Integrated crop-livestock system effects on soil N, P, and pH in a semiarid region

Authors: Liebig, Mark; RYSCHAWY, JULIE - Institut National De La Recherche Agronomique (INRA); Kronberg, Scott; Archer, David; SCHOLLJEGERDES, E - New Mexico State University; Hendrickson, John; TANAKA, D - Retired ARS Employee

Submitted to: Geoderma
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/28/2016
Publication Date: 12/1/2017
Publication URL: http://handle.nal.usda.gov/10113/5596006
Citation: Liebig, M.A., Ryschawy, J., Kronberg, S.L., Archer, D.W., Scholljegerdes, E.J., Hendrickson, J.R., Tanaka, D.L. 2017. Integrated crop-livestock system effects on soil N, P, and pH in a semiarid region. Geoderma. 289:178-184.

Interpretive Summary: Efficient use of plant nutrients serves as a defining attribute to concurrently achieve production and environmental goals in integrated crop-livestock systems (ICLS). Unfortunately, there is a lack of published findings on soil nutrient dynamics for ICLS, particularly in semiarid regions. To address this need, a study was conducted to determine effects of residue and grazing management on soil nitrate, available phosphorus, and soil pH over a 12 year period for an ICLS experiment near Mandan, ND USA. From 1999 to 2011, soil nitrate and phosphorus were measured in three residue management treatments (grazed, mechanically harvested, and no residue removal) every third year across a four foot soil depth, while soil pH was measured prior to deploying ICLS treatments in 1999 and again in 2011. Residue management had no effect on soil nitrate or phosphorus at any depth for any year, implying no accumulation of either nutrient under grazing compared to cropping. Similarly, no differences in soil nitrate or phosphorus were observed across grazed sampling zones. Soil nutrients, however, increased or fluctuated greatly over the 12 year period, suggesting a need for adaptive nutrient management. Soils became more acidic between 1999 and 2011, with the greatest decreases in soil pH at 0-3 inches under grazing and mechanical harvest. Management interventions targeting N conservation, such as seeding cover crops in late summer, may serve to reduce N loss by leaching and soil acidification in ICLS.

Technical Abstract: Integrated crop-livestock systems (ICLS) represent a potential means to sustainably intensify agriculture. Developing ICLS that concurrently achieve production and environmental goals is contingent upon efficiently managing plant nutrients in time and space. In this study, we sought to quantify residue management and field-zone effects on soil NO3-N, available P, and soil pH over a 12 year period for an ICLS experiment near Mandan, ND USA. From 1999 to 2011, soil nitrate-N and available P were measured in three residue management treatments (grazed, mechanically harvested, and no residue removal) every third year across a 122 cm soil depth, while soil pH was measured prior to deploying ICLS treatments in 1999 and again in 2011. Residue management did not affect soil NO3-N or available P at any depth for any year (P>0.1), implying no accumulation of available N and P under grazing compared to cropping. Similarly, no differences in available N and P were observed across grazed sampling zones. Soil nutrients, however, increased or fluctuated greatly over the 12 year period, suggesting a need for adaptive nutrient management. Soils became more acidic between 1999 and 2011, with the greatest decreases in soil pH at 0-8 cm under grazing (0.74 pH unit decline; P=0.0581) and mechanical harvest (0.86 pH unit decline; P=0.0138). Management interventions targeting nutrient conservation may serve to mitigate N and P loss and soil acidification in ICLS.