Department of Agriculture, Food and Environmental Sciences - D3A, Polytechnic University of Marche, 60131, Ancona, Italy.
Department of Agriculture, Food and Environmental Sciences - D3A, Polytechnic University of Marche, 60131, Ancona, Italy.
J Environ Manage. 2022 Nov 15;322:116031. doi: 10.1016/j.jenvman.2022.116031. Epub 2022 Aug 30.
Slash and burn is a land use practice widespread all over the world, and nowadays it is formally recognized as the principal livelihood system in rural areas of South America, Asia, and Africa. The practice consists of a land rotation where users cut native or secondary forest to establish a new crop field and, in some cases, build charcoal kilns with the cut wood to produce charcoal. Due to several socio-economic changes in developing countries, some scientists and international organizations have questioned the sustainability of slash and burn since in some cases, crop yield does not justify the soil degradation caused. To estimate the soil quality in agricultural and forest soils at different ages of the forest-fallow period (25, 35, and 50 years), this survey investigated rural areas in three locations in Manica province, central Mozambique: Vanduzi, Sussundenga, and Macate. Soil profiles were trenched and sampled with a pedological approach under crop fields and forest-fallow. The chronosequence was selected to test the hypothesis that the increase in forest-fallow age causes an improvement of soil fertility. Results highlighted discrete variations among locations in mineralogy, Al- and Fe-oxyhydroxides, sand, silt, pH, total organic carbon, humic carbon, total nitrogen, available phosphorous, chloride, nitrate, fluoride, and ammonium. Few differences in mineralogy, Fe-oxyhydroxides, available P, chloride, and nitrate were detected between crop fields and forest-fallow within the same location. Such differences were mostly ascribed to intrinsic fertility inherited from the parent material rather than a longer forest-fallow period. However, physicochemical soil property improvement did not occur under a forest age of 50 years (the longest forest-fallow considered), indicating that harmonization of intrinsic fertility and agronomic practices may increase soil organic matter and nutrient contents more than a long forest-fallow period.
刀耕火种是一种在世界各地广泛使用的土地利用方式，如今它被正式确认为南美洲、亚洲和非洲农村地区的主要生计系统。该方法包括轮作，使用者砍伐原生或次生林，建立新的作物田，在某些情况下，用砍伐的木材建造木炭窑来生产木炭。由于发展中国家的一些社会经济变化，一些科学家和国际组织对刀耕火种的可持续性提出了质疑，因为在某些情况下，作物产量不能证明土壤退化是合理的。为了评估不同森林休耕期（25、35 和 50 年）的农业和森林土壤的土壤质量，本研究在莫桑比克中部马兰杰省的三个地点（万杜齐、苏斯登登加和马卡特）的农村地区进行了调查。采用土壤学方法在作物田和休耕地中挖掘土壤剖面并取样。选择年代序列来检验这样一个假设，即随着休耕年龄的增加，土壤肥力会得到改善。结果突出了地点之间在矿物学、铝和铁氢氧化物、砂、粉砂、pH 值、总有机碳、腐殖质碳、总氮、有效磷、氯、硝酸盐、氟化物和铵方面的离散变化。在同一地点，作物田和休耕地之间的矿物学、铁氢氧化物、有效磷、氯和硝酸盐差异很小。这些差异主要归因于母质遗传的内在肥力，而不是更长的休耕期。然而，在 50 年的森林年龄（考虑到的最长休耕期）下，理化土壤性质并没有改善，这表明内在肥力和农艺措施的协调可能比长休耕期更能增加土壤有机质和养分含量。
