Southwest Louisiana Research Articles

Records of Baetisca obesa (Say) (Ephemeroptera: Baetiscidae) in Southeast Texas and Southwest Louisiana

Records of Baetisca obesa (Say) (Ephemeroptera: Baetiscidae) in Southeast Texas and Southwest Louisiana

Alternative Establishment Methods for Wheat Following Soybean1

AbstractA majority of wheat (Triticum aestivumL.) planted following soybean [Glycine max (L.) Merr.] in Louisiana is planted using conventional seedbed preparation. Delayed harvest of soybean due to late maturity or adverse weather may eliminate the option of planting a winter wheat crop. Field studies were conducted in southwest Louisiana on a Crowley silt loam (fine, montmorillonitic, thermic Typic Albaqualf) soil from 1980 to 1984 to compare various seeding methods for wheat following soybean. Planting methods included: (i) conventional seeding, (ii) overseeding at 50% soybean leaf defoliation (early overseeding), (iii) overseeding presoybean harvest, (iv) overseeding post‐soybean harvest, and (v) no‐till seeding in soybean residue. Wheat overseeded early was planted 16, 27, and 23 days prior to the other treatments in 1980, 1981, and 1983, respectively. Averaged over years, percent ground cover at approximately 100 days after early planting and at maturity was highest where wheat was overseeded early and lowest where it was seeded conventionally. Early season plant height averaged over years for wheat overseeded early was 21% greater than wheat overseeded preharvest, postharvest, and no‐till, and 47% greater than wheat seeded conventionally. Plant height at maturity was similar for all seeding methods. Yield obtained from wheat overseeded early was 14% higher than yields of the other treatments. Wheat yield was similar where wheat was seeded conventionally and no‐till. Differences in yield among the treatments were not reflected in wheat spike density or 500‐seed weight. Overseeding wheat in standing soybean and no‐till planting in soybean residue are viable alternative planting methods compared with conventional seedbed preparation. The earlier planting would allow wheat to establish more rapidly in the fall. Both overseeding and no‐till planting would be advantageous in a wet fall or where potential soil erosion would prohibit seedbed preparation.

Patterns of Late Quaternary Shelf-Margin Sedimentation, Southwest Louisiana: ABSTRACT

Patterns of Late Quaternary Shelf-Margin Sedimentation, Southwest Louisiana: ABSTRACT

Religion and Regional Culture: The Changing Pattern of Religious Affiliation in the Cajun Region of Southwest Louisiana

The hypothesis that large-scale economic development and population redistribution has led to the demise of regional culture is examined for the traditional Catholic Cajun community in southwest Louisiana. Using census type data, comparisons of religious affiliation patterns between the Cajun region, Louisiana, the South, and the nation demonstrate a small shift towards regional convergence over the 1950-80 period. An analysis of the twenty-two parishes in the Cajun region provides some limited support for the convergence argument. The results are discussed in light of earlier work by Newman and Halvorson (1984) reported in this journal.

Meander Scars as Evidence of Major Climate Change in Southwest Louisiana

Abstract Measurements of fossil meander features along the Sabine River near Merryville, Louisiana reveal that present day discharge is substantially less than when the Deweyville, Prairie, and Montgomery terrace surfaces were active floodplains. Available evidence indicates that these fills were laid down during interstadial or interglacial times and that the large discharges were the product of increased tropical storm activity.

Response of Solid‐Seeded Soybeans to Flood Irrigation. I. Application Timing1

AbstractVariation in seasonal rainfall accumulation directly affects soybean [Glycine max(L.) Merr.] yields. In southwest Louisiana, where soybeans are primarily grown in rotation with rice (Oryza sativaL.), moisture shortages frequently occur due to the presence of a traffic‐induced hardpan 15 to 20 cm below the soil surface, which restricts root development. Field studies were conducted in southwest Louisiana on a Crowley silt loam (fine, montmorillonitic, thermic Typic Albaqualf) soil during 1981–1983 to study response of solid‐seeded ‘Dare’ (Maturity Group V) and ‘Ransom’ (Maturity Group VII) soybeans to flood irrigation. Water was applied at R2 bloom (B), R5– R6 pod fill (PF), B + PF, and full season (FS) as needed based on tensiometer readings (60 to 65 cbar). A nonirrigated control was included for comparison. In 1981 rainfall was adequate prior to bloom, but deficient when plants entered the reproductive stage. In 1982 and 1983, rainfall was generally deficient prior to bloom but adequate during the reproductive stage. Yield responses to the irrigation treatments varied among years and were directly related to rainfall distribution. Averaged over years, Dare yields were 161 kg ha−1higher (P=0.05) than the control where water was applied at B + PF and Ransom yields were 168 and 323 kg ha−1higher (P=0.05) than the control where water was applied at B + PF and FS, respectively. Seed/pod for Ransom and 100‐seed weight for Ransom and Dare averaged over years were significantly higher than the control only where water was applied FS. Pods/plant, seed/plant, plant height at maturity, lower pod height, and plant density were not affected by the irrigation treatments. Results indicate that in years where moisture is limited prior to bloom, early application of water can be beneficial, provided it is applied as needed throughout the remainder of the growing season. In years where moisture is adequate in early season prior to bloom, water should be applied during the reproductive stage if water shortage occurs.

Environments of Sand Deposition, Southwest Louisiana Continental Shelf: ABSTRACT

A synthesis of approximately 20,000 km of high-resolution seismic profiles, coupled with vibracores and industrial platform borings, shows that various large sand bodies are present in the late Pleistocene and Holocene sediments of the southwest Louisiana continental shelf. Sand-deposition patterns have been largely controlled by glacio-eustatic sea level fluctuations, paleogeomorphology, subsidence, and salt tectonism. Sand deposits of the area fall into two categories: (1) those associated with sea level lowstands, or regressive deposits, and (2) those associated with rising sea levels, or transgressive deposits. Regressive facies include fluvial and deltaic sands, whereas transgressive sands are largely formed by the reworking of regressive deposits. End_of_Article - Last_Page 1430------------

PRODUCTION TRIALS OF PRAWNS COMPARING A MARINE RATION, CATFISH DIET AND AGRICULTURAL RANGE PELLET

ABSTRACTSupplemental prawn feeds were investigated in 1982 and 1983 at the Rockefeller Wildlife Refuge in southwest Louisiana. Brackish water ponds were stocked with postlarvae at 4.4/m2 and production compared among prawns fed: a commercially produced marine ration (25% protein); catfish ration (30% protein); or agricultural range pellets (10% protein).Prawns fed marine ration achieved the largest size and greatest biomass during both years. Excluding ponds which experienced survival less than 60% due to low oxygen, production of marine ration fed prawns ranged from 556 to 828 kg/ha (av. 704 kg/ha) in 1982 and 704 to 808 kg/ha (av. 733 kg/ha) in 1983. Production in ponds receiving catfish pellets ranged from 483 to 780 kg/ha (av. 588 kg/ha) and prawns fed crushed range pellets had production of 613 kg/ha. Average size of prawns receiving marine ration was 24 g in 1982 and 20 g in 1983. Those fed catfish ration averaged 17 g and range pellet produced prawns averaging 17 g. Food conversion factors were 0.9 and 1.1 for marine ration in 1982 and 1983, respectively; catfish ration and range pellets resulted in average factors of 1.0 and 1.1, respectively.Dissolved oxygen was a continuing problem throughout the study in most ponds. The ponds which received range pellets displayed the poorest water quality.

Water Use and Costs of Irrigating Rice in Southwest Louisiana

Water Use and Costs of Irrigating Rice in Southwest Louisiana

Small Topographic Differences Affect Slash Pine Response to Site Preparation and Fertilization

Abstract On a Wrightsville-Vidrine silt loam flatwoods in southwest Louisiana, six-year-old slash pines (Pinus elliottii Engelm. var. elliottii) planted on the better drained Vidrine-pimple mounds and Vidrine-like ridges were nearly four times larger than pines planted in the poorly drained Wrightsville depressions. Site preparation treatments did not affect tree growth on the better drained sites. In the poorly drained depressions pines planted on beds were 37 percent taller and averaged 49 percent more volume per tree than pines planted on harrowed plots. Fertilization did not increase yields on the poorly drained sites. On the better drained sites, pines fertilized with triple superphosphate were 24 percent taller and averaged 84 percent more volume per tree than unfertilized pines.

Effect of lowland rice culture on subsequent soybean response to phosphorus fertilization

Abstract Soybeans ( Glycine max (L.) Merr.) are primarily grown in rotation with rice ( Oryza sativa L.) in southwest Louisiana. A typical rotation program consists of rice and soybeans grown in alternate years, or 1 year of rice followed by 2 years of soybeans. Phosphorus (P) deficiency induced by drainage following soil submergence has been reported in crops grown following rice. Field studies were conducted in 1980 and 1981 on a Crowley silt loam (Typic Albaqualf) soil to determine if P deficiency occurs in soybeans following 1 year of rice and to determine the most efficient method of P fertilization in this rotational system. Phosphorus fertilizer at rates of 0, 12, 24, 36, and 48 kg/ha was either banded 2.5 cm below the seed or broadcast and incorporated. Soybean grain yields over the two growing seasons were not affected by method of P placement. Grain yields averaged over years increased 527 kg/ha when the P rate was increased from 0 to 48 kg/ha. Maximum yield response to P fertilization was obtained when P was applied at rates of between 24 and 36 kg/ha. The 100-seed weight increased with increasing P the 2nd year. Method of P placement had no effect on any of the other parameters measured. The number of pods per plant and leaf P and nitrogen (N) concentration increased with increasing P rates in 1980. Plant population, plant height, and whole plant dry matter production measured at R2 growth stage were similar for all P treatments in 1981. Even though P deficiency symptoms occurred early in the growing season, the similarity in plant height and dry matter production among P treatments indicated that plants had recovered by flowering. Phosphorus deficiency did not appear to be a major problem in soybeans when grown following rice in a 2-year soybean—1-year rice rotation. Soybeans may be less sensitive to P deficiency than other crops and/or transformations during flooding of rice that reduce soil P availability may have been reversed with time. Furthermore, infrequent flooding for rice in this rotation may not have been sufficient to induce P deficiency in the subsequent soybean crop. The experimental areas used in these studies were planted to rice only 1 year prior to soybeans. Flooding- and drainage-induced P fixation should be less severe in this rotation than when soybeans follow more frequently planted rice.

Relationships among Vertical Accretion, Coastal Submergence, and Erosion in a Louisiana Gulf Coast Marsh

ABSTRACT Vertical accretion in a southwest Louisiana Spartina patens brackish marsh has not kept pace with coastal submergence during the past three decades. The rate of accretion determined from 137Cs dating and the use of artificial marker horizons averaged 0.8 cm yr-1, whereas coastal submergence obtained from tide-gauge data averaged 1.2 cm yr-1. Conversion from marsh to open-water bodies closely paralleled the increase in coastal submergence. If the resulting aggradation deficit continues, the marsh will likely complete its transformation to an open bay in less than 40 years. In view of recent projections of increasing sea-level rise the results presented may foreshadow a more widespread phenomenon.

Recent Foraminifera Around Petroleum Production Platforms on Southwest Louisiana Shelf: ABSTRACT

In the spring, summer, and winter of 1978-79, 673 samples were taken from around petroleum production platforms and control sites on the southwest Louisiana continental shelf to assess the effects of long-term petroleum exploration, drilling, and production activity on marine organisms. The 64,326 living Foraminifera recovered represent 51 species and 35 genera. Standing crops are high (up to 3,294 living Foraminifera per 10 cm2), because of the large quantities of available food supplied by the Mississippi River, and because a wet picking method was used that preserved juvenile and delicate tests. Species diversity is generally low; two species, Nonionella basiloba and Buliminella bassendorfensis, account for nearly 76% of the total population. The species composition varies somewhat with season, water depth, and physical conditions. The statistical analyses show little negative effects of petroleum operations on the benthic Foraminifera of this area. The foraminiferal populations are controlled by the physical parameters of this naturally stressed environment, especially by water depth, temperature and salinity fluctuations, sediment movement, and dissolved oxygen values. Proximity to platforms appears to cause no adverse effects on the organisms. End_of_Article - Last_Page 1433------------

The Morgan Site: An Important Coles Creek Mound Complex on the Chenier Plain of Southwest Louisiana

The chenier plain of southwest Louisiana supported a relatively dense population in the Coles Creek period. The Morgan site, located on the Pecan Island chenier, was a major center for the local inhabitants in Middle and Late Coles Creek times (c. AD 800–1000). Recent excavations at this site by the Lower Mississippi Survey resulted in the delimitation of the site, revealing areas of intensive occupation. A rich midden was tested to work out temporal changes in the local ceramics of the Coles Creek period. The excavation techniques employed enabled us to distinguish micro-evolutionary changes within the Baytown Plain rim mode assemblage recovered at Morgan. Determining such changes within the ceramics of the Coles Creek period has contributed to the relative dating of the Morgan mounds. The excavation methods presented here provide a means for ascertaining which Coles Creek components in the region were occupied contemporaneously. This information is fundamental to further studies on settlement and subsistence in the chenier plain.

Ectoparasites of Wild Canids from the Gulf Coastal Prairies of Texas and Louisiana

Three tick, 1 louse and 2 mite species were recovered from 19 wild canids, including 5 Red Wolves ( Canis rufus gregoryi ), 6 Coyotes ( Canis latrans ), and 8 Red Wolf × Coyote hybrids, from the Gulf Coastal Prairies of southeast Texas and southwest Louisiana. An additional 386 canids, including Red Wolves, Coyotes, Red Wolf × dog hybrids, and Red Wolf × Coyote hybrids, were examined from 1974 through 1979 for sarcoptic mange. Ectoparasites recovered from wild canids included Amblyomma americanum (7% of hosts infected), Amblyomma maculatum (80%), Ixodes scapularis (1.3%), Trichodectes canis (7%), Sarcoptes scabiei (9%), and Demodex sp. (0.3%). This is the first report of a species of Demodex in a wild canid host and the first definitive report of S. scabiei from these hosts in Texas. The 34 cases of sarcoptic mange encountered in this study demonstrated varying degrees of alopecia, scabby encrustations, slate-gray discoloration, and thickening of the skin. A female Red Wolf with mange and several captive Red Wolves suffering from sarcoptic mange were treated by shampooing with Mycodex® pet shampoo with lindane followed by application of benzyl benzoate with lindane. This treatment was successful in curing most severe infections of sarcoptic mange and the single case of demodectic mange in these hosts. The ramifications of ectoparasitism, especially mange, in these hosts are discussed.

Variation in Age and Size at Maturity of the Slider Turtle (Pseudemys scripta)

The adaptive strategy of the slider turtle, Pseudemys scripta, in terms of age and size at sexual maturity is discussed. Populations from a natural aquatic habitat and from a cooling reservoir on the US DOE Savannah River Plant are compared. (HCR)

Dirofilariasis in wild canids from the Gulf coastal prairies of Texas and Louisiana, U.S.A.

Heartworms, Dirofilaria immitis, were recovered from 17 out of 24 (71%) coyotes, Canis latrans, 38 out of 46 (83%) coyote × red wolf hybrids and all of 8 (100%) red wolves, Canis rufus gregoryi, collected from the Gulf coastal prairies of southeast Texas and southwest Louisiana. Intensities of infection ranged from 1 to 176 ( x=25 ) worms per host. There was a significantly ( P<0.05) higher intensity of infection in red wolves. Prevalence of heartworms increased significantly with increasing age. There were no significant differences between coyotes, hybrids and red wolves or between different host sexes in terms of prevalence. The female to male ratio of heartworms was close to unity (1.2:1) and was not correlated with worm burdens. Nematodes were primarily localized in the right heart, frequently extending into the pulmonary artery and the pulmonary arterial tree in the lungs. In 13 instances, 1–4 adult heartworms were recovered from the venae cavae. Pathological responses in the right heart were variable, depending on the intensity of infection. In severe infections, there were small areas of infarctive necrosis with mild to severe interstitial edema in the myocardium. Lesions in the pulmonary artery and pulmonary arterial trunk varied from mild focal hyperplastic intimal changes to extensive exudative villous endarteritis. The latter was characterized by a hyperplastic collagenous stroma with numerous histiocytes, plasma cells and eosinophils. Lung pathology varied from patchy to extensive areas of congestion, edema, hemorrhage, interstitial pneumonitis and infarction. In cases with heartworms in the venae cavae, hepatic changes were minimal and associated with liver changes such as passive congestion and centrolobular necrosis seen in cases without adult worms in the venae cavae. In heavily infected animals, hemosiderosis of the liver, spleen and kidneys was pronounced. A microfilaremia was noted in 46% of the infected wild canids. Microfilariae were observed in tissue sections of the myocardium, lungs, liver, kidney, spleen, lymph nodes, pancreas and appendix. Wild canids from this area are regarded as natural definitive hosts and primary reservoirs for heartworms and it appears that this infection is an important factor in the morbidity and mortality of these hosts.

The louisiana Cajuns: The quest for identity through education

One of America's oldest and most distinctive ethnic minorities are the Cajuns of Louisiana.' Their expulsion (as Acadians) from Nova Scotia by the British in 1755 and their subsequent settlement in southwest Louisiana is an old, familiar epoch with all the necessary ingredients of a classical tragedy. Following a rather shaky period of resettlement and adjustment, they proceeded to adapt to their new, sub-tropical environment in ways that would eventually result in a modern way of life containing many of the elements of their eighteenth-century Acadian world. This essay is about the education of the Cajuns. The subject is an important one to consider in understanding the Cajuns, because it has its own unique history and contains particular aspects which, when combined, constitute something rather distinctive in American education.

Characteristics of Diapirs on Outer Continental Shelf-Upper Continental Slope Boundary, Northwest Gulf of Mexico: ABSTRACT

An 18,000 km2 segment of the shelf-slope boundary off southwest Louisiana was studied using high resolution seismic profiles. Mapping of the distribution of diapirs, faults, synclinal and anticlinal axes, and the configuration of the subseafloor surface of diapiric material revealed significant patterns. On the outer continental shelf, diapirs are characteristically either buried or exposed and severely eroded. Erosional surfaces on upper-slope diapirs can be used to estimate subsidence rates. The complex bathymetric contours on the upper slope are the result of diapiric activity and show characteristic fault patterns and relations to pierced sediments that can be attributed to gravity-induced movement of salt downslope triggered by the weight of overlying sediment prisms. Salt is present at shallow depths on the upper slope and is usually capped by a sheath of seismically chaotic, fine-grained sediments. Diapirism and the loading of sediments in depositional basins are interdependent processes actively reshaping the shelf-slope boundary through marginal accretion. End_of_Article - Last_Page 1689------------

Response of Bottom Waters on West Louisiana Shelf to Transient Wind Events and Resulting Sediment Transport: ABSTRACT

The predominantly longshore near-bottom currents in 10 m of water off the southwest Louisiana coast exhibited seasonal variability. Currents in winter were primarily westward, although easterly currents were generated rapidly by cold-front passages. Velocities increased during the spring, and the current motion was to the south-southwest as stratification developed and mechanisms other than the wind became active in the shallow waters. The summer current regime was characterized by slow, easterly motion in response to generally west and southwest winds. Sediments were entrained by wave action and bottom currents during transient wind events, such as summer storms, winter cold-front passages, and persistent southeasterly wind events during the spring. The summer storm and spring wind events transported sediments to the west at a rate of approximately 30 km/day. Sediments suspended in early winter were moved east and west by bottom currents, but little net transport occurred. Frontal passages in March and early April transported suspended sediments more than 250 km to the west. End_of_Article - Last_Page 1683------------