He Dongxiao, Chu Jianmin, Yang Hongxiao
Qingdao Agricultural University, Qingdao, China.
Research Institute of Forestry, Chinese Academy of Forestry; Key Laboratory of Tree Breeding and Cultivation, National Forestry and Grassland Administration, Beijing, China.
PeerJ. 2021 Nov 11;9:e12469. doi: 10.7717/peerj.12469. eCollection 2021.
Crude flats in delta areas are often saline-alkaline and unsuitable for agricultural cropping. In the 1990s, people residing in the Yellow River delta constructed terraces on the flats for agricultural development. Herein, we investigated environmental changes resulting from this agricultural development and evaluated whether the current land use is effective and sustainable.
We sampled soil and weeds from croplands, terrace slopes, and crude flats within the delta terrace landscape. The measured soil properties included soil salinity, pH, total N, total P, and organic matter in different lands and soil layers: 0-10, 10-20, and 20-30 cm. The surveyed weed characteristics were the biomass of roots and rhizomes, species composition, life form, cover and height. These indices were statistically verified by different land types and soil layers.
Soil salinity in the terrace crop lands was found to have reduced to <4 g·kg, whereas in the crude flats, remained >6 g·kg. Soil pH in the terrace croplands was surprisingly increased to >9 ; meanwhile, organic matter content decreased drastically, which is significantly different from that observed in the case of terrace slopes and crude flats. Total N and P content in the terrace crop lands were seemingly unchanged on averages but at the depths >20 cm, they reduced unavoidably. Plant underground organs were relatively scarcer in the croplands than in the other lands. Weeds grew well on the terrace slopes but were insufficient in the croplands. Overall, terrace construction is effective for developing coastal saline flats for agricultural use, but the traditional land use in the Yellow River delta has caused chronic soil degradation that is against a sustainable productive industry.
三角洲地区的原始平地通常盐碱化程度高，不适宜进行农业种植。20世纪90年代，居住在黄河三角洲的人们在平地上建造梯田用于农业开发。在此，我们调查了这种农业开发所导致的环境变化，并评估了当前的土地利用是否有效且可持续。
我们在三角洲梯田景观内的农田、梯田斜坡和原始平地上采集了土壤和杂草样本。测量的土壤性质包括不同土地和土壤层（0 - 10厘米、10 - 20厘米和20 - 30厘米）中的土壤盐分、pH值、全氮、全磷和有机质。调查的杂草特征包括根和根茎的生物量、物种组成、生活型、覆盖度和高度。这些指标通过不同土地类型和土壤层进行了统计验证。
发现梯田农田中的土壤盐分已降至<4克·千克，而在原始平地上仍>6克·千克。梯田农田中的土壤pH值惊人地升至>9；与此同时，有机质含量急剧下降，这与梯田斜坡和原始平地的情况有显著差异。梯田农田中的全氮和全磷含量平均看似没有变化，但在深度>20厘米处，它们不可避免地减少了。农田中植物的地下器官相对比其他土地稀少。杂草在梯田斜坡上生长良好，但在农田中不足。总体而言，梯田建设对于开发沿海盐碱平地用于农业是有效的，但黄河三角洲的传统土地利用已导致长期的土壤退化，不利于可持续的生产性产业。
