厌氧发酵牛粪对浮萍生长和养分吸收的影响

养分从牛粪到农田的循环利用是养牛场可持续发展、资源利用和环境保护的重点研究内容。利用奶牛场废水种植水生植物被认为是一种有效的废水处理及养分循环的方法。本文研究了3种浮萍少根紫萍0128（Landoltia punctata 0128）、膨胀浮萍7589（Lemna gibba 7589）和小浮萍9517（Lemna minuta 9517）]在厌氧发酵过的奶牛场废水中种植时的养分吸收和生物质变化。在28 d的测试期间，种植在稀释比例为1：18的厌氧发酵过的牛奶场废水中的少根紫萍01283获得最高的总氮吸收率（11.6%±1.6%），种植在稀释比例为1：27厌氧发酵过的牛奶场废水中的少根紫萍0128获得最高的总磷吸收率（15.4%±4.4%）；相应地少根紫萍鲜重的增长率分别为0.11 g·d^-1和0.17 g·d^-1。3种浮萍中，少根紫萍最具有吸收牛奶场废水氮、磷并获得较高生物质的潜力。

Growth and nutrient uptake rates of duckweed cultivated on anaerobically digested dairy manure

Nutrient cycling from flushed dairy manure systems to croplands is a national research priority for sustainable dairy operations, resource utilization, and environmental protection. Cultivating aquatic plants on dairy wastewaters has been considered an effective approach for wastewater treatment/reuse and nutrient recycling. This study aimed to investigate nutrient uptake and biomass production of duckweed strains on dairy wastewater. Three duckweed strains, namely Landoltia punctata 0128, Lemna gibba 7589, and Lemna minuta 9517, were cultivated on anaerobically digested (AD) dairy manure wastewater over a period of 28 days. The highest reduction rate of total nitrogen (TN) was achieved by L. punctata from the AD dairy manure with a dilution ratio of 1:18 (83.1 mg∙L^-1 TN) at 11.6% (±1.64%). The highest reduction rate of total phosphorus (TP) was achieved by L. punctata from the AD dairy manure with a dilution ratio of 1:27 (6.7 mg∙L^-1 TP) at 15.4% (±4.4%). The corresponding fresh weight-based growth rate constants of L. punctata were 0.11 g∙d^-1 and 0.17 g∙d^-1 for the dilution ratios of 1:18 and 1:27, respectively. It has been shown that, among the three duckweed strains tested in this study, L. punctata has the greatest potential to be cultivated on the medium of diluted AD dairy manure for best N and P reduction and biomass production.