Effects of Nitrogen Application on the Photosynthesis,Root Characteristics,and Soil Enzyme Activity during the Flowering and Fruiting Period of Greenhouse Tomatoes in Solar Greenhouse
Using the Saint Laurent tomato as the experimental material and employing semi-open ditch cultivation,under equal phosphorus and potassium fertilizer treatments,13 nitrogen application treatments were set to investigate the effects of different nitrogen application levels on the photosynthesis of leaves,root characteristics,and soil enzyme activity during the flowering and fruiting period of greenhouse tomatoes in solar greenhouse.The results showed that an appropriate nitrogen application level could promote the growth and development of greenhouse tomatoes during the flowering and fruiting period,as well as increase soil enzyme activity.Among the treatments,treatment T11 exhibited the highest content of chlorophyll a,chlorophyll b,and carotenoids in plant leaves,the lowest chlorophyll a/b ratio,the highest net photosynthetic rate in leaves,15.83%higher compared to the no nitrogen application treatment,the highest nitrate reductase activity in leaves[61.37 μg·g-1·h-1(FW)],the highest root vitality,the longest root length,and the highest activities of soil sucrase and acid phosphatase enzymes.In conclusion,under the conditions of this study,treatment T11,with a nitrogen application level of 45.0 kg·hm-2,was determined to be the most appropriate nitrogen application level during the flowering and fruiting period of greenhouse tomatoes in a solar greenhouse.
tomatoflowering and fruiting periodnitrogen applicationgrowth and developmentsoil enzyme activity