EFFECTS OF SOIL MOISTURE AROUND NODULES ON NITROGEN FIXATION BY WELL WATERED SOYBEANS

1976 ◽  
Vol 56 (4) ◽  
pp. 811-815 ◽  
Author(s):  
D. J. HUME ◽  
J. G. CRISWELL ◽  
K. R. STEVENSON
Keyword(s):  
Nitrogen Fixation ◽  
Soil Moisture ◽  
Near Field ◽  
Soil Layer ◽  
Field Capacity ◽  
Dry Weight ◽  
Bottom Layer ◽  
Leaf Water ◽  
Sand Mixture ◽  
Water Potentials

Soybeans (Glycine max (L.) Merr.) were grown at various soil moisture levels around nodules so effects on nitrogen fixation could be studied. Plants were grown in a growth room in 35-cm diam pots. Pots contained two layers of loam–sand mixture separated by a layer of coarse silica, intended to restrict capillary movement of soil moisture from the bottom to the top soil layer. At the beginning of seed development, pots received 200 ml water on the surface, 200 ml in the bottom layer through plastic tubes or 100 ml each way. Plants with good root development in the bottom soil layer maintained leaf water potentials greater than − 6 bars, while soil moisture around nodules varied from 4 to 20%. In three individual experiments, in which only plants with leaf water potentials greater than − 6 bars were considered, there was no relationship between soil moisture around nodules and mg N2[C2H2] fixed/g nodule dry weight × h. When results of two experiments with similar fixation means were combined, there was a barely significant (R2 =.19*) quadratic relationship, with very dry soil or soil near field capacity around nodules decreasing fixation slightly. Percent moisture in soil around nodules did not affect nodule moisture content, indicating that nodule moisture status was maintained if plants received adequate moisture from below the nodule zone.

scholarly journals Water extraction pattern and transpirational losses of peach trees Under well-watered and drying cycles

MAUSAM ◽  
2021 ◽  
Vol 47 (3) ◽  
pp. 287-294
Author(s):  
R.P. SAMUI ◽  
M.J. Mc FARLAND ◽  
J.W. WORTHINGTON
Keyword(s):  
Soil Moisture ◽  
Prunus Persica ◽  
Root Zone ◽  
Near Field ◽  
Soil Layer ◽  
Field Capacity ◽  
Moisture Stress ◽  
Rapid Changes ◽  
Extraction Pattern ◽  
Peach Trees

 Mature peach trees [Prunus Persica (L.) Batsch] grown in weighing lysimeters were subjected to soil moisture stress by shutting off irrigation. Initially transpiration (T) was at potential rate when available soil moisture in the active root zone was near field capacity. Rapid changes in soil moisture under drying cycles caused gradual decrease in transpirational rate. When 0 to 60 cm soil layer reached permanent wilting point, there was a sharp decline in water use. Mature peach trees require barest minimum of 10  mm of water for their metabolic activity. A regression model has been developed to estimate transpirational loss of peach from available soil profile water.    

WINTER CHANGES IN SOIL NITRATE AND EXCHANGEABLE AMMONIUM

1970 ◽  
Vol 50 (2) ◽  
pp. 151-162 ◽  
Author(s):  
C. A. CAMPBELL ◽  
W. S. FERGUSON ◽  
F. G. WARDER
Keyword(s):  
Soil Moisture ◽  
Near Field ◽  
Field Capacity ◽  
Early Spring ◽  
Soil Nitrate ◽  
Regular Monitoring ◽  
Late Fall ◽  
Loam Soil ◽  
Field Plots

Cylinders of a loam soil were placed in the field in late fall and sampled in midwinter and early spring. In soil wetted to near field capacity, nitrate and moisture moved upwards in winter and downwards again in early spring. The amount of movement was negligible in a soil wet to near the wilting percentage. To inhibit nitrification, N-serve was applied in 10 cm of water to field plots (120 × 120 cm) in late fall. Other plots received water but no N-serve. Regular monitoring of soil nitrate, exchangeable ammonium, and soil moisture and temperature in the top 90 cm of these plots showed evidence of upward moisture and nitrate movement as the soil froze. Large and sudden unexplainable decreases in exchangeable ammonium occurred following steady fall build-up.

EFFECTS OF DIFFERENT SOIL MOISTURE TENSIONS ON FLAX AND CEREALS

1966 ◽  
Vol 46 (3) ◽  
pp. 213-216 ◽  
Author(s):  
S. J. Bourget ◽  
B. J. Finn ◽  
B. K. Dow
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Winter Wheat ◽  
Plant Species ◽  
Spring Wheat ◽  
Soil Moisture Content ◽  
Near Field ◽  
Correlation Coefficients ◽  
Field Capacity

Young seedlings of flax and cereals, grown in a greenhouse, were subjected to 0, 12.5, and 25.0 cm of soil moisture tension for periods of 7, 14, and 21 days The grain, straw, and root yields of all plant species, except barky, increased with increasing soil moisture content was maintained near field capacity during the growth of plants. The yields of oats, winter wheat, and fall rye decreased with increasing duration of flooding, whereas those of barley, flax and spring wheat were variable. Correlation coefficients between yields of tops and roots were positive.

scholarly journals 683 PB 236 WATER STRESS REDUCES ASPARAGUS GROWTH

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 531d-531
Author(s):  
Dan Drost
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Root Zone ◽  
Near Field ◽  
Field Capacity ◽  
Fresh Weight ◽  
Irrigation Rate ◽  
Growing Period ◽  
Long Term Study ◽  
Irrigation Treatments

In 1992, a long term study was initiated to determine water use of asparagus and to assess water stress effects on asparagus growth. Asparagus (Syn 4-56) crowns were planted and maintained at soil moisture levels near field capacity during the first year. In 1993, irrigation treatments based on 60, 40, and 0 percent of evapotranspiration (ET) were applied to asparagus during the fern growing period (mid-June to October). Soil moisture, shoot and root growth, and fern water potentials were measured throughout the year. Prior to the irrigation treatments, asparagus had 39 buds per plant with a shoot and root fresh weight of 573 and 270 grams, respectively. Soil moisture in the root zone (0 to 60 cm) approached the permanent wilting point in the 40%. and 0% of ET treatments by mid-August. A decrease in irrigation rate from 80 to 0% of ET had no effect on fern fresh weight at the end of the growing season. However, as irrigation rate decreased from 80 to 0% of ET, root fresh weight (586, 533, 415 grams) and bud number (78, 59, 53) decreased linearly. These results suggest yield and growth may be reduced in 1994.

The Influence of Soil Moisture on the Foliar Activity of Diclofop

Weed Science ◽  
1980 ◽  
Vol 28 (5) ◽  
pp. 534-539 ◽  
Author(s):  
W. A. Dortenzio ◽  
R. F. Norris
Keyword(s):  
Soil Moisture ◽  
Near Field ◽  
Field Capacity ◽  
Herbicide Application ◽  
Wild Oats ◽  
High Soil Moisture ◽  
Herbicide Activity ◽  
Moisture Conditions ◽  
Soil Moisture Status ◽  
Wilting Point

Loss in activity of foliar-applied methyl ester of diclofop {2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid} occurred under low soil moisture conditions. A loss in control of yellow foxtail [Setaria lutescens(Weigel) Hubb.], wild oats (Avena fatuaL.), little-seed canarygrass (Phalaris minorRetz.), and barnyardgrass [Echinochloa crus-galli(L.) Beauv.], was observed under greenhouse and growth chamber conditions. When soil was maintained at 2 to 3% above wilting point as compared to near field capacity, herbicide activity was decreased by 15 to 50%. High soil moisture (at or above 67% of field capacity) for at least 2 to 4 days following treatment was needed to achieve maximum effectiveness of the herbicide. Daily furrow irrigations for a period of 10 days following treatment of barnyardgrass in the field resulted in highest activity as compared to that under single irrigation regimes within the 10-day period. The effect of low soil moisture was minimized by increased rates of herbicide application. Hoe-29152 {methyl-2-[4-(4-trifluoromethylphenoxy)phenoxy] propanoate} showed similar losses in activity associated with low soil moisture. No consistent changes in uptake or translocation of14C-labeled diclofop could be detected in association with altered soil moisture status.

Effect of soil moisture on nodulation of cowpea and hyacinth bean

1976 ◽  
Vol 86 (3) ◽  
pp. 553-560 ◽  
Author(s):  
H. A. Habish ◽  
A. A. Mahdi
Keyword(s):  
Nitrogen Fixation ◽  
Soil Moisture ◽  
Plant Growth ◽  
Dry Weight ◽  
Field Conditions ◽  
Pot Experiments ◽  
Irrigation Interval ◽  
Dry Conditions ◽  
Hyacinth Bean

SummaryPot experiments in which cowpea and hyacinth bean were grown at 15–45% soil moisture showed that nodulation, nitrogen fixation and plant growth were poor at 15%. The weights of nodules and plants were lower in January (winter) than in June (summer). In June cowpea was more tolerant of dry conditions giving good nodulation at 25–35% whereas hyacinth bean required 35–45%.Under field conditions the number and dry weight of nodules were affected by the irrigation interval whereas plant growth was affected by the amount of water applied. Applying 75 mm depth of water every 7 days gave the best combination of nodulation and plant growth.

PHYSICAL FACTORS INVOLVED IN THE FORMATION OF SOIL SHEATHS ON CORN SEEDLING ROOTS

1987 ◽  
Vol 67 (3) ◽  
pp. 591-600 ◽  
Author(s):  
A. FYSON ◽  
A. OAKS
Keyword(s):  
Soil Moisture ◽  
Field Capacity ◽  
Dry Weight ◽  
Physical Factors ◽  
Fluorescent Pseudomonad ◽  
Specific Mass ◽  
High Soil Moisture ◽  
Continuous Corn ◽  
Seedling Roots ◽  
Corn Seedling

A layer of soil (soil sheath) that is resistant to removal by shaking develops on corn seedling roots under a wide variety of environmental conditions. Low temperature (15 °C) and high soil moisture content (100% field capacity) promote the formation of the most substantial sheaths (> 11 mg of soil (dry weight) cm−1 root) in an Elora alfalfa soil. A diversity of corn genotypes and a teosinte form sheaths of comparable specific mass whereas much less soil adheres to pea and soybean roots in this soil. Cultivation history has a considerable influence on sheath mass. For example, at Elora, a soil under alfalfa for several seasons promotes sheaths of higher specific mass (9.9 ± 0.5 mg cm−1 root) than a continuous corn soil (7.1 ± 0.6 mg cm−1 root). Seeds inoculated with a fluorescent pseudomonad developed significantly more substantial sheaths in a 7-irradiated soil (11.2 ± 0.9 mg cm−1 root) than uninoculated, surface sterilized seeds (7.1 ± 0.6 mg cm−1 root). These observations suggest that a variety of factors influence the extent of sheath development. Key words: Soil sheath, temperature, soil moisture, soil type, fluorescent pseudomonads, corn

scholarly journals Response of Carbon Exchange and Growth Analysis in Tropical Pastures to Distinct Irrigation Levels

2018 ◽  
Author(s):  
Milton E. Pereira-Flores ◽  
Flavio Justino ◽  
Davi Boehringer ◽  
Anderson Adriano Martins Melo ◽  
Andressa Gazolla Cursi ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Conservation ◽  
Field Capacity ◽  
Dry Weight ◽  
Co2 Efflux ◽  
Tropical Pastures ◽  
Area Index ◽  
Soil Temperatures ◽  
Highly Correlated ◽  
Irrigation Levels

This study explores the effect of seasonality on soil carbon efflux and pasture growth based on field and lysimeter experiments during summer-fall and winter-spring in two years. Focus is also pointed on irrigation strategies to alleviate the crop response to seasonal fluctuations in precipitation and surface temperatures. Soil respiration, soil and air temperature, leaf photosynthesis, plant dry weight and leaf area index were quantified and analyzed. It has been found significant differences in the CO2 efflux between the two growing season. Emission of soil CO2 allowed to characterize and to prioritize the temperature and rain influence in seasonal brachiaria response. During the seasons, the transient variation of CO2 efflux was highly correlated with rainfall (r = 0.87, P < 0.05), and poorly correlated with soil temperatures (r = 0.5, P < 0.05). The CO2 efflux and plant response to different level of reposition of evapotranspiration demonstrated that irrigation during fall mitigates the reduction of growth conditioned by drying soil and the lower temperatures. The lower temperatures are limiting only when the soil moisture is below 32% of the field capacity. Thus, we propose to keep the soil moisture around 50% during the fall as a key practices for mitigating the effect of seasonality and its intensification with the climate change, even more if added to management routine practices the soil and water conservation.

scholarly journals Effects of Plant Residue Additives and Soil Moisture on Growth and Mn Content of Soybean Seedlings

1969 ◽  
Vol 61 (2) ◽  
pp. 221-229
Author(s):  
A. Vélez-Ramos ◽  
L. Standifer
Keyword(s):  
Soil Moisture ◽  
Near Field ◽  
Field Capacity ◽  
Plant Residue ◽  
Flooded Soil ◽  
Soybean Seedlings ◽  
Glycine Max L ◽  
Alfalfa Meal ◽  
Mn Content ◽  
Germination And Growth

Greenhouse experiments were conducted to study the effects of decomposing alfalfa meal additives and soil moisture on the Mn content of soybean seedlings (Glycine max L.). Soybean seedlings were grown in soil to which alfalfa meal was added in quantities from 0 to 4%. After the seedlings were established, the soil was subjected to flooding or near field capacity moisture for 7 days. In the absence of alfalfa meal, seedling growth was similar at both soil moisture levels. Increased levels of alfalfa meal progressively reduced germination and growth rate of seedlings. These effects were more pronounced in the flooded soil. Flooding resulted in a marked increase of seedling Mn content, whereas increasing alfalfa meal caused no definite change.

Soil Moisture Influence on Treatment and Extraction of DDT from Soils

1972 ◽  
Vol 55 (3) ◽  
pp. 532-536 ◽  
Author(s):  
R G Nash ◽  
W G Harris
Keyword(s):  
Soil Moisture ◽  
Extraction Method ◽  
Near Field ◽  
Field Capacity ◽  
Clay Soils ◽  
Extraction Column ◽  
Alkaline Soils ◽  
Moist Condition ◽  
Moisture Influence ◽  
Column Extraction

Abstract An investigation was conducted to determine techniques which prevented p,p’-DDT conversion to p,p’-DDE during (a) extraction of highly alkaline soils and (b) DDT treatment of highly alkaline soils. Moistening soils to near field capacity reduced DDT conversion to DDE during treatment and a new column extraction method was developed which prevented further conversion during extraction. Column extraction is more rapid than Soxhlet or shake extraction and requires less expensive equipment. However, column extraction was less efficient: about 4% DDT remained after extraction of incubated soils, whereas only about 1% remained in Soxhlet-extracted soils, except for clay soils in which both methods of extraction were low. Alkaline soils apparently can be extracted safely with either Soxhlet or column extraction without conversion of DDT to DDE, providing the soils have equilibrated in a moist condition.

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