The Fate of Nitrogen from Injected Liquid Manure in a Silt Loam Soil

Abstract

A field experiment was conducted on a Piano silt loam (Typic Argiudoll) in southcentral Wisconsin to monitor N transformations following liquid manure injections. Liquid manure with and without a nitrification inhibitor [nitrapyrin, 2‐chloro‐6‐(trichloromethyl)pyridine, 13 mg a.i. L−1 liquid manure] was injected into an uncropped area in June 1985. Soil samples were taken using a grid placed over the vertical cross‐section of the injected bands permitting spatial sampling in the vertical plane. Sampling was done 5, 12, 26, 39, 67, 99, and 350 d after manure application by progressive exposure of the band. Soil water content, pH, NH4‐N, (NO2 + NO3)‐N, Cl, and water‐soluble C were determined. The synagraphic computer program, SYMAP, was used to evaluate spatial changes in inorganic N concentrations in the manure injection zone. Nitrapyrin was not effective in inhibiting nitrification at the rate used. Nitrification occurred at the outer fringes of the band within 5 d; maximum concentrations of 300 to 800 mg NO3‐N kg−1 occurred throughout the injection zone at 26 d. High respiratory activity in the injection zone was indicated by an almost threefold decrease in water‐soluble C between day 5 (750 mg C kg−1) and day 12 (270 mg C kg−1). Water content remained higher than the surrounding soil in the injection zone for 99 d. Once NO3 leaching occurred, NO3‐N/Cl ratios decreased with depth under the injection zone. The abundant supply of NO3 and readily oxidizable C, combined with the high moisture environment, led to the conclusion that liquid manure injections created an environment conducive for denitrification.

Injection of Dicyandiamide-Treated Pig Slurry Reduced Ammonia Volatilization without Enhancing Soil Nitrous Oxide Emissions from No-Till Corn in Southern Brazil

“…These results show that conditions favorable to N 2 O production lasted longer in the injection slots than in the surface soil affected by broadcast application. This is in agreement with observations by Comfort et al (1988) of greater water content and NO 3 –N concentrations in the injection zone than in the surrounding soil 99 and 26 d after injection, respectively.…”

Ammonia, Methane, and Nitrous Oxide Emission from Pig Slurry Applied to a Pasture in New Zealand

“…The soil has considerable cation exchange capacity (15.4 cmol [Na + ] kg −1 ), and NH 4 would be adsorbed on the cation exchange complex in the surface soil as the slurry infiltrated. Immobilization would be expected to occur, especially as organic carbon was added in the slurry (Comfort et al, 1988; Kirchmann and Lundvall, 1993), but considerable NH 4 remained in the soil until Day 40, and only 22.5% of the TAN was lost as NH 3 Nitrogen uptake by plants should have been slow and small because the surface cover was small and growth slow because of the low soil and air temperatures. However, Thompson et al (1990) studied NH 3 loss from slurries in the absence of soil and concluded that the decline in NH 3 loss rates was due to the formation of a crust on the slurry surface.…”

Subsurface Application of Manures Slurries for Conservation Tillage and Pasture Soils and Their Impact on the Nitrogen Balance

“…*Values from within and outside the injection zone were significantly different ( P < 0.05). (Adapted from Comfort et al, 1988)…”

“…Circle indicates the location of the bottom center of the injection slot. (Adapted from Comfort et al, 1988)…”