Table_1_The income and food security impacts of soil and water conservation technologies in Tanzania.docx

Soil and water conservation technologies are critical in reducing drought and soil erosion risks and increasing crop yields and incomes. Yet, there is limited empirical evidence on the extent and impacts of adopting soil and water conservation technologies in Tanzania. The study’s objective is to evaluate the adoption (as well as the duration of adoption) and the impacts of soil and water conservation technologies on income and food security in Tanzania. The study employs a control function approach and the instrumental variable quantile treatment effects model to survey data from 575 households to estimate the average and distributional impacts of adoption. The results show that the adoption and duration of adopting soil and water conservation technologies had significant and positive effects on the total value of crop production and household income. Moreover, we find that the adoption and its duration had a significant and positive impact on the food security indicator—household dietary diversity. The results from the instrumental variable quantile treatment effects model also show that the impacts of adopting soil and water conservation technologies on the outcome variables are positive and significant, although they vary significantly across the income and food security distributions. The results indicate that even though adoption benefits households in both the lower and upper quantiles of the income and food security distributions, the marginal impacts of adoption are generally more significant for the households in the upper quantiles. The paper concludes by discussing the policy options for increasing and sustaining the adoption and impacts of soil and water conservation technologies in Tanzania.

水土保持技术（Soil and water conservation technologies）在降低干旱与土壤侵蚀风险、提升作物产量与农户收入方面至关重要。然而，目前针对坦桑尼亚境内水土保持技术的采纳规模及其影响的实证研究证据仍较为匮乏。
本研究的目标是评估坦桑尼亚地区水土保持技术的采纳情况（含采纳时长），及其对农户收入与粮食安全的影响。研究采用控制函数法（control function approach）与工具变量分位数处理效应模型（instrumental variable quantile treatment effects model），基于575户农户的调研数据，估算技术采纳的平均影响与分布异质性影响。
结果显示，水土保持技术的采纳行为及采纳时长对作物总产值与家庭总收入均具有显著正向影响。此外，技术采纳及其时长对粮食安全指标——家庭膳食多样性（household dietary diversity）——同样存在显著正向作用。工具变量分位数处理效应模型的结果还表明，尽管水土保持技术采纳对各结果变量的影响均为正向显著，但该影响在收入与粮食安全分布上存在显著差异。
研究发现，尽管技术采纳能为收入与粮食安全分布处于低分位与高分位的农户均带来收益，但总体而言，技术采纳的边际影响对高分位农户更为显著。
本文最后讨论了在坦桑尼亚境内提升并维持水土保持技术采纳率及其影响的政策路径。