Enhancing Agriculture through Farmer Managed Natural Regeneration (FMNR) in Burkina Faso

Research indicates that the use of trees by farmers in agroforestry systems improves household nutrition consistent with local culture and food traditions. Additionally, it enhances climate change adaptation while contributing to environmentally friendly agricultural products. Nonetheless, some scientists argue that trees reduce soil moisture content in agricultural settings and that associated water demand could effectively compete with crops over limited available moisture. This research explored these competing claims in the context of Burkina Faso, focusing on farmer managed natural regeneration (FMNR). To understand how FMNR impacts soil moisture, this research used a participatory approach, including citizen science, to collect soil matric potential data. Soil matric potential data were collected using the SR Series IRROMETER tensiometer marketed by the Irrometer Co., Inc., Riverside, CA. Data collection on croplands with FMNR consisted of the installation of two IRROMETER SR tensiometers within the canopy zone and in an open area, positioned 20 meters away from the canopy zone, at a depth of 45 centimeters. On croplands without FMNR, a single IRROMETER SR tensiometer was installed in an open area at the same depth. In this study, soil moisture tensiometers were installed under Vitellaria paradoxa (shea) trees, less than a meter away from the tree trunk within the tree canopy. Only mature trees with a trunk diameter of 50 centimeters or more at breast height were selected to ensure consistent evapotranspiration patterns. To analyze the data and assess the relationship between soil moisture within the canopy zone, away from the canopy zone on croplands with FMNR, and on croplands without FMNR, a one-way analysis of variance (ANOVA) was used, followed by a Games-Howell post-hoc test at the significance level of 0.05. Results indicate that FMNR increases soil water availability to plants and subsequent crop yield. Trees significantly increased soil moisture availability throughout the season, from croplands without FMNR to areas away from the tree canopy and areas within the tree canopy on croplands with FMNR.研究表明，农林业系统中农户利用林木，可在契合当地文化与饮食传统的前提下改善家庭营养状况。此外，该模式还能增强气候变化适应能力，并助力生产环境友好型农产品。不过，部分学者认为，农业场景中的林木会降低土壤含水量，且其需水量可能与作物争夺有限的可用水分，形成竞争性关系。本研究以布基纳法索为研究场景，围绕农户管理型自然再生（Farmer Managed Natural Regeneration, FMNR）展开，对上述两种相悖的观点进行了探究。为明晰FMNR对土壤含水量的影响，本研究采用包括公民科学（citizen science）在内的参与式研究方法，收集土壤基质势数据。土壤基质势数据通过由加利福尼亚州里弗赛德市Irrometer公司（Irrometer Co., Inc., Riverside, CA）推出的SR系列IRROMETER张力计采集。针对设有FMNR的农田，本研究分别在林木冠层区内，以及距冠层区20米开外的开阔区域各安装1台IRROMETER SR型张力计，埋设深度均为45厘米。针对未设有FMNR的农田，则仅在同等深度的开阔区域安装1台IRROMETER SR型张力计。本研究中，土壤张力计布设地点为乳木（Vitellaria paradoxa）树的冠层下，距树干不足1米处。仅选取胸径50厘米及以上的成熟林木作为研究对象，以确保蒸散模式的一致性。为分析数据并评估冠层区内、设有FMNR农田的冠层区外，以及未设有FMNR农田的土壤含水量之间的关联，本研究采用单因素方差分析（One-way Analysis of Variance, ANOVA），随后在0.05的显著性水平下进行Games-Howell事后检验。研究结果显示，FMNR可提升植物可利用的土壤水分含量及后续作物产量。整个生长季内，从无FMNR的农田，到设有FMNR的农田的冠层外区域，再到设有FMNR的农田的冠层内区域，林木均显著提升了土壤水分可利用性。