Effect of salinity on the microwave emission from dry soil surface

Emulsions of dieldrin, aldrin, isodrin, toxaphene and chlordane applied to the soil surface and incorporated to a depth of about 4 inches proved highly effective in controlling the red-back cutworm, Euxoa ochrogaster (Guen.) when tested in asparagus fields in the interior of British Columbia in the summer of 1953 and 1954. In 1953 aldrin emulsion mixed with the soil was much more effective than when it was left on the soil surface, Bran bait containing paris green, although giving fairly satisfactory control, was less effective and slower in action than the emulsions. In 1952, dieldrin, aldrin, and isodrin dusts, applied to the soil surface, were superior to and faster in action than bran baits containing aldrin or endrin; all of the 1952 treatments were apparently slower in action in dry soil than in relatively moist soil. A survey of asparagus fields treated by growers in 1953 but not in 1954 indicated that aldrin emulsion, mixed with the soil at about 4 lb. of toxicant per acre, protects asparagus for at least two years.

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Germination of Weedy Rice in Response to Field Conditions during Winter

Weed Technology ◽

10.1614/wt-d-10-00099.1 ◽

2011 ◽

Vol 25 (2) ◽

pp. 252-261 ◽

Cited By ~ 19

Author(s):

Silvia Fogliatto ◽

Francesco Vidotto ◽

Aldo Ferrero

Keyword(s):

Soil Surface ◽

Petri Dish ◽

Storage Condition ◽

Germination Percentage ◽

Climatic Conditions ◽

Field Conditions ◽

Weedy Rice ◽

Rice Seed ◽

Dry Soil ◽

Delayed Germination

Weedy rice is a problematic weed that infests paddy fields worldwide. Differing populations, with varying physiological and morphological traits, characterize this weed. In particular, seed dormancy makes its control difficult. The objective of this study was to evaluate the germination behavior of five Italian weedy rice populations (two awnless, two awned, and one mucronate) after exposure of seeds to different field storage conditions (flooding, burial, and dry soil surface) during winter in two sites (Grugliasco and Vercelli, Italy). Seed samples were taken from each population, storage condition, and site, every 15 d for petri dish germinability testing. The two sites displayed slightly different germination patterns, which were probably due to the differing climatic conditions. One of the awned populations showed the highest (always exceeding 80%) and fastest germination percentage in all field conditions and sites, compared with the other four populations. Although flooding promoted germination in one awnless population, it delayed germination in two others (one awned and one awnless), attaining only 20% germination after more than 100 d. In all populations, burial delayed germination, whereas seed placement on the dry soil surface enhanced it. Our study indicated that autumn tillage that promotes weedy rice seed burial should be discouraged; spring tillage that exposes seeds to the soil surface and cause their depletion should be encouraged. The tested technique of winter flooding can also improve weedy rice control, despite its varying efficacy among populations. Cycles of flooding and drying followed by spring tillage might improve weedy rice seed control.

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THE EFFICIENCY OF THE STRATEGY OF MUCILAGINOUS SEEDS OF SOME COMMON ANNUALS OF THE NEGEV ADHERING TO THE SOIL CRUST TO DELAY COLLECTION BY ANTS

Israel Journal of Plant Sciences ◽

10.1080/07929978.1997.10676695 ◽

1997 ◽

Vol 45 (4) ◽

pp. 317-327 ◽

Cited By ~ 37

Author(s):

Yitzchak Gutterman ◽

Shachar Shem-Tov

Keyword(s):

Plant Species ◽

Soil Surface ◽

Loess Soil ◽

Soil Crust ◽

Experimental Plot ◽

Annual Plant ◽

Dry Soil ◽

Annual Plant Species ◽

Crust Surface ◽

Plantago Coronopus

Groups of dry seeds of four annual plant species which occur in the Negev highlands were placed on a natural, dry or wet loess soil crust surface near Sede Boker on the Zin plateau during the autumn before the first rains, and on the first day with rain (1.15 mm). Ant nests ofMessor rugosuswere 8 to 14m from the experimental plot. The length of time it took these ants to collect the free or adhered seeds was observed. When the mucilaginous ombrohydrochoric seeds ofAnastatatica hierochuntica, Plantago coronopus, andCarrichtera annuaadhere to wet soil that remains moist, most of the seeds may have time to germinate in proper conditions before they are collected by ants. However, all but 5% of theReboudia pinnataseeds were collected within 2 h. The adhered seeds that had been moistened by wet soil crust and then dried, were collected by ants, in most cases, faster than when seeds and soil remained moist. Within 2 h none of the dry and free seeds situated on the dry soil surface remained. The first free seeds were collected after 7 min. Findings are discussed together with the mechanisms and strategies involved in seed dispersal by rain and germination of these plant species.

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Experimental Study of C Band Passive Microwave Remote Sensing of Soil Moisture

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.477-478.624 ◽

2013 ◽

Vol 477-478 ◽

pp. 624-627

Author(s):

Xiao Liu Gao ◽

Hui Hui Zhang

Keyword(s):

Remote Sensing ◽

Soil Moisture ◽

Emission Rate ◽

Soil Surface ◽

Microwave Remote Sensing ◽

Passive Microwave ◽

Microwave Emission ◽

Passive Microwave Remote Sensing ◽

Soil Surface Roughness ◽

Relationship Of

Passive microwave remote sensing is one of the most effective methods for inversing soil moisture. Under the condition of laboratory, firstly, C band microwave radiation was used to achieve the trial of ground-based remote sensing soil moisture, and then regression analysis was carried out according to the data measured, finally, got the C band experience regression model of soil moisture inversion. The results showed that: in the level-off state of soil surface, soil humidity and soil microwave emission rate is linear negative correlation, in the other words, soil microwave emission rate decreased while the soil moisture increased. Besides, with the increasing of soil surface roughness, both the value of microwave polarization index (MPDI) and microwave emission rate polarization difference Δe have the same trend of quick drop, stabilization and slow raise, and it presented the relationship of quadratic curve with the change of roughness.

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Chemical and Physical Modification of the Rhizosphere

Solute Movement in the Rhizosphere ◽

10.1093/oso/9780195124927.003.0011 ◽

2000 ◽

Author(s):

Peter B. Tinker ◽

Peter Nye

Keyword(s):

Root Hairs ◽

Soil Surface ◽

Fine Sand ◽

Root Surface ◽

Root Penetration ◽

Wheat Roots ◽

Order Of Magnitude ◽

Seminal Roots ◽

Dry Soil ◽

Living Organisms

The term ‘rhizosphere’ tends to mean different things to different people. In discussing how a root affects the soil, it is well to bear in mind the spread of the zone being exploited for a particular solute: if this is wide, there may be no point in emphasizing effects close to the root; but if it is narrow, predictions based on the behaviour of the bulk soil may be wide of the mark. In a moist loam after 10 days, a simple non-adsorbed solute moves about 1 cm, but a strongly adsorbed one will move about 1 mm. In a dry soil, the spread may be an order of magnitude less. The modifications to the soil in the rhizosphere may be physical, chemical or microbiological. In this chapter, we discuss essentially non-living modifications, and in chapter 8 the modifications that involve living organisms and their effects. Roots tend to follow pores and channels that are not much less, and are often larger, in diameter than their own. If the channels are larger, the roots are not randomly arranged in the void (Kooistra et al. 1992), but tend to be held against a soil surface by surface tension, and to follow the channel geotropically on the down-side. If the channels are smaller, good contact is assured, but the roots do not grow freely unless some soil is displaced as the root advances. For example, in winter wheat, Low (1972) cites minimum pore sizes of 390–450 μm for primary seminal roots, 320–370 μm for primary laterals, 300–350 μm for secondary laterals, and 8–12 μm for root hairs, though some figures seem large. Whiteley & Dexter (1984) and Dexter (1986a, b, c) have studied the mechanics of root penetration in detail (section 9.3.5). It may compact and reorient the soil at the root surface. Greacen et al. (1968) found that wheat roots penetrating a uniform fine sand increased the density only from 1.4 to 1.5 close to the root; and a pea radicle, a comparatively large root, raised the density of a loam from 1.5 to 1.55.

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Studies on seed pelleting as an aid to legume seed inoculation. 3. Survival of Rhizobium applied to seed sown into hot, dry soil

Australian Journal of Experimental Agriculture ◽

10.1071/ea9700739 ◽

1970 ◽

Vol 10 (47) ◽

pp. 739 ◽

Cited By ~ 11

Author(s):

J Brockwell ◽

LJ Phillips

Keyword(s):

Trifolium Pratense ◽

Rhizobium Meliloti ◽

Soil Surface ◽

Northern Territory ◽

Legume Species ◽

Legume Seed ◽

Seed Inoculation ◽

Lotus Pedunculatus ◽

Dry Soil ◽

High Degree

Seed of four legume species with various forms of lime pelleting and inoculation was sown into hot, dry soil at Katherine, Northern Territory, where it lay dormant for 7-9 weeks before germination commenced. Seedling nodulation was used as the index of inoculant survival. Where the seed was sown at a shallow depth, Rhizobium survival was poorer than on seed sown more deeply; this was attributed to the higher temperatures near the soil surface. Rhizobia survived best in those treatments in which peat inoculant was incorporated within the pellet. Rhizobium meliloti applied to Medicago sativa seed showed a high degree of tolerance of the conditions and seedling nodulation exceeded 90 per cent in several instances. Nodulation of Trifolium pratense and T. rueppellianum never exceeded 50 per cent and little nodulation occurred with Lotus pedunculatus. It is concluded that lime-pelleted Medicago seed with peat inoculant incorporated within the pellet can be sown into hot, dry soil with a strong expectation that the inoculant will survive and the seedlings nodulate.

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Redistribution of water following precipitation on previously dry sandy soils

Soil Research ◽

10.1071/sr9750013 ◽

1975 ◽

Vol 13 (1) ◽

pp. 13 ◽

Cited By ~ 8

Author(s):

BA Carbon

Keyword(s):

Soil Water ◽

Seedling Emergence ◽

Soil Water Potential ◽

Sandy Soils ◽

Soil Surface ◽

Field Capacity ◽

Wetting Front ◽

Applied Water ◽

Dry Soil ◽

The Relationship

Theoretical and experimental evidence is provided to show that the redistribution of a given amount of water some days after infiltration into a previously dry soil can be predicted, provided that the relationship between soil water potential and soil water content is known. The capillary potential at the wetting front during infiltration into the dry soil is also required. In sandy soils an increase in amount of applied water leads to a decrease in the soil moisture content at the soil surface. This change in 'field capacity' as a function of applied water is shown to strongly influence seedling emergence.

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The Effect of Bulk Density on Emission Behavior of Soil at Microwave Frequencies

International Journal of Microwave Science and Technology ◽

10.1155/2011/160129 ◽

2011 ◽

Vol 2011 ◽

pp. 1-6 ◽

Cited By ~ 8

Author(s):

V. K. Gupta ◽

R. A. Jangid

Keyword(s):

Dielectric Constant ◽

Bulk Density ◽

Soil Surface ◽

Microwave Remote Sensing ◽

Microwave Frequency ◽

Soil Samples ◽

Microwave Emission ◽

Complex Dielectric Constant ◽

Semiempirical Model ◽

Surface Boundary

Dielectric constant and dielectric loss (ε′ and ε″) of different soil samples with bulk densities varying from 1.3 to 2.0 gm/cm3 are determined at a single microwave frequency 9.78 GHz and at temperature 37.0°C. Different bulk densities of same soil are achieved by filling the wave guide cell with an equal volume but a different mass of soil. Further, ε′ and ε″ of these soil samples are also estimated by semiempirical model and compared with the experimental results. The values of ε′ and ε″ increase as bulk density of the soil increases. In view of microwave remote sensing, the Fresnel reflectivity of soil is computed from the knowledge of the complex dielectric constant and the surface boundary condition. Using Kirchhoff’s reciprocity theorem the microwave emissivity is estimated from Fresnel reflectivity of the surface. It is observed that the microwave emission from the soil surface inhibits as bulk density of soil increases. Further, the roughness of soil surface has been taken into consideration in the emissivity computation and observed that the emissivity increases with increasing roughness of the soil surface.

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Measurements of Soil Surface Roughness During the Fourth Microwave Water and Energy Balance Experiment: April 18 through June 13, 2005

EDIS ◽

10.32473/edis-ae363-2005 ◽

2019 ◽

Vol 2006 (3) ◽

Author(s):

Mi-joung Jang ◽

Kai-Jen Calvin Tien ◽

Joaquin Casanova ◽

Jasmeet Judge

Keyword(s):

Surface Roughness ◽

Energy Balance ◽

Soil Surface ◽

Theoretical Background ◽

Microwave Emission ◽

Publication Date ◽

Biological Engineering ◽

Soil Surface Roughness ◽

Microwave Signatures ◽

Roughness Measurements

Passive microwave signatures have been used to retrieve geophysical parameters, such as soil temperature [Njoku and Li, 1999], moisture [Jackson et al., 1995], and surface roughness [Wegmüller and Mätzler, 1999]. One of the challenges in the parameter retrieval is the effect of soil surface roughness on the microwave emission. We conducted soil surface roughness measurements as part of our fourth Microwave Water and Energy Balance Experiment (MicroWEX-4) to understand the effects of surface roughness on microwave signatures at 6.7 GHz (λ = 4.48 cm). The dataset will also be used to develop and validate surface roughness models. In this report, we summarize briefly the theoretical background of surface roughness characteristics and discuss methodology and results of the roughness experiments. This document is Circular 1483, one of a series of the Department of Agricultural and Biological Engineering, UF/IFAS Extension. Original publication date November 2005. CIR1483/AE363: Measurements of Soil Surface Roughness During the Fourth Microwave Water and Energy Balance Experiment: April 18–June 13, 2005 (ufl.edu)

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Survival of Oospores of Phytophthora capsici in Soil

Plant Disease ◽

10.1094/pdis-12-12-1123-re ◽

2013 ◽

Vol 97 (11) ◽

pp. 1478-1483 ◽

Cited By ~ 10

Author(s):

M. Babadoost ◽

C. Pavon

Keyword(s):

Phytophthora Capsici ◽

Soil Surface ◽

Soil Samples ◽

Burial Depth ◽

Infested Soil ◽

University Of Illinois ◽

Field Environment ◽

Dry Soil ◽

The University ◽

Depth Of Burial

This study assessed survival of Phytophthora capsici oospores in soil in Illinois. Soils differing in texture and other characteristics were collected from four Illinois Counties (Champaign, Gallatin, Madison, and Tazewell), equilibrated to –0.3 MPa, and infested with oospores of P. capsici at a density of 5 × 103 oospores/g of dry soil. Samples (25 g) of the infested soil were placed in 15-μm mesh polyester bags, which were sealed and placed at 2-, 10-, and 25-cm depths in 15.3-cm-diameter PVC tubes containing the same field soil as the infested bags. Tubes were buried vertically in the ground at the University of Illinois Vegetable Research Farm in Champaign in October 2004. Soil samples were assayed for recovery and germination of oospores 1 day and 3, 6, 12, 24, 30, 36, and 48 months after incorporation of oospores into the soil. Overall, the percentage of oospore recovery and the percentage of germination of oospores were not affected significantly by soil source and burial depth but both the oospore recovery and oospore germination were significantly (P = 0.001) affected by the duration of oospore burial. The rate of oospore recovery from soil samples was 61.06, 16.69, 10.28, 1.05, 0.30, 0.06, 0.05, and 0.004% after 1 day and 3, 6, 12, 24, 30, 36, and 48 months, respectively, following incorporation of oospores into the soil; and mean oospore germination was 47.17, 30.53, 21.33, 15.64, 7.42, 2.67, 2.61, and 0.00%, respectively. Survival of P. capsici oospores was compared in soil samples stored in a laboratory at 22°C versus on the soil surface or buried 2, 10, or 25 cm deep in a field. Oospores were recovered 1, 3, 6, 12, and 24 months after incorporation for both storage locations. The percentage of oospores recovered from samples stored in the laboratory was significantly (P = 0.004) greater than recovery from samples stored in the field, regardless of the depth of burial. Twenty-four months after incorporation of oospores, 26.52% of oospores were recovered from soil samples in the laboratory, whereas only 0.12% of oospores were recovered from soil samples in the field. Overall, the percentages of germination of oospores recovered from samples in the laboratory and field over 24 months were not significantly different. In both experiments, germinated oospores produced mycelia, sporangia, and zoospores, and were virulent on ‘California Wonder’ bell pepper. This study showed that oospores of P. capsici can survive and remain virulent in Illinois soils for more than 36 months but oospores were no longer viable after 48 months in soil in a field environment.

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