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Winter Rye Cover Crop Biomass Production, Degradation, and Nitrogen Recycling
Author(s) -
Pantoja Jose L.,
Woli Krishna P.,
Sawyer John E.,
Barker Daniel W.
Publication year - 2016
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2015.0336
Subject(s) - secale , cover crop , agronomy , biomass (ecology) , crop , crop rotation , chemistry , zoology , biology
Winter rye ( Secale cereale L.) cover crop (RCC) use in corn ( Zea mays L.) and soybean [ Glycine max. (L.) Merr.] production can alter N dynamics compared to no RCC. The objectives of this study were to evaluate RCC biomass production (BP) and subsequent RCC degradation (BD) and N recycling in a no‐till corn–soybean (CS) rotation. Aboveground RCC was sampled at spring termination for biomass dry matter (DM), C, and N. To evaluate BD and remaining C and N, RCC biomass was put into nylon mesh bags, placed on the soil surface, and collected multiple times over 105 d. Treatments included rye cover crop following soybean (RCC‐FS) and corn (RCC‐FC), and prior‐year N applied to corn. Overall, the RCC BP and N was low due to low soil profile NO 3 –N. Across sites and years, the greatest BP was with RCC‐FC that received 225 kg N ha −1 (1280 kg DM ha −1 ), with similar N uptake as with RCC‐FS (27 kg N ha −1 ). The RCC biomass and N remaining decreased over time following an exponential decay. An average 62% biomass with RCC‐FS and RCC‐FC degraded after 105 d; however, N recycled was greater with RCC‐FS than RCC‐FC [22 (80%) vs. 14 (64%) kg N ha −1 , respectively], and was influenced by the RCC C/N ratio. The RCC did not recycle an agronomically meaningful amount of N, which limited N that could potentially be supplied to corn. Rye cover crops can conserve soil N, and with improved management and growth, recycling of crop‐available N should increase.