1. Effects of the number of 15 N-injection needles on the estimation of gross N transformation rates using 15 N tracing tool including plant.
- Author
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Zhu, Qinying, Wang, Wenjie, Dai, Shenyan, Meng, Lei, He, Mengqiu, Chen, Shending, Dan, Xiaoqian, Cai, Zucong, Zhang, Jinbo, and Müller, Christoph
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LOAM soils ,CORN ,NEEDLES & pins - Abstract
It is not clear how the number of
15 N-injection needles affects the estimated results of gross N transformation rates in the presence of plants. To evaluate this, a15 N tracing study of sandy loam soil and a silty loam soil in the presence of maize (Zea mays L., cv. "Zhengdan 958") was conducted and the Ntraceplant tool was used to quantify gross N transformation rates. Our results showed that the number of15 N-injection needles could significantly influence the estimated results of gross N transformation rates in the studied soil–plant systems. There was no discernible difference in the gross rates of N mineralization (Min), the oxidation of NH4 + to NO3 − (ONH4 ), the oxidation of recalcitrant organic-N to NO3 − (ONrec ), the NH4 + and NO3 − plant uptake between 4-needle and 6-needle injections for both studied soils. However, for the 1-needle and 2-needle injections in the silty loam soil, Min was significantly lower than the 4-needle and 6-needle injections. While, in sandy loam soil, Min measured with 1-needle injection was significantly higher than the 4-needle and 6-needle injections. The ONH4 and ONrec also varied for the 1-needle and 2-needle injections, compared to the 4-needle and 6-needle injections. The total plant N uptake rate declined with the increase in the number of injection needles. Based on these results and considering the simplicity of the experimental procedure, we suggest that the 4-needle injection could be used in the15 N tracing studies conducted in pot (diameter = 6.4 cm in this study) experiments with plants, i.e., one needle for about 8 cm2 . [ABSTRACT FROM AUTHOR]- Published
- 2024
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