Several species of Potamogeton and Myriophyllum from New Jersey were collected and analyzed for 11 elements. Wide variations were observed in the inorganic composition of the plants, both within species and among species. In some instances, there appeared to be a relationship between the content of a specific element in a plant sample and the content of that element in the water in which the plants were growing. The nitrogen content of the plants was sufficiently high so that no extra nitrogen would be required to prepare composts from them.

Several contact and growth-regulator herbicides were evaluated as desiccants on greenhouse-grown cucumbers (Cucumis sativus L., var Ashly), sorghum (Sorghum bicolor L. Moench, var. Combine Kafir-60), mango (Mangifera indica L.), and field-grown guava (Psidium guajava L.). Pentachlorophenol (PCP) and 4,6-dinitro-o-sec-butylphenol (DNBP) consistently acted the fastest among compounds applied on several species. Herbicides such as 1,1'-dimethyl-4,4'-bipyridinium salt (paraquat) 6,7-dihydrodipyrido (1,2-a:2'c)pyrazidiinium salt (diquat), and the butyl esters of 2,4-dichlorophenoxyacetic acid plus 2,4,5-trichlorophenoxyacetic acid (2,4-D:2,4,5-T) were equally effective within 3 days after treatment of some species. Several other herbicides and herbicide mixtures were evaluated. Herbicide specificity and speed of desiccation varied with species. Adjuvants increased the phototoxicity of some herbicides.

Bioassay and chemical analyses of residual α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) from greenhouse and field experiments indicated that the persistence of this herbicide is increased by deep incorporation as compared to shallow incorporation or surface application. Laboratory studies using a charcoal vapor trap indicated that trifluralin volatilization decreased with increasing depth of incorporation. Volatilization appears to be an important mode of trifluralin dissipation from the soil.

In laboratory studies, the herbicide 3'-chloro-2-methyl-p-valerotoluidide (solan) when applied to soil was transformed in part to 3,3'-dichloro-4,4'-dimethylazobenzene. The biochemically mediated transformation followed the pattern established previously for 3,4-dichloroaniline-based acylanilides, but the 3-chloro-4-methylaniline intermediate did not accumulate. Compared to 3,4-dichloroaniline-based acylanilides, solan yielded less azo residue and did not inhibit soil respiration, even if applied at 200 times the recommended field rate.

A formulation containing 2-chloroethanephosphonic acid, its ethyl ester and anhydride (hereafter referred to as 66-329), caused defoliation and, subsequently, growth of inactive basal buds of honey mesquite [Prosopis juliflora var. glandulosa (Torr.) Cockerell]. With huisache [Acacia farnesiana (L.) Willd.], the same treatments increased the number of branches and leaves per node; however, apical buds often were killed. Application of 66-329 to mesquite increased the release of ethylene to levels in the experimental system which were physiologically active. Bud release by 66-329 appeared to be mediated by ethylene. Treatments that induce growth of basal and lateral buds of woody plants may allow the killing of more plants by subsequent herbicide application.

Postemergence applications of 0.5 and 1.0 lb/A of a potassium salt of 4-amino-3,5,6-trichloropicolinic acid (picloram) killed all or nearly all of the goldenrod (Solidago nemoralis Ait.) growing with timothy (Phleum pratense L.). Two lb/A of butoxy ethanol ester or dimethylamine salt of (2,4-dichlorophenoxy)acetic acid (2,4-D), and 1 and 2 lb/A of butoxy ethanol ester of 4-(2,4-dichlorophenoxy) butyric acid (2,4-DB) reduced yields of goldenrod 75 to 95%. Lower rates of herbicides were relatively unsatisfactory for controlling goldenrod. Timothy was not injured by the herbicides and yields increased 0.8 and 1.0 lb for each 1.0 lb of weeds that failed to grow.

Western ironweed (Vernonia baldwini Torr.) seedlings emerge from an exalbuminous achene. By 6 days after germination, a cortical collar was discernible between the hypocotyl and root. A pair of lateral buds arose exogenously from the outer two to three layers of this zone through dedifferentiation of cortical parenchyma. Sprouting of lateral buds could be stimulated in a few seedlings by 15 days after germination if they were clipped between the cotyledons and the hypocotyl-root transition zone. One of the seedling buds could be activated by top removal up to 40 days after germination when both could be stimulated to sprout. Ability to form new stems vegetatively was reflected in rate of anatomical maturity of the seedling buds.

A charcoal barrier method was devised to prevent the movement of S-ethyl dipropylthiocarbamate (EPTC) in the soil in order to expose certain parts of the plant without exposing the rest of the plant. Exposing the roots of barley (Hordeum vulgare L., var. Blue Mariot), oats (Avena sativa L., var. California Red), barnyardgrass (Echinochloa crusgalli L. Beauv.), annual ryegrass (Lolium multiflorum Lam.), wheat (Triticum vulgare L.), rice (Oryza sativa L., var. Belle Patna), cotton (Gossypium peruvianum Cav.), and yellow nutgrass (Cyperus esculentus L.) caused more injury than shoot exposure, while shoot exposure caused slightly more injury than root exposure to Johnsongrass (Sorghum halepense Pers.), sorghum (Sorghum vulgare Pers., hybrid Amak R-10), and peas (Pisum sativum L.). Seed exposure caused severe injury in some plant species but not others. The results obtained by this method disagree with published reports which claimed that only shoot exposure to EPTC led to injury. In numerous experiments with barley seeds accurately planted in a vertical position in a ½-inch layer of charcoal between two 1-inch layers of soil, root exposure always injured the plants more than shoot exposure. Exposing all parts (seeds, roots, and shoots) to EPTC caused the most injury to barley followed by exposing only the seeds, a combination of roots and shoots, roots, and shoots in decreasing order of injury symptoms. Similar results were obtained with oats when the depth of the treated soil above or below the seed was 1 inch, but increasing this depth to 1.5 inches or more resulted in more injury by shoot exposure than root exposure. The importance of root exposure was confirmed using another method of testing in which only the roots were exposed to the herbicide in nutrient solutions. Concentrations as low as 1 ppm of EPTC applied to the roots in nutrient solutions inhibited shoot growth of oats, barley, sorghum, and corn, while the growth of the roots was enhanced in some cases.

Greenhouse and growth chamber studies were conducted to investigate effects of herbicide placement in soil on toxicity to emerging seedlings. The use of a technique involving a plastic bag over the plants for 3 to 4 weeks to reduce soil moisture loss did not change the apparent site of 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) uptake by green foxtail (Setaria viridis (L.) Beauv.) or oats (Avena sativa L.). Atrazine was more effective on oats through root exposure and more effective on green foxtail through shoot exposure when an untreated buffer zone around the seed was used. But in subsequent studies without the buffer zone, atrazine was most active when placed immediately below the seed of both oats and green foxtail. Proximity to the seed increased effectiveness of atrazine, S-ethyl dipropylthiocarbamate (EPTC), and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron). Also, a narrow concentrated layer of these three herbicides adjacent to the seed was more effective than a wider dilute layer above or below the seed. A diurnal fluctuating temperature regime with a low night temperature increased toxicity of EPTC to oats through root exposure, when compared to a constant temperature regime.

Ioxynil (4-hydroxy-3,5-diiodobenzonitrile) and 2-(2,4-dichlorophenoxy)propionic acid (dichlorprop) appeared effective for control of fumitory (Fumaria officinalis L.) of the 10 herbicides tested in 1963. In 1964 and 1965, both herbicides were further tested under field conditions, but fumitory control results were erratic. Fumitory plants which had been treated with dichlorprop, although not killed, did not produce seed. Experiments under controlled environmental conditions showed that susceptibility of fumitory to ioxynil and dichlorprop was affected by temperature and humidity. High temperature and humidity were necessary for both herbicides to completely kill the plants although dichlorprop injured fumitory under all the environments. Fumitory was more susceptible to dichlorprop applied at the early stages of growth and more susceptible to ioxynil applied at the later stages.

Naturally-established turkey oak (Quercus laevis Walt.) shoots were treated with aqueous solutions of the product picloram + 2,4-D (4-amino-3,5,6-trichloropicolinic acid + 2,4-dichlorophenoxyacetic acid) and with picloram pellets. Various application methods were utilized at several dates during the year. Responses measured 14 and 17 months after initial treatments were percent control of original shoots, percent regrowth, plant height, and live stems/plant. Leaf-stem-basal treatments provided the highest degree of control of any method studied, averaging 87% total shoot control over five treatments dates. Foliar, mist-blower, and leaf-stem applications showed no differences, averaging 75%, 79%, and 78% control, respectively. Basal applications gave poorest results averaging only 12% control over five dates. No differences were observed among treatment dates for applications made during the growing season after the full-leaf stage, but treatments made before full-leaf provided less control than others. Soil applications of picloram pellets were more effective when applied during the early spring and summer than during fall or winter but were less effective than treatments applied to foliage at all dates.

The shoots of naturally established specimens of turkey oak (Quercus laevis Walt.) and red maple (Acer rubrum L.) were treated under conditions of approaching dormancy. Aqueous sprays of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) were applied as foliar treatments to the point of run-off at 2-week intervals beginning September 13 and continuing until three applications had been made for turkey oak and five had been made for red maple. Three experiments were conducted for turkey oak and two for red maple. Application rates were 2, 4, 8, and 16 lb of 2,4,5-T aehg of spray solution except that the 16-1b rate was deleted for turkey oak. Ester and amine derivatives were evaluated. Responses measured 9, 12, and 24 months after initiation of the experiments were percent control of original shoots, percent control of new shoots, shoot height, and number of live stems/plant. The average estimated control of original shoots of turkey oak and red maple increased from 42 to 54% as the application date was advanced from September 13 to October 11. The average height of the plants treated September 13 considering all evaluation dates was 3.4 ft compared to 2.6 ft for treatment made 4 weeks later. The results suggest two seasonal peaks in the response of some woody plants to foliar treatments of 2,4,5-T and that herbicidal effectiveness can be enhanced by application at the onset of senescence and dormancy.

Texas panicum (Panicum texanum Buckl.) seed were collected and treatments applied in an effort to increase germination. Also, plants were grown in the field and growth characteristics studied. Poor seed germination was obtained with all treatments, but wide variation in storage temperature produced the best germination. Seedlings emerged from seed planted as deep as 3 inches. An average of 118 heads per plant and 195 seed per head were produced, or 23,010 seeds per plant. Plant, seed head, and seed development followed sigmoid growth patterns. The species was resistant to most preplant and preemergence herbicides used in screening experiments.

A modification of an 8-ft, self-propelled combine for harvesting research plots of soybeans (Glycine max L.), sorghum [Sorghum bicolor (L.) Moench], and small grains is described. The combine facilitates efficient and precise harvesting of yield plots with considerable savings in time and labor.

A mixed stand of green rabbitbrush (Chrysothamnus viscidiflorus (Hook.) Nutt. var. puberulus Jepson) and big sagebrush (Artemisia tridentata Nutt.) was sprayed at different dates for 3 years with potassium salt of 4-amino-3,5,6-trichloropicolinic acid (picloram) at ¼, ½, and 1 1b/A, propylene glycol butyl ether esters of 2,4-dichlorophenoxyacetic acid (2,4-D) at 1, 2, and 3 1b/A, and a mixture of triisopropanolamine salts of picloram plus 2,4-D at ¼ plus 1 and ½ plus 2 1b/A. Picloram at ½ and 1 1b/A controlled rabbitbrush but not sagebrush. Poor rabbitbrush control and fair to good sagebrush control resulted from 2,4-D. The mixture of picloram and 2,4-D controlled rabbitbrush well but only partially controlled sagebrush. Forage release from brush control was negligible the first 2 years after spraying. During the third and subsequent years, production of crested wheatgrass (Agropyron desertorum (Fisch.) Schult.) was greatly increased.

We studied germination of seeds of 44 morphologically distinct, vegetative ecotypes of johnsongrass (Sorghum halepense (L.) Pers.). Seeds of most ecotypes were highly dormant. Without low temperature pretreatment, best germination occurred with continuous fluorescent light, a KNO3 substratum, and an alternating 20 to 35 C temperature regime. Pretreatment of the seeds for 2 weeks at 10 C, followed by a temperature shift to 40 C for 2 hr was effective in breaking seed dormancy. Germination of each of 12 ecotypes, from harvests in each of 2 years, was markedly similar. Interpretation of the evidence suggests that seed dormancy is largely imposed by the relative degree of mechanical restriction afforded by the seed coat.

In North Carolina, the shoots of naturally-established, field grown, foliated specimens of turkey oak (Quercus laevis Walt.) and red maple (Acer rubrum L.) were treated in August with aqueous dilutions of three herbicidal products at three rates each. Simulated rainfall was applied at ½ or 1 inch at 5, 15, 60, or 120 min after herbicidal application. Responses measured 10 and 13 months after herbicidal application were percent control of original shoots, percent control of new shoots, shoot height, and number of live stems/plant. Neither the ester nor amine derivatives of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) were reduced as to their action on woody plants by the simulated rainfall applied. The action on woody plants of 4-amino-3,5,6-trichloropicolinic acid (picloram) plus 2,4-dichlorophenoxyacetic acid (2,4-D) was markedly reduced by the application of all of the simulated rain treatments at any of the intervals at which they were applied following herbicidal treatment.

Studies conducted from 1964 to 1967 on three soil types indicated that α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin), dimethyl tetrachloroterephthalate (DCPA), and 4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline (nitralin) applied preplant and incorporated with two tandem diskings in March or April prior to bedding, gave excellent control of a mixture of Amaranthus sp. and volunteer sorghum (Sorghum bicolor (L.) Moench) in cotton (Gossypium hirsutum L.) planted in early May. Cotton was not stunted and yields were not appreciably reduced. When trifluralin was applied, soil residues the next year dictated that sorghum planting be delayed until May.

Some effects of ammonium thiocyanate (hereinafter referred to as NH4SCN) on the starch and reducing sugar content, amylase activity, photosynthetic O2 release, Hill reaction, and glycine-14C incorporation into amino acids, organic acids, and sugar fractions in excised leaf and cotyledonary tissue of cotton (Gossypium hirsutum L., var. Acala 44) were determined. The starch content of leaf tissue floated on Hoaglands nutrient solution containing 2000 ppm NH4SCN decreased at 1 and 2 days treatment. The amylase activity of excised cotyledons was increased by 2000 and 5000 ppm NH4SCN and the reducing sugar of the same tissue was decreased. Photosynthesis of small leaf disks, as measured by O2 exchange, was decreased and respiration was increased by 2000 ppm NH4SCN. Photosynthesis in isolated chloroplasts, as measured by the reduction of 2,6-dichlorophenolin dophenol in the Hill reaction, also was inhibited by NH4SCN at concentrations above 2000 ppm. Ammonium thiocyanate at 2000 ppm inhibited the conversion of glycine to sugars but had no effect on conversion of glycine to organic acids in leaf tissue.

A method was developed for quantitative determination of miserotoxin, a poison in timber milkvetch (Astragalus miser Dougl. ex Hook.). The presence and concentration of miserotoxin was determined in eight varieties of timber milkvetch. The seasonal variation in the concentration of the poison was followed in variety oblongifolius (Rydb.) Cron. Miserotoxin occurred primarily in the leaves with smaller amounts in the roots, flowers, and seeds. The poison level in leaves and stems decreased rapidly after seed dispersal. Miserotoxin was found in varieties oblongifolius (Rydb.) Cron., serotinus (Gray) Barneby, and hylophilus (Rydb.) Barneby, but was not found in varieties miser Dougl. ex Hook., tenuifolius (Nutt.) Barneby, crispatus (Jones) Cron., praeteritus Barneby, and decumbens (Nutt.) Cron. The three varieties containing miserotoxin were poisonous to 1-week-old chicks (Gallus domesticus, Arbor Acre 50 × Vantress hybrids); the other five varieties were not poisonous.