Impact of residue addition on soil nitrogen dynamics in complex agroecosystems

BICHEL, A.,; OELBERMANN, M.; ECHARTE, L.

GEODERMA

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017

0016-7061

Soil nitrogen (N) is one of themost important nutrients for plant productivity and microbial activity in terrestrialecosystems. However, soil N is also readily affected by land management practices, influencing N2O emissions.This study assessed N dynamics in soil from different crop systems including a 1:2 (one row of maize and tworows soybean) and 2:3 (two rows of maize and three rows of soybean) intercrop and a maize and soybeansole crop as a result of residue addition frommaize or soybeans. This was achieved through a 140-day incubationstudy using δ15N natural abundance. The effect of residue addition on soil TN was greater than its influence oncrop systems when compared to treatments with no residue addition (Cont). The influence of residue additionon intercrops was most readily observed in the fractionated soil. Light fraction N (LF-N) and soil microbial biomassN (SMB-N) were significantly greater (p b 0.05) in the intercrops than in the sole crops. Residue amendedtreatments were significantly (p b 0.05) depleted in δ15N-TN, δ15N-LF and δ15N-SMB compared to Cont treatments.The δ15N-SMBwas significantly enriched (p b 0.05) compared to that of the residue, TN and LF-N. Residueamended treatments had significantly lower (p b 0.05) N2O emissions than Cont treatments.However,N2Oemissionswere not significantly different (p b 0.05) between soybean and maize amended treatments, nor betweenintercrops and sole crops. Our results demonstrate that the addition of contrasting residue types influencedshort-term N dynamics in intercrops differently than sole crops.©