Soil moisture changes under grassland as measured by neutron probe in midland England

1983 ◽  
Vol 101 (2) ◽  
pp. 481-493 ◽  
Author(s):  
D. G. M. Hall ◽  
R. J. A. Jones
Keyword(s):  
Soil Moisture ◽  
Meteorological Data ◽  
The Other ◽  
Undisturbed Soil ◽  
Available Water ◽  
Neutron Probe ◽  
Moisture Regimes ◽  
Moisture Extraction ◽  
Probe Measurements

SUMMARYThe moisture regimes of three soils under grassland in midland England were investigated using a neutron probe moisture meter from May 1976 until August 1978. The main aim of the experiments was to compare the differential build-up of moisture deficits in the three soils of different texture by monitoring moisture extraction down to 1·50 m depth. The moisture deficits measured by neutron probe were also compared with those predicted from meteorological data using the Grindley (1970) model.The sandy (Newport) soil dried out more quickly and more completely than the clayey (Worcester) or fine loamy over clayey stagnogley (Salop) soil, particularly in 1976. This reflected the fact that the former had the smallest available water, most of which is held at low suctions, whereas the Salop soil, with much of its water bound at high suctions, continued to supply small amounts to plant roots when the available water in both the other soils was exhausted.The soil moisture deficits determined from neutron probe measurements were much larger at all three sites in 1976 than in the following 2 years. The deficit increased more slowly in the Salop soil than in the other two in the early part of 1976 and more slowly than predicted by the Grindley model. However, during July and August of the same year, deficits in the Salop and Worcester soils increased more quickly than predicted and maximum deficits were in proportion to the available water capacities of the three soils. Deficits in 1978 were very small (less than 70 mm) in all three soils because of the wetter weather.The results of this neutron probe study clearly show that the patterns of moisture extraction and the maximum deficits which developed in the three soils, particularly in 1976, are closely related to their physical properties, as determined from undisturbed soil cores.

Soil Moisture Deficits in South-Central Sweden

1989 ◽  
Vol 20 (2) ◽  
pp. 109-122 ◽  
Author(s):  
Lotta Andersson
Keyword(s):  
Soil Moisture ◽  
Field Capacity ◽  
Interannual Variations ◽  
Neutron Probe ◽  
South Central ◽  
Normal Ranges ◽  
Moisture Fluxes ◽  
In The Beginning ◽  
Probe Measurements ◽  
Different Parts

Some commonly used assumptions about climatically induced soil moisture fluxes within years and between different parts of a region were challenged with the help of a conceptual soil moisture model. The model was optimised against neutron probe measurements from forest and grassland sites. Five 10 yrs and one 105 yrs long climatic records, from the province of Östergötland, situated in south-central Sweden, were used as driving variables. It was concluded that some of the tested assumptions should not be taken for granted. Among these were the beliefs that interannual variations of soil moisture contents can be neglected in the beginning of the hydrological year and that soils usually are filled up to field capacity after the autumn recharge. The calculated climatic induced dryness was estimated to be rather insensitive to the choice of climatic stations within the region. Monthly ranges of soil moisture deficits (1883-1987) were shown to be skewed and it is therefore recommended to use medians and standard deviations in statistical analyses of “normal” ranges of soil moisture deficits.

scholarly journals A COMPARISON OF TWO METHODS FOR DETERMINING THE EVAPOTRANSPIRATION AND DRAINAGE COMPONENTS OF THE SOIL WATER BALANCE

1987 ◽  
Vol 67 (1) ◽  
pp. 43-54 ◽  
Author(s):  
C. P. MAULÉ ◽  
D. S. CHANASYK
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Gradient Method ◽  
Field Capacity ◽  
The Other ◽  
Soil Water Balance ◽  
Moisture Loss ◽  
Moisture Extraction ◽  
Soil Moisture Status ◽  
Capacity Method

Two simple techniques for separating soil moisture loss into drainage and evapotranspiration for cropped conditions were compared. The study was conducted during May through September 1983 at Ellerslie, Alberta. One technique, the field capacity method, utilized soil tension at − 4 kPa to demarcate the cessation of drainage; the other technique, the gradient method, utilized changes in soil moisture status relative to fallow conditions, to mark the onset of moisture extraction by roots. Both methods estimated similar amounts of drainage and evapotranspiration for the barley plots. Application and thus proper evaluation of these two methods were limited as more than 83% of the total drainage occurred during a 3-wk period in which only the Penman method for estimating evapotranspiration could be used. Key words: Water balance, drainage, evapotranspiration, field capacity method, gradient method

Are mesic communities less drought-resistant? A study on moisture relationships in dry sclerophyll forest at Inglewood, South Australia

1962 ◽  
Vol 10 (2) ◽  
pp. 106 ◽  
Author(s):  
HA Martin ◽  
RL Specht
Keyword(s):  
Soil Moisture ◽  
South Australia ◽  
Seedling Stage ◽  
The Other ◽  
Drought Period ◽  
Available Water ◽  
Sclerophyll Forest ◽  
Characteristic Species ◽  
Drought Resistant ◽  
Soil Moisture Reserves

Soil moisture changes under two adjacent forest associations (Eucalyptus obliqua association in the more mesic environment, E. elaeophora association in the more xeric sites) were recorded in the Inglewood area of the Mount Lofty Ranges, South Australia. The evidence indicated that the E. obliqua association had a higher index of evapotranspiration (Itr = Etr/Ew0.75) over most of the range of available water (soil moisture + rainfall) than the E. elaeophora association. The more mesic association consequently completely exhausted the stored soil moisture during periods of low rainfall and had to survive a drought period every year. The other association did not deplete the soil moisture reserves and in an average year, no drought occurred. Characteristic species of the more mesic association must be able to survive this drought period especially during the seedling stage.

scholarly journals Effect of Soil Moisture Management on the Development of Potato mop-top virus-Induced Tuber Necrosis

Plant Disease ◽  
2016 ◽  
Vol 100 (2) ◽  
pp. 418-423 ◽  
Author(s):  
O. Domfeh ◽  
N. C. Gudmestad
Keyword(s):  
United States ◽  
Soil Moisture ◽  
The United States ◽  
The Other ◽  
Powdery Scab ◽  
Moisture Regime ◽  
Gall Formation ◽  
Tuber Necrosis ◽  
Moisture Regimes ◽  
Potato Mop Top Virus

Potato mop-top virus (PMTV), transmitted by Spongospora subterranea f. sp. subterranea, the causal agent of powdery scab in potato, has become one of the most important tuber necrosis viruses in the United States. The virus has been confirmed in six major potato-producing states in the United States since its identification in 2003. Currently, no control methods are available for PMTV or its vector. A growth-chamber experiment was conducted to investigate the potential of using moisture regime adjustments to manage tuber necrosis caused by PMTV. Two commercial potato cultivars with varying levels of sensitivity to PMTV, ‘Dakota Crisp’ and ‘Ivory Crisp’, were grown in soil obtained from a PMTV-infested field. Over the course of the plant growth cycle, plants of each cultivar were subjected to moisture regimes of wet throughout (WT), wet early/dry late (WEDL), dry early/wet late (DEWL), and dry throughout (DT). Soil moisture levels of 90 and 60% field capacity were considered wet and dry, respectively, while early and late refer to first and last 50 days after planting, respectively. Results of visual assessment conducted 3 months after storage showed significant differences in root gall formation, powdery scab on tubers, and PMTV tuber necrosis among moisture regimes. Powdery scab incidence was significantly higher in the WT and DEWL regimes than WEDL and DT regimes. PMTV tuber necrosis incidence did not differ between the WT and DEWL or between DEWL and WEDL moisture regimes. However, PMTV tuber necrosis incidence was significantly higher in WT than under WEDL and DT regimes. The incidence of PMTV tuber necrosis was significantly lower in the DT regime than in the other three moisture regimes. Severity of PMTV tuber necrosis was significantly higher in the WT than the other regimes, which did not differ statistically among themselves. A significant interaction was found between cultivar and moisture regime on root gall formation, with the highest number of galls found on Ivory Crisp grown in the WT moisture regime. A significant correlation was found between powdery scab incidence on tubers and PMTV-induced tuber necrosis incidence. The results of this study provide useful basic information upon which further work can be built for formulating irrigation management schemes that have the potential of reducing the likelihood of powdery scab infection and PMTV-induced tuber necrosis development in potato.

Analysis of Water Budgets in Semi-Arid Lands from Soil Water Records

1995 ◽  
Vol 31 (2) ◽  
pp. 131-150 ◽  
Author(s):  
C. J. Pilbeam ◽  
C. C. Daamen ◽  
L. P. Simmonds
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Surface ◽  
Total Evaporation ◽  
Growing Seasons ◽  
Neutron Probe ◽  
Unsaturated Hydraulic Conductivity ◽  
Probe Measurements

SUMMARYFour components of the water budget for a growing season, namely storage, drainage, transpiration and direct evaporation from the soil surface, were estimated using a suite of techniques. The only data requirements were rainfall, neutron probe measurements of soil water content and microlysimeter measurements of evaporation from the soil. Data from four growing seasons at Kiboko, Kenya between 1990 and 1992 were used to provide examples of the estimations. Drainage was significant (about 10% of rainfall) in one season only; in the other seasons, total evaporation comprised at least 95% of the seasonal rainfall.Drainage was determined using a relationship between unsaturated hydraulic conductivity and soil water content that was determined during the early part of the rainy season when water was penetrating to depth. This analysis made it possible to identify a critical water content at the base of the soil profile, above which there would be significant drainage. However, there are large errors associated with estimation of drainage if significant drainage occurs.Estimates of direct evaporation from the soil surface were used as the basis of distinguishing transpiration from total evaporation. Microlysimetry was used to develop a model of evaporation from these sandy soils, which was based on the assumption that the evaporation from the soil surface following heavy rainfall is a unique function of time from rainfall, and little influenced by the presence of a sparse crop. This method showed that direct evaporation from the soil accounted for between 70 and 85% of total evaporation in seasons when total evaporation estimates ranged from 150 to 325 mm.

Moisture use characteristics of sugarcane genotypes under different available soil moisture regimes in alluvial entisols

1988 ◽  
Vol 110 (1) ◽  
pp. 5-11 ◽  
Author(s):  
R. L. Yadav ◽  
S. R. Prasad
Keyword(s):  
Soil Moisture ◽  
Sandy Loam ◽  
Field Trials ◽  
The Other ◽  
Cane Yield ◽  
Area Index ◽  
Moisture Regimes ◽  
Available Soil Moisture ◽  
Moisture Percentage ◽  
Loam Soil

SummaryTo study the response of three sugarcane genotypes (CO 1148, COJ 64 and CO 1158) to variations in moisture availability in sandy loam soil (entisol), field trials were conductedat Lucknow (26·5° N, 80·5° E, 120 m altitude) during 1984–5 and 1985–6. Three moisture regimes, i.e. wet (irrigation at 75% available soil moisture (ASM)), moist (irrigation at 50% ASM) and dry (irrigation at 25% ASM) were maintained during the pre-monsoon (before June) period in spring-planted (February-March) sugarcane. During the summer months (until June)the variety CO 1148 had a significantly greater sheath moisture percentage than COJ 64 and CO 1158. Under stress conditions, leaf area index was reduced most in COJ 64 and least in CO 1148.Underground shoots and roots grew faster in CO 1148, and the growth of above-ground parts was quicker in COJ 64. Compared with the 75% ASM regime the reduction in cane yield in the 25% regime was more in COJ 64 and CO 1158 (31 t/ha) than in CO 1148 (12 t/ha). The water requirement of COJ 64 was greater than that of the other varieties. Therefore, for higheryields COJ 64 needed frequent irrigation whereas CO 1148 performed well even under moderate irrigation (50% ASM).

scholarly journals Soil Moisture Deficits in South-Central Sweden

1989 ◽  
Vol 20 (2) ◽  
pp. 123-136 ◽  
Author(s):  
Lotta Andersson
Keyword(s):  
Soil Moisture ◽  
Water Deficit Stress ◽  
Neutron Probe ◽  
South Central ◽  
Time Period ◽  
Precipitation Record ◽  
Moisture Fluxes ◽  
Calculated Risk ◽  
Climatic Record ◽  
Probe Measurements

Soil moisture fluxes in forest and grassland soils were analyzed for a rather dry region in south-central Sweden in order to assess climatologically induced dryness variability. Time series were constructed, using a conceptual soil moisture model, optimised against neutron probe measurements. Data in a 105 yrs climatic record were used as driving variables. A method to deal with the inhomogeneity of the long precipitation record was developed. It was shown that large variations existed, not only between the median values, but even more for the range of the quartiles, depending on the choice of time period. The statistical distribution varied significantly even between the two 50 yrs series, where the latter showed larger fluctuations around the median caused by a trend towards increased amount of high summer soil moisture deficits. Estimates of the interannual variations of possible water deficit stress on vegetation were made. The only time (1883-1987) when there was a calculated risk for drought stress on the forest during four consecutive years was during 1973-1976. This might have increased the vulnerability to the threats of acidification. It was concluded that the use of standard- and return periods can hardly be justified as no sets of average conditions exists.

Quality and morphological characteristics of alfalfa as affected by soil moisture, pH and phosphorus fertilization

1992 ◽  
Vol 72 (1) ◽  
pp. 147-162 ◽  
Author(s):  
Hélène V. Petit ◽  
A. R. Pesant ◽  
G. M. Barnett ◽  
W. N. Mason ◽  
J. L. Dionne
Keyword(s):  
Soil Moisture ◽  
Soil Ph ◽  
Plant Morphology ◽  
Field Capacity ◽  
Phosphorus Fertilization ◽  
Moisture Regime ◽  
Available Water ◽  
Soil Moisture Regime ◽  
Temperature Regimes ◽  
Moisture Regimes

Alfalfa (Medicago sativa L. ’Saranac’) was grown in a greenhouse on Ste-Rosalie clay and Danby gravelly sandy loam to determine the effects of phosphorus fertilization, air temperature, soil moisture regime and soil pH on chemical composition and plant morphology. The following treatments were applied in factorial combination: three moisture regimes (1, semi-dry, with soil moisture between field capacity or 100% of available water and wilting point or 0% of available water; 2, optimal, between field capacity and 70% of available water; 3, wet, between saturation point and field capacity), three rates of phosphorus in the form of disodium phosphate (0, 12.5 and 25.0 P kg−1 of dry soil) and three soil pH levels (natural, near 5.4, 6.5 and 7.5). Half the alfalfa was grown in a warm greenhouse section with a minimum daytime temperature of 25 °C and 19 °C at night and the other half was grown in a cool section with a daytime minimum of 15 °C and 9 °C at night. Quality of alfalfa was generally improved by water deficit as shown by decreased concentrations of acid detergent fiber (ADF) and acid detergent lignin (ADL) and increased concentrations of crude protein (CP). Cold temperatures decreased ADF content which indicates that quality of alfalfa grown under cold compared to warm temperature regimes is better. Phosphorus fertilization seemed to have more effects on plant morphology and quality under cold than warm temperature regimes. In general, concentrations of CP, ADF and ADL, stem length, leaf area and the number of stems increased in parallel with soil pH. The data indicate that low temperature and low soil moisture regimes were generally associated with higher quality alfalfa than were high temperature and wet soil moisture regimes.Key words: Alfalfa, soil moisture regime, air temperature, phosphorus fertilization, soil pH

EFFETS DES RÉGIMES THERMIQUES ET HYDRIQUES, DES pH DU SOL ET DE LA FUMURE PHOSPHATÉE SUR LA RÉPONSE AU PHOSPHORE DE LA LUZERNE

1989 ◽  
Vol 69 (4) ◽  
pp. 1149-1163 ◽  
Author(s):  
J. L. DIONNE ◽  
A. R. PESANT ◽  
G. M. BARNETT ◽  
W. N. MASON
Keyword(s):  
Soil Moisture ◽  
Soil Ph ◽  
Phosphorus Uptake ◽  
Yield Response ◽  
Moisture Regime ◽  
Warm Temperature ◽  
Available Water ◽  
Soil Moisture Regime ◽  
Moisture Regimes ◽  
Phosphorus Application

The objectives of this study were to determine the effects of phosphorus application, air temperature, soil moisture regime and soil pH on the yield response of, and soil phosphorus availability to, alfalfa (Medicago sativa L ’Saranac’). The following treatments were used in factorial combination: three moisture regimes: (1) semi-dry, with soil moisture between FC (100% of available water or field capacity) and WP (0% of available water or wilting point), (2) optimal, between FC and 70% of available water, (3) wet, between saturation point and FC; three rates of phosphorus in the form of disodium phosphate (0, 12.5 and 25.0 P kg−1 of dry soil; and three soil pH levels: original (5.2 or 5.7), 6.5 and 7.5. Half of the alfalfa was grown in a warm greenhouse section with a minimum daytime temperature of 25 °C and 19 °C at night and the other half in a cool section with a daytime minimum of 15 °C and 9 °C at night. Although shoot yields were higher under warm than under cool conditions, yield response to phosphorus was greater under cool than warm growing conditions. Yield increases due to phosphorus were linear under optimum and wet soil moisture regimes and nonsignificant under the semi-dry regime. Phosphorus application increased root weight by 18% under the cool regime compared to 14% in the warm greenhouse. Phosphorus uptake by alfalfa increased with increasing rates of soil-applied P, except in semi-dry soils at warm temperature, where no effect of P on P uptake was recorded. Phosphorus uptake increased significantly with soil pH and was higher under warm temperature and optimal water regime.Key words: Phosphorus fertilization, available phosphorus, alfalfa, soil moisture regime, air temperature, phosphorus uptake

Effect of Wetting/Drying Cycles on Dissipation Patterns of Bioavailable Imazaquin

Weed Science ◽  
1996 ◽  
Vol 44 (2) ◽  
pp. 380-382 ◽  
Author(s):  
Todd A. Baughman ◽  
David R. Shaw
Keyword(s):  
Soil Moisture ◽  
Half Life ◽  
Field Capacity ◽  
The Other ◽  
Actual Concentration ◽  
Greenhouse Experiments ◽  
Moisture Regimes ◽  
Adsorption Desorption ◽  
Over Time

Greenhouse experiments determined differences in imazaquin bioavailability over time under various soil moisture regimes. All soils were initially fortified with 63 ppb (w/w) of commercially formulated imazaquin. Treatments consisted of maintaining at field capacity for 15 wk (FC), maintaining air-dry for 15 wk (AD), soil that was maintained air-dry for 2 wk and then wet to field capacity at 2 wk intervals (2WAD), and soil that was wet to field capacity at the initiation of the experiment and at 2 wk intervals (2WFC). Little dissipation of imazaquin occurred in the AD soil over the 100 d of this study. Rapid dissipation over the first 35 d occurred for the other three treatments. Imazaquin half-life ranged from 17 to 18 d for the FC, 2WAD, and 2WFC soils. Imazaquin concentration increased or only slightly decreased in samples taken after the second watering in both the 2WAD and the 2WFC soils. Due to differences in adsorption/desorption of imazaquin with changing soil moisture levels, bioassays may not determine the dissipation of the actual concentration of imazaquin contained in soil.

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