Effect of Injected Liquid Beef Manure on Soil Chemical Properties and Corn Root Distribution

Abstract

Concentrated bands of liquid manure resulting from knife injection may be responsible for documented corn (Zea mays L.) production problems including uneven corn growth, plant yellowing, and lack of corn roots in the manure zone. Soil injected with liquid beef manure was incubated to determine effects on soil chemical properties, soil atmosphere composition, and corn root growth and distribution in or near the manure zone. An equivalent field injection rate of 3000 gal manure/acre was introduced into a 2.5 in. diameter circular band in boxes filled with Derinda silt loam (fine, mixed, mesic Typic Hapludalf) soil. Corn roots did not grow in the manure zone for 26 d after manure application. Chemical transformations found within and at 1.5 in. (from the manure center) below and beside the manure zone indicated possible toxic conditions to root growth. These included: reducing conditions, as indicated by low Eh, high moisture content, and low O2 concentration in the soil atmosphere (plus the presence of CH4) for 28 d after application; NH3 toxicity, as indicated by high concentrations of NH4−N and high pH for 21 d; and accumulation of high concentrations of NO2−N from 14 to 35 d after application. Only limited effects on soil chemical properties and root growth were found beyond 1.5 in. from the center of the manure zone. These results provide plausible explanations for corn growth problems associated with knife injected liquid manure.