scholarly journals Root Pruning and Soil Type Affect Pecan Root Regeneration

1998 ◽  
Vol 8 (4) ◽  
pp. 573-575 ◽  
Author(s):  
B.D. McCraw ◽  
M.W. Smith

Taproots of 2-year-old `Apache' seedling pecan [Carya illinoensis (Wang)] trees were pruned to 1 ft (30 cm), 2 ft (60 cm), or 3 ft (90 cm) in combination with wounding treatments consisting of no wounding, scraping through pericycle tissue on one or two sides of the taproot, or longitudinally splitting the taproot for about half its length. The trees were planted in a Port silt loam soil and a Teller sandy loam soil and grown without irrigation. At the end of the first and second growing seasons, top growth was measured, trees were dug and root system regrowth was evaluated. Tree root weight and number of roots per tree decreased with increasing taproot length.

Weed Science ◽  
1990 ◽  
Vol 38 (1) ◽  
pp. 67-73 ◽  
Author(s):  
R. N. Stougaard ◽  
P. J. Shea ◽  
A. R. Martin

Laboratory and greenhouse studies were conducted to determine imazaquin and imazethapyr adsorption, mobility, and efficacy in Sharpsburg silty clay loam, Holdrege silt loam, and Tripp sandy loam soils after adjusting pH to 5, 6, and 7. Both herbicides were more strongly absorbed, less mobile, and less efficacious at a lower pH. Observations were attributed to ionic bonding resulting from protonation of basic functional groups on the herbicide molecules as pH decreased. Adsorption was greatest in the silty clay loam and least in the sandy loam soil. Conversely, the herbicides were more efficacious and mobile in the more coarse-textured soils. Imazethapyr was less mobile, more highly adsorbed, and more phytotoxic than imazaquin. Greater adsorption of imazethapyr was attributed to a stronger basic pKaand steric factors.


2004 ◽  
Vol 3 (1) ◽  
pp. 316
Author(s):  
M. Saleem Akhtar ◽  
Tammo S. Steenhuis ◽  
Brian K. Richards ◽  
Murray B. McBride

1982 ◽  
Vol 62 (4) ◽  
pp. 969-977 ◽  
Author(s):  
PATRICIA S. HOLLOWAY ◽  
ROBERT M. VAN VELDHUIZEN ◽  
CECIL STUSHNOFF ◽  
DAVID K. WILDUNG

Vegetative growth of lingonberries was observed on plants growing in four unsterilized, native-Alaskan substrates: coarsely-ground Lemeta peat, Fairbanks silt loam soil, a mixture of peat and silt loam soil and washed Chena very fine sandy loam soil. Following three growing seasons, plants in the peat treatment showed the greatest increase in vegetative growth as revealed by the number of new stems produced, stem length and dry weight per plant. Leaf size did not differ among substrate treatments. The leaves on plants grown in the peat substrate remained green throughout the entire experiment. The leaves of plants in all other treatments showed varying degrees of chlorosis followed by reddening and necrosis. Differences in concentration of N, P, K, Mn, Fe, Zn and Al in whole-plant tissue samples were recorded. The results indicate lingonberries should be grown in a peat substrate for maximum growth and dry matter accumulation.


1967 ◽  
Vol 45 (9) ◽  
pp. 1671-1682 ◽  
Author(s):  
R. F. Sutton

Three-year-old seedlings of Picea glauca and P. abies were outplanted in a fertile silt loam soil at Ithaca, New York, in a split-plot randomized block experiment involving large- and small-size classes of stock and four root-pruning treatments: control; laterals pruned to 5 cm; all roots pruned at 10 cm measured from the root collar; and all laterals pruned flush with the tap or main root.Survival was good except in the last treatment. First- and second-year height increments within each species were unaffected by root-pruning treatments, even the most extreme. This suggests that either water stress is not aggravated by root pruning or that root pruning has compensating advantages. In the second year, height increment of P. glauca was significantly inferior to that of the first year. Height increment of P. abies was significantly greater in the second than in the first year.Root systems of 20 P. glauca were excavated in the second year. Percentage increases of total root length (of all roots 1 cm or more long) in root-pruned trees were twice those of control trees. Highest values (> 1000%) were for vigorous trees in the moderate root-pruning treatments.


2014 ◽  
Vol 53 (8) ◽  
pp. 1976-1995 ◽  
Author(s):  
Jeffrey D. Massey ◽  
W. James Steenburgh ◽  
Sebastian W. Hoch ◽  
Jason C. Knievel

AbstractWeather Research and Forecasting Model forecasts over the Great Salt Lake Desert erroneously underpredict nocturnal cooling over the sparsely vegetated silt loam soil area of Dugway Proving Ground in northern Utah, with a mean positive bias error in temperature at 2 m AGL of 3.4°C in the early morning [1200 UTC (0500 LST)]. Positive early-morning bias errors also exist in nearby sandy loam soil areas. These biases are related to the improper initialization of soil moisture and parameterization of soil thermal conductivity in silt loam and sandy loam soils. Forecasts of 2-m temperature can be improved by initializing with observed soil moisture and by replacing Johansen's 1975 parameterization of soil thermal conductivity in the Noah land surface model with that proposed by McCumber and Pielke in 1981 for silt loam and sandy loam soils. Case studies illustrate that this change can dramatically reduce nighttime warm biases in 2-m temperature over silt loam and sandy loam soils, with the greatest improvement during periods of low soil moisture. Predicted ground heat flux, soil thermal conductivity, near-surface radiative fluxes, and low-level thermal profiles also more closely match observations. Similar results are anticipated in other dryland regions with analogous soil types, sparse vegetation, and low soil moisture.


Weed Science ◽  
1985 ◽  
Vol 33 (2) ◽  
pp. 229-232 ◽  
Author(s):  
D. J. Rydrych

Preemergence and postemergence application of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)-one] at 0.6 and 1.1 kg ai/ha controlled downy brome (Bromus tectorumL. ♯ BROTE) in winter wheat (Triticum aestivumL. ‘McDermid’) but caused considerable injury without the use of activated carbon over the seeded row. Activated carbon applied in 5-cm bands over the seeded row at 84, 167, and 336 kg/ha protected winter wheat at Pendleton on a silt loam soil. On a sandy loam soil, only a 336 kg/ha rate provided protection from metribuzin. Metribuzin toxicity to winter wheat was more difficult to neutralize when applied preemergence. Downy brome control was not reduced by carbon applied over the wheat row. The best treatment in this study was carbon at 336 kg/ha applied preemergence over the row followed by metribuzin at 0.6 or 1.1 kg/ha postemergence. A 10-week delay between preemergence carbon banding and postemergence metribuzin protected winter wheat from chemical injury.


1969 ◽  
Vol 9 (39) ◽  
pp. 428 ◽  
Author(s):  
VF McClelland

The production and persistence of nine cultivars of lucerne were studied at the Mallee Research Station, Walpeup, Victoria, over three seasons. Hunter River, Siro Peruvian, and African lucerne were similar in yield, but Siro Peruvian was less persistent. The superior yield of these three cultivars over two accessions of Flandria, Du Puits, and Socheville was largely due to their greater winter production. Two lines of Canadian creeping-rooted lucerne were found to be entirely unsuited to this district. Hunter River and Siro Peruvian lucerne were also compared on a sand and a sandy loam soil at Walpeup. The relative production of the two cultivars was the same on the two soil types but the effect of soil type was marked. The production and persistence of lucerne grown on the sand was far superior to that on the sandy loam.


Weed Science ◽  
1993 ◽  
Vol 41 (4) ◽  
pp. 641-647 ◽  
Author(s):  
Frederick M. Fishel ◽  
G. Euel Coats

Experiments were conducted in 1990 and 1991 to determine bioavailability of PRE herbicides at three soil profile depths and two soil types in established common bermudagrass sods. Prodiamine and oryzalin reduced ‘Tifgreen’ bermudagrass root growth in the 5- to 7.5-cm layer of a Bosket very fine sandy loam soil at 2 and 4 wk after treatment in 1991. These herbicides decreased bermudagrass root weight in both the Bosket and Marietta sandy clay loam both years in samples taken from the 2.5- to 5-cm depth layer. In the 0- to 2.5-cm soil layer, all herbicides reduced root weight in 1990. In a bioassay, prodiamine caused decreased Tifgreen bermudagrass root growth at concentrations as low as 4 ppb by wt in the very fine sandy loam soil, while 8 ppb was necessary in the sandy clay loam soil. Prodiamine was detected in the very fine sandy loam at 4 wk after treatment at all depths in 1991 (65, 45, and 39 ppb in the 0- to 2.5-, 2.5- to 5-, and 5- to 7.5-cm soil layers, respectively). Oryzalin was also detected at all depths in 1991 when sampled at 2 and 4 wk after treatment in the very fine sandy loam. Pendimethalin was present in concentrations of 38, 39, and 37 ppb in the sandy clay loam at 2 wk after treatment in the 0- to 2.5-, 2.5- to 5-, and the 5- to 7.5-cm soil layers, respectively. Pendimethalin was also detected in the very fine sandy loam at 2 wk after treatment at concentrations of 55, 69, and 36 ppb in the 0- to 2.5-, 2.5- to 5-, and 5- to 7.5-cm soil layers, respectively.


2001 ◽  
Vol 81 (1) ◽  
pp. 45-52 ◽  
Author(s):  
R H Azooz ◽  
M A Arshad

In areas of the northwestern Canadian Prairies, barley and canola are grown in a short growing season with high rainfall variability. Excessively dry soil in conventional tillage (CT) in dry periods and excessively wet soil in no-tillage (NT) in wet periods could cause a significant decrease in crop production by influencing the availability of soil water. The effects of CT, NT and NT with a 7.5-cm residue-free strip on the planting rows (NTR) on soil water drying (–dW/dt) and recharge (dW/dt) rates were studied in 1992 and 1993 during wet and dry periods to evaluate the impact of NTR, NT and CT systems on soil moisture condition. The soils, Donnelly silt loam and Donnelly sandy loam (both Gray Luvisol) were selected and soil water content by depth was measured by time domain reflectometry. Water retained at 6 matric potentials from –5 to –160 kPa were observed. In the field study, –dW/dt was significantly greater in CT than in NT in the silt loam for the 0- to 30-cm layer during the first 34 d after planting in 1992. The 0- to 30-cm soil layer in CT and NTR dried faster than in NT during a period immediately following heavy rainfall in the silt loam in 1993. The drying coefficient (–Kd ) was significantly greater in CT and NTR than in NT in the silt loam soil in 1993 and in the sandy loam soil in 1992 in the top 30-cm depth. The recharge coefficient (Kr) was significantly greater in NT and NTR than in CT for the silt loam soil. The NTR system increased the –dW/dt by 1.2 × 10-2 to 12.1 × 10-2 cm d-1 in 1992 and 1993 in the silt loam soil and by 10.2 × 10-2 cm d-1 in 1993 in the sandy loam soil as compared with NT. The dW/dt was 8.1 × 10-2 cm d-1 greater in NTR in 1992 and 1993 in the silt loam soil and was 1.9 × 10-2 greater in NTR in 1992 than in CT in the sandy loam soil. The laboratory study indicated that NT soils retained more water than the CT soils. The NTR practice maintained better soil moisture conditions for crop growth than CT in dry periods than NT in wet periods. Compared with NT, the NTR avoided prolonged near-saturated soil conditions with increased soil drying rate under extremely wet soil. Key words: Water drying, water recharge, water depletion, wet and drying periods, hydraulic properties, soil capacity to retain water


1980 ◽  
Vol 56 (3) ◽  
pp. 112-114 ◽  
Author(s):  
Douglas M. Stone

A 55-year-old stand of second-growth northern hardwood growing on a well-drained sandy loam soil was converted to red pine to compare with an adjacent 1929 plantation. Part of the plantation was cleaned during the second and third growing seasons and second-year survival was 72%. In the non-cleaned portion, which is reverting to maple sprouts, aspen suckers, brush, and weeds, pine survival was 38%. Annual height growth averaged 15.0 and 8.1 cm (6.0 and 3.2. in.), respectively. Differences in early success of the two plantings are attributed to: 1) greater competition after clearing pole-size hardwoods; 2) larger tops and better developed root systems of 2-1-2 transplants used in 1929; 3) planting in prepared spots in 1929; and 4) above normal growing season precipitation during 1929, and below normal in 1976. Converting pole-size northern hardwoods to red pine will be difficult and expensive. Competing vegetation will be the most serious problem, particularly on good hardwood sites. Investments in converting hardwoods to red pine should be concentrated in poor quality stands on well drained soils with a site index for maple of 50 or less.


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