Soil nitrogen sequestration in a long-term fertilizer experiment in central China

Xuemei Han,Zhi Zhang,Donghai Liu,Yunfeng Chen,Shuanglai Li,Cheng Hu,Yan Qiao,Jun Fan

doi:10.5424/sjar/2020181-15691

Abstract

Aim of study: To evaluate the effects of a long-term manuring and fertilization experiment on the soil total N concentration and its storage and sequestration rates in the rice-wheat cropping system.Area of study: A rice-wheat rotation area in central China.Material and methods: A 35-yr long-term fertilizer experiment was conducted with 9 treatments: unfertilized (Control), N, P, and K fertilizers, manure (M) and M combined with N, P, and K fertilizers treatments. Soil total N input amount, total N concentration, total N storage amount and N sequestration rate in soil were calculated.Main results: The soil total N input amount, N concentration, N storage amount and N sequestration rate were significantly influenced by M and chemical fertilizers. In total, 0.017-0.021 g N/kg soil accumulated in the organic M plots, whereas only 0.005-0.007 g in chemical fertilizer alone plots. The highest soil total N storage amount was 6.09 t/hain the M alone plot, and the lowest value was 4.46 tN/ha in the N fertilizer alone plot. The highest N sequestration rate in soil was 0.061 t N/ha/yr in the high amount M plus NPK fertilizers plot, and the lowest value was 0.002 tN/ha/yr in the N fertilizer alone plot. A significant nonlinear regression relationship existed between the total N sequestration rate in soil and annual total N input amount. Moreover, the average soil total N concentration was significantly positively correlated with the average grain yield of crop and soil organic C concentration. The soil total N sequestration rate in M alone or M combined with inorganic fertilizer treatments were increased compared with inorganic fertilizer alone treatments.Research highlights: Considering crop yields and total N sequestration rate in soil, the use of manure combined with inorganic fertilizer should be recommended in the rice-wheat cropping system.

Highlights

IntroductionChanges in soil total N concentration are largely responsible for variations in soil physical, chemical and biological properties and strongly influence crop productivity and environmental quality (Mazzoncini et al., 2011)
Nitrogen is one of the most important plant-available nutrients and is the most vital crop yield-limiting factor in agricultural systems (Pandey et al, 2017).Changes in soil total N concentration are largely responsible for variations in soil physical, chemical and biological properties and strongly influence crop productivity and environmental quality (Mazzoncini et al., 2011)
The average annual N input amount in the manure plots (MN, MNP, MNPK, hMNPK) was 61.07-101.14% higher than that in the

Summary

Introduction

Changes in soil total N concentration are largely responsible for variations in soil physical, chemical and biological properties and strongly influence crop productivity and environmental quality (Mazzoncini et al., 2011). Increasing soil N immobilization could reduce the amount of N fertilizer use, N leaching, and N 2O emission, mitigating greenhouse gases causing global warming (Sainju et al, 2008; Qiu et al, 2016). When the N fertilizer application is neither completely assimilated by plants nor sequestered as soil organic N, it will result in N losses and related environmental problems, such as greenhouse gases, groundwater contamination, atmosphere pollution, water eutrophication, and reduced biodiversity (Lin et al., 2016). Qiu et al (2016) reported that only organic manure combined with chemical fertilizer could increase the soil total N concentration in monoculture maize fields. The result in the paddy-upland cropping system is similar to upland soil or not, as there is little study

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