Survival of Chlamydospores of Phytophthora cinnamomi in Several Non-Sterile, Host-Free Forest Soils and Gravels at Different Soil Water Potentials

1979 ◽  
Vol 27 (1) ◽  
pp. 1 ◽  
Author(s):  
G Weste ◽  
K Vithanage
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Phytophthora Cinnamomi ◽  
Matter Content ◽  
Soil Types ◽  
Native Forest ◽  
Sterile Soil ◽  
Water Potentials ◽  
Chlamydospore Formation ◽  
Disease Free

Chlamydospore survival was investigated for six soil types, collected from disease-free areas of native forest in Victoria, in 50-g packs of non-sterile, unamended soils and gravels at five different matric soil water potentials ( ψ ). No chlamydospores survived in gravel free from OM, and only one chlamydospore survived at ψ -3000 kPa. In other packs the numbers of chlamydospores declined for 2 months then increased markedly at 4-6 months. Many chlamydospores remained viable for 8 months and some for 10 months despite the use of non-sterile soil and the absence of hosts. Maximum numbers survived in gravel from the Brisbane Ranges 6 and 8 months after inoculation at ψ -500 kPa. Decreasing soil moisture appeared to stimulate chlamydospore formation while a low rganic matter content and small numbers of microorganisms increased survival.

scholarly journals Soil water retention curves for the major soil types of the Kruger National Park

Koedoe ◽  
2014 ◽  
Vol 56 (1) ◽  
Author(s):  
Robert Buitenwerf ◽  
Andrew Kulmatiski ◽  
Steven I. Higgins
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Water Content ◽  
Carbon Cycling ◽  
Soil Water ◽  
National Park ◽  
Soil Water Potential ◽  
Kruger National Park ◽  
Soil Types ◽  
Soil Moisture Retention

Soil water potential is crucial to plant transpiration and thus to carbon cycling and biosphere–atmosphere interactions, yet it is difficult to measure in the field. Volumetric and gravimetric water contents are easy and cheap to measure in the field, but can be a poor proxy of plant-available water. Soil water content can be transformed to water potential using soil moisture retention curves. We provide empirically derived soil moisture retention curves for seven soil types in the Kruger National Park, South Africa. Site-specific curves produced excellent estimates of soil water potential from soil water content values. Curves from soils derived from the same geological substrate were similar, potentially allowing for the use of one curve for basalt soils and another for granite soils. It is anticipated that this dataset will help hydrologists and ecophysiologists understand water dynamics, carbon cycling and biosphere–atmosphere interactions under current and changing climatic conditions in the region.

scholarly journals Effect of Osmotic and Matric Potentials on the Availability of Water for Seed Germination

1971 ◽  
Vol 24 (3) ◽  
pp. 423 ◽  
Author(s):  
JR Mcwilliam ◽  
PJ Phlllips
Keyword(s):  
Soil Moisture ◽  
Seed Germination ◽  
Osmotic Stress ◽  
Soil Water ◽  
Seed Coat ◽  
Moisture Diffusivity ◽  
Matric Potential ◽  
Water Potentials ◽  
Germination Behaviour ◽  
Dry Soil

Under special conditions where soil-moisture diffusivity and seed-soil contact are non-limiting, the osmotic and matric potentials of the substrate were found to be equivalent in their effect on the germination of seeds of ryegrass and dehulled phalaris over a range of water potentials from 0 to -15 bars. However, with intact phalaris seeds it appears that the seed coat constitutes a large resistance to the absorption of soil water, and under these conditions the equivalence between osmotic and matric potential no longer holds, and results of germination under osmotic stress must be used with caution in predicting the germination behaviour of seeds in dry soil.

Rooting depth and plant water relations explain species distribution patterns within a sandplain landscape

2004 ◽  
Vol 31 (5) ◽  
pp. 423 ◽  
Author(s):  
Philip K. Groom
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Loss ◽  
Rooting Depth ◽  
Summer Drought ◽  
Tissue Water ◽  
Shrub Species ◽  
Water Deficits ◽  
Groundwater Levels ◽  
Water Potentials

Tree and shrub species of the Banksia woodlands on the sandplains of northern Swan Coastal Plain, Western Australia possess a range of strategies to avoid or tolerate soil water deficits during the annual summer drought. Shallow-rooted shrub species (< 1 m rooting depth) inhabit a range of locations in the landscape, from top of dune crests to wetland embankments. These are the most drought-tolerant of all sandplain species, surviving extremely low summer soil water potentials (< –7 MPa) and tissue water deficits by significantly reducing their transpirational water loss (< 0.2 mmol m–2 s–1). This is in contrast to the few shallow-rooted species restricted to low-lying or seasonally waterlogged areas which are reliant on subsurface soil moisture or groundwater to maintain their relatively high summer water use. Recent studies of water source usage of selected Banksia tree species have shown that these deep-rooted species access groundwater up to a maximum depth of 9 m depth during the summer months, or soil moisture at depth when groundwater was greater than maximum rooting depths, depending on the species. Medium- and deep-rooted (1–2 m and > 2 m, respectively) shrub species cope with the summer soil drying phase and related decrease in groundwater levels by conserving leaf water loss and incurring predawn water potentials between –1 and –4 MPa, enabling them to occur over a range of topographic positions within the sandplain landscape.

scholarly journals Online appendix 2:Soil water retention curves for the major soil types of the Kruger National Park

Koedoe ◽  
2014 ◽  
Vol 56 (1) ◽  
Author(s):  
Robert Buitenwerf ◽  
Andrew Kulmatiski ◽  
Steven I. Higgins
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Water Content ◽  
Carbon Cycling ◽  
Soil Water ◽  
National Park ◽  
Soil Water Potential ◽  
Kruger National Park ◽  
Soil Types ◽  
Soil Moisture Retention

Soil water potential is crucial to plant transpiration and thus to carbon cycling and biosphere–atmosphere interactions, yet it is difficult to measure in the field. Volumetric and gravimetric water contents are easy and cheap to measure in the field, but can be a poor proxy of plant-available water. Soil water content can be transformed to water potential using soil moisture retention curves. We provide empirically derived soil moisture retention curves for seven soil types in the Kruger National Park, South Africa. Site-specific curves produced excellent estimates of soil water potential from soil water content values. Curves from soils derived from the same geological substrate were similar, potentially allowing for the use of one curve for basalt soils and another for granite soils. It is anticipated that this dataset will help hydrologists and ecophysiologists understand water dynamics, carbon cycling and biosphere–atmosphere interactions under current and changing climatic conditions in the region.

scholarly journals Soil-water physical attributes under different managements systems in the humid tropics in Maranhão

2020 ◽  
Vol 13 (9) ◽  
pp. 38
Author(s):  
J. B. Martins Filho ◽  
K. C. Cunha Meneses ◽  
A. L. Brito Filho ◽  
C. E. L. Feitosa ◽  
M. F. Farias
Keyword(s):  
Soil Moisture ◽  
Physical Properties ◽  
Soil Water ◽  
Total Porosity ◽  
Native Forest ◽  
Water Capacity ◽  
Total Soil ◽  
Randomized Design ◽  
Vertical Hydraulic Conductivity ◽  
Physical Attributes

This study was conducted to evaluate the physical properties modifications of an Oxisol under different conditions of use and management. The research was conducted at Fazenda Sítio Novo and in native forest area, respectively in the municipalities of São Benedito do Rio Preto/MA and Chapadinha/MA. The research followed a completely randomized design with 3 treatments and 4 replications, with the following uses and management: no-tillage (PD); conventional planting (CP) and native forest (MN). The following physical properties were analyzed: bulk density, porosity and soil moisture and penetration resistance at depths of 0.0-0.20 m and 0.20-0.40 m. The water properties analyzed were: basic infiltration velocity, total soil water capacity and vertical hydraulic conductivity. The soil presented higher density and low conservation of moisture in PD and PC. Native forest presented higher total porosity and higher conservation of soil moisture. Total soil water capacity was higher in MN (39.89 mm) followed by PC (25.33 mm) and PD (18.84 mm). The uses and management employed in the soils analyzed on the farm reflect the degradation of the physical properties of the soil in relation to native forest. 

scholarly journals Online appendix 1: Soil water retention curves for the major soil types of the Kruger National Park

Koedoe ◽  
2014 ◽  
Vol 56 (1) ◽  
Author(s):  
Robert Buitenwerf ◽  
Andrew Kulmatiski ◽  
Steven I. Higgins
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Water Content ◽  
Carbon Cycling ◽  
Soil Water ◽  
National Park ◽  
Soil Water Potential ◽  
Kruger National Park ◽  
Soil Types ◽  
Soil Moisture Retention

Soil water potential is crucial to plant transpiration and thus to carbon cycling and biosphere–atmosphere interactions, yet it is difficult to measure in the field. Volumetric and gravimetric water contents are easy and cheap to measure in the field, but can be a poor proxy of plant-available water. Soil water content can be transformed to water potential using soil moisture retention curves. We provide empirically derived soil moisture retention curves for seven soil types in the Kruger National Park, South Africa. Site-specific curves produced excellent estimates of soil water potential from soil water content values. Curves from soils derived from the same geological substrate were similar, potentially allowing for the use of one curve for basalt soils and another for granite soils. It is anticipated that this dataset will help hydrologists and ecophysiologists understand water dynamics, carbon cycling and biosphere–atmosphere interactions under current and changing climatic conditions in the region.

scholarly journals Greenhouse Evaluation of Pinewood Biochar Effects on Nutrient Status and Physiological Performance in Muscadine Grape (Vitis rotundifolia L.)

HortScience ◽  
2021 ◽  
Vol 56 (2) ◽  
pp. 277-285
Author(s):  
Yuru Chang ◽  
Lorenzo Rossi ◽  
Lincoln Zotarelli ◽  
Bin Gao ◽  
Ali Sarkhosh
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Plant Root ◽  
Organic Matter Content ◽  
Net Photosynthesis ◽  
Nutrient Status ◽  
Matter Content ◽  
Perennial Crop ◽  
Physiological Performance ◽  
Muscadine Grape

Muscadine grape is a perennial crop that is highly responsive to local environmental factors and viticulture practices. Biochar is a promising soil amendment used to improve soil water and nutrient retention and promote plant growth. The present study aimed to assess the effects of different pinewood biochar rates on nutrient status and vegetative parameters of muscadine grape cv. Alachua grown on a nutrient-poor sandy soil, Ultisols (97.2% sand, 2.4% silt, and 0.4% clay), and mixed with five different rates (0%, 5%, 10%, 15%, and 20%) of biochar based on weight. Variations in soil moisture, temperature, and leaf greenness value [soil plant analysis development (SPAD) reading], net photosynthesis rate, and plant root and shoot dry weights were measured. In addition, the nutrient status of the soil, plant root, and shoot were determined. The results indicated that the higher rate of biochar could significantly (P < 0.05) improve soil moisture. Biochar can also decrease soil temperature, although there were no significant differences among treatments. Regarding the nutrient status, the biochar amendment increased the nutrient content of phosphorus (P), potassium (K), magnesium (Mg), and calcium (Ca), as well as the soil organic matter content and cation exchange capacity. Higher nutrient contents in soil lead to increased P and Mg in both aboveground and belowground muscadine plant tissues and decreased nitrogen (N), iron (Fe), and copper (Cu) in the root part. There were no significant differences observed in SPAD values, net photosynthesis, or dry weights of the root and shoot. This study demonstrates that the addition of biochar may enhance the soil water and nutrient status as well as improve plant P and Mg uptake; however, it showed no significant differences in the physiological performance of muscadine grape plants.

Laboratory calibration of different soil moisture sensors in various soil types

2020 ◽  
Author(s):  
Urša Pečan ◽  
Damijana Kastelec ◽  
Marina Pintar
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Bulk Density ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Bulk Density ◽  
Soil Samples ◽  
Soil Types ◽  
Soil Moisture Sensors ◽  
Dry Soil

&lt;p&gt;Measurements of soil water content are particularly useful for irrigation scheduling. In optimal conditions, field data are obtained through a dense grid of soil moisture sensors. Most of the currently used sensors for soil water content measurements, measure relative permittivity, a variable which is mostly dependant on water content in the soil. Spatial variability of soil characteristics, such as soil texture and mineralogy, organic matter content, dry soil bulk density and electric conductivity can also alter measurements with dielectric sensors. So the question arises, whether there is a need for a soil specific calibration of such sensors and is it dependant on the type of sensor? This study evaluated the performance of three soil water content sensors (SM150T, Delta-T Devices Ltd, UK; TRIME-Pico 32, IMKO micromodultechnik GmbH, DE; MVZ 100, Eltratec trade, production and services d.o.o., SI) in nine different soil types in laboratory conditions. Our calibration approach was based on calibration procedure developed for undisturbed soil samples (Holzman et al., 2017). Due to possible micro location variability of soil properties, we used disturbed and homogenized soil samples, which were packed to its original dry soil bulk density. We developed soil specific calibration functions for each sensor and soil type. They ranged from linear to 5&lt;sup&gt;th&lt;/sup&gt; order polynomial. We calculated relative and actual differences in sensor derived and gravimetrically determined volumetric soil water content, to evaluate the errors of soil water content measured by sensors which were not calibrated for soil specific characteristics. We observed differences in performance of different sensor types in various soil types. Our results showed measurements conducted with SM150T sensors were within the range of manufacturer specified measuring error in three soil types for which calibration is not necessary but still advisable for improving data quality. In all other cases, soil specific calibration is required to obtain relevant soil moisture data in the field.&lt;/p&gt;

SOIL TEMPERATURE AND SOIL WATER UNDER ZERO TILLAGE IN MANITOBA

1982 ◽  
Vol 62 (2) ◽  
pp. 311-325 ◽  
Author(s):  
E. GAUER ◽  
C. F. SHAYKEWICH ◽  
E. H. STOBBE
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Soil Water ◽  
Soil Surface ◽  
Conventional Tillage ◽  
Soil Types ◽  
Zero Tillage ◽  
Crop Canopy ◽  
Burned Soil

The influences of zero and conventional tillage on soil temperature and soil moisture were investigated on three soil types in Manitoba. When the straw was spread on the soil surface, zero-tilled fields were usually cooler than conventionally tilled fields. When the straw was removed by raking, the opposite was true. No consistent soil temperature differences occurred between conventional and zero-tilled soils when the straw was burned. Soil moisture was higher on the zero- than on conventionally tilled plots both when straw was spread on the surface and when the straw was removed by raking. No moisture differences occurred between the tilled and zero-tilled plots when the straw was burned. As the season progressed, differences in moisture and temperature decreased as the crop canopy developed, and as the straw and stubble disintegrated.

Seasonal Variation in Numbers of Chlamydospores in Victorian Forest Soils Infected With Phytophthora cinnamomi

1978 ◽  
Vol 26 (5) ◽  
pp. 657 ◽  
Author(s):  
G Weste ◽  
K Vithanage
Keyword(s):  
Seasonal Variation ◽  
Soil Water ◽  
Forest Soils ◽  
Phytophthora Cinnamomi ◽  
Soil Water Potential ◽  
Native Forest ◽  
Forest Sites ◽  
Significant Seasonal Variation ◽  
Different Types ◽  
Soil Temperatures

Chlamydospore numbers were counted for 2 years on replicated soil samples from three different types of naturally infected Victorian native forest. Soil temperatures and soil water potentials were recorded concurrently. A highly significant seasonal variation in chlamydospore numbers was observed with maxima from summer to autumn and minima from winter to spring. There was little variation either between replicates or between different forest soils in winter and spring counts, but there was highly significant variation between different forest sites during the large summer and autumn counts. At this period sandy soil contained five to 12 times the number of chlamydo- spores found in other soils. For example, in autumn 1977,286 chlamydospores were recorded per 50 g sample from deep sandy soils compared with 31 for krasnozem and 17 for shallow duplex soils. At this period soil temperatures were similar but the soil water potential for the duplex soil was very low (-82 bars).

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