Wang Can, Chen Siyu, Peng Fangli, Zhao Qiang, Gao Jie, Zhou Lingbo, Zhang Guobing, Shao Mingbo
Institute of Upland Food Crops, Guizhou Academy of Agricultural Sciences, Guiyang 550006, China.
Plants (Basel). 2025 May 3;14(9):1384. doi: 10.3390/plants14091384.
Waxy sorghum-soybean intercropping is a sustainable and intensive farming system in southwest China. However, there is limited knowledge about the effects of intercropped soybean combined with nitrogen application on nitrogen uptake and utilization in waxy sorghum. A two-year (2023 and 2024) field experiment was carried out using a randomized complete block design with three planting patterns and three nitrogen application rates to explore the responses of grain yield formation and nitrogen uptake, accumulation, transportation, metabolism physiology, and utilization of waxy sorghum for intercropped soybean combined with nitrogen application. Planting patterns included sole cropped waxy sorghum (SCW), sole cropped soybean (SCS), and waxy sorghum intercropped with soybean (WSI), and nitrogen application rates included zero nitrogen (N0), medium nitrogen (N1), and high nitrogen (N2). Results showed that the dry matter accumulation amount, nitrogen content, nitrogen accumulation amount, nitrogen transportation amount, nitrogen transportation rate, contribution rate of nitrogen transportation to grains, nitrogen metabolizing enzymes activities (including nitrate reductase, nitrite reductase, glutamine synthetase, glutamate synthetase, glutamate dehydrogenase, and glutamic-pyruvic transaminase), and active substances contents (including soluble sugar, soluble protein, and free amino acid) in various organs of waxy sorghum among planting patterns and nitrogen application rates were in the order of WSI > SCW and N1 > N2 > N0, respectively. In addition, the nitrogen uptake efficiency, nitrogen agronomy efficiency, nitrogen apparent efficiency, nitrogen recovery efficiency, nitrogen partial factor productivity, and nitrogen contribution rate of waxy sorghum among planting patterns and nitrogen application rates were in the sequence of WSI > SCW and N1 > N2, respectively. The changes in above traits resulted in the WSI-N1 treatment obtaining the highest grain yield (6020.66 kg ha in 2023 and 6159.81 kg ha in 2024), grain weight per spike (65.22 g in 2023 and 64.51 g in 2024), 1000-grain weight (23.14 g in 2023 and 23.18 g in 2024) of waxy sorghum, and land equivalent ratio (1.41 in 2023 and 1.44 in 2024). Overall, waxy sorghum intercropped with soybean combined with medium nitrogen application (220 kg ha for waxy sorghum and 18 kg ha for soybean) can help enhance the nitrogen uptake and utilization of waxy sorghum by improving nitrogen metabolizing enzymes' activities and active substances' contents, thereby promoting its productivity.
糯高粱与大豆间作是中国西南地区一种可持续的集约型种植系统。然而，关于间作大豆并施氮对糯高粱氮素吸收和利用的影响，目前了解有限。进行了为期两年（2023年和2024年）的田间试验，采用随机完全区组设计，设置三种种植模式和三种施氮量，以探究间作大豆并施氮条件下糯高粱产量形成及氮素吸收、积累、转运、代谢生理和利用的响应。种植模式包括单作糯高粱（SCW）、单作大豆（SCS）和糯高粱与大豆间作（WSI），施氮量包括不施氮（N0）、中氮（N1）和高氮（N2）。结果表明，不同种植模式和施氮量下，糯高粱各器官的干物质积累量、氮含量、氮积累量、氮转运量、氮转运率、氮转运对籽粒的贡献率、氮代谢酶活性（包括硝酸还原酶、亚硝酸还原酶、谷氨酰胺合成酶、谷氨酸合成酶、谷氨酸脱氢酶和谷丙转氨酶）以及活性物质含量（包括可溶性糖、可溶性蛋白和游离氨基酸）的顺序分别为WSI > SCW和N1 > N2 > N0。此外，不同种植模式和施氮量下，糯高粱的氮吸收效率、氮农学效率、氮表观效率、氮回收效率、氮偏生产力和氮贡献率的顺序分别为WSI > SCW和N1 > N2。上述性状的变化使得WSI-N1处理的糯高粱获得了最高产量（2023年为6020.66 kg/ha，2024年为6159.81 kg/ha）、单穗粒重（2023年为65.22 g，2024年为64.51 g）、千粒重（2023年为23.14 g，2024年为23.18 g）以及土地当量比（2023年为1.41，2024年为1.44）。总体而言，糯高粱与大豆间作并施中氮（糯高粱220 kg/ha，大豆18 kg/ha）可通过提高氮代谢酶活性和活性物质含量来增强糯高粱的氮吸收和利用，从而提高其生产力。
