Continental Terminal aquifer. Urbanization, population growth, and agricultural and industrial activities have resulted in a deterioration in the quality of these resources. To assess the quality of the delta’s groundwater and its suitability for human consumption and irrigation, a total of fourteen (14) physico-chemical parameters were analyzed in some forty existing water points between September 2020 and March 2021, using standard water analysis techniques. The values obtained were compared with the potability standards recommended by the World Health Organization (WHO) and the Republic of Benin and were subjected to statistical analysis (principal component analysis (PCA)). In addition, methods for determining the suitability of water for irrigation were used. The results showed that the waters are acidic to slightly neutral and influenced by ambient temperature. In addition, the waters are moderately mineralized, with conductivities (24 - 1205 μS/cm) in line with WHO standards. A comparison of the analytical results of the WHO (2017) and Benin (2001) standards indicates that the majority of the waters studied are of good quality for all the chemical parameters considered. Nevertheless, some samples show levels of nitrates (21%), potassium (14% to 16%), calcium (13%), ammonium (12%), nitrites (8%) and bicarbonates (10%) over their respective standards. The Wilcox and Riverside diagrams indicate that the majority of waters (90%) have excellent suitability for irrigation and no negative effect on soil fertilization.

Physico-Chemical Characterization of Some Honeys from the Savannah-Gallery Forest Complex and Primary Forest in Gabon

Honey harvesting throughout beekeeping is a technology recently introduced in Gabon comparing to the other African countries well known in international honey trade. The purpose of this study is to contribute to the knowledge of the quality of multi-flower honeys from the savannah-gallery forest complex and primary forest not well documented in Gabon. Physical and chemical parameters of different honeys were analyzed using the official methods of analysis of the Association of Official Analytical Chemists. The results of physico-chemical analysis show variations in pH (3.4 to 3.9), free acidity (37.12 to 76.65 meq∙kg−1), water content (17.49% to 21.21%), electrical conductivity (0.64 to 1.24 mS∙cm−1), density (1.02 to 1.03) and total sugar content (77% to 82%). These variations were significantly different (p < 0.05) between certain honeys, but independent of the type of ecosystem considered. The pH values confirmed the botanical origin of the five honeys. The physico-chemical parameters of the honeys show significant correlations (p < 0.05). Moisture content is negatively correlated with conductivity (r = −0.628), pH (r = −0.631), density (r = −0.552) and total sugar content (r = −0.890). Conductivity is positively correlated with free acidity (r = 0.688) and total sugar content (r = 0.776), and negatively correlated with water content (r = −0.628). All honeys were in line with Codex Alimentarius standards, except for 3 types of honey (M1, M2 and M4) for free acidity and electrical conductivity, showing possible fermentation of these honeys.

An Assessment and Geostatistics of Land-Use and Selected Physico-Chemical Properties of Soils in the Mount Cameroon Area

This work investigated the land-use/land-cover and some physico-chemical properties of the soils of Mt Cameroon and presented same in maps. ArcGIS Pro mapping software, Landsat images, Global Positioning Systems (GPS) coordinates collected from the field combined with updated shape files from competent services were used to produce the location and land-use/land-cover maps. Sixteen topsoil samples (0 - 20 cm) were collected, 4 from each land use/cover category: farmland, forest, plantation and settlement, and analysed for soil pH, cation exchange capacity (CEC), bulk density, moisture content and soil texture, in the laboratory using standard analytical procedures. This data was used to produce spatial distribution maps using ordinary kriging, in ArcGIS Pro. The main terrestrial land use/cover categories comprised of the forest (mangrove, lowland, montane and sub-montane), agroforestry, plantations, grassland, settlement, cropland, shrubby savannah, and bare lava. Bulk density showed the highest values in settlement areas and least values under forest land-use categories. Soil moisture content exhibited a reverse trend compared to that of soil bulk density. Forest soils were the sandiest while soils in plantation agricultural land were the most clayey. The soils were slightly acidic to neutral with soils from agricultural land being more acidic (pH(water) = 5.43). It is discernible from the results that the conversion from forest to other land use/cover classes enhances soil degradation and that soil physico-chemical properties adequately serve as indicators of soil quality in the Mt Cameroon area.

Effects of Plant Types on Physico-chemical Properties of Reclaimed Mining Soil in Inner Mongolia,China

A field experiment was conducted in Jungar Banner,Inner Mongolia,China to study the effects of plant types on the physical structure and chemical properties of open-cast mining soils reclaimed for 15 years,and to analyze the triggering factors of the soil formation.Results indicate that plant types affect soil-forming process especially in the upper layer (0-20 cm),and the spatial structure of reclaimed plant is the main reason for variability of the soil-forming process.In the upper soil layer at the site reclaimed with mixed plants,the concentrations of soil organic matter (SOM) and soil organic carbon (SOC) are the highest,and they were significantly higher at the sites reclaimed with Leymus chinensis,Caragana sinica,which is mainly due to a large amount of litter fall and root exudation in herbages and shrubs.However,the concentrations of SOM and SOC in the soils at the reclaimed sites are quite low comparing with those in local primary soil,which indicates the importance of using organic amendments during the ecological restoration in the study area.

Biochar Decreases Soil Cadmium(Cd) Availability and Regulates Expression Levels of Cd Uptake/Transport-Related Genes to Reduce Cd Translocation in Rice

Biochar has been used as a soil amendment for heavy metal-contaminated soils, and it has the potential to mitigate Cd accumulation in plants. In this study, we used rice straw biochar(RSB) and kitchen waste biochar(KWB) to clarify the effect of biochar on Cd-contaminated neutral soil, the physiological responses to biochar application, and the gene regulatory networks in a rice genotype.

Physico-Chemical Properties and Enzyme Activities of the Arable Soils in Lhasa,Tibet,China

An understanding of the physical,chemical,and biological properties of a soil provides a basis for soil use and management.This paper reports the major physico-chemical properties and enzyme activities of the soils of Lhasa's main arable lands and the factors that influence these soil properties.Composite and core samples were taken from the three main arable soil types(alluvial soil,subalpine arable steppe soil,and subalpine arable meadow soil) and were analysed using standard methods.The bulk density and the ventilation porosity ratio of the soils were close to the recommended values for arable lands,and the dominant soil texture was sandy.The soil moisture release rates were arable steppe soil > alluvial soil > arable meadow soil.Soil organic matter content,Cation-Exchange Capacity(CEC),total and available nitrogen content,and catalase activity of the arable meadow soil were higher than those of the alluvial and the arable steppe soils,while soil pH in the arable meadow was lower.Most of the measured properties did not show a significant variance among these three soils.However,the measured indices(apart from the total potassium) indicate that there are notable differences among the three types of soil.The results implied that the utilisation patterns of the arable soil or human activities,such as tillage practices and fertiliser applications,have a substantialeffect on the soil properties in this region.Our results suggest that the cultivation practices in the region have apparently positive impact on the soil organic matter,nutrient contents and bulk density probably due to the sound fertiliser management such as the applications of farmyard manure and chemical fertilisers.However,intense cultivation practices lowered the activity of most soil enzymes.The results demonstrate that the choice of soil management strategy had a significant impact on the soil physicochemical and biological properties in the region studied.

Subsoil tillage enhances wheat productivity,soil organic carbon and available nutrient status in dryland fields

Tillage practices during the fallow period benefit water storage and yield in dryland wheat crops.However,there is currently no clarity on the responses of soil organic carbon(SOC),total nitrogen(TN),and available nutrients to tillage practices within the growing season.This study evaluated the effects of three tillage practices(NT,no tillage;SS,subsoil tillage;DT,deep tillage)over five years on soil physicochemical properties.Soil samples at harvest stage from the fifth year were analyzed to determine the soil aggregate and aggregate-associated C and N fractions.The results indicated that SS and DT improved grain yield,straw biomass and straw carbon return of wheat compared with NT.In contrast to DT and NT,SS favored SOC and TN concentrations and stocks by increasing the soil organic carbon sequestration rate(SOCSR)and soil nitrogen sequestration rate(TNSR)in the 0-40 cm layer.Higher SOC levels under SS and NT were associated with greater aggregate-associated C fractions,while TN was positively associated with soluble organic nitrogen(SON).Compared with DT,the NT and SS treatments improved soil available nutrients in the 0-20 cm layer.These findings suggest that SS is an excellent practice for increasing soil carbon,nitrogen and nutrient availability in dryland wheat fields in North China.