scholarly journals Some observations on the relation between transpiration and soil moisture.

1958 ◽  
Vol 6 (2) ◽  
pp. 94-98
Author(s):  
J.F. Bierhuizen
Keyword(s):  
Water Management ◽  
Soil Moisture ◽  
Phaseolus Vulgaris ◽  
Light Intensity ◽  
Moisture Content ◽  
High Moisture ◽  
Pot Experiments ◽  
Light Intensities ◽  
Land Water

Transpiration rates of Phaseolus vulgaris were measured in pot experiments, at different soil moisture levels and light intensities. Transpiration increased with available moisture, becoming nearly constant at the higher levels. At the highest light intensity transpiration increased with available moisture content to a maximum at 16% moisture, but then showed a slight decrease; it is suggested that this effect is a result of O2 deficiency at high moisture levels.-Inst. Land Water Management Res., Wageningen. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Effect of Soil Moisture Content and End-Effector Speed on Pick-up Force and Lump Damage for Seedling Transplanting

2019 ◽  
Vol 1 (3) ◽  
pp. 343-356 ◽  
Author(s):  
Mohamed ◽  
Liu
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Soil Condition ◽  
Penetration Resistance ◽  
Force Balance ◽  
High Moisture Content ◽  
High Moisture ◽  
End Effector ◽  
End Effectors

Efficient transplanting has been identified as one of the essential steps towards achieving an increased yield in the farm. However, many factors are affecting these processes such as soil moisture content and the speed of pickup. This study was carried out to investigate the effect of different soil moisture content and pickup speeds on pickup force, balance, resistance, and lump damage during transplanting of seedlings. The results showed that penetration resistance was inversely proportional to the speed and soil moisture content. The highest penetration resistance (38 N) values were recorded under the lowest speed (0.5 mm/s) at the low moisture content; whereas, the lowest penetration resistance was obtained at highest speed (10 mm/s) under high moisture content. The highest pick-up force resistance values were recorded under the lowest speed (0.5 mm/s) at low moisture content than the lowest pick-up force resistance of 1.4 N at (10 mm/s) under the high moisture content. On the other hand, an increase of pick-up force led to a decrease in the pick-up force resistance. The pick-up damage and the pick-up speed are directly proportional—nevertheless, the former increased with a decreasing soil moisture content. The highest pick-up damage values (82%) were observed under the top-most speed (10 mm/s) at high moisture content. It can be concluded that for successful auto-transplanting of seedling the soil condition, the force applied and speed should be taken into consideration. This work will implement an effective seedling-picking performance and basis for the optimal design of end-effectors.

INFLUENCE OF AIR TEMPERATURE, LIGHT INTENSITY, SOIL MOISTURE STRESS AND SOIL AERATION ON MOISTURE USE BY WHEAT

1969 ◽  
Vol 49 (2) ◽  
pp. 129-137 ◽  
Author(s):  
C. A. Campbell ◽  
W. S. Ferguson
Keyword(s):  
Soil Moisture ◽  
Light Intensity ◽  
Dry Matter ◽  
Moisture Stress ◽  
High Moisture ◽  
Soil Moisture Stress ◽  
Stem Extension ◽  
High Soil Moisture ◽  
Poor Seed ◽  
Reduced Rate

In growth chamber experiments, it was found that total and rate of moisture use by wheat were directly proportional to light intensity, except under conditions which restricted growth.Increasing the day temperature from 21° to 27 °C reduced the total moisture use. This was attributed to the greater vegetative dry matter produced at 21 °C. Under high soil moisture stress, (0.2 to 15 atm), plants used less water at a slower rate than at the lower stress (0.2 to 1.4 atm), but the moisture treatment had little effect on moisture use per gram of dry matter Apparently, under the conditions of this experiment the most important cause of reduced transpiration at high moisture stress was reduced plant growth.At about the late tillering to stem-extension stage, wheat was surprisingly insensitive to changes in moisture stress. An increase in soil moisture stress during this period did not result in the usual reduced rate of moisture consumption.Irrespective of the growth stage at which the stress was changed (increased or decreased), stress had little influence on moisture use per unit of straw dry matter. If the soil was "wet" (0.2 to 1.4 atm) at about the stem-extension stage, poor seed set occurred and thus moisture use per gram of seed was increased. When plants were provided with adequate aeration, moisture use per gram of seed was one-third that of plants grown under poor aeration.

Experimental Study on Compaction and Strength Characteristic of Wetland Fine Grained Soil

2012 ◽  
Vol 256-259 ◽  
pp. 336-339
Author(s):  
Hong Xia Yang
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Optimum Moisture Content ◽  
Dry Density ◽  
High Moisture ◽  
Compacted Soil ◽  
Fine Grained ◽  
Fine Grained Soil ◽  
Work Effect

Through indoor the compaction test and unconfined compressive strength of compacted soil samples and CBR strength test, analyzes compaction characteristics of wetland fine grained soil and the change rule of compacted strength with compaction work and moisture content.The results show that under the same compaction work effect, when the soil moisture content is less than optimum moisture content,along with the increase of moisture content, dry density increases, when the soil moisture content is greater than the optimum moisture content, along with the increase of moisture content, dry density decreases and to a larger extent.When the compaction work is bigger, the soil dry density is bigger, the compaction strength is higher and the optimum moisture content is smaller.Strength decreases when under high moisture content condition, CBR value is relatively stable in the wet side of optimum moisture content.

The effects of fluctuations in soil moisture content on the availability of recently applied phosphate

Soil Research ◽  
1970 ◽  
Vol 8 (2) ◽  
pp. 209 ◽  
Author(s):  
JR Simpson ◽  
CH Williams
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Plant Uptake ◽  
Soil Moisture Content ◽  
Phosphorus Uptake ◽  
Organic Substrate ◽  
High Moisture Content ◽  
High Moisture ◽  
Phosphate Availability ◽  
Reduction Of Iron

Incubation for short periods at a high moisture content reduced the subsequent plant uptake of phosphorus from recently applied monocalcium phosphate in several soils. The effects on phosphorus uptake were reflected in the amounts of phosphate extracted by 0.5M sodium bicarbonate and by 0.01M calcium chloride. Phosphate availability decreased with increasing moisture content up to saturation. At saturation, availability decreased with increasing incubation period up to 4 days, but was not reversed by several weeks of subsequent incubation at 100 cm tension. The effect of waterlogging usually was greater on the air-dried soil than on soil which had undergone moist pre-incubation. The results suggest that the decrease in phosphate availability was closely associated with the reduction of iron during the anaerobic phase and its subsequent oxidation. Preincubation at 100 cm tension progressively decreased the amount of iron released, and phosphate subsequently immobilized. This appeared to be caused by oxidation of organic substrate during the aerobic phase, thus delaying the onset of anaerobiosis during waterlogging. Phosphate applied to the surface was affected by waterlogging in a similar way to phosphate mixed into the soil.

scholarly journals Processes in the Unsaturated Zone by Reliable Soil Water Content Estimation: Indications for Soil Water Management from a Sandy Soil Experimental Field in Central Italy

2020 ◽  
Vol 13 (1) ◽  
pp. 227
Author(s):  
Lucio Di Matteo ◽  
Alessandro Spigarelli ◽  
Sofia Ortenzi
Keyword(s):  
Water Management ◽  
Soil Moisture ◽  
Moisture Content ◽  
Soil Water ◽  
Unsaturated Zone ◽  
Central Italy ◽  
Moisture Index ◽  
Moisture Profile ◽  
Antecedent Soil Moisture ◽  
Experimental Field

Reliable soil moisture data are essential for achieving sustainable water management. In this framework, the performance of devices to estimate the volumetric moisture content by means dielectric properties of soil/water system is of increasing interest. The present work evaluates the performance of the PR2/6 soil moisture profile probe with implications on the understanding of processes involving the unsaturated zone. The calibration at the laboratory scale and the validation in an experimental field in Central Italy highlight that although the shape of the moisture profile is the same, there are essential differences between soil moisture values obtained by the calibrated equation and those obtained by the manufacturer one. These differences are up to 10 percentage points for fine-grained soils containing iron oxides. Inaccurate estimates of soil moisture content do not help with understanding the soil water dynamic, especially after rainy periods. The sum of antecedent soil moisture conditions (the Antecedent Soil moisture Index (ASI)) and rainfall related to different stormflow can be used to define the threshold value above which the runoff significantly increases. Without an accurate calibration process, the ASI index is overestimated, thereby affecting the threshold evaluation. Further studies on other types of materials and in different climatic conditions are needed to implement an effective monitoring network useful to manage the soil water and to support the validation of remote sensing data and hydrological soil models.

NET CARBON DIOXIDE EXCHANGE RATES IN PHASEOLUS VULGARIS L. AS INFLUENCED BY TEMPERATURE, LIGHT INTENSITY, LEAF AREA INDEX, AND AGE OF PLANT

1964 ◽  
Vol 42 (4) ◽  
pp. 393-401
Author(s):  
Douglas P. Ormrod
Keyword(s):  
Carbon Dioxide ◽  
Phaseolus Vulgaris ◽  
Light Intensity ◽  
Exchange Rates ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Planting Density ◽  
Carbon Dioxide Exchange ◽  
Area Index ◽  
Light Intensities

Plants of Phaseolus vulgaris were grown under controlled conditions for 10 to 60 days and then transferred to light intensities of from 0 to 12,000 ft-c at temperatures of 4 to 38 °C for measurement of net carbon dioxide exchange by means of an infrared analyzer. The net carbon dioxide exchange was not markedly influenced by temperature at higher light intensities, particularly with older plants and the greater planting density, but was strikingly influenced by temperature in darkness or low light intensity. The leaf area index affected the rate at which the maximum net carbon dioxide exchange rates were attained. The compensation point increased with aging and with denser planting. The net assimilation decreased at the onset of fruiting. Several features of the experimental method are discussed.

Drying kinetics of processed natural coffee with high moisture content

2017 ◽  
Vol 12 (3) ◽  
pp. 400 ◽  
Author(s):  
Valdiney Cambuy Siqueira ◽  
Flávio Meira Borém ◽  
Guilherme Euripedes Alves ◽  
Eder Pedroza Isquierdo ◽  
Afonso Celso Ferreira Pinto ◽  
...  
Keyword(s):  
Moisture Content ◽  
Drying Kinetics ◽  
High Moisture Content ◽  
High Moisture ◽  
Kinetics Of

Objetivou-se, com o presente trabalho, propor um novo método de processamento e secagem, assim como avaliar o comportamento dos grãos submetidos a este processo, por meio da taxa de redução de água e do ajuste de diferentes modelos matemáticos aos dados experimentais da secagem. Os frutos colhidos no estágio maduro foram divididos em três lotes. O primeiro foi seco continuamente à temperatura de 40±1 °C. O segundo consiste na secagem do café natural até os teores de água de 0,56±0,02, 0,41±0,02, 0,28±0,02 e 0,20±0,02 decimal (base seca, b.s.), seguido de beneficiamento e secagem contínua nas temperaturas de 35±1 ºC e 40±1 ºC. O terceiro lote correspondeu à secagem contínua do café descascado e desmucilado na temperatura de 40±1 °C. Em todos os lotes, a secagem foi encerrada quando os grãos atingiram o teor de água de 0,12±0,05 (b.s.). Aos dados experimentais da secagem foram ajustados dez modelos matemáticos utilizados para representação da secagem dos produtos agrícolas. Além da representação da cinética de secagem foi avaliada a taxa de redução de água dos grãos. Conclui-se que a taxa de redução de água é maior para a temperatura de secagem de 40±1 °C, especialmente para maiores teores de água. O tempo total de secagem do café beneficiado com alto teor de água é expressivamente reduzido, quando comparado ao tempo de secagem completa do café natural. O modelo de Midilli descreve satisfatoriamente a cinética de secagem do café beneficiado.

Analysis on Soil Moisture Content in the Middle Reaches of the Yellow River

2011 ◽  
Vol 28 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Run-chun LI ◽  
Xiu-zhi ZHANG ◽  
Li-hua WANG ◽  
Xin-yan LV ◽  
Yuan GAO
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Yellow River ◽  
The Yellow River
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