温室夏闲季种植翻压绿肥对土壤可溶性有机碳氮及无机氮的影响

摘要

To understand the characteristics of soil dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and inorganic nitrogen (Nmin ) responding to different green manures used as summer catch crops, six species of green manures were chosen in this study. These species belong to three families of Leguminosae (Mung bean, Sesbania, India cowpea), Gramineae (Sweet corn, Gaodan grass) and Amaranthaceae (Amaranth), respectively. A control treatment without green manure was in-cluded. Green manures were returned into soil in two ways, i. e. , all biomass returned and only the roots returned. The soils were sampled in 0 ~100 cm soil profiles at an interval of 20 cm on 1 d before and on 20 d after the green manures returned. The results showed that, the soil DOC contents increased after planting green manures, especially in 0 ~40 cm layer. Planting green manures reduced the soil DON and the Nmin contents. When all biomass returned into the soils, the DOC contents in the whole soil profile were increased in all green manure treatments, and the treatments of Leguminosae and Gramineae enhanced more than the treatment of Amaranthaceae did. Turning over the green manures could increase the soil DON and Nmin contents as well, es-pecially in the treatments of all biomass returned. The soil DON and Nmin contents varied among different treatments with the trend of Leguminosae treatments < control < Gramineae and Amaranthaceae treatments. When the roots only returned, the soil DOC, DON and Nmin of the green manure treatments were all lower than those in the control treatment. This study provided theoretical and technical supports for both the suitable green manure selection as summer catch crops in greenhouse and the appropriate utili-zation methods of green manure biomass as follows: The low fertility soil is recommended using legume crops with moderate bio-mass and total returning as far as possible. So the effect of nitrogen fixation and the ability of nutrient supply to soil could be exer-ted. While the high fertility soil in greenhouse should be considered the environmental risk and crops with deeper roots and larger biomass as summer catch crops such as amaranth and gaodan grass should be chosen, and also combined with post harvest vegeta-bles fertilizing measures to determine the amount of green manure incorporation eventually.%为明确温室土壤可溶性有机碳(DOC)、可溶性有机氮(DON)和无机氮(Nmin )对夏闲绿肥措施的响应特征,选取豆科(绿豆、田菁、印度豇豆)、禾本科(甜玉米、高丹草)和苋科(籽粒苋)6种绿肥,研究了不同夏季填闲绿肥种植、翻压对温室土壤 DOC, DON 和 Nmin含量及其剖面分布的影响。结果表明,种植不同绿肥品种均增加了土壤 DOC 含量,0~40 cm 土层增加显著；减少了土壤 DON 及无机氮含量。绿肥全量还田后,土壤剖面 DOC 含量均有所增加,苋科处理低于豆科和禾本科处理；土壤 DON 及 Nmin含量较绿肥翻压前均有不同程度增加,不同处理间表现有所差异,总体表现为豆科处理<对照处理<禾本科、苋科处理。绿肥根茬还田时,土壤DOC、 DON 及 Nmin含量均低于不种绿肥处理。本研究为温室夏闲绿肥的应用提供了参考：低肥力土壤建议采用生物量适中的豆科作物并尽可能全量还田,以发挥其固氮效果及对土壤的养分供应能力；而高肥力温室土壤中要着重考虑环境风险,应当选择籽粒苋、高丹草等根系较深、生物量大的夏季绿肥作物作为填闲作物,同时结合后茬蔬菜的施肥措施来决定绿肥还田量。