@article{BAI2022, 
author = {Fei BAI and GuiPing BAI and ChunYun WANG and Zhen LI and DePing GONG and Wei HUANG and YuGui CHENG and Bo WANG and Jing WANG and ZhengHua XU and Jie KUAI and GuangSheng ZHOU},
title = {Effects of Tillage Depth and Shading on Root Growth and Nutrient Utilization of Rapeseed},
year = {2022},
journal = {Scientia Agricultura Sinica},
volume = {55},
number = {14},
pages = {2726-2739},
keywords = {rapeseed, shade, deep tillage, root, nutrient},
url = {https://www.sciopen.com/article/10.3864/j.issn.0578-1752.2022.14.004},
doi = {10.3864/j.issn.0578-1752.2022.14.004},
abstract = {【Objective】The rapeseed (Brassica napus L.) production district in the Yangtze River valley lacks sufficient radiation due to abundant rainfall during its growing season. In addition, the application of dense planting technology intensifies the competition for radiation among individuals. Insufficient radiation and poor soil texture have become main factors for restricting high yield of rapeseed in this area. In order to provide the theoretical support for stable yield and increased income, the effects of tillage depth on root growth and nutrient utilization of shaded rapeseed were studied.【Method】The experiment designed by the split-split plot method in three replications was conducted in the tested site of Huazhong Agricultural University in Wuhan, Hubei province, from 2019 to 2021. The experiment consisted of three factors arranged in a split-split plot design with 2 varieties: Xiangzayou 518 (XZY518) and Zheyou 50 (ZY50) in main plots, two levels of tillage depth: 5 cm (T5) and 20 cm (T20) in sub plots, and two levels of shading rate: 0% shading (S0) and 30% shading (S1) in sub-sub plots. The effects of different tillage depths on physical and chemical properties of soil, the antioxidant enzyme activity, nutrient absorption of the root and the dry matter accumulation of root and shoot were evaluated.【Result】Deep tillage promoted the accumulation of organic matter, alkali-hydrolyzed nitrogen, available phosphorus, and available potassium in each layer of soil, with the largest increase (by 7.5%-42.3%) in 10-20 cm soil. Shading decreased the soil electrical conductivity, root surface area (decrease by 13.3%-36.6%), the utilization efficiency of nitrogen (decrease by 3.0%-28.4%) and root dry weight, while it increased the main root length, root to shoot ratio, lateral root proportion, and the activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) in roots. The increasing tillage depth in shading condition alleviated the reduction of soil water content, promoted taproot elongation, increased the activities of antioxidant enzymes (POD and SOD) and the root surface area, root to shoot ratio, lateral root ratio finally improved the utilization efficiency of nitrogen, and the accumulation of dry matter. The analysis of variance showed that the interaction between tillage depth and shading on root morphology, dry matter accumulation, antioxidant enzyme activity and nutrient utilization reached a significant or extremely significant difference. Compared with normal light, the root surface area were decreased by 24.9%-36.6% and 13.3%-19.2%, the utilization efficiency of nitrogen were decreased by 10.0%-28.4% and 3.0%-23.9% after shading under the shallow tillage and deep tillage, respectively.【Conclusion】Under the weak light stress, the deep tillage increased soil nutrients and main root elongation, the ratio of lateral root and root surface area, the activity of antioxidant enzymes in the root, dry matter accumulation, and enhanced the nutrient absorption capacity and nitrogen use efficiency, also delayed the aging of the root system. As a result, all these factors promoted rapeseed growth.}
}