生产方式的转变对元阳哈尼梯田系统氮磷平衡的影响

EFFECT OF CHANGES IN PRODUCTION MODE ON NITROGEN AND PHOSPHORUS BALANCE IN YUNNAN HANI TERRACED SYSTEM

关键词:  哈尼梯田  人类活动净氮输入量（NANI）  人类活动净磷输入量（NAPI）  氮平衡  磷平衡

Key words:  Hani terrace fields  net anthropogenic nitrogen inputs (NANI)  net anthropogenic phosphorus inputs(NAPI)  nitrogen balance  phosphorus balance

摘要:

目的 研究长时间尺度下生产方式的改变对梯田系统物质流动模式的影响，可为保护哈尼梯田、合理开发利用哈尼地区生态资源、实现哈尼梯田的可持续利用提供科学依据。方法 文章采用人类活动净氮/磷输入模型（NANI/NAPI）对1985—1986年、2009—2020年元阳县两个不同发展时期的NANI和NAPI及其相关构成进行核算。结果 （1）元阳县NANI、NAPI整体呈现先上升后下降的趋势，NANI和NAPI在1985年分别为2 914 kg/（km²·年）和249 kg/（km²·年），到2016年均达到最高值，分别为9 860 kg/（km²·年）和685 kg/（km²·年），随后呈现下降趋势，到2020年分别降至6018 kg/（km²·年）和321 kg/（km²·年）。（2）NANI的4个组成中，食品/饲料净氮输入占20%~45%、沉降氮输入占12%~40%、作物固氮输入占6%~12%、肥料氮输入占5%~52%；NAPI的3个组成中，食品/饲料净磷输入3%~50%、肥料氮输入占32%~57%、非食品磷输入占19%~41%。（3）元阳县NANI/NAPI比值存在明显阶段性变化，1985年和1986年NANI/NAPI比值分别为11.7和11.0，至2018—2020年基本稳定在18.5~18.8左右。（4）从NANI、NAPI与其组成的相关关系看，NANI与食品/饲料氮输入的R²为0.81（P＜0.01），与化肥氮输入的R²为0.81（P＜0.01）；NAPI与食品/饲料磷输入的R²为0.90（P＜0.01），与化肥磷输入的R²为0.59（P＜0.01）。结论 元阳县NAPI与NANI变化趋势呈现高度一致，均为先上升后下降的阶段性变化，与当地生产方式的转变相契合。

Abstract:

This research aims to investigate the impact of long-term changes in production modes on the material flow patterns in terrace systems, so as to establish a scientific basis for preserving Hani terraced fields, promote sustainable development and ecological resources utilization in the Hani region, and achieve sustainable use in Hani terraced fields. To accomplish the purposes of this study, the Net Anthropogenic Nitrogen/Phosphorus Inputs model (NANI/NAPI) was used to calculate NANI and NAPI values and their relevant components during two different development periods in Yuanyang county, from 1985 to 1986 and from 2009 to 2020. The overall trend of NANI and NAPI in Yuanyang county showed an initial increase followed by a decrease. In 1985, NANI and NAPI were 2914 kg/(km²·a) and 249 kg/(km²·a), respectively. Both reached their highest values in 2016, with values of 9 860 kg/(km²·a) and 685 kg/(km²·a), respectively, followed by a downward trend. The NANI comprised four components, each of which contributed to the overall NANI in the following ranges: food/feed net nitrogen input (20% to 45%), atmospheric nitrogen deposition (12% to 40%), crop nitrogen fixation (6% to 12%), and fertilizer nitrogen input (5% to 52%). The NAPI included three components, with food/feed net P (phosphorus) input accounting for 3% to 50% of the total NAPI. The contribution of P fertilizer application and non-food P application to the total NAPI was 32%~57% and 19%~41%, respectively. There was an observable stepwise change in the NANI/NAPI ratio in Yuanyang county, with NANI/NAPI ratios of 11.7 and 11.0 in 1985 and 1986, respectively. The NANI/NAPI ratios remained unvarying at approximately 18.5~18.8 from 2018 to 2020. Based on the correlation between NANI, NAPI, and their components, it was found that the R² value between NANI and food/feed nitrogen input was 0.81 (P<0.01), which was same as the R² value between NANI and fertilizer nitrogen input. Similarly, the R² value between NAPI and food/feed phosphorus input was 0.90 (P<0.01), while the R² value between NAPI and fertilizer phosphorus input was 0.59 (P<0.01). In summary, the trend of NAPI exhibited a strong correlation with NANI in Yuanyang county, showing a distinct stepwise pattern of initial increase followed by a subsequent decrease. This trend is consistent with the shift in local production modes.