城市污泥堆肥用作草皮基质对草坪草生长的影响

The Municipal Sewage Sludge Compost Used as Lawn Medium

研究了城市污泥堆肥生产草坪基质的应用效果。试验结果表明 ,城市污泥堆肥基质能明显提高黑麦草的地上和地下生物量和叶绿素含量 ;与不施化肥和施用化肥的对照相比 ,城市污泥堆肥可以增加土壤有效态氮、磷含量 ,促进植物叶片对氮的吸收 ,提高草坪的质量。用经过无害化处理的城市污泥生产草坪基质 ,既可以解决城市污泥的出路 ,又可以降低草坪的生产成本 。

Sewage sludge is a by-product of wastewater treatment plants, which receive a great deal of effluents from industrial, municipal and/or rural sources. According to the national planning, an increase of sewage sludge production will occur in China very soon. So, more attention should be paid to its disposal. Sewage sludge has several characteristics: (1) it contains organic matter; (2) the organic fraction contains humic substances coming from the degradation of organic matter; (3) it contains varying concentrations of trace elements and synthetic organic compounds. The occurrence of disposal and utilization of sewage sludge is much later in China than in other developed countries and most of works in China focused on the sludge and compost using in vegetables and crops. Sewage sludge and compost used as medium for plant growth and fertilizer for lawny production were popular in many countries, but few was reported in China. In this experiment, the sewage sludge compost was used as lawn medium for ryegrass. The purpose was to examine the effects of sewage sludge compost on lawny-grass growth and the soil fertility. The pot experiment was conducted in April of 2000, which was composed of 5 treatments including check (0N-0P-0K-0compost), fertilizer (N∶P∶ K∶ compost=3∶ 1∶ 2∶ 0, 1.4t/hm 2), compost A (7t/hm 2 compost), compost B (14t/hm 2 compost), compost C (70t/hm 2 compost). Two types of soils (topsoil and subsoil) with the same experiment treatments were used. Each treatment was replicated six times. The experiments were carried out in the green house with temperature of 15~25℃ and 14 hours of light per day. The relative humidity of the green house was kept between 50～60 percent. Soil and compost samples were extracted by 1mol/L NaOH for available N and by 0.5 mol/L NaHCO 3 for available P and 1 mol/L NH 4AC for available K, respectively. The elements in the extraction were determined with hydrochloric acid titration, spectrophotometer and flame photometry. Heavy metal contents were analyzed after extraction using EDTA by AAS determination (Vario 6). The results suggested that, with the enhancement of sewage sludge compost, the biomass of the ryegrass raised. The weight of dry matter of ryegrass in compost B and C treatments were significantly higher than that in NPK and check treatments. The compost B and C also improved ryegrass root growth, especially the compost C with the highest amount of compost. After five months growing, the chlorophyllous content was enhanced obviously with the utilization of the sewage sludge compost increasing, the leaf color was deep green and chlorophyllous content reached to the first class. Compared with the control and NPK treatments, the sewage sludge compost increased the soil available N and P content. The available N concentrations of 14 and 70t/hm 2 compost treatments in subsoil was 1.6 and 2.3 times as much as the control (soil only) respectively, and were 23.9% and 78.6% higher than N P K treatment. The sewage sludge compost could also improve the P status. Contrast to the control, the available P content in subsoil in compost B and C increased by 59.7% and 592.5%. The available P of 70 t/hm 2 compost treatment was 4.3 times as much as that in N P K treatment. The available P content of 7t/hm 2 compost in subsoil was not statistically different from the control, and was statistically lower than (α=0.05) the N P K fertilizer treatment. Concentration of available K in the soil seemed not to be affected by the compost application. The nutrient change in topsoil was similar with the subsoil. The sewage sludge compost used as a medium for lawn growth, which can not only solve the sewage sludge outlet problem, but also reduce the lawn production cost . It is an economical and sustainable development approach.