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Acta Prataculturae Sinica ›› 2022, Vol. 31 ›› Issue (3): 114-123.DOI: 10.11686/cyxb2021008

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P accumulation and P removal potential of a P-accumulating ecotype of Polygonum hydropiper for different manure types

Yu-jie LI1(), Qi-wei SHEN1, Ao ZHANG1, Dan LIU2, Dai-hua YE1(), Ting-xuan LI1   

  1. 1.College of Resources,Sichuan Agricultural University,Chengdu 611130,China
    2.Environmental Protection Bureau of Ziliujing,Zigong 643000,China
  • Received:2021-01-05 Revised:2021-04-22 Online:2022-03-20 Published:2022-01-15
  • Contact: Dai-hua YE

Abstract:

The study of P accumulation and P removal potential of P-accumulating plants for different manure types provides data for the development of methodology for extracting excess soil P and reducing non-point source pollution of P. Two pot experiments were conducted to investigate the characteristics of P accumulation and P removal potential of a mining ecotype (ME) of Polygonum hydropiper grown in soilsfertilized with poultry manure (P), swine manure (S) or dairy manure (D). In the first experiment, different manure doses (0, 25, 50, 75, 100 g·kg-1; M0, M25, M50, M75, M100, respectively) were applied to investigate the P accumulating capacity of the ME. In the second experiment, the optimum doses of each kind of manure were applied to clarify periodic P accumulation and P removal potential of the ME over four growth periods (6, 8, 10, 12 weeks). It was found that: 1) Across the range of manure application doses, shoot biomass and P accumulation of the ME were maximized for the respective manure types for treatments PM75, SM100 and DM100. The greatest shoot P accumulation values for the three manure types were 158.64, 204.05 and 128.92 mg·plant-1, respectively, and these values were 5.47-8.66 times higher than those of the M0 treatments. 2) Under the optimum application dose of each manure type (i.e. treatments PM75, SM100 or DM100), the maximum ME shoot biomass was observed at week 12, and the maximum P accumulation at week 8. Hence the P accumulation rate for a regrowth interval was optimized at 6-8 weeks of regrowth. After 8 weeks, the P-removal capacity of the ME under the optimum manure application changed slightly; Its P extraction ratio was 5.84%-19.36% and the plant effective number was 4-6 plants. Based on these results, harvesting after 8 weeks regrowth is the recommended harvest interval for the ME under the optimum manure application rates. 3) The P accumulation of the ME varied among the different manure types. During the first 6 weeks of regrowth, the apparent P accumulation rate of the ME under the DM100 treatment was higher than under treatments with lower application doses, whereas the P accumulating rate of the ME increased rapidly under PM75 or SM100 treatments after 6 weeks. At the 8th week, the ME shoot P accumulation of the PM75 and SM100 treatments was, respectively, 1.19 and 1.27 times higher than for DM100. In summary, the mining ecotype of P. hydropiper showed greatest potential for P accumulation and P removal from soil fertilized with poultry manure at 75 g·kg-1, swine manure at 100 g·kg-1 or dairy manure at 100 g·kg-1, among the tested manure application doses. The ME P extraction in soil fertilized with swine manure or poultry manure was superior to that after dairy manure application. These results will assist in developing efficient practices for reduction of excessive P loss from farmed soils into the environment.

Key words: manure, Polygonum hydropiper, P accumulation, P removal, growth period