Managing soil nutrient buildup by rotating crops and fertilizers following repeated poultry litter applications

Authors: Tewolde, Haile; BUEHRING, NORMIE - Mississippi State University; Feng, Gary; Way, Thomas - Tom

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/18/2020
Publication Date: N/A
Citation: N/A

Interpretive Summary: Poultry litter which has proven to be an excellent row crop fertilizer is composed of mostly organic matter (˜60%) but is also a rich source of all mineral elements needed for healthy plant growth. However, the mineral nutrients in litter are not balanced. So, when litter is applied to the same field continuously for several years, some elements such as phosphorus (P) accumulate in the soil and become a concern for the environment. Currently, the most recommended management practice to prevent excess nutrient buildup in the soil is to apply just enough litter to meet the P need of the crop. In this study, we studied whether an alternative management strategy that involves cessation of litter application for two or more years and rotation of three crops including cotton, corn, and soybean would minimize nutrient accumulation from repeated litter applications. The results showed that applying poultry litter for a few years at a relatively high rate (to meet the need of all nutrients of cotton) and suspending the application for two or three years during which only a synthetic nitrogen fertilizer is applied offers an effective and sustainable litter management strategy in row crop production systems. This strategy may also increase crop yields. Rotating the three crops within a five-year period was not a reliable practice for purposes of managing soil nutrient buildup.

Technical Abstract: The most recommended poultry litter (PL) management practice to prevent excess soil nutrient buildup, P in particular, is applying the PL at a rate that meets the P need of the crop. In this study, an alternative management strategy that utilizes cessation of PL application and drawing down nutrient buildup was tested. Cotton, corn, and soybean were grown in rotation and fertilized with five fertility treatments which included an unfertilized control (UTC), a standard fertilization with conventional synthetic fertilizers to meet crop nutrient requirements (Std), and three PL fertilization plans. The PL treatments included P-based litter application every year for 5 yr (P5L), N-based litter application every year for 5 yr (N5L), and N-based litter application each of the first 2 yr and synthetic N application at the same rate as the Std in the last 3 yr (N2L). The level of residual mineral elements in the soil was measured after imposing these treatments for 5 yr. The results showed that, relative to the Std, the N5L treatment elevated extractable soil P, Cu, and Zn by >100% and soil K and Mg by ˜90%. The N2L treatment, in which PL application was suspended for 3 yr, did not lead to such nutrient buildup. A similar outcome was achieved with the P5L treatment which is the P-based PL application method. Rotating the three crops within a 5-yr period may not be a reliable practice for purposes of managing soil nutrient buildup. The results overall show that applying PL at a relatively high rate to meet the N need of cotton for a few years and suspending the application for 2 to 3 yr during which only synthetic N fertilizer is applied offers an effective and sustainable PL management strategy in row crop production systems.