Exploring Temperature-Related Effects in Catch Crop Net N Mineralization Outside of First-Order Kinetics

TY - JOUR

T1 - Exploring Temperature-Related Effects in Catch Crop Net N Mineralization Outside of First-Order Kinetics

AU - Miranda Vélez, Jorge Federico

AU - Cronin, Iris Vogeler

PY - 2021/4

Y1 - 2021/4

N2 - Catch crops are an effective method for reducing nitrogen (N) leaching in agriculture, but the mineralization of incorporated catch crop residue N is difficult to predict and model. We conducted a five-month incubation experiment using fresh residue from three catch crops (hairy vetch, fodder radish and ryegrass) with three temperature treatments (2 °C, 15 °C and 2–15 °C variable temperature) and two termination methods (glyphosate and untreated). Mineral N (ammonium and nitrate) in soil was quantified at 0, 1, 2, 4, 8 and 20 weeks of incubation. Ammonium accumulation from residue decomposition showed a lag at low and variable temperature, but subsequent nitrification of the ammonium did not. Mineral N accumulation over time changed from exponential to sigmoidal mode at low and variable temperature. Incubation temperature significantly affected mineralization rates in a first-order kinetics (FOK) model, while plant type and termination method did not. Plant type alone had a significant effect on the final mineralized fraction of added catch crop N. FOK models modified to accommodate an initial lag were fitted to the incubation results and produced better goodness-of-fit statistics than simple FOK. We suggest that initial lags in residue decomposition should be investigated for the benefit of mineralization predictions in cropping models

AB - Catch crops are an effective method for reducing nitrogen (N) leaching in agriculture, but the mineralization of incorporated catch crop residue N is difficult to predict and model. We conducted a five-month incubation experiment using fresh residue from three catch crops (hairy vetch, fodder radish and ryegrass) with three temperature treatments (2 °C, 15 °C and 2–15 °C variable temperature) and two termination methods (glyphosate and untreated). Mineral N (ammonium and nitrate) in soil was quantified at 0, 1, 2, 4, 8 and 20 weeks of incubation. Ammonium accumulation from residue decomposition showed a lag at low and variable temperature, but subsequent nitrification of the ammonium did not. Mineral N accumulation over time changed from exponential to sigmoidal mode at low and variable temperature. Incubation temperature significantly affected mineralization rates in a first-order kinetics (FOK) model, while plant type and termination method did not. Plant type alone had a significant effect on the final mineralized fraction of added catch crop N. FOK models modified to accommodate an initial lag were fitted to the incubation results and produced better goodness-of-fit statistics than simple FOK. We suggest that initial lags in residue decomposition should be investigated for the benefit of mineralization predictions in cropping models

KW - catch crops

KW - first-order kinetics

KW - glyphosate

KW - incubation

KW - modeling

KW - nitrogen mineralization

KW - soil microbes

KW - soil organic matter

UR - http://www.scopus.com/inward/record.url?scp=85120988831&partnerID=8YFLogxK

U2 - 10.3390/nitrogen2020008

DO - 10.3390/nitrogen2020008

M3 - Journal article

SN - 2504-3129

VL - 2

SP - 110

EP - 127

JO - Nitrogen

JF - Nitrogen

IS - 2

ER -