畜禽粪便处理下矿山生态型水蓼磷积累及去除能力研究

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

研究磷富集植物对畜禽粪便施用土壤中过量磷的积累及去除能力,可为利用植物提取土壤过剩磷以降低磷造成的非点源污染提供科学依据。采用两期土培盆栽试验,以矿山生态型水蓼为研究对象,探讨不同用量(0、25、50、75、100 g·kg^(-1))鸡粪、猪粪和牛粪处理下矿山生态型水蓼的磷积累能力,分析适宜用量畜禽粪便处理下矿山生态型水蓼在不同生长时期(6、8、10、12周)的磷积累特征及磷去除能力。结果表明:1)随着畜禽粪便用量的增加,矿山生态型水蓼地上部生物量和磷积累量均在75 g·kg^(-1)鸡粪(PM_(75))、100 g·kg^(-1)猪粪(SM_(100))和100 g·kg^(-1)牛粪(DM_(100))时达到最大,地上部磷积累量分别为158.64、204.05和128.92 mg·株^(-1),是不施畜禽粪便处理的5.47~8.66倍。2)适宜用量畜禽粪便(PM_(75)、SM_(100)、DM_(100))处理下,矿山生态型水蓼生物量和磷积累量分别在12和8周时达到最大,地上部磷积累速率在6~8周时最高。8周后,各适宜用量畜禽粪便处理下矿山生态型水蓼磷去除能力无显著变化,磷提取率可达5.84%~19.36%、植株有效数为4~6株。8周为适宜用量畜禽粪便处理下矿山生态型水蓼的适宜收获时期。3)不同畜禽粪便处理下矿山生态型水蓼磷积累能力存在较大差异,在0~6周时,DM_(100)处理下矿山生态型水蓼地上部磷积累速率明显高于其他处理;在6周后,PM_(75)和SM_(100)处理下矿山生态型水蓼地上部磷积累速率均迅速增加,地上部磷积累量在8周时分别是DM_(100)处理的1.19和1.27倍。综上,在75 g·kg^(-1)鸡粪、100 g·kg^(-1)猪粪、100 g·kg^(-1)牛粪的土壤中,矿山生态型水蓼生长良好,磷积累和磷去除能力强,可高效提取畜禽粪便施用土壤中的磷以降低过量磷对环境的威胁,且对猪粪、鸡粪处理土壤中磷的提取效果优于牛粪处理土壤。

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 soils fertilized 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,M_(75),M_(100),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 PM_(75),SM_(100) and DM_(100).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 PM_(75),SM_(100) or DM_(100)),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%^(-1)9.36% 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 DM_(100) treatment was higher than under treatments with lower application doses,whereas the P accumulating rate of the ME increased rapidly under PM_(75) or SM_(100) treatments after 6 weeks.At the 8 th week,the ME shoot P accumulation of the PM_(75) and SM_(100) treatments was,respectively,1.19 and 1.27 times higher than for DM_(100).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.