Soil dispersion in an aqueous solution of sodium hexametaphosphate and sodium bicarbonate facilitates extraction of seeds by flotation with megnesium sulphate. The percentage viability of seeds collected in this manner subsequently can be determined with 2,3,5-triphenyl-tetrazolium chloride. Extraction of seeds usually is 100% efficient and enumeration of viable seeds via the tetrazolium test is accomplished much more rapidly than with conventional methods.

Herbicides which contain primary or secondary amino groups may be detected on thin layers of silica gel G or silica gel H with 1% tert-butyl hypochlorite, followed with an aqueous solution of 1% KI and 1% soluble starch. Detection limits range from approximately 1 μg to less than 0.05 μg, depending upon the herbicide in question. The technique also appears to be effective for aromatic or aliphatic iodides.

Four new biodegradable alkylpolyoxyethylene glycol surfactants (15-S-9, DN-65, 15-S-3, and 15-S-3A) provided excellent visual wetting of corn foliage in spray solutions of 1,1′-dimethyl-4,4′-bipyridinium salt (paraquat), 2,2-dichloropropionic acid (dalapon), and 3-amino-1,2,4-triazole (amitrole) and many combinations were equal or superior to standard surfactants Tween 20, X-77, and Osamul 95 in enhancing phytotoxicity. Exceptions were observed, apparently due to specific but incompletely understood herbicide-surfactant-plant surface interactions. All four biodegradable surfactants and Osamul 95 were slightly toxic when sprayed alone on corn foliage.

Effect of 3,5-dimethyltetrahydro-1,3,5,2H-thiadiazine-2-thione (DMTT) on the growth of Monterey pine (Pinus radiata) seedlings was studied at constant levels of soil moisture maintained by capillary fringes. A high content of water depressed the growth of plants but preserved their normal morphological balance. A low content of water produced succulent seedlings with inferior root systems. The results suggest that DMTT is better adapted to fine-textured soils with restricted aeration. Maintenance of water supply at field capacity of the soil also may improve the balance of nursery stock and its survival potential.

A laboratory sprayer, designed to make herbicide applications to potted plants and to study spray distribution patterns with different nozzles, is described. An activated charcoal air filter was installed to minimize herbicide contamination to adjoining greenhouse-laboratory facilities during the spraying operation.

Growth of Oxalis cernua Thunb. was determined in different temperature regimes. Growth occurred in the 55 to 75 F range. Temperature variation promoted growth. Bulbs sprouted more rapidly and uniformly after storage at 35 F than after storage at 95 F. The weed probably is best adapted to areas with winter soil temperatures between 55 and 75 F.

A truck sprayer for applying herbicides to brush is described. It consists of a three-section, hydraulically controlled boom capable of spraying about a 22-ft swath on brush up to 12 ft tall. The spraying system is mounted on a ⅓-T truck equipped with additional lights for night spraying. Plots 22 ft wide by 50 to 200 ft long are sprayed.