ABSTRACT

Shifting cultivation or Jhum, a form of traditional agroforestry system, constitutes the basic subsistence of livelihood among ethnic tribes throughout the Eastern Indian Himalayas. Shortening of fallow phase length in Jhum cycle to fulfill recent inclining population is one of the challenges concerned for co-existence between agriculture and hill forest-ecosystem. The present investigation is focused on comparative analysis of soil fertility at different fallow lengths, viz. 2, 4, and 8-years for both traditional (T-JF) and alder-Based (Alnus nepalensis D. Don) Jhum (AB-JF) with reference site (Natural forest) in Kohima, Nagaland, India. Soil pH, electrical conductivity (EC), soil organic carbon (SOC), available nitrogen (Avl-N), available phosphorus (Avl-P), exchangeable potassium (Avl-K), microbial biomass carbon (MBC), acid-phosphomonoesterase activity (PHA), dehydrogenase activity (DHA), and potential mineralizable nitrogen (PMN) were analyzed for the comparison between different Jhum systems. All soil parameters in AB-JF system showed a significant difference at P < 0.05 over T-JF (non-alder) except soil pH. This shows the superiority of AB-JF system over T-JF. The findings signify the importance of systematically managed alder trees in the Jhum cultivation system. The impact of fallow length on all soil parameter values was in the order 2 < 4 < 8 years old regardless of AB-JF and T-JF system. The values of SOC, Avl-N, PMN, MBC, PHA, and DHA decreased, while pH, EC, Avl-P, and Avl-K increased in respective fallow length of both Jhum systems after burning of biomass. In conclusion, AB-JF system has specific advantages over T-JF system in terms of improved soil fertility and nutrient cycling potentials.

摘要

轮垦或Jhum是一种传统的农林业系统形式，构成了整个东印度喜马拉雅山脉各民族部落的基本生计。缩短Jhum循环中的休耕期长度以满足最近倾斜的人口是农业与山地森林生态系统共存的挑战之一。本调查的重点是对不同休耕长度的土壤肥力进行比较分析，即。传统 (T-JF) 和基于桤木( Alnus nepalensis D. Don) Jhum 的 2、4和 8 年(AB-JF) 与参考地点（天然森林）位于印度那加兰邦的 Kohima。土壤pH值、电导率（EC）、土壤有机碳（SOC）、有效氮（Avl-N）、有效磷（Avl-P）、交换性钾（Avl-K）、微生物生物量碳（MBC）、酸性磷酸单酯酶分析了不同Jhum系统之间的活性 (PHA)、脱氢酶活性 (DHA) 和潜在矿化氮 (PMN) 。除土壤 pH 值外，AB-JF 系统中的所有土壤参数均与 T-JF（非桤木）相比，在P < 0.05处存在显着差异。这表明AB-JF系统优于T-JF。研究结果表明在Jhum中系统管理桤木的重要性栽培系统。无论 AB-JF 和 T-JF 系统如何，休耕长度对所有土壤参数值的影响都在 2 < 4 < 8 年之间。燃烧生物质后，两种Jhum系统的休耕长度中 SOC、Avl-N、PMN、MBC、PHA 和 DHA 的值下降，而 pH、EC、Avl-P 和 Avl-K 的值增加。总之，AB-JF 系统在提高土壤肥力和养分循环潜力方面比 T-JF 系统具有特定优势。