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| Optimizing root morphology through combined application of organic and inorganic fertilizers to reduce nitrogen loss |
| Received:June 18, 2025 |
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| KeyWord:open vegetable field;nitrogen fertilizer rate;type of organic fertilizer;root morphology;runoff |
| Author Name | Affiliation | E-mail | | XU Yehong | School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
National Agricultural Experimental Station for Agricultural Environment, Luhe, Nanjing 210014, China | | | BA Wenwen | School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China | | | LU Chao | Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
National Agricultural Experimental Station for Agricultural Environment, Luhe, Nanjing 210014, China | | | LUO Jia | Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
National Agricultural Experimental Station for Agricultural Environment, Luhe, Nanjing 210014, China | | | MA Yan | Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
National Agricultural Experimental Station for Agricultural Environment, Luhe, Nanjing 210014, China | mayan@jaas.ac.cn |
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| Abstract: |
| The combined application of organic and inorganic fertilizers is an effective way to optimize nutrient management and reduce nitrogen loss. Most studies focused on the relationships between nitrogen loss and the aboveground growth of vegetables, whereas the response of the underground root morphology to organic-inorganic fertilizer application and its mechanism affecting nitrogen loss in vegetable fields remain unclear. In this study, a field plot experiment was conducted using different nitrogen application rates combined with spent mushroom（SM）or manure compost（MC）, selected for their different mineralization capacities. Cellulase（E）was specifically co-applied to promote the mineralization of high-cellulose organic fertilizer. The effects on vegetable yield, root morphology and nitrogen loss through runoff under natural rainfall conditions were investigated. The experiment included six treatments：conventional nitrogen rate （N450）, conventional nitrogen rate combined with organic fertilizer（N450 + SM, N450 +MC）, 30% -reduced nitrogen rate（N315）, and 30% - reduced nitrogen rate combined with organic fertilizer（N315 + SM, N315 + SM + E）. The results showed that, compared to N450 treatment, N315 treatment did not significantly influence cabbage yield, while combined organic and mineral fertilization treatments significantly increased both cabbage yield and partial factor productivity of nitrogen fertilizer by 14.2% - 39.1% and 26.8% - 64.5%, respectively. Compared to N450 treatment, N315, N315+SM, and N315+SM+E treatments significantly reduced total dissolved nitrogen and nitrate loss through runoff by 26.9%-44.3% and 32.4%-47.5%, respectively, while the ammonium loss through runoff was significantly reduced by 11.7% - 13.6% under N315 + SM and N315 + SM + E treatments. Compared to N450 treatment, N315 treatment reduced the number of cabbage root tips by 11.0%. In contrast, compared to N315 treatment, N315 + SM and N315 + SM +E treatments significantly increased total root length, total root surface area, number of root tips and total amount of fine roots of cabbage, with increases ranging from 24.5% to 33.2%, 16.0% to 24.5%, 26.0% to 33.7% and 26.5% to 34.1%, respectively. In addition, their total root length, root tip number, total amount of fine roots and the proportion of fine roots were better than those under N450+SM and N450+MC treatments. The nitrogen uptake of cabbage showed significant positive correlations with its total root volume and surface area. Total dissolved nitrogen and nitrate loss through runoff showed significant negative correlations with the total root length, total amount of fine roots and the proportion of fine roots of cabbage. The optimization of root morphology played an important role in mitigating nitrogen loss through runoff. In conclusion, combining a 30%-reduced nitrogen rate with spent mushroom and cellulase can improve root morphology and nitrogen uptake amount of vegetables, which is recommended to enhance yield as well as reduce nitrogen loss through runoff in open-field vegetable production system. |
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