The physical environment of two semi-arid tropical soils with partial surface mulch cover

Soil Research ◽  
1989 ◽  
Vol 27 (3) ◽  
pp. 577 ◽  
Author(s):  
KL Bristow ◽  
DG Abrecht
Keyword(s):  
Soil Surface ◽  
Tropical Soils ◽  
Bare Soil ◽  
Loamy Sand ◽  
Maximum Temperature ◽  
Clay Loam ◽  
Row Width ◽  
Dry Conditions ◽  
Mulch Cover ◽  
Semi Arid

The seedbed microenvironment in soils with partial surface mulch cover will be affected by the width of the bare row zones. In this paper we compare seedbed conditions under four bare row widths [0 cm (completely mulched), 5 cm, 15 cm and completely bare] during a drying cycle in a loamy sand and clay loam soil in a semi-arid, tropical environment. It is shown that for both soils the rates of drying were greatest in the bare soil and least in the mulched soil, with the 5 and 15 cm bare row width treatments showing trends which were intermediate between the two extremes. Although soil surface temperatures were not noticeably different between the two soils, differences at depth became substantial as the soils dried, with the maximum temperature at 5 cm depth in the loamy sand exceeding that in the clay loam. There was also a steepening in the temperature gradient with depth as the soils dried. Under both wet and dry conditions, maximum temperature at 5 cm depth increased significantly with bare row width up to a width of about 25 cm which, for mulch of negligible height, approximates a bare soil. Results of this work demonstrate the benefits of maximizing surface mulch cover in the semi-arid tropics.

EFFECT OF CANOPY AND INCORPORATION ON METRIBUZIN PERSISTENCE IN SOILS

1989 ◽  
Vol 69 (3) ◽  
pp. 711-714 ◽  
Author(s):  
K. I. N. JENSEN ◽  
E. R. KIMBALL ◽  
J. A. IVANY
Keyword(s):  
Key Words ◽  
Half Life ◽  
Field Tests ◽  
Soil Surface ◽  
Bare Soil ◽  
Field Conditions ◽  
Row Width ◽  
Sampling Zone

The half-life of metribuzin applied to a bare soil surface was calculated to be 3–7 d over four field tests. An artificial cover erected after application or a shallow incorporation increased the half-life of metribuzin approximately 2.5- to 3-fold. Leaching out of the 0- to 5-cm-deep sampling zone could not account for loss of metribuzin. It was concluded that metribuzin persistence may be affected by volatility and/or photodecomposition losses under field conditions, especially shortly after application. Key words: Metribuzin half-life, volatility, photodecomposition, row width

Effects of depth and time of sowing on emergence of Danthonia richardsonii Cashmore and Danthonia linkii Kunth

1993 ◽  
Vol 44 (6) ◽  
pp. 1311 ◽  
Author(s):  
GM Lodge ◽  
AJ Schipp
Keyword(s):  
New South ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Maximum Temperature ◽  
Sowing Time ◽  
Sand Mixture ◽  
South Wales ◽  
Seed Field ◽  
Dry Conditions ◽  
Soil Temperatures

Two experiments examined the effects of sowing time and depth (surface and 10, 25, 50 mm) on emergence of Danthonia richardsonii Cashmore and Danthonia linkii Kunth. Experiment 1 was conducted from January to December 1990 on a loam/sand mixture in boxes. Emergence was highest in both species for seeds sown onto the soil surface in summer and autumn (P < 0.05). Sowing at any depth at any time of the year, or surface sowing in winter and spring, markedly reduced emergence. Experiment 2 was conducted in the field at Tamworth, northern New South Wales from September 1991 to August 1992, on a red brown earth and a black earth. This study confirmed that emergence in both species was highest from surface sown seed. Field emergence was lowest in winter, but in contrast to experiment 1, it was higher in spring, particularly on the black earth. Seedling emergence appeared to be related to mean maximum temperature, decreasing in winter as it declined below 20�C, and increasing in spring when it was greater than 23�C. Differences in seed weight were reflected in emergence of D. richardsonii and D. linkii in experiment 1. Similar emergence was recorded for the loamlsand mixture and sand, indicating that there was little effect of texture. Phalaris aquatica L. cv. Sirosa surface sown in December had lower emergence ( P < 0.05) than both Danthonia spp., but emergence of this larger seeded cultivar was higher at depths of 10 and 25 mm. Laboratory studies to determine reasons for the low emergence of D. richardsonii and D. linkii from depth, indicated that neither had an obligate light requirement for germination. Depth, however, reduced germination (P < 0.05) compared with surface sowing of seed. Seedlings at depth also were observed to have slower rates of shoot and root elongation. In the field, the most successful establishments of D. richardsonii and D. linkii seedlings are likely to occur from surface sowings in April and May. Sowing in spring may also be possible if mean maximum soil temperatures exceed 23�C, and seedlings can establish before the onset of hot, dry conditions in summer.

Soil water storage in a semi-arid Eucalyptus populnea woodland invaded by woody shrubs, and the effects of shrub clearing and tree ringbarking.

1984 ◽  
Vol 6 (2) ◽  
pp. 75 ◽  
Author(s):  
GG Johns
Keyword(s):  
Soil Water ◽  
Water Storage ◽  
Soil Surface ◽  
Bare Soil ◽  
Arid Environment ◽  
Soil Water Storage ◽  
Water Response ◽  
Shrub Clearing ◽  
Eucalyptus Populnea ◽  
Semi Arid

Soil water was monitored over a six year period in an intact shrub invaded semi-arid Elrcalyptlts popztlrlea woodland (control) and on areas which had been treated by either shrub-clearing, or by ringbarking of trees and shrub-clearing. Measurements were made under both the shrubby thicket areas near the eucalypt, and the sparsely shrubbed interthicket areas more distant from the trees. Average soil water storage over the six years for all treatments was only 26 nun. Much of this water was stored in the upper 500 Inm of the profile and hence was susceptible to direct evaporation from the usually bare soil surface. In the intact n.oodland and following wet weather, significantly more soil water was stored under thickets than under the interthicket areas. With the return of dry weather this cxtra soil water was rapidly depleted, and thicket soils would often become drier than interthicket soils. After pro- longed dry weather, soil matric potentials of - 10 to -1 2 MPa were recorded at a depth of 500 mm. Matric potentials by this time were least negative under thickets. Shrub clearing without rinpbarking increased thicket and interthicket soil water storage by 17% and 2396 respectively. The ring- barking and shrub clearing treatment increased thicket profile storage more than that of the interthicket (81% and 64% respectively). The effect of ringbarkinp lvas often pronounced at a distance of 25 rn from the tree. The contrasting soil water response to the two treatments indicated that in this semi-arid environment only a relatively srnaU change in soil water balance may accrue from incomplete clearing. The ren~oval of both shrubs and trees is probably necessary to make a large difference to soil water storage.

scholarly journals The importance of plant water use on evapotranspiration covers in semi-arid Australia

2012 ◽  
Vol 9 (10) ◽  
pp. 11911-11940 ◽  
Author(s):  
A. Schneider ◽  
S. Arnold ◽  
D. Doley ◽  
D. R. Mulligan ◽  
T. Baumgartl
Keyword(s):  
Plant Species ◽  
Mine Waste ◽  
Vapour Pressure Deficit ◽  
Soil Surface ◽  
Bare Soil ◽  
Vegetation Coverage ◽  
Plant Water Use ◽  
Unsaturated Hydraulic Conductivity ◽  
Cover Systems ◽  
Semi Arid

Abstract. We estimated the evapotranspiration (ET) for an area vegetated with characteristic semi-arid native Australian plant species on ET mine waste cover systems. These systems aim to minimise drainage into underlying hazardous wastes by maximising evaporation (E) from the soil surface and transpiration from vegetation. An open top chamber was used to measure diurnal and daily ET of two plant species – Senna artemisioides (silver cassia) and Sclerolaena birchii (galvanised burr) – after a simulated rainfall event, as well as E from bare soil. Both ET and E decreased with increasing time after initial watering. Different temporal patterns were observed for daily ET from the two plant species and E from bare soil, revealing Senna artemisioides as intensive and Sclerolaena birchii as extensive water exploiters. A strong positive linear relationship was identified between ET (and E), and the atmospheric water demand represented by the vapour pressure deficit. The relationship always was more pronounced in the morning than in the afternoon, indicating a diminishing water supply from the soil associated with a declining unsaturated hydraulic conductivity of the soil in the afternoon. The slopes of the regression lines were steepest for Senna artemisioides, reflecting its intensive water-exploiting characteristics. We used the derived estimates of ET and E to predict the effect of species composition on plot ET in relation to total vegetation coverage. Although both species proved suitable for an operational ET cover system, vegetation coverage should exceed at least 50% in order to markedly influence plot ET, a value which is likely to be unsustainable in semi-arid climates.

scholarly journals Soil Texture and Planting Depth Affect Large Crabgrass (Digitaria sanguinalis), Virginia buttonweed (Diodia virginiana), and Cock’s-comb Kyllinga (Kyllinga squamulata) Emergence

HortScience ◽  
2013 ◽  
Vol 48 (5) ◽  
pp. 633-636 ◽  
Author(s):  
Jared A. Hoyle ◽  
J. Scott McElroy ◽  
Elizabeth A. Guertal
Keyword(s):  
Soil Texture ◽  
Soil Surface ◽  
Loamy Sand ◽  
Clay Loam ◽  
Weed Species ◽  
Planting Depth ◽  
Virginia Buttonweed ◽  
Water Holding ◽  
Weed Emergence ◽  
Large Crabgrass

Greenhouse studies were conducted to explore soil texture and planting depth effects on emergence of large crabgrass, Virginia buttonweed, and cock’s-comb kyllinga. Soil textures examined were sand, loamy sand, and clay loam with planting depths of 0, 0.5, 1, 2, 4, 6, and 8 cm. Percent emergence was standardized relative to surface emergence to allow comparisons among tested weed species. The three-way interaction of weed species, planting depth, and soil texture was never significant for emergence. Significant interactions occurred between weed species and soil texture, weed species and planting depth, and soil texture and planting depth. For all weed species and soil textures, emergence decreased as planting depth increased with the greatest percent emergence at the soil surface. The planting depth at which weed emergence was decreased 50% [relative to surface emergence (D50)] was predicted by regression analysis. Large crabgrass emerged from deepest depths (8 cm) followed by Virginia buttonweed (6 cm) and cock’s-comb kyllinga (2 cm). Large crabgrass, Virginia buttonweed, and cock’s-comb kyllinga D50 occurred at 3.9, 1.1, and 0.8 cm, respectively. Sand, loamy sand, and clay loam D50 occurred at 0.9, 2.3, and 1.9 cm, respectively, with D50 higher in the soils with greater water-holding capacity.

REHABILITATION OF THE SOIL STRUCTURE WITH THE DIRECT SOWING IN THE STAVROPOL REGION DRY ZONE

1970 ◽  
pp. 27-31
Author(s):  
V. P. Belobrov ◽  
S. А. Yudin ◽  
V. А. Kholodov ◽  
N. V. Yaroslavtseva ◽  
N. R. Ermolaev ◽  
...  
Keyword(s):  
Cover Crops ◽  
Soil Surface ◽  
Plant Residues ◽  
Agricultural Technologies ◽  
Row Crops ◽  
Dry Zone ◽  
Erosion Effect ◽  
Stavropol Region ◽  
Dry Conditions ◽  
Direct Sowing

The influence of different systems of soil cultivation is considered - traditional (recommended) technology and direct sowing, which is increasingly used under dry conditions of the region. The rehabilitation of the degraded southern chernozems and dark chestnut soils structure during 13 and 7 years of direct sowing, respectively, has not been established. It takes much longer to rehabilitation the aggregate state of soils, which is currently in a critical condition of the content of aggregates> 10 mm in size and the sum of agronomically valuable aggregates. The soils under 60-year treeline, as a control, showed a satisfactory range of aggregates, which indicates a high degree of soil degradation in the past and a long period of their recovery time. The effectiveness of direct sowing usage in the cultivation of a wider range of grain and row crops (winter wheat, sunflower, peas, chickpeas, rapeseed, buckwheat, corn) is due to the peculiarities of agricultural technologies. Abandoning of naked fallows and soil treatments with the simultaneous use of plant residues and cover crops on the soil surface between the harvest and sowing of winter crops provides an anti-erosion effect and, as a consequence, a decrease in physical evaporation, an increase in moisture and biota reserves, an increase in microbiological processes, which are noted in the form trends in improving the agrochemical and agrophysical properties of soils.

Comparison of oxidoreductive enzyme activities in three coal tar creosote-contaminated soils

Soil Research ◽  
2019 ◽  
Vol 57 (8) ◽  
pp. 814 ◽  
Author(s):  
Arkadiusz Telesiński ◽  
Teresa Krzyśko-Łupicka ◽  
Krystyna Cybulska ◽  
Barbara Pawłowska ◽  
Robert Biczak ◽  
...  
Keyword(s):  
Contaminated Soils ◽  
Sandy Loam ◽  
Coal Tar ◽  
Loamy Sand ◽  
Clay Loam ◽  
Oxidoreductase Activity ◽  
Sandy Clay Loam ◽  
Sandy Clay ◽  
Polycyclic Aromatic ◽  
Negative Effect

This study used laboratory experiments to compare the effects of coal tar creosote on the activity of oxidoreductive enzymes in sandy loam, loamy sand and sandy clay loam soils. Different amounts of coal tar creosote were added to soil samples as follows: 0 (control), 2, 10 or 50 g kg–1 dry matter. The activity of soil dehydrogenases (DHAs), o-diphenol oxidase (o-DPO), catalase (CAT), nitrate reductase (NR) and peroxidases (POX) was determined. Contamination of soil with coal tar creosote affected oxidoreductase activity. Oxidoreductive enzyme activity following soil contamination with coal tar creosote was in the following order: DHAs &gt; CAT &gt; NR &gt; POX &gt; o-DPO in loamy sand and in sandy loam; and DHAs &gt; POX &gt; CAT &gt; NR &gt; o-DPO in sandy clay loam. The index of soil oxidoreductive activity (IOx) introduced in this study confirms the negative effect of coal tar creosote on oxidoreductase activity in soil. DHAs were the most sensitive to the contamination of soil with coal tar creosote. Moreover, the greatest changes in oxidoreductase activities were observed in loamy sand. Knowledge of the mechanism underlying the effects of coal tar creosote on oxidoreductive processes may enable development of a method for the bioremediation of polycyclic aromatic hydrocarbon-contaminated soils.

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