Broadcast applications

Spray nozzle type plays an important role in the success of agrochemical application. For broadcast applications to soil, flat fan nozzles should be used. Newer spray tips such as the DG TeeJet, XR TeeJet, Turbo TeeJet and similar nozzles supplied by Lechler and Hardy have provided acceptable results in a number of studies. For a given nozzle type, the lower the application pressure, the larger is the spray droplet size and the less potential for spray drift. Similarly, the closer the boom is positioned to the soil surface, the less is the potential for spray drift." Most applications are made with spray tips having 80° or 110° spray angles and boom heights of about 50 cm above the soil surface. 

Figure 8.9 Profiles of urea-N, ammoniacal-N and pH with depth following broadcast application of urea on ricefield floodwater, and the corresponding rates of NH3 volatilization (calculated with the model of Rachhpal-Singh and Kirk, 1993a,b)...

Bouldin DR, Alimago BV. 1976. NH3 volatilization from IRRI paddies following broadcast applications of fertilizer nitrogen. IRRI Miscellaneous Report. Manila International Rice Research Institute. 

Algorithmic delay Depending on the application, the delay is or is not an important criterion. It is very important for two way communications applications and not relevant for pure storage applications. For broadcasting applications some 100 ms delay seem to be tolerable. 

As atrazine went beyond trial use, farmers, dealers, and custom applicators hne-tuned application practices. In an effort to decrease cost and soil carryover potential, atrazine rates were decreased. Farmers moved from band to broadcast applications to achieve greater efficiency. They also sought maximum weed control by using atrazine in mixtures, especially for better grass control, tailored to each agricultural situation. 

Researchers have also used immunoassay techniques for analysis of triazines in soil leachate. Tasli et al. (1996), for example, analyzed soil water from an irrigated com plot by immunoassay and GC/NPD. Amistadi et al. (1997) analyzed leachate collected from different tillage systems for atrazine by EIA and GC/NPD. Guillard et al. (1999) used an EIA to compare the concentration of atrazine in leachate from plots receiving band or broadcast applications. 

The 2,4-DP product is recommended for use in broadcast applications to be sprayed after pines have completed the first growth flush of the season. It is quite effective on oak species. At present another method of application involves directed sprays with knapsack sprayers. 

In the light of the poor efficiency of broadcast applications of pheromones in air permeation techniques the alternative practice of scattering or placing a limited number of release points at suitable distances apart over the treated area merits consideration. Since each point will then act as an individual source the treated area will be permeated by a set of individual plumes of pheromone vapor whose direction will vary with airflow through the crop or woodland. Large... 

Table 3.4 Dry and wet pahn transfer efficiencies of pesticides from one press onto plush new carpet, nsed carpet and vinyl flooring treated by broadcast application (mean standard deviation of six replicates (%)) wet-to-dry palm press ratios given in italics ...

Koehler, P.G. and H.A. Moye (1995a). Airborne insecticide residues after broadcast application for cat flea (siphonaptera pulicidae) control, J. Econ. Entomol, 88, 1684-1689. 

Vaccaro, J.R. and R.J. Cranston (1990). Evaluation of Dislodgeable Residues and Absorbed Doses of Chlorpyrifos Following Indoor Broadcast Applications of Chlorpyrifos-based Emulsifiable Concentrate, The Dow Chemical Company, Midland, MI, USA. 

For purposes of screening-level assessments, while multiple applications may exist for a given pesticide, e.g. indoor residential exposures may originate from pesticide applications to ornamental and landscape plantings, typically a worst-case or high-end exposure scenario is selected for the initial assessment. For example, turf grass broadcast application is the use pattern that often serves to provide the worst-case estimates of human contact and exposure for most outdoor uses of a pesticide. 

Few pesticides are available for non-rodent vertebrate pest control, and most require special local permits for use. The chemicals which are registered are usually bait applications. A few chemicals designed for aquatic pests or massive populations of pest birds are used as broadcast applications. 

The even net fan nozzle makes a narrow oval pattern. Spray delivery is uniform across its width. It is used for band spraying and for treating walls and other surfaces. It is not useful for broadcast applications. Boom height and nozzle spray angle determine the width of the band sprayed. These tips are available in brass, plastic, stainless steel, and hardened stainless steel. 

When environmental contamination occurs, it is the result of either point-source or non-point-source pollution. Point-source pollution comes from a specific, identifiable place (point). A pesticide spill that moves into a storm sewer is an example of point-source pollution. Non-point-source pollution comes from a wide area. The movement of pesticides into streams after broadcast applications is an example of non-point-source pollution. 

Carbaryl is effective as both a contact and an ingested agent and is one of the most widely used broad-spectrum insecticides. Uses include control of a wide variety of pests on field crops, fruits, vegetables, nuts, ornamentals, turf, lawns, and domestic animals in agricultural, commercial, and residential environments. Liquid broadcast applications to residential lawns in the United States are to be voluntarily canceled, however. Formulations include dusts, wettable powders, granules, oils, aqueous suspensions, and baits. 

In the same experiment, 1984 treatments included rotation to a weedy check or cycloate (S-ethyl cyclohexylethylcarbamo-thioate) + atrazine followed by a broadcast application of butylate + atrazine (4.5 + 1.7 kg ai/ha) in 1985. A one year rotation away from butylate increased the recovery of butylate from 0.72 ppm to between 2.11 and 2.26 ppm 7 days after the 1985 application and appeared to eliminate enhanced biodegradation in these treatments. 

Sims and Wells (1990) reported that use of NPK fertilizers containing Mo resulted in higher leaf yields of hurley tobacco (Nicotiana tabacum L.) with band application than with broadcast application. Including Mo in the transplant solution also increased tobacco-leaf yields in 1 of 3 years. 

Another method of Mo application is to include a soluble Mo source in the transplant solution. Sims, Suchy, and Cornelius (1983) reported that inclusion of Na2Mo04 in the transplant solution for hurley tobacco resulted in higher Mo concentrations, nitrate reductase activity, and cured-leaf yields. Responses to Mo were greater with transplant-solution application than with broadcast application of the same Mo source. 

The main Mo sources are ammonium molybdate, sodium molybdate, and molybdenum trioxide. The three sources generally are equally effective, and the selection will depend on the method of application. The application methods are band or broadcast application (generally of Mo contained in P or NPK fertilizers) to soil, foliar sprays, and seed treatment. 

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