Soil Bulk Density Values Research Articles

Effects of Organic Amendments on Soil Fertility and Environmental Quality: A Review

The main objective of this paper is to review the main effects of organic amendments on soil fertility and environmental quality. The review showed that both organic amendment types could improve the physical, chemical and biological characteristics of soil and environmental quality in a dose dependent manner and frequency of application. Application of organic amendments lower soil bulk density values by more than 5% versus sole urea fertilized soil and for each 1% increase inorganic matter, soil water holding capacity increased by up to 3.7%. Organic amendments play a positive role in chemical characteristics of the soil including increase in organic carbon (up to 58% with 120 t ha-1 versus unfertilized soil) and organic nitrogen up to 90% depending on the type and the level applied. Repeated application of organic amendments to cropland led to an improvement of microbial biomass by up to 100% and increased enzymatic activity by 30%. Organic amendments also play a positive role in climate change mitigation by soil carbon sequestration although the size of which is dependent on their type, rates and frequency of application. However, organic amendments have more of long-term return rather than short-term positive effect and there is competition of organic materials for the purpose of fodder or fuel. As a result, additional measures such as physical and biological soil conservation measures should get due attention and it is better to use the combination of organic and inorganic fertilizers in order to sustain soil fertility and environmental quality.

Impact of Organic Wastes on Physical and Chemical Properties of Sandy and Loamy Soils in Egypt

The aim of this study was to evaluate the effect of two organic wastes used as soil amendments i.e. filter mud cake (FMC) and vinasse (V) on some physical and chemical properties of sandy and loamy sandy soils. Applications of organic were incubated with the soils for a three periods of 15, 30 and 60 days at four application rates (0, 0.5, 1 and 2%). This study was carried out in a two way randomized completely block design with three replications. After incubation periods, bulk density, porosity, water retention, soil pH, electrical conductivity (EC) and organic matter were determined.
 Results showed that the values of soil bulk density and soil pH were decreased with increasing the application rates of filter cake or vinasse compared with the control in two soils. In addition, application of different filter mud cake and vinasse rates to the study soils increased soil porosity, field capacity (FC), wilting point (WP), available water (AW), electrical conductivity (EC) and organic matter contents (OM) as compared to control at different period incubation time. The data of this study concluded that, organic wastes or byproducts of sugar industries could be applied to improve some soil properties.

Least limiting water range as influenced by tillage and cover crop

Brazil has been experiencing a trend of increased mechanization, although there are no studies addressing the relationship between tillage and cover crops, which affects soil physical attributes, cover crop dry biomass, roots dry biomass, yield, soil water content, and the influence on the least limiting water range (LLWR), defined as the range of volumetric soil water content in which limitations to plant growth occur. This study aimed to i) assess LLWR during two cycles in a sugarcane area using different cover crops and soil tillage systems; ii) correlate the LLWR with different soil physical attributes (soil bulk density, macroporosity and soil penetration resistance); and iii) evaluate the potential use of LLWR as an index of soil and crop quality. The study was conducted under field conditions in a sugarcane culture in the municipality of Ibitinga, São Paulo, Brazil. We used four cover crops (sunn hemp, millet, peanut and sorghum) and three soil tillage systems [no tillage (NT), minimum tillage (MT), and minimum tillage with deep subsoiling (MT/DS)] and compared them with a control treatment [conventional tillage with lack of plant cover (CT)] using an experimental design with split-plot scheme. The soil physical attributes were more affected during the cane cycle by the soil tillages and cover plants. Regarding soil water content, sunn hemp and sorghum obtained the highest soil water content over time with the use of MT/DS, also because the soil bulk density values using sunn hemp and sorghum MT/DS (1.64 and 1.59 kg dm−3, respectively) are 8% lower than the CT for the layer 0.15–0.30 m for the cane plant cycle. In what concerns LLWR, the treatments that maintained their soil water contents within the range for more than 3 months in a row were sunn hemp and millet MT/DS. LLWR was an important indicator, showing that the treatments that obtained LLWR equal to zero, even with high root growth and low penetration resistance, were not enough to express differences in productivity. This proved that the index aggregates all the information and produces satisfying results.

EFFECT OF SOME AGRICULTURAL PRACTICES ON IMPROVING SALTS ‎AFFECTED SANDY SOIL PRODUCTIVITY.‎

A field experiment was conducted on sandy soil at Ismailia Governorate. The aim of the present study is to improve the productivity of salts affected sandy soil by treat it with different rates of bentonite, chicken manure and their combination. Soil application rates were bentonite (1, 2.5 and 5 %), chicken manure (5, 10 and 15 ton/fed) and their combination (2.5% bentonite with each of 5, 10 and 15 ton /fed chicken manure) were mixed in the upper soil layer (0-15 cm soil depth) and their effects on some soil physical properties and crop productivity of fennel plant (Foeniculum Vulgare Mill.) were investigated during the winter season of 2018. The results revealed that, all studied treatments were significantly decreased of soil bulk density compare to control. The applications of bentonite 1, 2.5 and 5% lead to, reduction of the value of soil bulk density by 4.17, 5.95 and 10.71%. In addition, the applications of chicken manure 5, 10 and 15 ton/fed, lead to reduction of the value of soil bulk density by 8.93, 11.31 and 14.88 %. Also, application of 2.5% bentonite combined with each of 5, 10 and 15 ton/fed chicken manure, lead to reduction of the value of soil bulk density by 11.31, 15.48 and 17.86% as compared with control, respectively. Data indicated also that there are an increase in the percentages of retained moisture in the soil at all treatments under study. Bentonite and chicken manure individually or combined being higher with increasing the applied rate of bentonite and/or chicken manure. Also the application rates of bentonite 1, 2.5 and 5% lead to, increasing the values of water-holding pores (WHP) with 6.87, 8.05 and 10.55%. In addition, WHP values increased to 9.21, 10.43 and 11.27% with the application of chicken manure 5, 10 and 15 ton/fed. Also, data refer that WHP increased to 12.03, 12.81 and 14.11% by application rate of 2.5% bentonite combined with each of 5, 10 and 15 ton/fed chicken manure, as compared with control, respectively. The values of water infiltration rates (cm/h), were affected by different soil applications and can be arranged in the following ascending order: 2.5% bentonite + 15 ton/fed chicken manure 2.5% bentonite + 10 ton/fed chicken manure > 2.5% bentonite + 5 ton/fed chicken manure > 15 ton/fed chicken manure > 10 ton/fed chicken manure > 5 ton/fed chicken manure > 5% bentonite > 2.5% bentonite > 1% bentonite > control. ‎

Pengaruh Kompos Limbah Sagu Terhadap Bawang Merah (Allium ascalonicum L.), dan Karakteristik Sifat Fisik Tanah Serta Populasi Cacing Tanah (Lumbriscus terestris) Dilahan Kering Musim Kemarau

The utilization of sago waste as a source of organic material, namely compost will provide positive values for both plants and soil productivity and reduce the cost of purchasing chicken manure which is increasingly expensive. Research conductedon dry land in the dry seasonat a land plot of header/ tajuk varieties red onionusing the treatment of sago waste compost dosage. The treatment of sago waste compost doses, among others KS 0 = control, KS 1 = 35 t/ha, KS 2 = 70 t/ha dan KS 3 = 105 t/ha. The results showed no significant differences between treatments on the growth parameters of red onion aged 2 MST and 4 MST. However, the dry production parameters show that KS treatment differs only with KS 0. Respectively 11,56 t/ha compared to 9,61 t/ha. The treatment of sago waste compost dosage also has a good effect on decreasing the value of soil bulk density, increasing soil water content and also soil porosity. It is associated with the increased dose of sago waste compost then further increase the number of earthworm populations at different depths in the soil. At a depth of 0-15 cm the highest population of earthworms at KS 3 reached 1,077/ 2m2while KS 0 is only 309/2m2.

Microbial hotspot areas of C and N cycles in old-growth Hyrcanian forests top soils

Microbial activity of top soils is directly linked with carbon (C) and nitrogen (N) turnover in terrestrial ecosystems, and thus is an indicator to identify hot spot areas of C and N cycling in forest habitats. The Hyrcanian forests are one of the last remnants of natural deciduous forests in the world and Oriental Beech (Fagus orientalis Lipsky) is one of the most abundant tree species of these forests. It has not been resolved which forest properties of Hyrcanian forests facilitate hotspots with high microbial process rates. We studied those primary causes (i.e. forest properties) of changes on soil characters and processes within old-growth Vaz forests, Northern Iran, and separately sampled different landform positions (i.e. catena, pit-mound and gilgai), single-trees, deadwoods and canopy gaps. Principal component analysis (PCA) of the 31 soil parameters resulted in two principal components that explained more than 60% of the total variance. The first component (PC1) explained the highest variance (48.13%) in the results; while second component (PC2) accounted for 13.68% of the variance. The obtained PCA results indicate a clear differentiation in selected soil properties among forest properties and thus, three groups of drivers for microbial activities were identified. Group 1 (foot and toe slope of V-shape catena, toe slope ofΛ-shape catena, pit structure of hornbeam, decay class 4 of beech deadwoods, small and medium canopy gaps) enhanced soil microbial process and enzyme activities. Group 2 (pit structure of beech, control or non-gilgai position, beech and hornbeam single-trees, decay class 3 and 4 of hornbeam deadwoods and large canopy gap) enhanced soil microbial biomass and greenhouse gas fluxes. Group 1 and 2 drivers were associated with high values of soil water content, organic C, total N, available nutrients, organic matter fractions, earthworm and nematode activities. Group 3 drivers (summit and shoulder slope of V- and Λ-shape catena, back slope of V-and Λ-shape catena, foot slope ofΛ -shape catena, mound of beech and hornbeam, position in a gilgai, decay class 2 and 3 of beech deadwoods, decay class 1 and 2 of hornbeam deadwoods and very large canopy gap) correlated with lowest microbial activities and was associated with high values of soil bulk density, pH, electrical conductivity and C/N ratio. Thus, distribution of microbial hotspot areas in the Hyrcanian forests can be considered as mosaic of pedons characterized by specific sets of key parameters, which depend on landform, especially the toe slope of V-shape catena, and stand characteristics (e.g. tree species or canopy gap).

Effect of cover crop management on soil hydraulic properties

Cover crops are important for improving soil quality. They can provide multiple soil, agricultural and environmental benefits. The objective of the study was to compare the effects of cover crop management on soil hydraulic properties which included saturated hydraulic conductivity (Ksat), soil water retention, bulk density, and pore-size distributions over time. The experiment was carried out on a Grundy silt loam (fine, smectitic, mesic Aquertic Argiudolls) at the Chariton Country Soil Health Farm, Missouri, USA The main grain crops were a corn (Zea mays L.)/soybean (Glycine max L.) rotation. Cover crops included radish (Raphanus sativus L. var. longipinnatus), cereal rye (Secale cereals L.), cowpeas (Vigna unguiculata), buckwheat (Fagopyrum esculentum), barley (Hordeum vulgare L.), red clover (Trifolium pretense), turnips (Brassica rapa L.), hairy vetch (Vicia villosa Roth.), triticale (Triticale hexaploide Lart.), and winter peas (Lathryrus hirsutus L.). Undisturbed soil cores, 7.62 (diam.) by 7.62 (L) cm, were collected 1, 2 and 5 years after cover crops were established from six replicate locations by 10-cm depth increments from the surface to the 40-cm depth. Results illustrated that cover crop management significantly affected Ksat by year. The highest Ksat values (64.6%) were observed 5 years after cover crop establisment compared to first and second year soil samples. However, bulk density, soil water retention and pore-size distributions were affected significantly by soil depths. Soil bulk density values were significantly lower at the soil surface 0–10 cm depth. Macropores, coarse and fine mesopores, and Ksat values were significantly higher at the 0–10 cm and 10–20 cm depths compared to deeper soil depth. Soil water content was higher at the 30–40 cm depth for all soil water pressures due to higher clay content. Significantly higher water retention was determined 5 years after cover crop establishment for the −2.5 kPa soil water pressure. This study demonstrated that cover crops slightly improve some hydraulic properties in claypan soils but the changes may take several years.

Spatial variability of soil bulk density and its controlling factors in an agricultural intensive area of Chengdu Plain, Southwest China

Soil bulk density is a basic but important physic soil property related to soil porosity, soil moisture and hydraulic conductivity, which is crucial to soil quality assessment and land use management. In this study, we evaluated the spatial variability of soil bulk density in the 0–20, 20–40, 40–60 and 60–100 cm layers as well as its affecting factors in Southwest China's agricultural intensive area. Results indicated the mean value of surface soil bulk density (0–20 cm) was 1.26 g cm−3, significantly lower than that of subsoil (20–100 cm). No statistical difference existed among the subsoil with a mean soil bulk density of 1.54 g cm−3. Spatially, soil bulk density played a similar spatial pattern in soil profile, whereas obvious differences were found in details. The nugget effects for soil bulk density in the 0–20 and 20–40 cm layers were 27.22 and 27.02% while 12.06 and 3.46% in the 40–60 and 60–100 cm layers, respectively, gradually decreasing in the soil profile, indicating that the spatial variability of soil bulk density above 40 cm was affected by structural and random factors while dominated by structural factors under 40 cm. Soil organic matter was the controlling factor on the spatial variability of soil bulk density in each layer. Land use and elevation were another two dominated factor controlling the spatial variability of soil bulk density in the 0–20 and 40–60 cm layers, respectively. Soil genus was one of the dominated factors controlling the spatial variability of soil bulk below 40 cm.

Primary and Secondary Igapó Forests in the Peruvian Amazon: Floristics, Physical Structure and the Predictive Value of Soil Bulk Density

Igapó forests are a key part of the Amazon.  And so, it is important to know their floristics and physical structure, and how they may be influenced by their soil.  The floristics and physical structure of 16 primary [1o] and secondary [2o] igapó forest plots in Loreto Province, Peru was described and linear regressions were computed to explore whether soil bulk density could predict structural parameters. In the 1o forest, Fabaceae, Malvaceae and Rubiaceae were the most common families and Calycophyllum spruceanum, Ceiba samauma, Inga spp., Cedrela odorata, Copaifera reticulata, Phytelephas macrocarpa, Guazuma rosea, and Piptadenia pteroclada were the most common species. And as flooding increased, bulk density, stem density, stem size, species richness, Fishers α, basal area and above-ground biomass all decreased. In the 2o forest, Urticaceae, Rubiaceae and Euphorbiaceae were the most common families and Cecropia membranacea, Sapium glandulosum, Pourouma guianensis and Byrsonima arthropoda were the most common species. The number of stems was greatest in the island 2o forest and lowest in the 1o forest under water for more than four months, and mean stem size, species richness, Fishers α, basal area and above-ground biomass was lowest in the sandy beach 2o forest and highest in the 1o forest under water one to two months. Soil bulk density predicted mean stem size, species richness and Fishers α well, where all three decreased as soils became more sandy. I conclude that as soil becomes less sandy with more clay content there is an increase in forest structural complexity, unpredictable flooding in 2o forests reduces structure more than the predictable flood pulse 1o forests receive, and soil bulk density may have a causal role for diversity in igapó forests.

Variation in carbon stock in litterfall, fine root and soil in Sal (Shorea robusta Gaertn.) forests of eastern Nepal

Global climate change is a major problem generated by increasing concentration of carbon dioxide in the atmosphere. Forests and their soils are major sink of carbon and thus constitute an effective role in the global carbon cycle. Present study was conducted to quantify and compare the amount of carbon stock in litterfall, fine root and soil between Tarai Sal forest and Hill Sal forest of eastern Nepal. Carbon stock in litter and fine root was estimated by ash content method and in soil by multiplying the value of soil organic carbon, bulk density and soil depth. Carbon stock in litterfall was higher (3.94 Mg ha-1) in TSF than HSF (3.26 Mg ha-1) and in fine root (0-5 mm size) in 0-30 cm soil depth it was higher in HSF (2.76 Mg ha-1) than TSF (2.19 Mg ha-1). In soil (0-30 cm depth) the value was higher in HSF (58.23 Mg ha-1) than TSF (50.81Mg ha-1). Tarai Sal forest accumulated higher carbon stock in the litterfall and lower in fine root than Hill Sal forest which was mainly attributed to the amount of litterfall and fine root biomass rather than organic carbon concentration. In Tarai Sal forest the carbon stock in soil was relatively low than Hill Sal forest that may be due to the higher net uptake and mineralization of carbon in the situation of higher growth rate of plant. These outcomes verified that the forest plays important role for mitigation of global warming by storing the atmospheric carbon dioxide in plant parts and the soil. So, it concludes that conserving the considerable quantity of carbon in forests is inevitable for proper forest management.

IMPACT OF TILE DRAINAGE SYSTEM AND WATER QUALITY ON SOME SOIL PROPERTIES AND CROP YIELDS OF WHEAT AND MAIZE

The current study was carried out in two successive seasons (winter 2015/2016 and summer 2016) on two areas (Mahallet Rooh and Saft Torab). Both areas belong to El-Santa District (about 13 km to Tanta, Gharbia Governorate, Egypt). This work was conducted in clay loam soils to study the feasibility of installing tile drainage at farm level and using fresh and mixed water (fresh and drainage water i.e.1:1) on some soil properties, wheat and maize productivity. Moreover, the obtained field data were used to evaluate the field drains through comparing the calculated drain spacing using Hooghoud equation with the actual drain spacing. Both areas have a covered drainage system. The laterals were constructed at 1.2 m depth and 30 m drain spacing with a length varies from 250-275 m. Five feddans in each area were selected to carry out this study. Moreover, non- tiled drained areas were selected in both two areas as control areas. The results of irrigation water analysis revealed that generally, both fresh and mixed water applied in this study could be used safely according to the standard guidelines of FAO (1994) which means that, using such mixed water safely can save about 50% of fresh water needed for crop water requirements. Also the results proved that, at Mahallet Rooh area where fresh irrigation water is used, the soil salinity reduced by about 30.7% as compared with the initial value in the area not provided with tile drainage, but the reduction in soil salinity was about 58.9% in the area provided with tile drainage system. The total amounts of leached salts from the top 60 cm of soil were 1850.4 and 2051.8 kg/fed for non- tiled and tiled areas of Mahllet Rooh area, respectively. Concerning Saft Torab area, where mixed water is used for irrigation, these amounts were 1222.1 and 1965.2 kg/fed for the top 60 cm of soil, respectively. The obtained results confirmed that, the tiled areas at Mahallet Rooh, where fresh irrigation water is applied, showed a relatively higher values of quickly drainable pores (QDP), slowly drainable pores (SDP) and consequently, the total drainable pores (TDP) as compared with that of Saft Torab area where mixed water is used for irrigation. On contrary, the water holding pores (I.e. fine and coarse capillary pores values) were relatively higher as compared with that of Mahallet Rooh area. The non-tiled areas in both Mahallet Rooh and Saft Torab showed almost the same values of pore size distribution components, but the fine capillary pores value (FCP) was slightly higher for Saft Torab as compared with that obtained for Mahallet Rooh area. The results showed that soil bulk density values were lower in areas provided with tile drainage either in Mahallet Rooh or Saft Torab area resulting higher total porosity values as compared with that not provided with tile drainage. The results indicate that water table levels during winter season were much deeper than that observed in summer season in both areas under this study. The tile drainage areas showed a pronounced effect on lowering water table level as compared with the areas that not provided with tile drainage system. The results indicate that using mixed irrigation water which has a relatively higher salt content caused a higher salinity of water table as compared with that of Mahallet Rooh area where fresh irrigation water is used. Drain spacing is calculated according to Hooghoudt equation using the field data measurements of soil hydraulic conductivity and water table levels midway between drains. The results revealed that, using the field data the calculated drain spacing was 27 m at Mahallet Rooh area, while it was to 30 m spacing at Saft Torab. The designed values were 30 m which is almost the same as the calculated values. These results indicate to the good performance of tile drains in both areas under the study according to the field actual measurements. The results revealed that, both grain and biological wheat and maize yields in drained areas and that irrigated with fresh water are higher than that obtained in non-drained areas and that irrigated with mixed water.

Enhancement of Depleted Loam Soil as Well as Cucumber Productivity Utilizing Biochar Under Water Stress

ABSTRACTBiochar has recently received increased attention because it improves poor soil fertility. However, its potentiality to enhance soil physical properties under water stress conditions not yet deeply investigated. Hence, extensive field investigations were carried out to study the effects of biochar addition (BA) with deficit irrigation (DI) on soil bulk density (BD), porosity percentage (P%), soil moisture content (SMC%), soil hydraulic conductivity (K), cucumber yield and water use efficiency (WUE) during two consecutive seasons (2016 and 2017). The biochar treatments were B0 (0 ton ha−1), B1 (10 ton ha−1and B2 (20 ton ha−1), while the DI treatments were 1.0 (W1), 0.60 (W2) and 0.40 (W3) of the reference evapotranspiration (ET0). The parameters were measured at soil depths of 0–10 (d1), 10–20 (d2) and 20–30 cm (d3) for measurement periods of before sowing (P1), mid-season (P2) and after harvest (P3). The results showed that the B2W1 combination gave the highest yield (57 and 45.2 t ha−1), WUE (10.94 and 11.27 kg m−3), SMC (39.2 and 40.1%) in both seasons, respectively. The B2W3 had the highest porosity (47.5 and 46.1%) values at the d1. Meanwhile, the lowest soil BD values of 1.1 and 1.05 g cm−3 were obtained by the B2W1 at d1 for 2.16 and 2017, respectively. Statistically, most of the parameters studied under B2W2 and B0W1 had non-significant differences between them. Hence, the addition of biochar with DI could be an integrated approach to address the drought stress, while enhancing soil and plant properties.

Soil physical and biological properties in an integrated crop-livestock system in the Brazilian Cerrado

Abstract: The objective of this work was to evaluate the soil physical and biological properties in an integrated crop-livestock system (ICLS), with or without cattle grazing, in different seasons. The experiment was carried out in the Cerrado biome, in Brazil, in a Rhodic Eutrudox. The treatments consisted of grazing areas (Urochloa ruziziensis) at 0.25, 0.35, and 0.45 m heights (with soybean cultivation after grazing) and of nongrazed areas. The ICLS had no negative effects on soil bulk density, total porosity, macroporosity, and microporosity. After ICLS implementation, the values of soil bulk density decreased, and those of soil macroporosity increased, in the grazed and nongrazed areas. However, after three years, bulk density and macroporosity were reestablished to values similar to those before ICLS implementation. Soil penetration resistance was higher in the ICLS, mainly at 0.00-0.05 m soil depth. After four years, ICLS promoted the increase of microbial biomass C and N and the reduction of the metabolic quotient. The microbial biomass carbon and the metabolic quotient were related to the weighted mean diameter. ICLS benefits to soil physical and biological properties are associated with adequate ICLS implementation, adequate grazing height (0.35 m), and maintenance of soil cover.

Bio-intensive Modulation of Sugarcane Ratoon Rhizosphere for Enhanced Soil Health and Sugarcane Productivity Under Tropical Indian Condition

Intensive cropping and exhaustive nature sugarcane crop in tropical India have led to depletion of inherent soil fertility resulting in serious threat to sustainable sugarcane production. Improving soil organic matter and soil fertility are important factors for sustainable sugarcane production. Microbial consortia comprising of Trichoderma viride, Humicola spp, Paecilomyces lilacinus, Gluconacetobater diazotropicus, Azospiriillum brasilense, and Bacillus subtilis have great potential to recycle crop residue and restore soil fertility which eventually promote sugarcane growth. Field experiments with in situ trash management in plant crop and bio-intensive modulation of sugarcane ratoon rhizosphere in ratoon crops were conducted during 2014, 2015 and 2016 at ICAR—Sugarcane Breeding Institute, Coimbatore, Tamil Nadu, India. The results revealed that green manuring with sunnhemp, in situ trash management and application of 280:62.5:120 kg NPK ha−1 in plant crop sustained the soil health by way of reducing soil bulk density (1.26 kg dm−3), lower soil penetration resistance in the ratoon rhizosphere (1.79, 1.82 and 1.75 MPa) and higher soil organic carbon (0.52%) which in turn increased ratoon cane yield 12.24% (99.02 t ha−1) and sugar yield by 8.64% (12.83 t ha−1) over the control. Further, bio-intensive modulation of ratoon rhizosphere by off barring, trash shredding plus soil incorporation with microbial consortia and application of 350:62.5:120 kg NPK ha−1 in ratoon crop recorded significantly higher cane yield (100.95 t ha−1) and sugar yield (13.19 t ha−1) over the control. The improvement in cane yield and sugar yield to the tune of 16.35 and 14.10% due to bio-intensive modulation of ratoon rhizosphere over control have clearly established that productivity of sugarcane ratoon can be significantly improved with balanced use of fertilizers, green manuring, crop residue recycling and microbial consortia application. Similarly, bio-intensive modulation of sugarcane ratoon rhizosphere (S3) with lowest soil bulk density (1.26 kg dm−3) and soil penetration resistance values (1.69, 1.81, and 1.75 MPa) was found effective in minimising the soil compaction and improving nutrient availability (NPK) with build-up of soil microbial population than control (Trash removal). Based on the results of 3-year field experiments, it is concluded that sunnhemp green manuring and in situ sugarcane trash management coupled with application of 280:62.5:120 kg NPK ha−1 in plant crop followed by bio-intensive modulation of ratoon rhizosphere including off barring, trash shredding and soil incorporation with microbial consortia and application of 350:62.5:120 kg NPK ha−1 in ratoon crop can be recommended for sustaining soil health and sugarcane productivity under wide-row sugarcane planting systems of tropical Indian condition.

Mulching and water diversion structures on skid trails: Response of soil physical properties six years after harvesting

In recent years, the application of mulch on machine operating trails has gained popularity as a method of reducing post-harvest soil erosion and water runoff following ground-based harvesting operations. Three treatments immediately applied after ground-based skidding operations were sawdust mulch (SM), water diversion structure or contour-felled log erosion barrier (WDS), and untreated/bare trail (U) in May 2011. At the time of skidding, weather conditions had been very dry and warm. The SM treatment was manually spread on the entire trail surface at a rate of 3.65 kg m−2. WDS was created by placing felled logs with diameters ranging from 25 to 30 cm and 4 m in length in a perpendicular direction to the skid trails with the distance between adjacent WDS set at 10 m. This study aimed to determine and compare the effectiveness of three treatments on the recovery of soil physical properties from compacted soil caused during logging operations over a six-year period (from May 2011 to July 2017) in the Hyrcanian forest, north of Iran. Soil bulk density, total porosity, penetration resistance, and rut depth (wheel rut) were measured to assess the recovery process on three abandoned skid trails with varying longitudinal gradients (10%, 20%, and 30%) exposed to different levels of machine traffic (low, medium, and high). On trails with a 10% gradient, the highest recovery values of bulk density (7.8%) and total porosity (8.5%) were observed in the SM treatment, while on the steepest gradients (20 and 30%), the highest recovery values of bulk density (10.9%) and total porosity (12.9%) were found in the WDS treatment. The average recovery of penetration resistance for soil located in the SM and WDS treatments was 19.1% and 10.5%, respectively. Average rut depth recovery, expressed in percent of post-harvest values, was higher on all trail gradients subjected to the WDS treatment (30.6%) as compared to the SM treatment (13.1%). In general, values of soil bulk density, total porosity, penetration resistance and rut depth continued to show signs of machine-induced disturbance over the 6-year monitoring period, compared to the undisturbed area as a benchmark.

SPATIAL VARIABILITY OF SOIL PROPERTIES AND EFFECTS ON RICE YIELD GROWN ON EL-GEMMIEZA CLAYEY SOIL (MIDDLE OF NILE DELTA OF EGYPT)

Understanding the relationships between rice yield and soil properties is very critical importance in precision farming. The objective of this work was to evaluate the relationships between special variability of soil properties and rice yield (Oryza sativa). The area under study is 41.67 ha in EL-Gemmieza Agriculture Research Station,of the Agric. Rese. Center (ARC), El Gharbiah Governorate, Egypt (Middle of Nile Delta). The studied location divided into two sites varied in their productivity of rice. Soil pH was found slightly alkaline at site (1) and alkaline at site (2). The EC and CEC in site (1) were higher than at site (2). On contrary values of ESP were higher at site (2) than at site 1. Higher exchangeable cations were observed under site (1) than site (2) except of exchangeable -Na+showed a contrary behavior. Data also showed that values of soil bulk density were lower under site 1 than site (2) whereas; total porosity, hydraulic conductivity and infiltration rate were higher in site (1) than site (2). Higher values of grain yield, straw yield, harvest index and NPK content and uptake in grain and straw were found in site (1) than in site (2). The values of variation coefficients (CV) of the most studied traits showed low variability (< 20). At site 1 there is a significant correlation at 5% level with positive trends between grain yield and the traits of CEC, soluble K, exchangeable Ca++, Mg++, available N and K, total porosity and hydraulic conductivity. While, negative significant correlations at 5% level with negative trends were noticed between exchangeable Na+ and bulk density. On the other hand, result of satirical analysis of site 2 indicated a positive and significant correlations between grain yield of rice plant and all the traits of harvest index, N and K uptake in straw, CEC, O.M, exchangeable - Ca++& K+, available - N & available -P, total porosity and hydraulic conductivity. As the results of the stepwise regression analysis of site (1), it can arrange the soil physical characteristics, as their effective on rice yield, in the following order of: infiltration rate > soil total porosity > saturated hydraulic conductivity (Ksat). While the order of soil chemical characteristics were: ESP > pH > EC > O.M. As for soil available nutrients, their continuation factors were 90.7, and 7.0 % for soil available–K & available–N, respectively. For site (2) it can arrange the soil physical characteristics, as their effective on rice yield, in the following order of: bulk density > saturated hydraulic conductivity. While the order of soil chemical characteristics was: ESP > pH > CEC > O.M. As for soil available nutrients, their continuation factors were 91.1 and 5.6 % for soil available–K, and P, respectively.

EFFECT OF SULPHUR, GYPSUM AND COMPOST ADDITION AND TILLAGE METHODS ON SOIL PROPERTIES AND WHEAT PRODUCTIVITY IN SALINE SOIL

Effective use of salt affected soils needs the development of the most efficient and suitable reclamation technology to optimize farm management and better crop yields. Different chemical methods and amendments are used to reclaim the salt affected soils, and after reclamation such soils may be used for sustainable agricultural production. Choice of a chemical amendment depends on its availability, cost, handling and time of application. A field experiment was conducted for two successive winter seasons 2014/2015 and 2015/2016 at Sahl El-Hossinia Agric. Res. Station, El-Sharkia Governorate, Egypt, to evaluate two tillage methods (surface and subsurface) and three soil amendments (elemental sulphur S, gypsum Gy, compost Co, compost + sulphur, compost + gypsum, gypsum + sulphur and compost + sulphur + gypsum) on some soil properties and wheat yield. The studied treatments were arranged within the experimental units in a split plot design in three replicates. Statistical analysis of grains and straw yield data showed that all the added amendments significantly increased the grains and straw yield of wheat compared with control. The addition of Gy+Co+S was the most effective addition in increasing the grains and straw yield in surface and subsurface tillage. Also, it is clear that grains and straw yields of wheat in the treatments of subsurface tillage were slightly higher than those in the treatments of surface tillage. Data showed that all applications of soil amendments under different tillage methods decreased soil pH and EC, but there is an increase in the values of organic matter and cation exchange capacity. This effect is more obvious in case of applying Gy+Co+S. Subsurface tillage associated by high values of O.M (%) and CEC (c.mole) than surface tillage. Soil OM (%) and CEC (c.mol/kg) were significantly increased as a result of added amendments. Data showed that values of total dry stable aggregates (DSA) and water stable aggregates (WSA) were increased in all treatments under study compared to control. The highest increase in values of total stable aggregates (DSA and WSA) was observed in the treatment of Gy+Co+S with subsurface tillage method compared to the treatments of surface tillage method and control. The highest values of hydraulic conductivity, total porosity, field capacity and available water were found by applying Gy+Co+S treatment in subsurface tillage method compared to control and other treatments of surface and subsurface tillage. The values of soil bulk density at different soil depths of all treatments were relatively low and the maximum decrease exists in case of the treatment Gy+Co+S with subsurface tillage method compared to other treatments and control. Generally, it can be concluded that gypsum, sulphur and compost application had decreased the hazardous effect of salinity of soil and hence exerted favorable effects on growth and yield of wheat. Subsurface tillage method improved soil chemical and physical properties which are reflected on growth and grain yield of wheat compared with the surface tillage method.

Soil and vegetation development along a 10-year restoration chronosequence in tailing dams in the Xiaoqinling gold region of Central China

Gold mining has increased sharply in response to global demand. Gold extraction usually causes the formation of tailing dams, in which organic matter and microbial activity decrease, and this consequently constrains plant growth. However, a full understanding of plant-soil interaction and plant community development in terms of natural restoration of gold mine tailing dam has not yet been developed. Three tailing dams, which had been naturally restored for 2 (R2), 5 (R5), and 10 (R10) years in the Xiaoqinlin gold region of Central China, were chosen to explore soil and plant community development in August, 2015. This study showed that soil bulk density and pH value were the lowest, whereas soil organic carbon, total nitrogen, microbial biomass carbon and nitrogen were the highest in the R10 tailing dam across two soil depths (0–10 cm and 10–20 cm). Soil organic carbon, total nitrogen, microbial biomass carbon and nitrogen decreased with soil depth across the restoration periods. The highest ratio of soil organic carbon to total nitrogen in the R10 tailing dam suggests that the rate of soil organic carbon accumulation may be restricted by the total nitrogen content in the long-term. Restoration stimulated plant community diversity and productivity, due to increment in soil nutrient content and microbial biomass carbon and nitrogen. The various ratios of root biomass to aboveground plant biomass among three tailing dams were caused by the shifting of the plant community composition from annual to perennial varietals. The mechanism by which plant-soil interaction and plant community composition change over time can be used to guide restoration programs in tailing dams in Central China.

EFFECT OF FARM MACHINERY ON SOME SOIL PHYSICAL PROPERTIES USING HYPERSPECTRAL DATA

Traditional soil analyses are expensive, time-consuming, and may also result in environmental pollutants. The objective of this study was to develop a methodology to predict soil physical properties specifically the soil bulk density using spectral reflectance (SR) as an alternative to traditional methods. Additionally to critically examine the suitability of Visible and Near-infrared (Vis- NIR) (350–2500 nm) measurements for calibration procedures and methods to predict the value of soil bulk density. Five different seedbed preparation systems were applied. Spectroradiometer ASD was used to measure the soil spectral reflectance of each system. Stepwise multiple linear regression (SMLR) was used to construct calibration models subjected to the independent validation. The obtained regression models were of good quality (R2 = 0.959, 0.868, 0.811, 0.751 and 0.677 for system 5, system 1, system 3, system 4 and system 2, respectively). Thus, Visible and Near-infrared (Vis-NIR) reflection spectroscopy is cost- and time-effective procedure that can be used as an alternative to the traditional methods of measuring soil physical properties.

Complex pedological analysis of paleosols buried under kurgans as a basis for periodization of the Timber-grave archaeological culture in the Southern Cis-Ural, Russia

The problem of periodization of the Timber-grave culture of the Late Bronze Age on the territory of the Southern Cis-Ural is far from being solved. This situation exists because the funeral ceremony looks very similar throughout the history of the Timber-grave culture existence. To assign stages of this culture's development, a complex approach was used, including archaeological observation, radiocarbon dating, technical and technological analysis of ceramics and study of paleosols buried under kurgans. The paleopedological analysis was a key approach because the relative chronological order of the construction of kurgans was initially determined within one kurgan cemetery based on morphological observation and physical and chemical properties of the buried paleosols.Five kurgan cemeteries (which included 19 kurgans overall) of the Timber-grave culture were studied in the Orenburg region (the Southern Cis-Ural). It was found that the paleosols buried under the earliest kurgans of the studied culture show the maximal values of soil bulk density in the humus and carbonate horizons, the minimal content of humus in the uppermost 50 cm of the profile, the highest content of carbonates and the closest to surface location of the Bk horizon, the highest content of gypsum, and the highest portion of exchangeable sodium of the sum of exchangeable bases. Based on the set of mentioned properties of the buried paleosols, the transitional and the latest groups of kurgans were also suggested. In the latest group, the paleosols show minimal values of bulk density, maximal content of humus in the uppermost 50 cm, minimal content of carbonates and total lack of gypsum and exchangeable sodium throughout profiles. Such differences in the paleosols' properties buried under different groups of the Timber-grave kurgans were probably caused by climatic fluctuations during the period of the culture's functioning. The reconstruction showed that, in the most part, this culture had been developed in favorable climatic conditions with a sufficient quantity of precipitation and comparatively soft climatic continentality, whereas the previous period was characterized by an arid and continental climate.Based on archaeological observation, radiocarbon dating, technical and technological analysis of ceramics, three chronological stages were allocated in the history of the functioning of the Timber-grave antiquities for the steppe Cis-Ural. According to calibrated radiocarbon dates, the chronological limits are as follows: the first stage – XIX century BC, the second – XVIII – XVII centuries BC, and the third – XVII – XV centuries BC.