We developed two tractor-mounted spraying systems which utilize compressed air for dispensing the spray. The nursery sprayer consists of a spraying platform, two windshields, and two hand booms, and was developed to spray brush up to 6 ft tall. A field sprayer was developed to spray brush up to 15 ft tall. This sprayer has two 20-ft booms, mounted on a modified front end loader which could be rotated hydraulically to either side of the tractor.

Early spring spray applications of the potassium salt of 4-amino-3,5,6-trichloropicolinic acid (picloram) and certain formulations of 1:1 mixtures of picloram plus (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T) controlled yaupon (Ilex vomitoria Ait.). Ester formulations of picloram or picloram plus 2,4,5-T were ineffective. Combinations of surfactant and oil: water carriers usually did not improve herbicide performance over water carriers. Granular picloram was superior to sprays when applied as soil treatments at equal rates and controlled yaupon at most dates of application. Post oak (Quercus stellata Wangenh.) and blackjack oak (Quercus marilandica Muenchh.) were controlled more effectively by picloram or picloram plus 2,4,5-T sprays on the foliage than by granular picloram as a soil treatment. Picloram granules usually killed winged elm (Ulmus alata Michx.) regardless of date of application.

A soil sampler was constructed for moisture and pesticide residue determinations that will retrieve soils with rocky and heavy clay layers. The sampler consisted of a commercially constructed worm-gear driven auger mounted in a 3.7-m-tall vertical frame. Depth, speed, accuracy, and ease of sample retrieval were substantially increased, compared to manual sampling.

Samples of the spray pattern delivered by a tractormounted field sprayer were intercepted with 10 petri dishes divided between two heights in each of eight plots sprayed with 1.12 kg/ha of 4-amino-3,5,6-trichloropicolinic acid (picloram). The sprayer produced predictable residues on the intercept plates; no differences occurred between residues collected at ground level and 46 cm above the ground; and no differences occurred between replicate plots. Fractionation and analysis of specific plant parts, whose position relative to direction of spray and surrounding brush had been noted, revealed that the spray system delivered uniform coverage almost regardless of brush orientation.

We modified a cereal huller to thresh seed of honey mesquite [Prosopis juliflora (Swartz) DC. var. glandulosa (Torr.) Cockerell]. The device threshes seed of other mesquite varieties, huisache [Acacia farnesiana (L.) Willd.], and other leguminous species.

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.