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Legacy Effect of Fertilization and Tillage Systems on Nitrogen Mineralization and Microbial Communities
Author(s) -
Wyngaard Nicolás,
Franklin Dorcas H.,
Habteselassie Mussie Y.,
Mundepi Abha,
Cabrera Miguel L.
Publication year - 2016
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2016.03.0070
Subject(s) - tillage , mineralization (soil science) , human fertilization , nitrification , agronomy , conventional tillage , chemistry , ammonium , fertilizer , archaea , ammonia , zoology , environmental chemistry , soil water , biology , nitrogen , bacteria , ecology , biochemistry , genetics , organic chemistry
Core Ideas Soil C and N dynamics were still affected by past fertilization treatments (8 yr). Soil C and N dynamics were still affected by past tillage systems (3 yr). Ammonia‐oxidizing bacteria were affected by ammonium concentration and pH. Ammonia‐oxidizing bacteria and archaea were associated with N mineralization. Poultry litter (PL) is widely used as an alternative to inorganic fertilizers (IF) in conventional (CT) and no‐tillage systems (NT). The objective of this work was to evaluate the legacy effect of a 16‐yr factorial study that combined fertilization (PL or IF) and tillage (CT or NT) treatments on soil C and N pools and microbial communities. Soil samples were collected from the 0 to 5 and 5 to 20 cm depths after 8 and 3 yr of suspending fertilization and tillage, respectively. Samples were analyzed for total organic C (TOC), total organic N (TON), N mineralization rate ( k 0 ), and abundance of ammonia‐oxidizing bacteria (AOB) and archaea (AOA). The TOC and TON concentrations (range: 5.8–20.8 and 0.5–1.8 g kg −1 , respectively) were affected by tillage system and fertilizer source. Legacies of fertilization and tillage affected k 0 (range: 0.20–0.87 mg kg −1 d −1 ) which was correlated with TOC and TON ( r 2 ∼ 0.9). The abundance of AOA (5.3–7.6 log 10 copies g −1 ) and AOB (7.1–8.9 copies log 10 g −1 ) was greater in CT than NT in the 0 to 5 cm layer, whereas the opposite was observed in the 5 to 20 cm layer. Both AOA and AOB were associated with k 0 ( r 2 = 0.5 and 0.8, respectively), suggesting the dependence of ammonia oxidizers on mineralization of the organic N pool. Our results indicate that 8 and 3 yr after fertilization and tillage treatments were suspended, soil C and N and microbial dynamics were still being influenced by previous management practices.