Edaphic Factors Affecting the Activity of Terbutryn

Weed Science ◽  
1972 ◽  
Vol 20 (1) ◽  
pp. 28-30 ◽  
Author(s):  
L. F. Figuerola ◽  
W. R. Furtick
Keyword(s):  
Winter Wheat ◽  
Soil Temperature ◽  
Water Content ◽  
Root System ◽  
Sandy Soils ◽  
Field Capacity ◽  
Edaphic Factors ◽  
Factors Affecting ◽  
High Soil ◽  
High Soil Temperature

Injury from 2-(tert-butylamino)-4-(ethylamino)-6-(methylthio)-s-triazine (terbutryn) was greater on winter wheat(Triticum aestivunVill. ‘Host’) grown at high soil temperature than on that grown at low soil temperature. The injury was more severe when the herbicide was incorporated into the soil close to the root system. In postemergence applications 2-week-old plants were more susceptible to terbutryn injury than 4-week-old plants. High soil water content (75% to 100% of field capacity) favored the uptake of terbutryn through the root system. Terbutryn caused greatest damage under high transpiration rates and in sandy soils.

EFFECT OF SOIL WATER CONTENT ON THE WINTER SURVIVAL OF WINTER WHEAT, RYE AND TRITICALE

1990 ◽  
Vol 70 (3) ◽  
pp. 667-675 ◽  
Author(s):  
YVES CLOUTIER ◽  
ANDRÉ COMEAU ◽  
MICHÈLE BERNIER-CARDOU ◽  
DENIS A. ANGERS
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Winter Wheat ◽  
Soil Temperature ◽  
Water Content ◽  
Field Capacity ◽  
Winter Rye ◽  
Winter Cereal ◽  
Ice Encasement ◽  
Wilting Point

A field study was conducted to determine the effect of soil moisture on the survival of three winter cereal species. Treatments were applied by watering and weighing the soil to the desired water content. Plants were overwintered in a plastic greenhouse in 1988 and in 1989, in which the air was not heated, but the soil was slightly heated on cold days to avoid very low temperatures. Soil temperature did not fall below −16 °C. Soil temperature rate of change was dependent on moisture content. Puma winter rye and Otrastajuskaja 38 winter wheat were the hardiest, followed by Wintri winter triticale and Norstar winter wheat. Harus winter wheat was less hardy, and Champlein winter wheat was totally winter killed. The highest survival rate was obtained at moderate to high soil moisture content. The soil contained 44% water at field capacity and 19% at the wilting point. The drier the soil in the range 13–23%, the greater the mortality indicating a negative effect of long-term drought on plant survival. By contrast, the wettest treatments: 58% and partial ice encasement, did not reduce survival. However, total ice encasement killed 50–75% of the plants depending on the cultivar. There was an interaction between cultivar and moisture treatment. The data suggest that a moisture level intermediate between the wilting point and field capacity should be sought in studies of cold hardiness.Key words: Moisture, winterkill, ice encasement, wheat, rye, triticale

Properties and Management of Allophanic Soils

2003 ◽  
Author(s):  
Anthony S. R. Juo ◽  
Kathrin Franzluebbers
Keyword(s):  
Water Content ◽  
Bulk Density ◽  
Water Retention ◽  
Field Capacity ◽  
High Water ◽  
Soil Porosity ◽  
Water Retention Capacity ◽  
Soil Taxonomy ◽  
Retention Capacity ◽  
High Soil

Allophanic soils are dark-colored young soils derived mainly from volcanic ash. These soils typically have a low bulk density (< 0.9 Mg/m3), a high water retention capacity (100% by weight at field capacity), and contain predominantly allophanes, imogolite, halloysite, and amorphous Al silicates in the clay fraction. These soils are found in small, restricted areas with volcanic activity. Worldwide, there are about 120 million ha of allophanic soils, which is about 1% of the Earth's ice-free land surface. In tropical regions, allophanic soils are among the most productive and intensively used agricultural soils. They occur in the Philippines, Indonesia, Papua New Guinea, the Caribbean and South Pacific islands, East Africa, Central America, and the Andean rim of South America. Allophanic soils are primarily Andisols and andic Inceptisols, Entisols, Mollisols, and Alfisols according to the Soil Taxonomy classification. Allophanic soils generally have a dark-colored surface soil, slippery or greasy consistency, a predominantly crumb and granular structure, and a low bulk density ranging from 0.3 to 0.8 Mg/m3. Although allophanic soils are apparently well-drained, they still have a very high water content many days after rain. When the soil is pressed between fingers, it gives a plastic, greasy, but non-sticky sensation of a silty or loamy texture. When dry, the soil loses its greasiness and becomes friable and powdery. The low bulk density of allophanic soils is closely related to the high soil porosity. For example, moderately weathered allophanic soils typically have a total porosity of 78%, with macro-, meso-, and micropores occupying 13%, 33%, and 32%, respectively. Water retained in the mesopores is readily available for plant uptake. Water retained in the micropores is held strongly by soil particles and is not readily available for plant use. The macropores provide soil aeration and facilitate water infiltration. The high water retention capacity is also associated with the high soil porosity. In allophanic soils formed under a humid climate, especially those containing large amounts of allophane, the moisture content at field capacity can be as high as 300%, calculated on a weight basis. Such extremely high values of water content seem misleading.

Coping with soil and climatic hazards during crop establishment in the semi-arid tropics

1996 ◽  
Vol 36 (8) ◽  
pp. 971 ◽  
Author(s):  
DG Abrecht ◽  
KL Bristow
Keyword(s):  
Soil Temperature ◽  
Water Deficit ◽  
Weather Data ◽  
Simulation Studies ◽  
Management Options ◽  
Crop Species ◽  
Crop Establishment ◽  
High Soil ◽  
High Soil Temperature ◽  
Semi Arid

Climatic induced hazards (e.g. water deficit, high soil temperature and high soil strength) that adversely affect seedling emergence and establishment of annual crops on red earth soils (Kandsols) at Katherine in the Daly basin of the Northern Territory are reviewed and results of some recent simulation studies and experiments are presented. Simulation studies, using 100 years of historical weather data, have shown that maize and sorghum density at Katherine is rarely reduced by water deficit during crop establishment. However, the median number of days between 1 December and 20 January during which seedlings may be exposed to damagingly high soil temperature (>55�C between 2 and 7 days after sowing) was 5.5, out of an estimated 21 days suitable for sowing. While the exposure of a crop to inclement conditions during establishment may have immediate and dramatic effects on the mortality of pre-emergent and post-emergent seedlings, there may also be longer-term and less evident adverse effects on crop growth and development. The responses of developing seedlings to inclement conditions following sowing are described and management options (eg adjusting planting dates, changing crop species, changing seedbed configurations, using surface mulch) for the amelioration of the seedbed environment are discussed. Of the possible management options for ameliorating adverse seedbed conditions during crop establishment in the semi-arid tropics (SAT), it appears that the best practice is to maintain a soil surface cover (mulch) in close proximity to the emerging seedlings. The presence of surface mulch extends the window of opportunity for establishing crops by slowing soil drying, delaying the onset of high soil temperatures and high soil impedance, and by improving the availability of water to the young seedlings at this critical stage.

scholarly journals Changes in Fatty Acid Composition and Saturation in Leaves and Roots of Creeping Bentgrass Exposed to High Soil Temperature

2004 ◽  
Vol 129 (6) ◽  
pp. 795-801 ◽  
Author(s):  
Xiaozhong Liu ◽  
Bingru Huang
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Soil Temperature ◽  
Acid Composition ◽  
Creeping Bentgrass ◽  
High Soil ◽  
Leaves And Roots ◽  
High Soil Temperature

Previous studies found that high soil temperature is more detrimental than high air temperature for the growth of creeping bentgrass (Agrostis palustris L.). The objective of the study was to investigate changes in fatty acid composition and saturation levels in leaves and roots for creeping bentgrass exposed to high soil temperature. Shoots and roots of `Penncross' plants were subjected to a differential air/soil temperature of 20/35 °C in a growth chamber. Soil temperature was controlled at 35 °C using an immersion circulating heater in water bath. Shoot injury induced by high soil temperature was evaluated by measuring level of lipid peroxidation expressed as malonyldialdehyde (MDA) content, chlorophyll content, and photochemical efficiency (Fv/Fm) of leaves. MDA content increased while chlorophyll content and Fv/Fm decreased at high soil temperature. The content of total fatty acids and different species of fatty acids were analyzed in both leaves and roots. Total fatty acid content in leaves increased initially at 5 days of high soil temperature and then decreased at 15 days, while total fatty acid content in roots decreased, beginning at 5 days. Linolenic acid was the major fatty acid in leaves and linoleic acid and palmitic acid were the major fatty acids in roots of creeping bentgrass. Leaf content of all fatty acid components except oleic acid increased initially and then decreased at high soil temperature. Root content of all fatty acid components except palmitoleic acid and oleic acid decreased, beginning at 5 d of high soil temperature. Oleic acid in leaves and palmitoleic and oleic acid in roots did not change during the entire experimental period. Leaf content of saturated fatty acids and unsaturated fatty acids increased during the first 5 to 10 days of high soil temperature and decreased at 15 and 25 days, respectively. Root content of saturated fatty acids and unsaturated fatty acids decreased beginning at 5 days of high soil temperature. Double bond index decreased in both leaves and roots. High soil temperature induced changes in fatty acid composition and saturation levels in leaves and roots, and this could be associated with physiological damages in leaves even though only roots were exposed to high temperature.

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