Soil chemical properties 12 years after termination of cattle manure and swine effluent applications

For how long the nutrient supply from long-term application of manure and swine effluent will last to sustain crop production after applications had ceased is a research gap. We quantified the change in soil chemical properties 12 years after cattle manure and swine effluent applications had ceased. Data were collected in 2008 (termination of applications) and 2020 on a long-term animal waste study at the Kansas State University, Southwest Research-Extension Center near Tribune, KS. Treatments were three levels of cattle manure and swine effluent (phosphorus, P; nitrogen, N and 2N) and an untreated control. Soil profile NO3-N declined 78%-95%, 70%-82%, and 58% from the initial amount in 2008 compared to the amount remaining in 2020 in the swine effluent, cattle manure, and an untreated check, respectively. Profile NO3-N levels were greatly elevated by the P-based swine effluent treatment and the 2N rate of both cattle manure and swine effluent and remained high (>250 kg ha-1) after 12 years. Total nitrogen in the surface soil decreased by 11%-27% for cattle manure treatments with little change in the swine effluent and check treatments. Total carbon concentration in the surface soil decreased from 22% to 31% for cattle manure treatments and from 7% to 14% for swine effluent and check treatments. Mehlich-3 P decreased significantly for the cattle manure treatments (41%-53%) but still remained very high (>100 mg kg(-1)). Soil test P levels in the swine treatments were similar to the check treatment. Application of cattle manure and swine effluent has lasting effects on many soil chemical properties long after ceasing applications.