Browsing by Author "Yi Z"

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    Effect of Reaction-Finished Solution of Hydrochar (HRFS) Application on Rice Grain Yield and Nitrogen Use Efficiency in Saline Soil
    (Tech Science Press, 2022) Yi Z; Jeyakumar P; Jiang J; Zhang X; Yue C; Sun H
    We conducted a pot experiment to examine the feasibility of applying a reaction-finished solution of hydrochar (HRFS) to enhance rice production in a saline soil. With this purpose, HRFS was applied (0, 10, 20, 40, 60, 80 and 100 mL/pot) and rice yield and nitrogen (N) use efficiency (NUE) were determined. HRFS application significantly (P < 0.05) increased rice grain yield by 19.6%–30.0% compared to the control treatment (CKU, with N but without HRFS addition). Moreover, HRFS application promoted plant height and straw biomass of rice. Increases of rice yield were mainly achieved by increases in the number of panicles and grains per panicle. Compared with the CKU treatment, the NUE of HRFS amendments significantly (P < 0.05) increased by 56.3%–71.7%. This indicated that the improvement of NUE was one of the mechanisms to improve rice grain yield with HRFS amendment. The results of regression analysis showed that there was a positive relationship (R2 = 0.8332) between rice yield and HRFS application rate within an appropriate range. The highest rice yield was recorded with the HRFS application of 40 mL/pot, but a further increase in HRFS application rate appeared to reduce rice yield. Based on the results of this pot study, HRFS application can increase rice yield in a saline soil by regulating its yield components and enhancing NUE. However, impact of HRFS on these variables showed a “dose effect”.
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    Effects of biochar in combination with varied N inputs on grain yield, N uptake, NH3 volatilization, and N2O emission in paddy soil
    (Frontiers Media, 12/05/2023) Yi Z; Jeyakumar P; Yin C; Sun H
    Biochar application can improve crop yield, reduce ammonia (NH3) volatilization and nitrous oxide (N2O) emission from farmland. We here conducted a pot experiment to compare the effects of biochar application on rice yield, nitrogen (N) uptake, NH3 and N2O losses in paddy soil with low, medium, and high N inputs at 160 kg/ha, 200 kg/ha and 240 kg/ha, respectively. The results showed that: (1) Biochar significantly increased the rice grain yield at medium (200 kg/ha) and high (240 kg/ha) N inputs by 56.4 and 70.5%, respectively. The way to increase yield was to increase the rice N uptake, rice panicle number per pot and 1,000 grain weight by 78.5–96.5%, 6–16% and 4.4–6.1%, respectively; (2) Under low (160 kg/ha) N input, adding biochar effectively reduced the NH3 volatilization by 31.6% in rice season. The decreases of pH value and NH4+-N content in surface water, and the increases of the abundance of NH4+-N oxidizing archaea and bacteria (AOA and AOB) communities contributed to the reduction of NH3 volatilization following the biochar application; (3) Under same N input levels, the total N2O emission in rice season decreased by 43.3–73.9% after biochar addition. The decreases of nirK and nirS gene abundances but the increases of nosZ gene abundance are the main mechanisms for biochar application to reduce N2O emissions. Based on the results of the current study, adding biochar at medium (200 kg/ha) N level (N200 + BC) is the best treatment to synchronically reduce NH3 and N2O losses, improve grain yield, and reduce fertilizer application in rice production system.