为实现富营养化水体的修复,对影响凤眼莲[Eichhornia crassipes ( Mart.) Sloms]高产高效的放养及采收条件(包括初始放养日期、采收标准和采收比例)进行了研究,并对凤眼莲的生长曲线以及 N、P 和 K 的积累量进行了分析。 实验结果表明:在总氮、总磷和钾含量分别为 3. 41 ~ 7. 18、0. 05 ~ 0. 27 和 2. 24 ~ 5. 18 mg· L^-1的水体中,在生长前期由于产生分蘖和植株个体生长,凤眼莲生物量快速增加;当植株生长至一定高度,生物量增幅减小;通过这一生长过程,凤眼莲的最高生物量可达 28. 28 kg· m^-2 。 初始放养日期对凤眼莲的生长曲线和生物量均有明显影响,随初始放养日期的推迟生物量逐渐增大,在 4 月 10 日、4 月 17 日、4 月 24 日、5 月 1 日和 5 月 8 日放养的凤眼莲经过 63 d 的放养,生物量均明显增加,其中,5 月 8 日放养的凤眼莲总生物量最高,达到 24. 36 kg· m^-2 。 采收标准和采收比例对凤眼莲的采收频率和累计采收量以及 N、P 和 K 积累量具有显著影响。 按照 10 ~ 15、15 ~ 20、20 ~ 25、25 kg· m^-2以上及最高生物量的采收标准以及 1 / 2 和 2 / 3 的采收比例进行采收,凤眼莲的累计采收量均高于一次性采收(对照),且与其生物量呈抛物线型关系,但采收频率则与生物量成反比;采取不同的采收标准及采收比例,凤眼莲的干物质含量及 N、P 和 K 含量及总量均有一定的差异,但除干物质含量外,N、P 和 K 含量及总量均明显高于一次性采收;总体上,采用 20 ~ 25 kg· m^-2的采收标准及 2 / 3 采收比例,凤眼莲的累计采收量最高、采收频率较少,对 N、P 和 K 的积累量最大。 综合比较结果显示:在南京地区凤眼莲可于 4 月初开始放养,4 月至 5 月分蘖,6 月以后正常生长,并可按照 20 ~ 25 kg· m^-2的采收标准和 2 / 3 的采收比例进行采收。

In order to achieve remediation of eutrophic water, the planting and harvest conditions ( including initial planting date, harvest standard and ratio ) effected on high production and high efficiency of Eichhornia crassipes (Mart.) Sloms were studied, and also, growth curve and accumulative amount of N, P and K were analyzed. The results show that in water with TN, TP and K contents of 3. 41-7. 18, 0. 05-0. 27 and 2. 24-5. 18 mg· L^-1, respectively, E. crassipes biomass increases rapidly due to tiller emergency and plant growth at the beginning of growth period, and the range of biomass increasing begins to decrease when the plant grows to a certain height. And the highest biomass reaches 28. 28 kg· m^-2 during the whole growth process. The initial planting date has an obvious effect on growth curve and biomass, and the biomass increases gradually with delaying of the initial planting date. The biomasses of E. crassipes planted respectively on 10th, 17th, 24th of April and 1st, 8th of May for 63 d all increase obviously, in which, that planted on 8th May is the highest with a value of 24. 36 kg· m^-2. Harvest standard and ratio have significant effects on harvest frequency, cumulative harvest and accumulative amount of N, P and K. And the cumulative harvests of E. crassipes harvested according to the harvest standard of 10-15, 15-20, 20-25, >25 kg· m^-2 and the highest biomass and the harvest ratio of 1 / 2 and 2 / 3 all are higher than that of one-time harvest ( the control), and have a parabola relationship with biomass, but the harvest frequency is inversely proportional to biomass. In E. crassipes harvested according to different harvest standards and different harvest ratios, the content of dry matter and the contents and total amounts of N, P and K all have some differences, but these all are obviously higher than that of one-time harvest except dry matter content. Generally, according to the harvest standard of 20-25 kg· m^-2 and 2 / 3 harvest ratio E. crassipes has the highest cumulative harvest, fewer harvest frequency and the highest accumulative amount of N, P and K. The comprehensive comparison result suggests that in Nanjing, E. crassipes should be planted initially in early April, tillering from April to May and normally growing after June, and be harvested according to the harvest standard of 20-25 kg· m^-2 and 2 / 3 harvest ratio.