关键词: 小麦, 轮耕, 根系, 光合作用, 产量, 潮土

Abstract:

【Objective】 This study aimed to explore the optimum tillage mode in northern Henan province based on the long-term experiment. 【Method】 This study was based on the long-term tillage experiment started from 2016, which included different combination of three tillage practices, rotary tillage, shallow rotary tillage, and deep tillage before winter wheat sowed. The different combinations were 3-year cycle. Five typical treatments were selected: (1) continuous rotary tillage (RT-RT-RT); (2) Deep tillage-rotary tillage-rotary tillage (DT-RT-RT); (3) Deep tillage-rotary tillage-shallow rotary tillage (DT-RT-SRT); (4) Deep tillage- shallow rotary tillage- shallow rotary tillage (DT-SRT-SRT); (5) Deep tillage- shallow rotary tillage-rotary tillage (DT-SRT-RT). During the wheat season in 2021, root growth indexes, wheat photosynthetic characteristics, total nutrients of all organs at maturity, soil porosity, soil bulk density, aggregate distribution and wheat yield were measured and analyzed. 【Result】 Compared with RT-RT-RT, the wheat root indexes were improved under the treatments with rotation tillage, therein, DT-SRT-RT displayed the outstanding one. The highest increment of root indexes was at jointing stage. The total root length (RL), surface area (SA), volume (RV), and diameter (RD) were increased by 80.8%, 54.1%, 51.5%, and 21.9%, respectively. The increment was decreased with wheat growth, with the relevant value as 39.0%-28.8% (RL), 21.7%-10.8% (SA), 12.4%-17.8% (RV), and 17.5%-24.5% (RD), respectively. Rotational tillage treatments promoted the wheat photosynthetic characteristics, similar as root indexes, while DT-SRT-RT was demonstrated the better effect among all the treatments. Compared with RT-RT-RT, under DT-SRT-RT, the net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr) was increased by 25.7%, 41.5%, and 20.5% respectively, at the jointing stage, which was increased by 55.4%, 21.7%, and 17.4%, respectively, at the flowering stage. At the filling stage, the Pn and Gs were increased by 9.7% and 13.6%, respectively, while the Tr was decreased by 6.7%. The nutrient in wheat organ was promoted under the treatments with rotation tillage compared to RT-RT-RT. Therein, under DT-SRT-RT, the TN in leaves, stems, and roots was increased by 66.2%, 80.1% and 61.1%, respectively; the TP in leaves and stems increased by 31.2% and 38.4%; the TK in roots was increased by 50.0%. Compared with RT-RT-RT, the soil porosity was improved in the 20-30 cm soil layer with the increment of 27.1%. The treatments with rotation tillage decreased the soil bulk density in the 0-30 cm soil layer. Meanwhile, the aggregate size with >0.25 mm was increased under the treatments with rotation tillage, especially, it was significant increases under DT-SRT-SRT in the 0-20 cm soil layer. However, the silt and clay proportion were decreased under the treatments with rotation tillage. Additionally, the root-shoot (R/S) ratio, numbers of ears, grain number per spike, 1000-grain weight and yield under the treatments with rotation tillage were higher than those under RT-RT-RT. The R/S ratio increased by 55.6%, numbers of ears increased by 45.3%, and yield increased by 20.7% under DT-SRT-RT. The correlation analysis showed that the yield positively correlated with root length and Stomatal conductance and net photosynthetic rate. 【Conclusion】 In conclusion, the rotation tillage mode improved the soil porosity and root architecture, raised the photosynthetic rate, enriched the TN, TP, and TK in wheat organs, and increased wheat yield. Therein, the DT-SRT-RT demonstrated the better effect.

Key words: wheat, rotation tillage, root, photosynthetic characteristics, yield, fluvo-aquic soil