Randomized complete block design field experiments were conducted to determine the effects of rates and methods of liquid swine manure application on volatile NH3‐N losses from cropland. In addition, a greenhouse study was conducted to determine the effect of wind on the rate of NH3‐N volatilization from soil and the accuracy of NH3‐N loss measurements under field conditions. A partially closed system was utilized to directly collect volatilized NH3‐N from microplots.The NH3‐N collection system did not accurately estimate volatile N losses when windy conditions existed as often encountered in the field. Using direct measurement of NH4+‐N in waste before and after exposure to the atmosphere to correct for the low estimates of NH3‐N loss under field conditions, an average of 48.1% of the volatilized N was collected under greenhouse conditions with relatively constant temperature and wind.The rate of NH3‐N loss from manure increased with increasing temperature and air movement. The proportions of the applied NH4+‐N lost as NH3‐N during a 3.5‐day sampling period in the spring from swine manure (pH 6.4) applied to soil (pH 6.4) and corrected for the effect of wind were: 14.0%, 12.2%, and 11.2% for the 90, 135 and 180 metric ton/ha, respectively, of surface applied liquid swine manure; 2.5% for both the 90 and 180 metric ton rates, respectively, of injected liquid swine manure; 14.7% for surface applied urea fertilizer (168 kg N/ha); and 65.8% of the applied NH4+‐N from swine manure surface applied (90 metric tons/ha) on a plastic liner. Fresh swine manure (pH 7.8) surface applied at the rate of 135 metric tons/ha on greenhouse loam soil (pH 7.0) lost 82.5% of the applied NH4+‐N in an 8‐day sampling period.

A 3‐year field experiment was conducted to study the agronomic effects of methods and rates of liquid swine manure application to Brookston‐Crosby silt loam soil (fine, mixed mesic Aeric Ochraqualfs) cropped to corn (Zea mays L.). Swine manure (5.2–6.6% dry matter) from an anaerobic pit was applied to soil annually at 90, 135, and 180 t/ha by injection (30 cm below soil surface) and broadcast (surface) methods. These three rates provided averages of 428, 643, and 857 kg N/ha; 133, 200, and 266 kg P/ha; and 155, 232, and 310 kg K/ha per year; respectively. Check and inorganic fertilizer (168 kg N/ha, 56 kg P/ha, and 112 kg K/ha) treatments were also studied.The injection method of liquid manure application increased corn grain yield an average of 2,130 kg/ha each year, compared with the broadcast method at similar rates of application. Injection of swine manure was associated with higher corn‐leaf N levels the first year; corn‐leaf N, P, and K levels the second year; and corn‐leaf N and K the third year of the study when compared with corn leaves from the broadcast method. Rate of manure application had little influence on corn‐leaf analyses, and inconsistent effects on corn yield.Nutrient loadings of the soil from liquid manure applications were in excess of crop requirements, as evidenced by nutrient accumulations, particularly P and K, in the soil. Increases in soil nutrient levels at different depths in the profile reflected the initial placement of the manure by application methods (broadcast vs. injection). Volatile losses of NH3‐N from surface‐applied liquid manure were reflected in lower corn yield response, lower corn‐leaf N content, and lower soil NH4+ and NO3− levels when comparing these parameters with the injection treatment. Application of liquid swine manure by injection at the 90 t/ha rate increased corn grain yield 14% above that from the inorganic fertilizer treatment.

The use of leaf amendment in woodchips/sludge composting was studied in pilotscale and full-scale operations. Use of leaves at a rate of 20 percent by volume was compatible with present practices and equipment at the Columbus Compost Facility, but higher rates caused materials handling and curing problems and would necessitate system modifications. Only very slight reduction in new woodchip usage was observed for the 20 percent leaf amendment, but output of sieved-finished compost was doubled. Leaf usage increased airflow requirement per unit dry matter during the initial stage of composting but decreased ammonia release throughout the composting process. On the other hand, use of recycled materials, compost and sieved woodchips, increased ammonia release. Adequate moisture and periodic turning in the pilot-scale studies enhanced composting for all treatments. Leaf usage may necessitate forced aeration during curing to keep full size piles aerobic. In addition, leaf usage increased the total materials handling requirement for operating the full-scale system by 16 percent, and it was concluded that careful consideration of materials handling is the major concern for a system's operating efficiency.

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