Ren Wenhao, Li Xianyue, Liu Tingxi, Chen Ning, Xin Maoxin, Liu Bin, Qi Qian, Li Gendong
College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot, China.
Collaborative Innovation Center for Integrated Management of Water Resources and Water Environment in the Inner Mongolia Reaches of the Yellow River, Hohhot, China.
Front Plant Sci. 2024 Aug 14;15:1440859. doi: 10.3389/fpls.2024.1440859. eCollection 2024.
The depth of fertilizer application significantly influences soil nitrate concentration (SNC), sunflower root length density (RLD), sunflower nitrogen uptake (SNU), and yield. However, current studies cannot precisely capture subtle nutrient variations between soil layers and their complex relationships with root growth. They also struggle to assess the impact of different fertilizer application depths on sunflower root development and distribution as well as their response to the spatial and temporal distribution of nutrients.
The Agricultural Production Systems sIMulator (APSIM) model was employed to explore the spatial and temporal patterns of nitrogen distribution in the soil at three controlled-release fertilizer (CRF) placement depths: 5, 15, and 25 cm. This study investigated the characteristics of the root system regarding nitrogen absorption and utilization and analyzed their correlation with sunflower yield formation. Furthermore, this study introduced the modified Jaccard index (considering the compatibility between soil nitrate and root length density) to analyze soil-root interactions, providing a deeper insight into how changes in CRF placement depth affect crop growth and nitrogen uptake efficiency.
The results indicated that a fertilization depth of 15 cm improved the modified Jaccard index by 6.60% and 7.34% compared to 5 cm and 25 cm depths, respectively, maximizing sunflower yield (an increase of 9.44%) and nitrogen absorption rate (an increase of 5.40%). This depth promoted a greater Root Length Density (RLD), with an increases of 11.95% and 16.42% compared those at 5 cm and 25 cm, respectively, enhancing deeper root growth and improving nitrogen uptake. In contrast, shallow fertilization led to higher nitrate concentrations in the topsoil, whereas deeper fertilization increased the nitrate concentrations in the deeper soil layers.
These results provide valuable insights for precision agriculture and sustainable soil management, highlighting the importance of optimizing root nitrogen absorption through tailored fertilization strategies to enhance crop production efficiency and minimize environmental impact.
施肥深度对土壤硝酸盐浓度（SNC）、向日葵根长密度（RLD）、向日葵氮素吸收（SNU）和产量有显著影响。然而，目前的研究无法精确捕捉土壤层间细微的养分差异及其与根系生长的复杂关系。它们也难以评估不同施肥深度对向日葵根系发育和分布的影响，以及其对养分时空分布的响应。
采用农业生产系统模拟器（APSIM）模型，探究三种控释肥（CRF）施肥深度（5、15和25厘米）下土壤中氮素分布的时空模式。本研究调查了根系对氮素吸收和利用的特征，并分析了它们与向日葵产量形成的相关性。此外，本研究引入修正的杰卡德指数（考虑土壤硝酸盐与根长密度之间的兼容性）来分析土壤-根系相互作用，从而更深入地了解控释肥施肥深度的变化如何影响作物生长和氮素吸收效率。
结果表明，与5厘米和25厘米深度相比，15厘米的施肥深度分别使修正的杰卡德指数提高了6.60%和7.34%，使向日葵产量最大化（增加9.44%）和氮素吸收率最大化（增加5.40%）。该深度促进了更大的根长密度（RLD），与5厘米和25厘米深度相比分别增加了11.95%和16.42%，促进了根系向深层生长并提高了氮素吸收。相比之下，浅施肥导致表土中硝酸盐浓度较高，而深施肥增加了深层土壤中的硝酸盐浓度。
这些结果为精准农业和可持续土壤管理提供了有价值的见解，强调了通过定制施肥策略优化根系氮素吸收以提高作物生产效率和最小化环境影响的重要性。
