[Environmental Effects of Algae Bloom Cluster: Impact on the Floating Plant Water Hyacinth Photosynthesis].

It is an efficient and effective ecological restoration method by using the adaptability, large biomass of aquatic plants to purify the polluted water at present. However, there is a lack of systematic research on the impact on the physiological ecology of aquatic plants and its environmental effects of algae blooms cluster in summer. The aim of this paper is to reveal the mechanism of macrophytes demise in a shallow ecosystem by studying the influence on photosynthesis of water hyacinth caused by the cynaobacterial blooms gathered, and also to provide the theoretical basis for full effects of purification function of macrophytes to reduce the negative effects on the aquatic plants after algae blooms gathered during the higher temperature (not lower 25 degrees C) through simulating experiments.

[Effects of nitrogen application rates on apparent soil nitrogen surplus of late sowing wheat with straw returning in rice-wheat rotation].

Field experiments were conducted to study the effects of varying rates of nitrogen application on soil mineral nitrogen content, amount of nitrogen released from the straw, and grain yield of late sowing wheat with straw returning. The result showed that a high nitrogen fertilizer application rate enhanced the mineral nitrogen content in the soil layer of 0 to 50 cm, and also in the lower soil layers when using N at 270 and 360 kg · hm(-2) with the advance of growth stages. The amount of nitrogen released form the straw increased as the nitrogen application rate increased; the lowest appeared from overwintering to jointing, and the highest from jointing to maturity.