Row Pattern Research Articles

Control of Bollworm/Budworm Complex in Mississippi Cotton, Trial III, 1992

Abstract Treatments were applied on 14 Aug using a CO2 powered backpack sprayer calibrated to deliver 9.9 gal of finished spray per acre through 8001 nozzle tips at 48 psi. The crop had been planted on a skip row pattern, 2 and 1, on 36 inch rows. The plots, which were located in Madison County, were 6 rows wide by 40 ft long, arranged in a randomized complete block design with 4 replications. Counts were made 3 and 7 DAT by searching the terminal area of 25 plants per plot for larvae; 4 randomly chosen fruiting structures (squares and young bolls) from each plant were examined for larval damage. No rain fell on the plots prior to the 3 DAT sample date. Pretreatment infestation level within the plot area was 12% eggs and 10% small larvae. Of 13 larvae collected from check plots at 3 DAT, 77% were identified as tobacco budworms.

First-principles simulation of STM/STS of Si(100) reconstructed surfaces

The STM images and the STS spectra of silicon (100) reconstructed surfaces are theoretically simulated by the first-principles local density approximation (LDA) method and the tunneling Hamiltonian formalism. A new method for evaluating a tail of the surface wave function, which is important for tunneling of electrons, is also employed. Our simulation shows that the symmetric dimer structure seems to reproduce STM images of occupied states, but it cannot reproduce STM images of unoccupied states or STS spectra. On the other hand, simulations of all asymmetric dimer structures reproduce STS spectra in the seemingly symmetric dimer region as well as the zigzag dimer row patterns of the STM images. These results imply that observed symmetric images by STM may be asymmetric dimer structures.

Correlation of the arrangement pattern of enamel rods and secretory ameloblasts in pig and monkey teeth: a possible role of the terminal webs in ameloblast movement during secretion.

Enamel rod architecture and ameloblast arrangement were examined in pig and monkey teeth using light microscopy and scanning and transmission electron microscopy. Enamel rods in the pig teeth were arranged in longitudinal straight rows in the initial enamel layer, in longitudinal wavy rows in the inner enamel layer, and in a staggered pattern in the outer enamel layer. Rod decussation was seen only in the inner layer. Cross-sectioned enamel rods in the pig were arcade-shaped in the initial and inner layers, and mostly round in shape with circular boundaries in the outer layer. Arrangement of secretory ameloblasts at the level of the distal terminal web and Tomes' processes, and shape of Tomes' processes, corresponded to those of the enamel rod in the enamel layers. Distal terminal webs were well developed between straight rows of the ameloblasts forming the initial layer and between wavy rows of the ameloblasts forming the inner layer, and less developed within a row. The filament bundles in the distal terminal webs were also oriented along the rows. However, in the ameloblasts forming the outer layer, which lost their row pattern, distal terminal web filaments were distributed uniformly at the cell periphery. A similar arrangement of wavy rows of ameloblasts at the level of distal terminal web and Tomes' processes was also seen in monkey teeth.

Constructional morphology of photoreceptor patterns in percomorph fish

The frequently occurring photoreceptor patterns in fish are explained using functional and environmental demands in a geometric model. The shape of the double cone provides a number of constructional properties leading to a limited number of appropriate configurations. The probability of their occurrence is estimated from the degree to which the combination of properties of each configuration meets specific environmental light conditions. A row pattern of merely double cones is especially suitable for vision in a dim homochromatic environment; a triangular pattern is quite appropriate for high resolution and accurate movement detection, whereas the known square pattern has a high adaptive capacity to varying spectral distributions. In this context the transforming capacities of both square and row patterns can be understood.

AC 303630 Bollworm/Tobacco Budworm Insecticide Trial, 1990

Abstract Seven treatments were tested for efficacy against bollworm/tobacco budworm in cotton planted 18 May. Treatments were arranged in randomized complete blocks replicated 4 times (6.7 (2 rows) × 50 ft). Application was with a compressed air spray system mounted on a John Deere, model 6000 high clearance sprayer (5.5 mph, 7.3 gal/acre, 42 psi, Conejet TX-8 nozzle tips). The cotton crop was planted in a 2 × 1 skip row pattern. Treatments were arranged so that the treated rows in each plot were bordered on each side by 2 untreated planted rows and 1 untreated skip row. Bollworm/tobacco budworm larval infestation and damage observations were made by examination of the top 6 inches (terminal area) of 25 plants per plot for larvae, and examination of 25 squares from the terminal area for larval damage. Data are converted to larvae per 100 terminals and percent larval damaged squares. Since bollworm/tobacco budworm infestations in 1990 were atypically low during most of the season, only pretreatment and posttreatment means for larvae in terminals and larval damaged squares for the first application date, 10 Aug, are presented.

Grass Weed Management Systems in Grain Sorghum (Sorghum bicolor)

Field experiments in 1984 and 1985 near Headland, AL involved the influence of 18 integrated weed management systems incorporated from nine herbicide-tillage systems (H-T) and two row patterns on control of large crabgrass and Texas panicum, crop yield, and net returns in grain sorghum. The conventional-tillage system plus herbicide combinations; alachlor preplant incorporated (PPI), atrazine postemergence (POST), and paraquat POST directed, provided 90% or greater control of large crabgrass throughout the season and high sorghum yields in one of two years; and 90% or greater control of Texas panicum from mid-June through mid-August and high sorghum yields in both years. Results in 1984 and 1985 similar to those above were obtained with strip tillage plus herbicide combinations; alachlor PPI, atrazine POST, and paraquat POST directed; alachlor PPI and tridiphane plus atrazine POST; and tridiphane plus atrazine POST and paraquat POST directed. Row patterns did not consistently influence control of large crabgrass, Texas panicum, or sorghum yield. Economic net returns ranged from – $20 to $210 per hectare for the large crabgrass control systems in 1984; however, low sorghum yields in 1985 resulted largely in negative returns. Similar net returns were obtained in the Texas panicum experiment.

Effects of Corn Row Pattern and Intercropping with Legumes on Silage Corn

(...) A paired-row arrangement of silage corn for intercropping was tested on a Sultan silt loam (fine silty, mixed, mesic, Aquic Xerofluvent). The paired-row pattern, with 12 in. between the two rows of the pair and 60 in. between pairs, was compared in monoculture with a conventional 30-in. single-row pattern. Fertilizer treatments ranged from 0 to 180 lb N/acre; and 0, 26, and 39 lb P/acre. Dry matter yields and tissue concentrations of N, P, and K varied among years and fertility levels, but were not significantly different between the two corn row patterns (P<0.05). (...)

SAR observations and modeling of the C-band backscatter variability due to multiscale geometry and soil moisture

The effect of the multiscale surface geometry on the sensitivity of C band synthetic aperture radar (SAR) data to soil moisture is studied. The experimental data consist of C-band SAR images of an agricultural site, including fields with various combinations of three distinct roughness components from small to large scale. The backscatter variability due to surface roughness has been analyzed. The effect of random roughness associated with soil clods is never less than 2 dB, and the effect of a row pattern can be as strong as 10 dB. In addition, the periodic drainage topography induces a backscatter variability due to soil moisture variation and drainage relief. The results indicate that airborne C-band SAR data cannot be easily inverted into soil moisture data. However, with ERS-1 or Radarsat data at an incidence angle of about 20 degrees , the effect of random and periodic roughness can be reduced to about 2 dB if the look angle is less than 50 degrees .< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Correlation between photoluminescence and electrical local fluctuations in liquid encapsulated Czochralski semi-insulating GaAs substrates

We have developed a non-destructive technique, based upon scanning photoluminescence, which is capable of qualifying GaAs semi-insulating substrates used for the fabrication of large scale integrated circuits. The optical results (microscopic fluctuations of the integrated photoluminescence intensity) have been quantitatively correlated with a-posteriori electrical procedure called the dense row pattern procedure which determines the microscopic and macroscopic fluctuations of the MESFET's threshold voltage.

Effects of Mepiquat Chrloride on Natural Plant Resistance to Tobacco Budworm in Cotton1

The effects of mepiquat chloride (1,1‐dimethyl‐piperidinium chloride) (Pix®) on natural plant resistance to the tobacco budworm (TBW), (Heliothis rirescens F.) in cotton (Gossypium hirsutum L.) was studied in 1984 and 1985. A split plot randomized complete block experimental design with six replications was used. ‘Stoneville 213’ was grown in two row plots (2 ✕ 13.7 m) in a two‐planted oneskip row pattern on a Marietta sandy loam (fine‐loamy, siliceous, thermic Fluvaquentic Eutrochrepts) soil at Mississippi State, MS. Main plot treatments were with and without TBW and subplot treatments were three levels of mepiquat chloride (0, 50, and 100 g a.i. ha−1). The 100 g a.i. ha−1 level was split into 50 g at the recommended time of application and 50‐g 14 days later. Mepiquat chloride treatments caused significant yield increases at first harvest, but not in total yield, suggesting the typical induced earliness with this plant growth regulator. In the presence of an artificial infestation of TBW, no significant differences in yield were recorded either year among mepiquat chloride levels, indicating no increased plant resistance to artificial infestations of TBW.

Growth and Development of the Florunner Peanut Cultivar as Influenced by Population, Planting Date and Water Availability1

Abstract The influence of planting date, plant population, and row pattern on peanut (Arachis hypogaea L.) growth and development was studied at two locations in Georgia. Twin rows were found to give faster canopy closure at high populations (212,000 plants ha-1) but not at low populations (26,500 plants ha-1). No yield differences due to row pattern were found. Increasing population increased competition for light which increased plant height and the percent of total dry matter partitioned to the stem. Population effect on yield was dependent on planting date and environmental conditions. When an optimum planting date (28 April 1983) was combined with adequate moisture (65 cm of water during season), increasing population from 30,000 to 240,000 plants ha-1 increased yield from 5290 to 6840 kg ha-1. A combination of an optimum planting date and moisture-limiting conditions (33 cm) resulted in a positive yield response of 20% as population was increased from 26,000 to 208,000 plants ha-1. Combining a late planting date (3 June 1983) with either adequate moisture (66 cm) or moisture-limiting conditions (35 cm) resulted in no yield response due to population. Late planting dates significantly reduced grade.

Yield Response of Two Cotton Cultivars to Tobacco Budworm Infestation1

Two cotton, Gossypium hirsutum L., cultivars were artifically infested with tobacco budworm, Heliothis virescens (F.), larvae for different time intervals during the first 8 weeks of fruiting to determine impact on yield reduction and maturity delay. The cultivars tested were ‘Stoneville 213’ (full‐season) and ‘Tamcot CAMD‐E’ (short‐season) grown in 1 ✕ 13.7 m long single row plots in a two‐planted one‐skip row pattern during the 1982 and 1983 growing seasons on a Leeper silty clay loam (fine, montmorillonitic, nonacid, thermic Vertic Haplaquepts). Treatments consisted of applying 12 first instar larvae in the terminal area of each plant, once per week for the following combination of weeks after fruiting had begun: none (control), Weeks 1 to 2, to 4, 1 to 6,1 to 8, 7 to 8, 5 to 8, 3 to 8, 3 to 4, to 6, and 3 to 6. When larvae were not applied in a given week, plots were protected with an insecticide. Plots were machine harvested three times for yield determinations and delays in maturity. All treatments involving larval applications the first 2 weeks of fruiting resulted in significant reductions in yield, compared with the control, for both cultivars at first harvest. Tamcot CAMD‐E with larval treatments produced a larger percentage of its total yield at first harvest than did Stoneville 213. When first and second harvest were accumulated, the same trends were apparent. Total yield of Stoneville 213 was significantly reduced only when larvae were applied for at least a 4‐week time period. The same trend was apparent with Tamcot CAMD‐E: timing of applications (rather than length of time) had the greatest effects; however, reduction in yield was not significant. Subclass regression analysis of yield as a function of larval application indicated that yield reduction trends averaged over years were significant and the responses of the two cultivars were found to be significantly different from each other as tested by homogeneity of slopes. The yield of Tamcot CAMD‐E was not reduced or delayed as much as that of Stoneville 213 when tobacco budworm larvae were applied during early‐, mid‐, and full‐season. The application of larvae during the early stage of fruiting had a greater impact on reducing yield and delaying maturity than when larvae were applied during mid‐ and late‐season.

Weed Management in Minimum-Tillage Peanuts (Arachis hypogaea) as Influenced by Cultivar, Row Spacing, and Herbicides

Field experiments were conducted in 1982 and 1983 on a Dothan sandy loam (Plinthic Paleudult) at Headland, AL, to investigate minimum-tillage production of peanuts (Arachis hypogaeaL.). The experiments included two peanut varieties: a) ‘Pronto’ (an earlier maturing Spanish type), and b) ‘Florunner’ (a later maturing runner type). Two row-spacing patterns were used: a) conventional 91-cm rows, and b) a modified twin 18-cm row pattern. A constant seeding rate (140 kg/ha) was used regardless of row spacing. Six herbicide systems were evaluated within each combination of variety and row spacing. The Florunner variety outyielded the Pronto variety across both years and weed management systems. Modified twin 18-cm rows outyielded conventional 91-cm rows across years and peanut varieties. Two of the six weed management systems were successful: 1) paraquat (1,1’-dimethyl-4,4’-bipyridinium ion) + oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide) (preemergence), paraquat (ground cracking), naptalam (N-1-naphthylphthalamic acid) + dinoseb (2-sec-butyl-4,6-dinitrophenol) (postemergence); and 2) paraquat + pendimethalin [N-(1-ethylpropyl-3,4-dimethyl-2,6-dinitrobenzenamine] (preemergence), acetochlor [2-chloro-N(ethoxymethyl)-6’-ethyl-o-acetotoluidide] + dinoseb (ground cracking), and cyanazine {2-[[4-chloro-6-(ethylamino)-s-triazine-2-yl]amino]-2-methylpropionitrile} (early postdirected spray). Both systems provided the best overall control of Texas panicum (Panicum texanumBuckl. ♯ PANTE), Florida beggarweed [Desmodium tortuosum(Sw.) DC. ♯ DEDTO], and sicklepod (Cassia obtusifoliaL. ♯ CASOB) and were acceptable for use in minimum-tillage peanut production.

Row Pattern and Weed Management Effects on Peanut Production1

Abstract Field experiments were conducted from 1981 through 1983 on a Dothan sandy loam (Plinthic Paleudults) at Headland, Alabama, to investigate the effects of row patterns and weed management systems on weed control, peanut yield, and net returns to land and management. Treatments consisted of three row patterns, a) conventional 91-cm rows, b) dual twin 18-cm rows, and c) triple twin 18-cm rows, and six weed management systems ranging from none to various combinations of herbicide and mechanical inputs. The experimental area was naturally infested with bristly starbur (Acanthospermum hispidum DC), sicklepod (Cassia obtusifolia L.), Florida beggarweed [Desmodium tortuosum (Sw.) DC.], large crabgrass [Digitaria sanguinalis (L.) Scop.], and Texas panicum (Panicum texanum Buckl.). Results showed that weed control was affected somewhat by row patterns with broadleaf weeds being more responsive to row pattern manipulation than grass weeds. Weed fresh weights were generally lower as row patterns narrowed from conventional 91-cm spacing, however exceptions did occur. Highest yields and net returns were obtained when peanuts were planted in the dual twin 18-cm rows and weed management included benefin applied preplant incorporated, plus alachlor applied preemergence, and two timely cultivations.

Intercropped Corn–Soyabean Density Studies. I. Yield Complementarity

SUMMARYIntercropped corn and soyabean were grown in a randomized block design (RBD) and a systematic design (SD) in 1981 and 1982 to evaluate total yield, yield complementarity, crop competition and land-use efficiency as affected by corn and soyabean densities. In the RBD, three corn density treatments were applied to corn–corn–soyabean–soyabean, corn–corn–soyabean, and corn–soyabean intercrop row patterns and to monocultures. In the SD, 9 or 10 corn densities were factorially combined with up to 13 soyabean densities in a corn–soyabean row pattern (91 cm spacing). In the RBD, total intercrop yields were similar to corn monoculture yields (60.8 to 62.7 t ha−1 in 1981) in the corn–corn–soyabean and corn–soyabean patterns at high corn densities but were less at low density. The corn–corn–soyabean–soyabean pattern yielded 87% of the corn monoculture at high density in 1982. These results were confirmed in the SD, where total intercrop yields were highly responsive to corn density and poorly responsive to soyabean densities. Both experiments indicated that high corn row densities are needed to maintain yields in corn–soyabean intercrops, possibly higher than the levels studied. Land equivalent ratios were above 1.0 for all but the low density corn–corn–soyabean–soyabean pattern in the RBD. The ability of an intercrop with as many as half the corn rows replaced by soyabean to produce yields similar to corn monoculture indicates a biological complementarity for dry matter production in the mixtures.

Skip‐Row Planting and Row Pattern Effects on Virginia‐Type Peanut Cultivars1

AbstractSince increasing peanut (Arachis hypogaea L.) production per area of land is a constant goal of researchers, skip‐row planting was an avenue that needed exploring. A 3‐year study was conducted at the Tidewater Research and Continuing Education Center in Suffolk, Va. to determine the effects of two planting patterns, two row patterns, and two cultivars on the yield, value, and grade characteristics of virginia‐type peanut. Planting patterns of solid (all rows planted) and skip‐row (two 0.91 m rows planted and one 0.91 m wide row fallow) were used in a 2 × 2 × 2 factorial arrangement with row patterns of a single row centered in a 0.91 m wide row and twinrows (0.18 m apart) centered in a 0.91 m wide row for the cvs. Florigiant and NC 7. Plots were 3.66 m wide and 10.67 m long with the two center rows harvested for the single row planting and the four center rows harvested for the twin row planting. Soil types for the study were Dragston fine sandy loam (coarse‐loamy, mixed, thermic, Aerie Ochraquults) in 1979, Dragston loamy fine sand in 1980, and an Eunola loamy fine sand (fine‐loamy, siliceous, thermic Aquic Hapludults) in 1981. NC 7 produced a higher percentage of extra large kernels (ELK), sound mature kernels (SMK), total meat (TM) and had a higher dollar value ha−1 than Florigiant. No differences were found between the two cultivars for yield or percentage of fancy size pods (FP). The two row patterns had no effect on yield, value or any grade characteristic. Skip‐row planting produced a significantly (P &lt; 0.01) higher yield and value on a planted hectare basis than did solid planting, while no differences were recorded for any grade characteristic. The highest yield (4599 kg ha−1) and value (2266 dol ha−1) were recorded for NC7 in the twin‐row pattern with skip‐row planting.

Weed Management in Cotton (Gossypium hirsutum) Grown in Two Row Spacings

Tillage plus trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) and prometryn [2,4-bis (isopropylamino)-6-(methylthio)-s-triazine] and tillage plus trifluralin and fluometuron [1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea] applied as soil-incorporated preplanting treatments were compared with tillage alone in cotton (Gossypium hirsutumL.) grown in 51-cm and 102-cm rows on fine sandy loam soil. Over 3 yr, cotton grown in 51-cm rows yielded 15% more than cotton grown in 102-cm rows. Final cotton emergence was not altered by weed-control treatment or by planting pattern. Weed-control treatments with herbicides provided essentially complete, season-long control of grass and broadleaf weeds. At cotton layby, more weeds were in no-herbicide plots with 51-cm rows compared with 102-cm rows, but at cotton harvest numbers of weeds in both row patterns were essentially equal.

Preliminary Studies of Intercropping Combinations Based on Pigeonpea or Sorghum

SUMMARYVarious intercrops were examined in an alternate row pattern with pigeonpea or sorghum on both Alfisol (red soil) and Vertisol (black soil). The slow-establishing and later-maturing pigeonpea combined well with earlier cereals and legumes to give very large yield advantages as measured by the Land Equivalent Ratio. In the pigeonpea/cereal combinations, the earlier the cereal the bigger the yield advantage tended to be, attributed to improved use of resources over time as the difference in maturity periods of the component crops increased. Sorghum was generally more competitive than pigeonpea and intercropping advantages tended to be less. But even where there was little difference in maturity periods of the component crops, both sorghum/legume and sorghum/cereal combinations gave substantial and statistically significant advantages, suggesting that improved ‘spatial’ use of resources was also important.

Weed and Disease Responses to Herbicides in Single- and Double-Row Cotton (Gossypium hirsutum)

For 3 yr, herbicide treatments of preplant trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), postemergence diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea], both herbicides, or none were superimposed on cotton (Gossypium hirsutumL. ‘Acala SJ-2′) grown on beds centered at 102 cm using a single row or two rows spaced 28 cm apart. Cotton stand, after thinning, was 5.1 plants/m in each cotton row. Herbicides controlled annual weeds regardless of planting pattern. Cultivation, without herbicides, controlled annual grass weeds much better in cotton grown in single rows than in double rows. Preplant applications of trifluralin did not influence populations of cotton plants, regardless of row pattern. Single- and double-row plots treated with trifluralin always yielded more than untreated double rows. In two of three seasons, however, single-row plots without herbicides yielded as much as those treated with trifluralin. The lower yields in the double-row cotton were associated with reduced annual grass control especially in plots not treated with trifluralin. Weed control treatments or planting patterns did not influence the occurrence ofPythium ultimumTrow orRhizoctonia solaniKühn on cotton seedlings. The presence ofThielaviopsis basicola(Berk &amp; Br.) Ferr. on cotton seedlings was not influenced by planting pattern but was increased by trifluralin in the third year of the study. Percentage of cotton plants with symptoms of verticillium wilt (Verticillium dahliaeKleb.) was not influenced by weed control treatments, but the percentage of diseased plants was higher in single-row than in double-row planting patterns. We attribute this response to fewer plants per hectare in single rows compared to double rows.

Organization of the Cone Cells in the Retinae of Salmon (Salmo salar) and Trout (Salmo trutta trutta) in Relation to Their Feeding Habits

Regional variations of cone density, cone types and cone mosaic were investigated by light microscopy in yolk sac fry, parr and adults of salmon (Salmo salar) and trout (Salmo trutta trutta) and related to the feeding habits of different stages. The retinal organization of the two species is similar, as are their feeding habits. In parr and adults of both species a region with high cone density was found in the ventro-temporal part of the retina. The lowest values of cone density were found centrally in the dorsal half of the retina. An increase in cone density towards the ora serrata was noted in all retinae investigated. There is a good agreement between the density distribution of the cones in parr of salmon and trout and their feeding habits. The parr feed to a great extent on the invertebrate drift. Facing the current, the parr search the water region in front and above themselves for food organisms, thereby probably making use of the ventro-temporal area of high cone density. The connection between the cone density distribution and the feeding habits is less clear in adult salmon and trout, but the high cone density region is probably used when they feed on surface organisms and schooling prey. The ecological significance of cone types and cone mosaics is discussed. During growth there was a change of the cone mosaic from a regular square pattern in the fry towards a less regular square or row pattern in the adults. The position of regions with high and low cone density did not change during development in each species and had a similar distribution in the two species. On the other hand, the range of cone density values becomes relatively greater as the animal grows older. The cone density distribution seems to be more homogeneous in parr than in adults. Differences in the relative density distribution of the cones are influenced by recruitment at the retinal periphery and by spreading out of existing cells. In addition to the ora serrata, mitoses were also observed in more central parts of the retina having well-differentiated receptors and a cone mosaic. Mitoses were noted in all three nuclear layers but were most frequent in the outer nuclear layer, in which the resulting cells probably differentiate into rods. Undifferentiated zones similar to the peripheral growth zone of the retina were found on both sides of the falciform process in fry. In parr and adults an undifferentiated zone persisted only on the temporal side. It probably contributes to the high cone density in the ventro-temporal part of the retina by a delivery of new cells.