Department of Biological Environment, Kangwon National University, Chuncheon 200-701, Republic of Korea.
Chemosphere. 2011 Oct;85(4):677-82. doi: 10.1016/j.chemosphere.2011.06.073. Epub 2011 Jul 20.
Rapeseed (Brassica napus L.) has been cultivated for biodiesel production worldwide. Winter rapeseed is commonly grown in the southern part of Korea under a rice-rapeseed double cropping system. In this study, a greenhouse pot experiment was conducted to assess the effects of rapeseed residue applied as a green manure alone or in combinations with mineral N fertilizer on Cd and Pb speciation in the contaminated paddy soil and their availability to rice plant (Oryza sativa L.). The changes in soil chemical and biological properties in response to the addition of rapeseed residue were also evaluated. Specifically, the following four treatments were evaluated: 100% mineral N fertilizer (N100) as a control, 70% mineral N fertilizer+rapeseed residue (N70+R), 30% mineral N fertilizer+rapeseed residue (N30+R) and rapeseed residue alone (R). The electrical conductivity and exchangeable cations of the rice paddy soil subjected to the R treatment or in combinations with mineral N fertilizer treatment, N70+R and N30+R, were higher than those in soils subjected to the N100 treatment. However, the soil pH value with the R treatment (pH 6.3) was lower than that with N100 treatment (pH 6.9). Use of rapeseed residue as a green manure led to an increase in soil organic matter (SOM) and enhanced the microbial populations in the soil. Sequential extraction also revealed that the addition of rapeseed residue decreased the easily accessible fraction of Cd by 5-14% and Pb by 30-39% through the transformation into less accessible fractions, thereby reducing metal availability to the rice plant. Overall, the incorporation of rapeseed residue into the metal contaminated rice paddy soils may sustain SOM, improve the soil chemical and biological properties, and decrease the heavy metal phytoavailability.
油菜（Brassica napus L.）已在全球范围内被用于生物柴油生产。冬油菜在韩国南部地区通常与水稻-油菜复种制度相结合进行种植。本研究通过温室盆栽试验，评估了单独或与矿物 N 肥结合施加油菜残体对污染稻田中 Cd 和 Pb 形态及其对水稻（Oryza sativa L.）可利用性的影响。还评估了油菜残体添加对土壤化学和生物学性质的变化。具体而言，评估了以下四种处理：100%矿物 N 肥（N100）作为对照、70%矿物 N 肥+油菜残体（N70+R）、30%矿物 N 肥+油菜残体（N30+R）和油菜残体单独处理（R）。与 N100 处理相比，施加油菜残体或与矿物 N 肥处理（N70+R 和 N30+R）结合处理的稻田土壤的电导率和可交换阳离子更高。然而，施加油菜残体处理（pH 6.3）的土壤 pH 值低于 N100 处理（pH 6.9）。油菜残体作为绿肥的使用导致土壤有机质（SOM）增加，并增强了土壤中的微生物种群。连续提取还表明，油菜残体的添加通过将 Cd 的易接近部分减少 5-14%和 Pb 的易接近部分减少 30-39%，将其转化为不易接近的部分，从而降低了金属对水稻的可利用性。总体而言，将油菜残体掺入金属污染稻田土壤中可能会维持 SOM，改善土壤化学和生物学性质，并降低重金属的植物可利用性。
