Colangelo D J, Brand M H
Department of Plant Science, Univ. of Connecticut, Storrs 06269-4067, USA.
J Environ Qual. 2001 Sep-Oct;30(5):1564-74. doi: 10.2134/jeq2001.3051564x.
Container production of nursery crops is intensive and a potential source of nitrogen release to the environment. This study was conducted to determine if trickle irrigation could be used by container nursery producers as an alternative to standard overhead irrigation to reduce nitrogen release into the environment. The effect of overhead irrigation and trickle irrigation on leachate nitrate N concentration, flow-weighted nitrate N concentration, leachate volume, and plant growth was investigated using containerized rhododendron (Rhododendron catawbiense Michx. 'Album') supplied with a controlled-release fertilizer and grown outdoors on top of soil-monolith lysimeters. Leachate was collected over two growing seasons and overwinter periods, and natural precipitation was allowed as a component of the system. Precipitation accounted for 69% of the water entering the overhead-irrigated system and 80% of the water entering the trickle-irrigated system. Leachate from fertilized plants exceeded the USEPA limit of 10 mg L(-1) at several times and reached a maximum of 26 mg L(-1) with trickle irrigation. Average annual loss of nitrate N in leachate for fertilized treatments was 51.8 and 60.5 kg ha(-1) for the overhead and trickle treatments, respectively. Average annual flow-weighted concentration of nitrate N in leachate of fertilized plants was 7.2 mg L(-1) for overhead irrigation and 12.7 mg L(-1) for trickle irrigation. Trickle irrigation did not reduce the amount of nitrate N leached from nursery containers when compared with overhead irrigation because precipitation nullified the potential benefits of reduced leaching fractions and irrigation inputs provided under trickle irrigation.
容器育苗生产集约化，是氮素向环境释放的一个潜在来源。本研究旨在确定容器育苗生产者是否可以使用滴灌替代标准的顶喷灌溉，以减少氮素向环境中的释放。使用装有控释肥料并种植在土壤柱状渗滤计顶部户外的容器化杜鹃（Rhododendron catawbiense Michx. 'Album'），研究了顶喷灌溉和滴灌对渗滤液硝酸盐氮浓度、流量加权硝酸盐氮浓度、渗滤液体积和植物生长的影响。在两个生长季节和越冬期间收集渗滤液，系统中允许自然降水作为一部分。降水占进入顶喷灌溉系统水量的69%，占进入滴灌系统水量的80%。施肥植物的渗滤液多次超过美国环保署规定的10 mg L(-1)限值，滴灌时最高达到26 mg L(-1)。施肥处理的渗滤液中硝酸盐氮的年平均损失量，顶喷处理和滴灌处理分别为51.8和60.5 kg ha(-1)。施肥植物渗滤液中硝酸盐氮的年平均流量加权浓度，顶喷灌溉为7.2 mg L(-1)，滴灌为12.7 mg L(-1)。与顶喷灌溉相比，滴灌并没有减少从育苗容器中淋溶出的硝酸盐氮量，因为降水抵消了滴灌条件下淋溶分数降低和灌溉投入带来的潜在益处。
