Subsoil macropore space of a transitional red-brown earth after either deep tillage, gypsum or both .I. Physical effects and short term changes

Soil Research ◽  
1991 ◽  
Vol 29 (2) ◽  
pp. 123 ◽  
Author(s):  
PS Blackwell ◽  
NS Jayawardane ◽  
TW Green ◽  
JT Wood ◽  
J Blackwell ◽  
...  
Keyword(s):  
Pore Space ◽  
Application Rate ◽  
Short Term ◽  
Matric Potential ◽  
Deep Tillage ◽  
Surface Sealing ◽  
Physical Effects ◽  
Considerable Loss ◽  
Space Volume ◽  
Gypsum Application

This research aimed to improve understanding of the processes which cause deterioration of macropore space (volume and permeability of air-filled pores at -10 kPa matric potential), as well as providing some guidelines for improving management. This paper reports the effects of amelioration treatments on soil fragment sizes and horizon-of-origin, as well as the distribution of solid gypsum in the profile immediately after deep cultivation. The macropore space of the subsoil after initial winter cropping is described from measurements on soil cores collected from the experiment. The finer fragments from slotting at low speed resulted in smaller macroporosity than in the ripped soil. Macroporosity, permeability and organization of pore space generally increase with the amount of gypsum initially mixed with the soil. In spite of the smaller volume of soil disturbed by slotting than by ripping, the reduction in runoff was similar to the ripped soil when the gypsum application rate to the slotting was twice that applied to the ripped soil. Where no gypsum was applied to the slotted soil, slumping and swelling led to considerable loss of macroporosity formed by the initial deep tillage, as well as surface sealing by dispersed clay. Hence runoff from this treatment was similar to the unameliorated soil.

Subsoil macropore space of a transitional red-brown earth after either deep tillage, gypsum or both .II. Chemical effects and long term changes

Soil Research ◽  
1991 ◽  
Vol 29 (2) ◽  
pp. 141 ◽  
Author(s):  
PS Blackwell ◽  
NS Jayawardane ◽  
TW Green ◽  
JT Wood ◽  
J Blackwell ◽  
...  
Keyword(s):  
Control Treatment ◽  
Matric Potential ◽  
Deep Tillage ◽  
Chemical Effects ◽  
Uncultivated Soil ◽  
Texture Contrast ◽  
Summer Fallow ◽  
Considerable Loss ◽  
Gypsum Application

The management of sodic texture-contrast soils of the riverine plains of S.E. Australia for crops other than rice is difficult because improved subsoil structure often deteriorates after a few seasons of irrigated cropping. This research aimed to improve understanding of the processess which cause deterioration of macropore space (volume and permeability of air-filled soil at -10 kPa matric potential) as well as providing some guidelines for improved management. A transitional red-brown earth was ameliorated by eight different treatments and compared with an unameliorated control treatment in a field experiment. The treatments included surface gypsum application, deep ripping after gypsum application, five designs of gypsum-enriched slots and traffic-free beds after addition of gypsum and deep ripping. The macropore space of the subsoil after initial winter cropping and summer fallow is described from measurements on soil cores collected from the experiment. An index of electrochemical stability (EC/ESP) is proposed which explains the loss of macroporosity of cultivated subsoil in the absence of significant soil stressing by wheels. Considerable loss of macropore volume and permeability after the first summer crop could be associated with loss of soluble gypsum, some increases of exchangeable sodium and compression by lateral swelling of the uncultivated soil from between the slots. These changes were compensated by an increase in the number of vertical fissures, directly observed and deduced from measurements of water entry into whole plots. Thus, management of the balance of soluble salts is essential for the long-term productivity and profitability of such systems of amelioration using deep tillage zones and gypsum application. This is in the absence of significant compaction under wheels or opportunities for addition or organic matter and formation of biopores by roots and soil animals. The relief of lateral swelling of the uncultivated B horizon by the loose slots and formation of extra vertical fissures is a process which may provide long-term benefits and deserves further research.

scholarly journals Potential short-term losses of N<sub>2</sub>O and N<sub>2</sub> from high concentrations of biogas digestate in arable soils

SOIL ◽  
2017 ◽  
Vol 3 (3) ◽  
pp. 161-176 ◽  
Author(s):  
Sebastian Rainer Fiedler ◽  
Jürgen Augustin ◽  
Nicole Wrage-Mönnig ◽  
Gerald Jurasinski ◽  
Bertram Gusovius ◽  
...  
Keyword(s):  
Pore Space ◽  
Organic Fertilizer ◽  
Application Rate ◽  
Loamy Sand ◽  
Nutrient Concentrations ◽  
Soil Core ◽  
Anaerobic Conditions ◽  
Short Term ◽  
Clayey Silt ◽  
Biogas Digestate

Abstract. Biogas digestate (BD) is increasingly used as organic fertilizer, but has a high potential for NH3 losses. Its proposed injection into soils as a countermeasure has been suggested to promote the generation of N2O, leading to a potential trade-off. Furthermore, the effect of high nutrient concentrations on N2 losses as they may appear after injection of BD into soil has not yet been evaluated. Hence, we performed an incubation experiment with soil cores in a helium–oxygen atmosphere to examine the influence of soil substrate (loamy sand, clayey silt), water-filled pore space (WFPS; 35, 55, 75 %) and application rate (0, 17.6 and 35.2 mL BD per soil core, 250 cm3) on the emission of N2O, N2 and CO2 after the usage of high loads of BD. To determine the potential capacity for gaseous losses, we applied anaerobic conditions by purging with helium for the last 24 h of incubation. Immediate N2O and N2 emissions as well as the N2 ∕ (N2O+N2) product ratio depended on soil type and increased with WFPS, indicating a crucial role of soil gas diffusivity for the formation and emission of nitrogenous gases in agricultural soils. However, emissions did not increase with the application rate of BD. This is probably due to an inhibitory effect of the high NH4+ content of BD on nitrification. Our results suggest a larger potential for N2O formation immediately following BD injection in the fine-textured clayey silt compared to the coarse loamy sand. By contrast, the loamy sand showed a higher potential for N2 production under anaerobic conditions. Our results suggest that short-term N losses of N2O and N2 after injection may be higher than probable losses of NH3 following surface application of BD.

Urea hydrolysis and inorganic N in a Luvisol after application of fertiliser containing rare-earth elements

Soil Research ◽  
2003 ◽  
Vol 41 (4) ◽  
pp. 741 ◽  
Author(s):  
Xingkai Xu ◽  
Zijian Wang ◽  
Yuesi Wang ◽  
Kazuyuki Inubushi
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Substantial Reduction ◽  
Application Rate ◽  
Urea Hydrolysis ◽  
High Rate ◽  
Short Term ◽  
N Content ◽  
N Fertilisers ◽  
Hydrolysis Of

In recent decades, Chinese agriculturists have used rare-earth-containing fertilisers as basal fertilisers together with N fertilisers (e.g. urea). We studied urea hydrolysis and its hydrolysis products in a laboratory experiment using urea-N fertiliser with rare earths at rates from 0.5 to 50% (w/w). The results indicated that application of rare earths at a high rate could result in a short-term inhibition of urea hydrolysis and an increase in soil (NH4+ + NO3– + NO2–)-N content. When the application rate of rare earths was higher than 5% of the applied urea-N (corresponding to 10 mg/kg soil), soil exchangeable NH4+-N content increased significantly following the hydrolysis of the applied urea. Increasing the application rate of rare earths appeared to reduce the content of soil urea-derived (NO3– + NO2–)-N. A substantial reduction in soil pH was found immediately after application of rare earths and urea. We conclude that application of rare earths at >10 mg/kg may lead to a substantial increase in the content of urea-derived N in the soil, via the inhibition of urea hydrolysis and nitrification.

scholarly journals N<sub>2</sub>O and N<sub>2</sub> losses from simulated injection of biogas digestate depend mainly on soil texture, moisture and temperature

2017 ◽  
Author(s):  
Sebastian Rainer Fiedler ◽  
Jürgen Augustin ◽  
Nicole Wrage-Mönnig ◽  
Gerald Jurasinski ◽  
Bertram Gusovius ◽  
...  
Keyword(s):  
Agricultural Soils ◽  
Pore Space ◽  
Inhibitory Effect ◽  
Application Rate ◽  
Organic Fertiliser ◽  
Potential Capacity ◽  
Clayey Silt ◽  
Biogas Digestate ◽  
Silty Soils

Abstract. Biogas digestate (BD) is increasingly used as organic fertiliser, but has a high potential for NH3 losses. Its proposed injection into soils as a counter-measure has been suggested to promote the generation of N2O, leading to a potential trade-off. Furthermore, the effect on N2 losses after injection of BD into soil has not yet been evaluated. We performed a simulated BD injection experiment in a helium-oxygen atmosphere to examine the influence of soil substrate (loamy sand, clayey silt), water-filled pore space (WFPS; 35, 55, 75 %), temperature (2° C, 15° C) and application rate (0, 160, 320 kg N ha−1) as a proxy for row spacing of injection on the emissions of N2O, N2, and CO2. To determine the potential capacity for these gaseous losses, we incubated under anaerobic conditions by purging with helium for the last 24 h of incubation. N2O and N2 emissions as well as the N2 / (N2O + N2) ratio depended on soil type and increased with WFPS and temperature, indicating a crucial role of soil gas diffusivity for the formation of these gases in agricultural soils. However, the emissions did not increase with the application rate of BD, i.e. a broader spacing of injection slits, probably due to an inhibitory effect of the high NH4+ content of BD. Our results suggest that the risk of N2O and N2 losses even after injection of relatively large amounts of BD seems to be small for dry to wet sandy soils and acceptable when regarding simultaneously reduced NH3 emissions for dry silty soils.

Topsoil and subsoil C and N turnover are affected by superficial lime and gypsum application in the short-term

2021 ◽  
pp. 108456
Author(s):  
Jéssica P.Q. Barcelos ◽  
Eduardo Mariano ◽  
Davey L. Jones ◽  
Ciro A. Rosolem
Keyword(s):  
Short Term ◽  
N Turnover ◽  
C And N ◽  
Gypsum Application

scholarly journals Effect of Gypsum Application Rate, Soil Type, and Soil Calcium on Yield, Grade and Seed Quality of Runner Type Peanut Cultivars

2017 ◽  
Vol 44 (1) ◽  
pp. 13-18 ◽  
Author(s):  
J.A. Arnold III ◽  
J.P. Beasley ◽  
G.H. Harris ◽  
T.L. Grey ◽  
M. Cabrera
Keyword(s):  
Field Experiments ◽  
Seed Quality ◽  
Soil Depth ◽  
Application Rate ◽  
Seed Vigor ◽  
Application Rates ◽  
Peanut Cultivars ◽  
Research And Education ◽  
The University ◽  
Gypsum Application

ABSTRACT Calcium (Ca) availability in the 0 to 8 cm soil depth often limits peanut yield and influences grade in the southeastern United States. Field experiments were conducted in 2012 and 2013 at the University of Georgia's Coastal Plain Experiment Station, Tifton, GA (CPES) and the Southwest Georgia Research and Education Center, Plains, GA (SWREC) to determine large-seeded (Georgia-06G) and medium-seed sized (Georgia Greener) runner-type cultivar response to gypsum application rates of 0, 560, 1120, 1650 kg/ha. Peanut pod yield and grade (TSMK) were significantly different between locations with 7610 and 6540 kg/ha at CPES and SWREC, respectively. However, there were no differences between peanut cultivars or gypsum rates. Standard germination, seed vigor (cold germination), and seed Ca content analysis were also conducted on subsamples from each plot. Average peanut seed germination was 97% across all samples. No differences were observed for standard germination or vigor testing. Differences in locations were observed for yield, TSMK, percent jumbo, percent medium kernels, and seed Ca content. Peanut cultivar and gypsum application rate had effects on seed Ca concentration. Seed Ca concentration levels were 825 and 787 mg/kg for Georgia Greener and Georgia-06G, respectively. Seed Ca content increased as field gypsum application rate increased at both locations.

scholarly journals Phosphorus leaching in sandy soils .I. Short-term effects of fertilizer applications and environmental conditions

Soil Research ◽  
1988 ◽  
Vol 26 (1) ◽  
pp. 177 ◽  
Author(s):  
DM Weaver ◽  
GSP Ritchie ◽  
GC Anderson ◽  
DM Deeley
Keyword(s):  
Soil Solution ◽  
Environmental Conditions ◽  
Management Practices ◽  
Sandy Soils ◽  
Summer Rainfall ◽  
Application Rate ◽  
Short Term ◽  
Coastal Superphosphate ◽  
Soil Solutions ◽  
Soil Solution P

The consequences of previous as well as current environmental conditions and management practices on the potential for phosphorus (P) to be lost by drainage from sandy soils in the short term (< 1 year) were studied in the laboratory and the field. The potential for P losses by drainage was estimated by measuring soil solution P levels and rapidly released P. Rapidly released P was measured by determining the concentration of dissolved inorganic P contained in filtered (<0.45 pm) soil solutions after incubating soil at saturation for 15 min at ambient temperature. In the laboratory, sandy soils were incubated with ordinary superphosphate, coastal superphosphate (a granulated mixture of equal parts of superphospate, rock phosphate and elemental sulfur) or lime-superphosphate (a lime-reverted superphosphate with 18% kiln dust) and sequentially desorbed with deionized water. The effects of the extent of leaching, fertilizer type, application rate and the time of contact with the soil on soil solution P levels were investigated. The influence of annual pasture death and summer rainfall on rapidly released P in soils that had been pre-treated by leaching were also investigated. Phosphorus concentrations decreased logarithmically in the successive supernatants of the sequentially desorbed soils. More P was desorbed from soils incubated with superphosphate and lime-superphosphate than soil incubated with coastal superphosphate. At each level of pre-leaching, the P concentrations in the soil solution increased with increasing time. The level, to which the P concentration in the soil solution increased at each time, decreased with increased extent of pre-leaching. The addition of P fertilizers increased the concentration of P in the soil solution. The concentrations increased with increasing application rate and were much higher for superphosphate than for coastal superphosphate; however, there was little effect of contact time on soil solution P levels. Rapidly released P levels after leaching increased during a period of no further leaching. Additional moisture or plant material during this period of no further leaching increased the rate and extent to which rapidly released P increased. Monitoring of rapidly released P in the 0-2, 2-5, 5-10 and 10-20 cm layers of field plots, with and without applications of superphosphate, showed that sampling depth, water flow path, fertilizer management, rainfall pattern and background P levels would affect the estimate of short-term P losses. Rapidly released P in the 0-2 cm layer varied markedly with time and was higher (P < 0.05) than that in lower soil layers. Rapidly released P increased after the winter and spring rains diminished and then decreased after the rains commenced again at the end of the summer. A possible annual cycle of P in sandy soils in a mediterranean climate is postulated by considering the laboratory and field data in combination.

Thixotropy and dilatancy

Clay Minerals ◽  
1966 ◽  
Vol 6 (4) ◽  
pp. 323-331 ◽  
Author(s):  
G. H. Cashen
Keyword(s):  
Water Potential ◽  
Pore Space ◽  
Matric Potential ◽  
Air Interface ◽  
Water Films ◽  
The Difference ◽  
Characteristic Features

AbstractThe matric potential of water in gels of five-sixths neutralized aluminium montmorillonite (bentonite) and aluminium kaolinite changes during periods of shear and periods of rest. Shear increases the potential of water in bentonite gels, and in kaolinite gels containing little water, but decreases the potential in kaolinite gels containing more water. All these effects can be explained by changes in the curvature of water films at the gel-air interface. The difference between thixotropic and dilatant behaviour is the increasing and decreasing of the water potential on shearing. In dilatant pastes of silt-size particles, and for which the effects of electric charges are small, the pressure deficiency can reach large values after an increase in pore space, and this suffices to explain the characteristic features of dilatant behaviour.

scholarly journals Worth replacing a loss of medial meniscal tissue with a polyurethane substitute (Actifit®) when performing a valgus tibial osteotomy addition

2014 ◽  
Vol 2 (12_suppl4) ◽  
pp. 2325967114S0025
Author(s):  
Pablo E. Gelber ◽  
Anna Isart ◽  
Juan I. Erquicia ◽  
Marc Tey ◽  
Xavier Pelfort ◽  
...  
Keyword(s):  
Marked Improvement ◽  
Tibial Osteotomy ◽  
Short Term ◽  
Medial Meniscectomy ◽  
Meniscal Tissue ◽  
Degree Of Satisfaction ◽  
Tibial Valgus ◽  
Genu Varus ◽  
Considerable Loss

Introduction: The addition tibial valgus osteotomy (ovat) is a common treatment of symptomatic genu varus. This frequently is accompanied by considerable loss of medial meniscal tissue. The aim was to evaluate, in the context of performing a ovat, restoring the functional impact of this lack of medial meniscal tissue with Actifit® compared with the simple meniscectomy. Material and Methods: Sixty patients with symptomatic genu varo operated with ovat were studied prospectively. In 30 patients we have left a medial meniscal defect> 25 mm (M) and in 30 a medial Actifit® was implanted(A). The evaluations were performed using Womet, IKDC, Kujala, EVA and satisfaction (0-4). Results: Both groups were statistically comparable preoperatively, including follow-up time (31.2 months; range, 24-47.5; p = 0.35). 53.4 ± 8.4 Womet improved and 42.4 ± 17.2 points in M and A (p = 0.002), improved IKDC 56.7 ± 12 and 50.3 ± 15.6 points in M and A (p = 0.107), 50.4 ± 14.7 Kujala improved to 38.9 ± 21.6 points M and A (p = 0.02) and VAS decreased 6.9 ± 2.1 and 4.7 ± 2.8 points in M and A (p = 0.006). The satisfaction was 3.3 ± 0.8 and 3.3 ± 1 in M and A (p = 0.84). Conclusions: The symptomatic genu varus treated with OVAT associated to medial meniscectomy led, compared to when it was associated with the implantation of a medial Actifit®, to a marked improvement in most of the scales tested. There was no difference in the degree of satisfaction. Based on short-term results of this study, restitution replacement with polyurethane substitute can not be recommended to perform a ovat.

scholarly journals An Assessment of the Capabilities of the ERS Satellites' Active Microwave Instruments for Monitoring Soil Moisture Change

1997 ◽  
Vol 1 (1) ◽  
pp. 159-174 ◽  
Author(s):  
K. Blyth
Keyword(s):  
Soil Moisture ◽  
Satellite Observation ◽  
Residual Effects ◽  
Radar Altimeter ◽  
Short Term ◽  
Moisture Change ◽  
Radar Sensors ◽  
Microwave Radar ◽  
Physical Effects ◽  
Inversion Modelling

Abstract. The launch of the European Remote sensing Satellite (ERS-1) in July 1991 represented an important turning point in the development of Earth observation as it was the first of a series of satellites which would carry high resolution active microwave (radar) sensors which could operate through the thickest cloudeover and provide continuity of data for at least a decade. This was of particular relevance to hydrological applications, such as soil moisture monitoring, which generally require frequent satellite observations to monitor changes in state. ERS-1 and its successor ERS-2 carry the active microwave instrument (AMI) which operates in 3 modes (synthetic aperture radar, wind scatterometer and wave seatterometer) together with the radar altimeter which may all be useful for the observation of soil moisture. This paper assesses the utility of these sensors through a comprehensive review of work in this field. Two approaches to soil moisture retrieval are identified: 1) inversion modelling, where the physical effects of vegetation and soil roughness on radar backscatter are quantified through the use of multi-frequency and/or multi-polarization sensors and 2) change detection where these effects are normalized through frequent satellite observation, the residual effects being attributed to short-term changes in soil moisture. Both approaches will be better supported by the future European Envisat-l satellite which will provide both multi-polarization SAR and low resolution products which should facilitate more frequent temporal observation.

Sign in / Sign up

Export Citation Format

Share Document