Abstract

Hyperaccumulator–cash crop intercropping remediation is a research hotspot for heavy metal contaminated farmland, but few studies evaluated its feasibility based on practice. Field experiments and survey statistics were conducted to obtain parameters of Pteris vittata–Citrus reticulata/Zea mays intercropping, and potential of intercropping remediation was evaluated based on remediation efficiency and economic benefits. The results showed that intercropping hyperaccumulator with cash crop (especially herbs) had a certain negative effect on remediation efficiency because of the influence on planting density and harvest times of hyperaccumulator; while trees could partly alleviate this effect. Until achieving the predetermined target, the net remediation cost of P. vittata–Z. mays was 18.2 $/g As, followed by P. vittata monoculture (13.3 $/g) and P. vittata–C. reticulata (8.6 $/g). Based on the proposed evaluation model, nealy half of the P. vittata intercropping modes had low economic benefits, insufficient to compensate the cost of sacrificing remediation efficiency. Based on the data from two soil remediation projects, when net income of cash crops intercropped with As-hyperaccumulators exceeded 5865/1607 $/hm² (herbs/trees), the economic benefit of intercropping will be relatively obvious. Therefore, cash crops should be considered from three aspects: planting conditions, spatial allocation and economic benefits.

Novelty statement: This work analyzed remediation efficiency and economic benefits of intercropping remediation. An economic benefit evaluation model was established to evaluate intercropping remediation modes. The selection principle and net income threshold of cash crops in intercropping was put forward for the first time.

1. Highlights

2. The selection principle of cash crops in intercropping remediation was put forward.

3. An evaluation model of P. vittata intercropping remediation was established.

4. The net cost of extracting 1.0 g of soil As in each remediation mode was proposed.

5. Net income of herb/tree intercropped with P. vittata should exceed 5865/1607 $/hm².

摘要

超富集-经济作物间作修复是重金属污染农田的研究热点，但很少有研究基于实践评估其可行性。通过田间试验和调查统计，获得了凤尾草-柑桔/玉蜀黍间作参数，从修复效率和经济效益两方面评价间作修复潜力。结果表明，超富集植物与经济作物（尤其是草本植物）间作对修复效果有一定的负面影响，因为其对超富集植物的种植密度和收获时间都有影响；而树木可以部分缓解这种影响。在达到预定目标之前，净修复成本为P. vittata-Z。mays为 18.2 $/g As，其次是P. vittata单一栽培 (13.3 $/g) 和P. vittata–C。网状植物（8.6 美元/克）。基于所提出的评价模型，近一半的油菜间作模式经济效益低，不足以弥补牺牲修复效率的成本。根据两个土壤修复项目的数据，当经济作物与As-高富集植物间作的纯收入超过5865/1607 $/hm ²（草本/树木）时，间作的经济效益会比较明显。因此，经济作物应从种植条件、空间配置和经济效益三个方面考虑。

新颖性声明：这项工作分析了间作修复的修复效率和经济效益。建立经济效益评价模型对间作修复模式进行评价。首次提出了间作经济作物的选择原则和纯收入门槛。

1. 强调

2. 提出了间作修复中经济作物的选择原则。

3. 建立了油菜间作修复评价模型。

4. 提出了每种修复模式提取 1.0 g 土壤 As 的净成本。

5. 与P. vittata间作的草本/树木的净收入应超过 5865/1607 美元/hm ²。