Corrigendum - Effect of local advection on evaporation rate and plant water status.

1964 ◽  
Vol 15 (1) ◽  
pp. 85
Author(s):  
BD Millar
Keyword(s):  
Growth Rate ◽  
Soil Moisture ◽  
Absorption Rate ◽  
Evaporation Rate ◽  
Soil Moisture Content ◽  
Water Status ◽  
Leading Edge ◽  
Plant Water ◽  
Early Afternoon ◽  
Very High

The effects of local advection on the evaporation rate (E) and the relative turgidity (RT) of Ladino clover grown in lysimeters were measured at four distances down wind from the leading edge of a small irrigated field adjoining a drier area. Both E and RT decreased with increasing distance down wind from the leading edge, and were directly proportional to powers of the down-wind dimension (x). Presumably plant growth rate may also depend on the distance down wind.Plants near the leading edge showed early afternoon wilt during a mild day in autumn, although soil moisture content was very high. This is in keeping with the concept of a "ceiling absorption rate". Some agronomic implications of these advective effects are discussed.

Effect of local advection on evaporation rate and plant water status

1964 ◽  
Vol 15 (1) ◽  
pp. 85 ◽  
Author(s):  
BD Millar
Keyword(s):  
Growth Rate ◽  
Soil Moisture ◽  
Absorption Rate ◽  
Evaporation Rate ◽  
Soil Moisture Content ◽  
Water Status ◽  
Leading Edge ◽  
Plant Water ◽  
Early Afternoon ◽  
Very High

The effects of local advection on the evaporation rate (E) and the relative turgidity (RT) of Ladino clover grown in lysimeters were measured at four distances down wind from the leading edge of a small irrigated field adjoining a drier area. Both E and RT decreased with increasing distance down wind from the leading edge, and were directly proportional to powers of the down-wind dimension (x). Presumably plant growth rate may also depend on the distance down wind.Plants near the leading edge showed early afternoon wilt during a mild day in autumn, although soil moisture content was very high. This is in keeping with the concept of a "ceiling absorption rate". Some agronomic implications of these advective effects are discussed.

Effects of root severing treatments on loblolly pine

1988 ◽  
Vol 18 (11) ◽  
pp. 1376-1385 ◽  
Author(s):  
William C. Carlson ◽  
Constance A. Harrington ◽  
Peter Farnum ◽  
Stephen W. Hallgren
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Root System ◽  
Loblolly Pine ◽  
Water Status ◽  
Lateral Roots ◽  
Second Order ◽  
Plant Water Status ◽  
Plant Water ◽  
First Order

Six-year-old loblolly pine seedlings were subjected to root severing treatments varying from 0 to 100% of first-order lateral roots. Separate treatments severed surface-oriented or deep-oriented roots. Plant water status was monitored periodically for several months. After all measurements were taken, gross root system structure was determined by excavation. Treatment responses were evident on all dates of measurement. Relationships between percentage of root system cut and leaf conductance or water potential were stronger when surface-oriented roots were cut than when deep-oriented roots were cut. Severing surface-oriented first-order lateral (SOFOL) roots probably resulted in greater impact on plant water status than severing deep-oriented first-order lateral (DOFOL) roots because (i) SOFOL roots had both surface-oriented and deep-oriented second-order lateral roots that could tap both surface and subsurface soil horizons for soil moisture, and (ii) the deep-oriented second-order roots (originating from the SOFOL roots) were spatially distributed over a much larger area than the DOFOL roots and thus would have access to soil water in a larger volume of soil. For SOFOL roots the relationship between percentage cut and leaf conductance or transpiration was strongly negative; for DOFOL roots, no relationship between these variables was observed. Initially water potential decreased with the percentage of roots cut in both groups; in later measurements, water potential was affected more by severing SOFOL than DOFOL roots. Calculation of soil moisture depletion by depth indicated that both surface- and deep-oriented second-order lateral roots were important for water uptake. Severing SOFOL roots significantly decreased nitrogen, phosphorus, and potassium levels in needles of the first growth flush of the year. Levels of these elements in terminal buds were not affected by severing SOFOL roots, but were significantly reduced by severing DOFOL roots. Secondary xylem production was reduced proportionately to the amount of root system cross-sectional area severed.

Effects of Mulches on Soil Water Content and Water Status of Tea Plants in Kenya

1980 ◽  
Vol 16 (3) ◽  
pp. 295-302 ◽  
Author(s):  
C. O. Othieno
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Water Status ◽  
Different Types ◽  
Continuous Application ◽  
Black Plastic ◽  
Tea Plants ◽  
Water Holding ◽  
Better Than

SUMMARYSoil moisture content and plant water status of young clonal tea plants were affected differently by five different types of mulches (black plastic, stone chippings and three types of grass) when compared with a control without mulch. During prolonged droughts, soil moisture content was generally highest under Napier grass and black plastic but any type of mulch was better than no mulch in conserving moisture to 90 cm depth. Tensiometer data at the onset of rains after an unusual prolonged dry season suggest that the infiltration was fastest under grass mulches. After four years of continuous application grass mulches had significantly most effect on water holding capacity, but induced shallow rooting systems, which made the mulched tea more susceptible to drought.

STUDIES ON RHIZOCTONIA SOLANI KÜHN.: IV. EFFECT OF SOIL TEMPERATURE AND MOISTURE ON VIRULENCE

1938 ◽  
Vol 16c (5) ◽  
pp. 203-213 ◽  
Author(s):  
G. B. Sanford
Keyword(s):  
Growth Rate ◽  
Soil Moisture ◽  
Moisture Content ◽  
Soil Temperature ◽  
Growth Rates ◽  
Nutrient Medium ◽  
Soil Moisture Content ◽  
Soil Temperatures ◽  
Dry Soil ◽  
Soil Temperature And Moisture

The effects of soil temperatures between 16° and 25 °C., and of soil moisture content between 19 and 40% of the moisture-holding capacity, on the virulence and type of attack of Rhizodonia Solani on young potato sprouts, were studied under controlled conditions and the results from 13 separate tests are discussed. The comparative growth rates of the pathogen on nutrient agar and in soil are outlined.At 25 °C. the disease diminished very abruptly. Between 23° and 16 °C., the pathogen appeared equally virulent throughout the range of soil moisture mentioned. The fluctuations which occurred in separate tests were not definite or consistent enough to warrant a conclusion that the virulence is greater at 16° than at 23°, or that a dry soil is more or less favorable to it than a wet one.In a fertile, steam sterilized loam, at medium moisture content, it required about ten days for the pathogen to grow as far as it did on the surface of a nutrient medium in four days. The growth rate at either 23° or 16 °C. was slightly higher in a wet soil than in one of medium moisture content, but in a dry soil the rate was somewhat less at 23° than at 16° in a medium or wet soil. Even in a fairly dry soil (19% moisture-holding capacity) at 16° the growth of the pathogen covered a distance of 5 cm. in ten days, which would appear adequate for infection of young sprouts from a set bearing viable sclerotia.The effort of the host to recover, by means of secondary and tertiary sprouts from the attacked primary sprout, was better in a wet soil than in a dry one at both 16° and 23 °C. The best effort was in a wet soil at 23°. A distinction is made between the effects of soil moisture and temperature in stimulating growth of the host, and their effect on parasitism itself.The remarkable tendency of the secondary sprouts to escape infection, regardless of soil temperature and soil moisture, is indicated. There was evidence that certain factors other than soil temperature and moisture may play an important role in the parasitism of R. Solani.

Effects of Herbaceous Weeds on Fourth Year Water Relations and Gas Exchange of Loblolly Pine

1991 ◽  
Vol 5 (4) ◽  
pp. 753-758 ◽  
Author(s):  
Thomas H. Green ◽  
Robert J. Mitchell ◽  
Kailash C. Paliwal ◽  
Uday V. Pathre ◽  
Bruce R. Zutter ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Weed Control ◽  
Loblolly Pine ◽  
Water Status ◽  
Stand Development ◽  
Plant Water ◽  
Direct Benefit ◽  
Available Soil Moisture ◽  
Plant Water Potential ◽  
Loblolly Pines

Stands of four-year-old loblolly pines grown with and without herbaceous competition were compared to determine whether early increases in soil moisture and plant water status had been maintained throughout the first four years. Non-weeded stands tended to have greater soil moisture than weeded stands, although these differences were never statistically significant (P > 0.05). Plant water potential was remarkably similar between treatments, as were photosynthesis and stomatal conductance. The increase due to weed control in foliage production early in stand development apparently caused a depletion in available soil moisture to levels similar to non-weeded stands. Therefore, the direct benefit of increased soil resources with weed control is short lived.

The relationship of grain yield to vegetative growth and post-flowering leaf area in the wheat crop under conditions of limited soil moisture

1966 ◽  
Vol 17 (3) ◽  
pp. 281 ◽  
Author(s):  
RA Fischer ◽  
GD Kohn
Keyword(s):  
Soil Moisture ◽  
Grain Yield ◽  
Leaf Area ◽  
Vegetative Growth ◽  
Water Status ◽  
Plant Water Status ◽  
Flowering Plant ◽  
Wheat Crop ◽  
Plant Water ◽  
Relative Differences

Trials were conducted in 1961 and 1962 at Wagga Wagga in southern New South Wales to investigate the yield physiology of the wheat crop. Various cultural treatments were applied to a single variety (Heron). This paper covers aspects directly related to grain yield. In the rate of sowing and fertilizer trials relative differences in grain yield were invariably less than relative differences in total dry weight at or before flowering. In some cases increased vegetative growth depressed grain yield. These results appear to be mainly the consequence of increased post-flowering competition for limited soil moisture in denser crops. High soil nitrogen had an additional detrimental effect. When as a result of later sowing flowering was delayed, both vegetative growth and post-flowering plant water status decreased; as a consequence grain yield decreased with successively later sowings. For the 1962 crops, grain yield was closely correlated (r = 0.969**) with leaf area duration after flowering, which in turn was related to leaf area index at flowering and to the rate of senescence of photosynthetic tissue. Increased rates of senescence were usually associated with reduced post-flowering plant water status, as indicated by the relative turgidity of the leaves. These results are discussed in relation to the importance of numerical components of grain yield and to improvement of grain yield in the wheat crop.

The interactive effects of increased evaporative demand and soil water on photosynthesis in maize

1991 ◽  
Vol 71 (1) ◽  
pp. 31-39 ◽  
Author(s):  
R. G. Berard ◽  
G. W. Thurtell
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Water ◽  
Soil Moisture Content ◽  
Water Status ◽  
Interactive Effects ◽  
Evaporative Demand ◽  
Photosynthetic Rates ◽  
Root Medium ◽  
Wide Range

A field-portable whole-plant enclosure system was used to study the effect of increased evaporative demand on photosynthetic rates of maize (Zea mays L.) subjected to various root medium treatments. The system consisted of two transparent chambers, each capable of maintaining a fully grown maize plant at ambient conditions while enabling different evaporative demand treatments by controlling the humidity. The rooting media consisted of silt loam soil held at three levels of soil moisture content covering a wide range of available moisture, and a hydroponic medium consisting of 25-L pails containing "Turface" and supplied three times daily with a nutrient solution. Measurements were carried out during the post-silking period from 22 July to 6 Sept. 1987 and consisted of at least 4 d of continuous monitoring of photosynthesis and transpiration rates from early morning till sundown. The effect of increased evaporative demand on photo-synthetic rates was relatively small, with average photosynthetic reductions of approximately 4–6% in all root medium treatments. Soil moisture content did not have any effect on the reduction of photosynthesis which occurred at high evaporative demand. However, absolute photosynthetic rates were significantly reduced by low soil moisture. It is suggested that atmospheric conditions leading to high transpiration rates are much less important than soil moisture conditions in causing yield reductions due to reduced photosynthetic rates. The results support recent evidence by other workers that soil water status can influence stomatal conductance and photosynthesis without the intermediary influence of leaf water status. Key words: Photosynthesis, transpiration, maize, soil water content, VPD, leaf conductance

Photosynthesis in Coffea arabica. II. Effects of Water Stress

1980 ◽  
Vol 16 (1) ◽  
pp. 21-27 ◽  
Author(s):  
D. Kumar ◽  
Larry L. Tieszen
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Coffea Arabica ◽  
Water Status ◽  
Stomatal Closure ◽  
Leaf Water ◽  
Plant Water

SUMMARYExperiments were carried out to relate soil moisture to leaf water potential (Ψ1), and to determine the effects of varying Ψ1, on leaf conductances and photosynthesis in coffee. Stomatal conductance was maximum at 0900 h, but plants growing in drier soil showed marked mid-day stomatal closure. After 1500 h, stomata began closing although plant water status improved. Photosynthesis in relation to changing Ψ1 appeared to exhibit roughly three different rates. At the fixed experimental temperature (25°C) low Ψ1 reduced photosynthesis throughits influence on stomata, but under field conditions low Ψ1 and an accompanying rise in temperature could lower the rate by lowering both mesophyll and stomatal conductances.

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