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ARS Home » Midwest Area » St. Paul, Minnesota » Soil and Water Management Research » Research » Publications at this Location » Publication #404186

Research Project: Developing Aspirational Practices Through Improved Process Understanding to Protect Soil and Air Resources and Increase Agricultural Productivity in the Upper Midwest U.S.

Location: Soil and Water Management Research

Title: Estimating nitrogen inputs from a kura clover living mulch system for maize production

item Alexander, Jonathan
item Venterea, Rodney - Rod
item Baker, John

Submitted to: Plant and Soil
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary: Kura clover living mulch (KCLM) systems provide nitrogen (N) to the interseeded cash-crop, however, the magnitude of these N contributions is unknown. We used intensive field measurements and in-situ litter bags to quantify where clover biomass is deposited and when it is mineralized. We found that the KCLM system provides 7-23 kg N ha-1 in the first six weeks of the growing season and 59-84 kg N ha-1 from mid-June to mid-October. We used these estimates to calculate nitrogen use efficiency, and found that maize took up 88% of total N inputs (fertilizer + clover), and fertilizer recovery efficiency was 56%.

Technical Abstract: Kura clover living mulch (KCLM) is thought to provide in-season nitrogen (N) to the cash crop. Because of interactions between cropping system and crop performance, the magnitude of in-season N inputs from KCLM cannot be quantified using common N rate research methods. This research measured the temporal distribution of clover biomass with intensive sampling, vertical biomass distribution using bead tracer analysis, and residue decomposition using in situ litter bags. These data were used as inputs to a process model that estimated the in-season N contributions from KCLM. Our results found that spring management contributed 7-23 kg N ha-1 during the first 6 weeks of the growing season, while shade suppression contributed 59 – 84 kg N ha-1 from mid-June to mid-October. Daily N inputs peaked on 8 August at 1.14 kg N ha-1 d-1. When these estimates were added to fertilizer N inputs and analyzed against crop N uptake, we found that the maize took up 88% of the total N inputs and fertilizer recovery efficiency was 56%. This study provides a process modeling approach to generate estimates that may be used in future research related to N cycling and management in KCLM and other legume intercropping systems.