Managing Dust In Dry Lots

Aug 01, 2016

By Joe Darrington

Hot and dry summer conditions combined with dirt cattle lots can lead to significant dust formation, especially in windy conditions. Though seemingly unavoidable in South Dakota’s windy environment, there are methods to reduce the amount of dust generated in a dry lot. We will examine some straightforward solutions to dust problems in dry lots.

Organic Matter Removal

Small particles are more easily carried by the wind than larger particles. Organic matter in the form of feces and feed are very small particles that are extremely light when dried. The most critical strategy to reduce the amount of dust liberated in a dry lot is to avoid build-up of organic matter. In order to minimize dust generation fastidious cleaning and removal of manure to keep the depth of loose manure less than 2 inches is very important. It is generally recommended to scrape lots a minimum of once every 3-4 months.

Removing feces and feed on a regular basis not only limits the amount of dust in dry conditions, but also helps limit moisture build up in the soil surface when the weather is wetter.

Lot Treatments to Reduce Dust

The most common lot treatment is water application. Systems can either be permanent or truck based. The amount of water required will depend on the area of the lot and the dryness of the lot surface. The surface manure in a lot should be maintained between 25% and 35% moisture to limit both dust emissions and odor (don’t get it too wet). If the lot is very dry, apply water at a rate of 1 gallon per square yard daily in the evening until the surface soil moisture level reaches the desired range (25-35%). After the range is reached maintain the moisture level with daily additions of .5-.75 gallon per square yard applied in the evening. Treatments should occur in the evening when cattle are more active, and the lot surface is at its driest after the heat of the day. Table 1 below demonstrates the amount of water required to initially treat and then maintain lot surface moisture levels between 25-35%.

Table 1. Water Requirements for Dust Mitigation

Number of Cattle on Feed	Lot Area(Assuming 300 ft2/hd)	Water Requirement in Gallons (1 gallon/yard2)	Water Requirement in Gallons (.5 gallon/yard2)
40	12,000	1333	667
80	24,000	2667	1333
120	36,000	4000	2000
200	60,000	6667	3333
600	180,000	20000	10000
999	299,700	33300	16650
1500	450,000	50000	25000
2500	750,000	83333	41667

*Note: If you would like to precisely calculate your water requirements to limit dust in dry conditions. 1) Determine your area in square feet and divide by 9 to get the area in square yards. 2) The area in square yards is equivalent to the gallon requirement to re-wet dry surfaces (1 gallon/square yard). 3) Half of the area in square yards is equivalent to the gallon requirement to maintain 25-35% surface moisture (0.5 gallon/square yard)

For larger lots utilizing trucks to move and apply water can be time consuming. As an example consider the 2500 head lot above in table 1. Each day the operator would have to apply 41,667 gallons of water to the lots. A 4000 gallon tank truck would require 11 trips every evening. Permanent sprinkler systems reduce the amount of time that is required to manage the system as water can be delivered directly to the animals and only pumped once. They can be constructed and operated for a total cost of ~$1.25 - $2.35 per head marketed, assuming a functional system life of 25 years. More information on pricing can be found in the 4th document from Texas A&M in the recommended references. One benefit of developing a dust management strategy is that the same system can be used for heat stress management. View Heat Stress Preparations for Feedlot Cattle for more information.. There are several commercially available chemical compounds that are meant to reduce dust on roadways and in industry applications. The chemical treatments have not been demonstrated to be useful in dry lot situations, and in some cases can complicate manure disposal.

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