Soil properties and carbon and nitrogen pools in a young hillside longan orchard after the introduction of leguminous plants and residues

Huimin Xiang; Yuan Zhang; Hui Wei; Jia-En Zhang; Benliang Zhao

doi:10.7717/peerj.5536

Soil properties and carbon and nitrogen pools in a young hillside longan orchard after the introduction of leguminous plants and residues

PeerJ. 2018 Aug 30:6:e5536. doi: 10.7717/peerj.5536. eCollection 2018.

Authors

Huimin Xiang^{1

2

3}, Yuan Zhang^{1

2

3}, Hui Wei^{1

2

3}, Jia-En Zhang^{1

2

3}, Benliang Zhao^{1

2

3}

Affiliations

¹ Department of Ecology, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, Guangdong, China.
² Key Laboratory of Agro-Environment in the Tropics, Ministry of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China.
³ Guangdong Engineering Research Center for Modern Eco-agriculture and Circular Agriculture, South China Agricultural University, Guangzhou, Guangdong, China.

Abstract

The intensification of young hillside Dimocarpus longan orchard cultivation has led to increase soil erosion and decrease soil fertility in South China. Leguminous crops are often used for improving soil properties. An approximately 2-year-long field experiment in lateritic soil in South China was conducted to evaluate the effects of legume introductions on soil properties and carbon (C) and nitrogen (N) pools. Two leguminous and one non-leguminous plant species, including Arachis hypogaea L. (a leguminous oilseed crop species, DA), Stylosanthes guianensis (a perennial herbaceous leguminous species, DS) and Lolium perenne L. (an annual non-leguminous forage species, DL), were introduced into a D. longan orchard as three treatments and compared to the monoculture of D. longan (the control, D0). And the harvested biomass residues of the three cover plants were returned to their corresponding plots as green manure. Soil samples were collected from depths of 0-10 and 10-20 cm approximately 2 years after treatment application. The results showed that, compared with D0, DA significantly improved the contents of soil available phosphorus, dissolved organic carbon (DOC), total nitrogen, ammonium and the N pool. In addition, DS significantly increased the contents of DOC, microbial biomass carbon and ammonium in the soil. However, DL did not affect any soil properties or the C and N pools. In addition, neither DA nor DS altered the soil bulk density or the contents of available nitrogen, total organic carbon and the C pool. The improvement of soil properties by DS and DA was positively correlated with the plant residues amount, plant N content but negatively correlated with the plant C:N ratios. Besides, the plant growth of longan was significantly improved by DA. In conclusion, compared with that of S. guianensis, the introduction of A. hypogaea L. was more helpful for restoring and improving soil properties, N pool and longan growth within the young hillside orchard in South China.

Keywords: C pool; Legume; N pool; Soil properties; Young hillside longan orchards.

Grants and funding

This research was supported by the National Science and Technology Pillar Program of China (2012BAD14B16-04), Science and Technology Program of Guangdong Province (2012B020310005 and 2015B090903077), and National Natural Science Foundation of China (U1701236). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.