Effects of Urea Application on Soil Organic Nitrogen Mineralization and Nitrogen Fertilizer Availability in a Rice–Broad Bean Rotation System

Xinyan Liu, Huanhao Han (), Shixiang Gu and Rong Gao
Additional contact information
Xinyan Liu: Faculty of Modern Agricultural Engineering, Kunming University of Science and Technology, Kunming 650500, China
Huanhao Han: Faculty of Modern Agricultural Engineering, Kunming University of Science and Technology, Kunming 650500, China
Shixiang Gu: Yunnan Institute of Water and Hydropower Engineering Investigation, Design and Research, Kunming 650051, China
Rong Gao: Yunnan Institute of Water and Hydropower Engineering Investigation, Design and Research, Kunming 650051, China

Sustainability, 2023, vol. 15, issue 7, 1-17

Abstract: Rice cultivation is facing a situation where rice production stagnates while nitrogen fertilizer (NF) application continues to increase. The effectiveness of the NF residues from the rice season on the growth of rotating broad beans is unclear. High NF use in rice cultivation also affects the nitrogen supply through soil organic nitrogen (SON) mineralization (SONM). However, the rules of SONM and the NF availability in the rice–broad bean rotation system (RBRS) are unknown. A field trial of the RBRS was conducted using 15 N-labeled urea (CO( 15 NH 2 ) 2 ) as the partial NF source ( 15 N accounted for 5.3% of the total pure nitrogen applied) for the rice and no NF for the broad bean. It was found that 33.0–38.1% of NF in the rice season was utilized. NF availability was low in the broad bean season (3.6–4.0%). SONM was the most important source, providing approximately 60% of the nitrogen for rice growth. The SONM into mineral nitrogen and the fixation of mineral nitrogen into SON occurred simultaneously, with SONM dominating in most cases. SON content decreased slowly in the rice season and dramatically in the broad bean’s podding stage with a 0.64 g kg −1 (24.1%) decrease. The high nitrogen application in rice season promoted SONM and aggravated groundwater pollution. Soil urease activity, rather than catalase, phosphatase, and invertase activities, can be the main monitoring object of SONM. Furthermore, fungal abundance (especially Aspergillaceae, Neuroceae, and unclassified_o__Helotiales), rather than bacteria, was the primary target for SONM monitoring. It is unreasonable to apply large amounts of NF in the rice season but not in the broad bean season in the RBRS. N1 (135 kg N ha −1 ) had the best comprehensive benefits regarding crop yield, nitrogen supply by SONM, NF utilization, and nitrogen loss on the environment in the RBRS.

Keywords: paddy rice-upland rotation; 15 N tracing; microorganisms; soil enzymatic activity (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2023
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/2071-1050/15/7/6091/pdf (application/pdf)
https://www.mdpi.com/2071-1050/15/7/6091/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jsusta:v:15:y:2023:i:7:p:6091-:d:1113246

Access Statistics for this article

Sustainability is currently edited by Ms. Alexandra Wu

More articles in Sustainability from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().