CONTEXT

Nitrogen (N) is an essential input for food production, but at the same time N raises serious concerns for air, water and soil pollution due to its overuse. Research shows that N use is influenced by socio-economic factors beyond the environmental circumstances while heavily depending on the agronomic practices and technologies used. Micro-level studies based on real farm observations are still scarce in this context.

OBJECTIVE

Therefore, this study estimated N use efficiency (NUE) and its climatic and socio-economic determinants, as well as N₂O and NH₃ emissions from organic and inorganic fertiliser-amended fields.

METHODS

Through exploring primary data collected from 155 wheat growers from north-western Bangladesh, we estimated NUE of wheat production as the ratio of the total quantity of N produced in the harvested grain and the total quantity of N applied to soil through inorganic and organic fertilisers. Then we estimate a Tobit model to determine the socio-economic and farm-level practices influencing NUE. Finally, for N₂O and NH₃ emissions, we applied region-specific emission factors, which are not sensitive to management practices but can give an approximation of emission and emission intensity of the production.

RESULTS AND CONCLUSIONS

The estimated mean NUE for North-West Bangladesh was 37.4%, which widely varied across different farm categories and farming practices used. Agronomic practices, including those induced by climate change, positively contributed to NUE. NUE was higher for the farmers cultivating high-yielding, drought-tolerant, and short-duration wheat varieties. NUE significantly increased when a farmer applied a combination of organic and inorganic fertilisers. Irrigation water pricing was critical in NUE since it influences farmers' water management practices. A notable quantity of N loss as N₂O (5.98 kg/ha) and NH₃ (45.58 kg/ha) was emitted, and the farms managed by landless and marginal farmers emitted quantities more than others. Farmers with better landholding size, education and access to extension services operated at a relatively higher level of NUE. The policy suggestions to increase NUE include strengthening extension services, particularly for promoting a balanced supply of nutrients from organic and inorganic fertilisers, promoting volumetric irrigation water pricing and encouraging long-term tenurial arrangement.

SIGNIFICANCE

The paper is relevant to policy makers since, unlike earlier works based on experimental data, it estimates more robust indices of NUE and considers the role of different farms and farmer-specific socio-economic, anthropogenic and institutional factors in farm production. Finally, the paper estimates N₂O and NH₃ emissions associated with wheat production.

中文翻译：

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农场调查评估的氮利用效率和气体排放的决定因素：孟加拉国小麦的案例

语境

氮 (N) 是粮食生产的重要投入，但与此同时，由于过度使用，氮引起了对空气、水和土壤污染的严重关注。研究表明，氮的使用受环境条件以外的社会经济因素的影响，同时在很大程度上取决于所使用的农艺实践和技术。在这种情况下，基于真实农场观察的微观研究仍然很少。

客观的

因此，本研究估算了氮利用效率 (NUE) 及其气候和社会经济决定因素，以及有机和无机肥料改良田地的N ₂ O 和 NH _{3排放量。}

方法

通过探索从孟加拉国西北部 155 名小麦种植者收集的原始数据，我们估算了小麦产量的 NUE，即收获谷物中产生的 N 总量与通过无机和有机肥料施入土壤的 N 总量之比。然后我们估计一个 Tobit 模型以确定影响 NUE 的社会经济和农场层面的做法。最后，对于 N ₂ O 和 NH ₃排放，我们应用了区域特定的排放因子，这些因子对管理实践不敏感，但可以给出生产的排放和排放强度的近似值。

结果和结论

孟加拉国西北部的估计平均 NUE 为 37.4%，这在不同的农场类别和使用的耕作方式中差异很大。农艺实践，包括气候变化引起的农艺实践，对 NUE 有积极贡献。种植高产、耐旱、短熟小麦品种的农民的营养利用率较高。当农民结合使用有机肥和无机肥时，NUE 显着增加。灌溉水定价对 NUE 至关重要，因为它会影响农民的水资源管理实践。_{N 2} O (5.98 kg/ha) 和 NH ₃的大量 N 损失（45.58 公斤/公顷）被排放，由无地农民和边际农民经营的农场排放量高于其他农场。拥有更好土地面积、受教育程度和获得推广服务的农民的 NUE 水平相对较高。提高 NUE 的政策建议包括加强推广服务，特别是促进有机和无机肥料的养分均衡供应，促进灌溉用水按体积定价，并鼓励长期使用权安排。

意义

该论文与决策者相关，因为与基于实验数据的早期作品不同，它估计了更稳健的 NUE 指数，并考虑了不同农场和农民特定的社会经济、人为和制度因素在农业生产中的作用。最后，该论文估算了与小麦生产相关的N ₂ O 和 NH _{3排放量。}