Nitrogen Budget in a Paddy-Upland Rotation Field with Soybean Cultivation

Fumiaki Takakai,Shinpei Nakagawa,Masato Takeda,Tomomi Sato,Takemi Kikuchi,Yoshihiro Kaneta,Yasuhiro Aono,Takashi Sato,Kentaro Yasuda,Saki Kanamaru

doi:10.5772/intechopen.103023

Abstract

To reduce the over-production of rice, the paddy-upland rotation system, which alternates every few years between paddy rice cultivation and upland crop cultivation in drained (converted) paddy fields, is now commonly practiced in Japan. Recently, depletion of available soil nitrogen (N) and a subsequent decline in soybean yield in converted upland fields with repeated rotation have been reported in northern Japan. To evaluate the N budget in the paddy-upland rotation field with soybean and rice, a 6-year lysimeter experiment was conducted. In the rotation system, a considerable loss of N occurred in both the upland soybean and paddy rice cultivation periods (−11.9 and − 2.3 g N m−2 y−1, respectively). To mitigate the N loss in the rotation system, N supply from organic matter application is required. The effects of applying different types of organic matter (leguminous green manure, hairy vetch, and livestock manure compost) on the N budget in soybean cultivated fields were investigated. Compared to the N loss in the control plot without organic matter application, the N loss was mitigated in the hairy vetch plot, and N accumulation occurred in the livestock manure compost plot (−13.7, −3.5, and +11.8 g N m−2 y−1, respectively).

Highlights

Detailed N budget in a paddy-upland rotation field was evaluated for 6 years (3 years for upland soybean, 3 years for flooded paddy rice) in a lysimeter plot at the Akita Prefecture Agricultural Experiment Station, located in the Tohoku region, northern Japan [18, 19]
In paddy-upland rotation fields including soybean cultivation, the field N budget in both upland soybean and paddy rice is negative, and soil N fertility is likely to decrease due to repeated rotation [6]
It will be necessary to evaluate the effect of organic matter application on the N budget in the entire paddy-upland rotation system, including paddy rice cultivation

Summary

Introduction

In Japan, rice production has been restricted for more than 40 years due to declining rice consumption. Nishida et al [7, 8] reported a decrease in available soil N with an increase in upland frequency (i.e., the number of years in soybean cultivation per total cultivation years) in fields with paddy-upland rotation in Akita, Tohoku region, northern Japan (Figure 2). Detailed N budget in a paddy-upland rotation field was evaluated for 6 years (3 years for upland soybean, 3 years for flooded paddy rice) in a lysimeter plot at the Akita Prefecture Agricultural Experiment Station, located in the Tohoku region, northern Japan [18, 19].

Results

Conclusion