Effect of Nitrogen Reduction on Yield Stability of Sugarcane-Soybean Intercropping System
Welcome to Chinese Journal of Tropical Crops,

Chinese Journal of Tropical Crops ›› 2020, Vol. 41 ›› Issue (7): 1354-1365.DOI: 10.3969/j.issn.1000-2561.2020.07.010

• Plant Cultivation, Physiology & Biochemistry • Previous Articles     Next Articles

Effect of Nitrogen Reduction on Yield Stability of Sugarcane-Soybean Intercropping System

XU Xia1,2,3,GOU Yonggang1,2,3,LUO Shasha1,2,3,WANG Yushu1,2,3,YU Lingling1,2,3,*(),WANG Jianwu1,2,3,*()   

  1. 1. Key Laboratory of Tropical Agro-Environment, Ministry of Agriculture and Rural Affairs, Guangzhou, Guangdong 510642, China
    2. Guangdong Provincial Key Laboratory of Eco-Circular Agriculture, Guangzhou, Guangdong 510642, China
    3. College of Natural Resources and Environment, South China Agricultural University, Guangzhou, Guangdong 510642, China
  • Received:2019-10-16 Revised:2019-11-19 Online:2020-07-25 Published:2020-08-24
  • Contact: YU Lingling,WANG Jianwu


Sugarcane is an important economic crop in South China. The yield and quality are declined because of the long-term practice of monoculture agriculture and high chemical nitrogen application. Intercropping system is a sustainable and stable agricultural practice that enables the effective utilization of water, nutrient and light. In the paper, a field experiment was conducted at Experimental Center of South China Agriculture University (23°08°N, 113°15°E) for 10 years (from 2009 to 2018) to investigate the dynamic changes of sugarcane-soybean and system yields under two nitrogen levels [reduced rate 300 kg/hm2(N1) and conventional rate 525 kg/hm2 (N2)] and four cropping patterns [sugarcane monocropping (MS), soybean monocropping (MB), sugarcane-soybean (1∶1) intercropping (SB1), and sugar-cane-soybean (1∶2) intercropping (SB2)]. The study analyzed the dynamic change of land equivalent ratio and evaluated the stability of system yield by Wi2 (Wricke’s ecovalence), CV (coefficient of variation) and SYI (sustainability index), aiming to explore the effects of reduced nitrogen application on the time stability of sugarcane-soybean intercropping system in Guangdong, China. The yield of sugarcane, soybean and the total system under different treatment showed obvious annual dynamic changes and was significantly affected by different years and planting patterns. Nitrogen application level did not affect the yield of sugarcane, soybean and the system yield significantly. The land equivalent ratio (LER) of all intercropping systems was greater than 1 (between 1.09 and 1.97) for 10 years, and the SB2-N1 optimally improved the land utilization rate among all treatments. There was no significant difference in Wi2and CV for sugarcane yield, but the SYI of MS-N1 was significantly higher than that of MS-N2. Meanwhile, the Wi 2 value of monocropping soybean was significantly higher than that of intercropping pattern, and the yield stability of monocropping soybean was lower than that of intercropping soybean. And the stability of soybean yield under reduced nitrogen application was higher than that under conventional nitrogen application. Planting pattern had a significant effect on the stability of the total yield of the system, and intercropping soybean increased the stability of the total yield of the system. The sucrose content and gravity purity of sugarcane juice was decreased with the increase of cultivation years, and the sucrore content and fiber content of bagasse, the sugar brix, sugar pol, apparent purity of sugarcane juice was not influenced by cropping year. In addition, the quality of sugarcane was not influenced by different cropping patterns and nitrogen rates in the same year, which indicating that sugarcane quality was stable under different treatments. From 2010 to 2018, soil pH, organic matter and total nitrogen were decreased significantly, but there was no significant difference in total phosphorus, available phosphorus, and available potassium in all treatments except for the soybean monoculture treatment. Sugarcane continuous cultivation and continuous application of chemical fertilizer led to the decrease of soil organic matter and pH. Reducing nitrogen application and intercropping soybean are sustainable and green production models for efficient utilization of resources and stable system yield in sugarcane producing areas in Guangdong, China, but organic fertilizer application and promotion of sugarcane leaf returning technology are needed to improve sugarcane field fertility.

Key words: sugarcane-soybean intercropping, reduced nitrogen application, yield stability, sugarcane quality, soil fertility

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