Photosynthetic Characters of Canopy and Storage Root Yield of Sweet Potato (Ipomoea batatas L.) Grow in Different Soil Compaction

A field experiments were carried out with two varieties in control, loose, and compacted soil conditions. Then, Canopy Apparent Photosynthesis (CAP), gas exchange parameters, Photochemical reflectance index (PIabs) of the functional leaves, and SR yield were measured, and the relationship between yield and photosynthetic characters was studied as well. Compared with the control, the SR yield was significantly increased in loose soil with an average increase of ۲۷.۰۳~۳۸.۷۴%, but decreased in compacted soil with an average reduction of ۱۷.۸۷~۱۵.۹۲%. Both loosening and compaction treatments increased the Leaf Area Index (LAI), and the increase in the latter was significantly higher than that in the former. Canopy interception rate in loosening treatment was much higher than that of the compacted soil. The CAP showed a similar change in yield, with a strong positive correlation to Storage Root (SR) yield and single storage root weight. Loose soil also improved gas exchange parameters, and PIabs, the reverse was found in compacted soil. Compared to the control, the loose treatment significantly improved economic coefficient and reduced leaf starch content, while the compaction treatment showed the opposite trend. Path analysis revealed that the net Photosynthetic rate (Pn) had the most total effect and higher direct effect on increasing CAP. Therefore, soil compaction primarily regulates SR yield through CAP, with Pn exerting a significant impact on CAP. Enhanced soil compaction led to reduced photosynthate output in functional leaves, resulting in decreased Pn and increased LAI. Consequently, an inappropriate canopy structure with low canopy interception was formed.

کلیدواژه ها:

Canopy apparent photosynthesis ، Enhanced soil compaction ، Gas exchange parameters ، PIabs.