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.

Influence of Moisture on Soil-Incorporated Diclofop

Weed Science ◽  
1979 ◽  
Vol 27 (1) ◽  
pp. 83-87 ◽  
Author(s):  
Christiaan E. G. Mulder ◽  
John D. Nalewaja
Keyword(s):  
Soil Moisture ◽  
Methyl Ester ◽  
Sandy Loam ◽  
Field Capacity ◽  
Wild Oat ◽  
Soil Columns ◽  
Herbicide Application ◽  
Water Volumes ◽  
And Control ◽  
Wilting Point

The influence of soil moisture on wild oat control from soil-incorporated methyl ester of diclofop {2-[4-(2,4-dichlorophenoxy)-phenoxy] propanoic} was determined in the greenhouse. Wild oat control with soil-incorporated diclofop at 1.5 or 3 ppmw increased linearly when soil moisture in a Tiffany sandy loam increased from 18.5 to 23.5% (75% to 125% of field capacity). The efficacy of soil-incorporated diclofop was not reduced when soil moisture was allowed to decrease from 21 (field capacity) to 18.5, 16, 13.5, or 11% (wilting point) before rewatering to 21%. The soil moisture level at the time of herbicide application determined the degree of wild oat control with soil-incorporated diclofop. Wild oat control with diclofop increased when a Tiffany sandy loam with 16% moisture (50% of field capacity) at the time of herbicide application, was watered to field capacity after 8 or 12 days delay, and control did not change with watering to field capacity at the time of herbicide application or when delayed 4 or 16 days. The movement of14C-diclofop in soil columns was greater within coarse than fine textured soils and increased with water volumes applied, regardless of soil type. Further, the leachability of14C-diclofop was two and a half times greater than that of14C-trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine).

scholarly journals Sprinkler irrigation on clay soils in southern Finland I. Sprinkler irrigation, its technique and effect on soil moisture

1967 ◽  
Vol 39 (2) ◽  
pp. 67-77
Author(s):  
Paavo Elonen ◽  
Lasse Nieminen ◽  
Osmo Kara
Keyword(s):  
Soil Moisture ◽  
Root Zone ◽  
High Capacity ◽  
Sprinkler Irrigation ◽  
Field Capacity ◽  
Clay Soils ◽  
Available Water ◽  
Spring Cereals ◽  
Moisture Conditions ◽  
Wilting Point

During the last three years, 1964—66, investigations on sprinkler irrigation of spring cereals have been carried out. The experimental fields were clay soils in Southern Finland. Neutral river and lake waters containing small amounts of soluble salts were applied in the nighttime. The application rate of the rotary sprinklers used was 2.5—4 mm per hour with the radius of 12±2 m. With this technique the experimental soils having poor structure endured the irrigation without any crust formation. It was found that the sprinklers equipped with two nozzles distributed the water more uniformly than those with one nozzle. With the former sprinklers a fairly good uniformity was attained: The amount of water usually varied between 25 and 35 mm with an average of 30 mm, except in a relatively small area nearest to the sprinklers which received too much water and in the area at the greatest distance from the sprinklers with less than the average amounts of water. The soil water conditions were followed by gypsum blocks inserted at different depths. In each experimental year, within 2—3 weeks from sprouting, the available water in the top soils decreased to 50 per cent of the total capacity. This dry condition existed for two months in the years 1964 and 1966 and for one month in 1965. During these dry periods the top soils were near the wilting point for a long time, and in 1966 the available water was wholly exhausted. The influence of transpiration was effective also in deeper layers. In 1966, the soil reached the wilting point also at the depth of 40 cm and stayed at this condition for about one month. The effect of a 30—37 mm irrigation on the soil moisture conditions lasted only for 1—2 weeks. Thus, the rate of evapotranspiration was as much as 4 mm per day. The plants consumed water simultaneously from the whole root zone, yet, most effectively from the surface layers. The top soil (20 cm in thickness) which had reached the wilting point was not completely moistened by the amounts of water applied. This indicates the high capacity of clay soils to store water. It is also noteworthy that a part of irrigation water percolated to 40 cm before the soil at the depths of 10 and 20 cm had time to get to the field capacity. In experimental years, to ensure favourable moisture conditions to spring cereals several high applications of water would have been needed. This proves that also during the short growing season in Finland a serious shortage of water may occur.

Evaluation of Presswheels and Seed Coverers for Direct Seeding of Brassica

HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 599E-600
Author(s):  
Regina P. Bracy ◽  
Richard L. Parish
Keyword(s):  
Soil Moisture ◽  
Sandy Loam ◽  
Visual Observation ◽  
Mustard Seed ◽  
High Soil Moisture ◽  
Loam Soil ◽  
Direct Seeded ◽  
Plant Emergence ◽  
Moisture Conditions ◽  
Determine Effect

Improved stand establishment of direct-seeded crops has usually involved seed treatment and/or seed covers. Planters have been evaluated for seed/plant spacing uniformity, singulation, furrow openers, and presswheel design; however, effects of presswheels and seed coverers on plant establishment have not been widely investigated. Five experiments were conducted in a fine sandy loam soil to determine effect of presswheels and seed coverers on emergence of direct-seeded cabbage and mustard. Seed were planted with Stanhay 870 seeder equipped with one of four presswheels and seed coverers. Presswheels included smooth, mesh, concave split, and flat split types. Seed coverers included standard drag, light drag, paired knives, and no coverer. Soil moisture at planting ranged from 8% to 19% in the top 5 cm of bed. Differences in plant counts taken 2 weeks after planting were minimal with any presswheel or seed coverer. Visual observation indicated the seed furrow was more completely closed with the knife coverer in high soil moisture conditions. All tests received at least 14 mm of precipitation within 6 days from planting, which may account for lack of differences in plant emergence.

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

Effect of Stand Density on Water Use of Mulga (Acacia aneura F.muell.) Woodlands in South-Western Queensland

1976 ◽  
Vol 24 (2) ◽  
pp. 177 ◽  
Author(s):  
AJ Pressland
Keyword(s):  
Soil Moisture ◽  
Water Use ◽  
Stand Density ◽  
Tree Density ◽  
Pan Evaporation ◽  
Permanent Wilting Point ◽  
The Mean ◽  
Acacia Aneura ◽  
Soil Moisture Status ◽  
Wilting Point

The important Australian fodder tree mulga (Acacia aneura F. Muell.) was thinned to densities ranging between 0 and 4000 trees ha-1 near Charleville, Queensland. Water use by the ensuing communities was studied from December 1971 to October 1973. Evapotranspiration over this 22 month period increased with tree density from 814 mm for the totally cleared plots to 852 and 891 mm for those plots supporting 4000 and 640 trees ha-1 respectively. Regression analysis was used to relate soil moisture to time since rain; it was established that the soil had dried to its permanent wilting point within 60 days of rain sufficient to recharge the soil to a depth of 135 cm. The mean apparent maximum evapotranspiration of the mulga communities was 4.7 mm day-1. The ratios of evapotranspiration to pan evaporation (Et/Eo) were influenced by both soil moisture status and tree density. Et/Eo ratios ranged between 0.55 and 0.07 in the summer of 1972, and between 1.05 and 0.05 the following summer. In the winters of 1972 and 1973 Et/Eo ratios ranged between 0.92 and 0.04, and 1.33 and 0.09 respectively. The significance of the results to production and management of mulga lands in south-western Queensland is discussed.

Dark Island heath (Ninety-mile Plain, South Australia). V. The water relationships in heath vegetation and pastures on the Makin sand

1957 ◽  
Vol 5 (2) ◽  
pp. 151 ◽  
Author(s):  
RL Specht
Keyword(s):  
Soil Moisture ◽  
Balance Sheet ◽  
South Australia ◽  
Field Capacity ◽  
Severe Drought ◽  
Soil Moisture Storage ◽  
Drought Conditions ◽  
Moisture Storage ◽  
Medicago Sativa L ◽  
Soil Moisture Status

Heath vegetation shows a major flush of growth during the mediterraneantype summer season, a time when calculations of the soil moisture storage by the techniques of Thornthwaite (1948) or Prescott, Collins, and Shirpurkar (1952) indicate that severe drought conditions should oocur. Monthly observations on the moisture status of the Makin sand under heath vegetation and, for comparison, under various pastures are therefore recorded. The problems of obtaining an accurate water balance-sheet for such a heterogeneous vegetation as the heath are discussed. Difficulties in the use of the various techniques for measuring soil moisture in sand, which has a low pF of 1.85 at field capacity, are enumerated. The following relationships were found between the evapotranspiration index (Itr = Etr / Ew0.75) and the available water (W). These data were calculated for 6 ft of sand. (i) Heath vegetation (10–14 years old) log (2.4–Itr) = 0.420–0.0383 W (ii) Heath vegetation (burnt) log (2.4–Itr) = 0.461–0.0380 W (iii) Oenothera odorata Jacq. pasture log (2.4–Itr) = 0.395–0.0269 W (iv) Medicago sativa L. pasture log (2.4–Itr) = 0.390–0.0270 W (v) Ehrharta calycina Sm. pasture log (2.4–Itr) = 0.400–0.0339 W From these equations the mean monthly quantities of rainfall which may be stored in 6 ft of sand under the various treatments described were calculated. Drought conditions are shown to occur in December and January, but are relieved in the later months of summer. Even if the stored moisture below 8 ft is considered, the soil moisture status would be expected to be just sufficient to maintain the vegetation in a "dormant" state, and yet the major growth of the heath vegetation occurs at this time. The calculated mean annual values of Itr range from 0.53 to 0.60 for these perennial communities. Close approximations to the actual soil moisture status can be obtained by substituting these values for K in Prescott's formula for potential evaporation, i.e. Etr = K x Ew0.75. Supplementary data on transpiration, growth, and the root systems of the pastures are also included.

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 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.

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.

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