Abstract
Management of soil micronutrients for better crop production needs a sound understanding of their status and causes of variability. This is more relevant for acid soils of the mountain ecosystem of Eastern Himalaya (Northeast India). We assessed the status, and the effect of land uses along altitudinal gradients (14 to 4090 masl) on soil properties and micronutrient concentrations (DTPA extractable Fe, Mn, Cu, and Zn) across the region. Soils varied widely in micronutrient concentrations: Fe from 0.665 to 257.1 mg kg−1 while Mn, Cu, and Zn from traces to 93.4, 17.1, and 34.2 mg kg−1, respectively. On conversion of evergreen forests (EF) to upland agriculture (Shifting—SC and Settled—SA) and plantation (PH), Mn, Cu, and Zn concentrations decreased significantly from 30.5, 1.74, and 2.13 mg kg−1 to 6.44–17.8, 0.68–0.81, and 1.06–1.42 mg kg−1, respectively. Grassland (GL) and lowland paddy (LP) had comparable Fe, Mn, and Cu concentrations (except Zn). Degradation of EF to scrubland (SL) recorded the lowest Mn (5.91 mg kg−1), Cu (0.59 mg kg−1), and Zn (0.68 mg kg−1) concentrations. Fe concentration was however increased in degraded SL (+ 73%) over EF (48.7 mg kg−1). The distribution of micronutrients among the land uses was inconsistent and followed the order: (i) Fe: SL > PH > LP > EF > GL > SC > SA, (ii) Mn: EF > GL > LP > PH > SC > SA > SL; (iii) Cu: EF > GL > LP > SC > SA = PH > SL; and (iv) Zn: GL > EF > LP > SC > SA > PH > SL. Four micronutrients responded differently and followed a non-linear, 6th—order polynomial trend along the altitudinal gradients (< 500 to 4100 masl). Peak concentrations of Fe, Mn, and Cu were recorded at 1001–2000 m while Zn was recorded at > 4000 masl. The variability (54–64%) in soil micronutrients was mainly controlled by three key soil properties: acidity, clay, and organic carbon contents. Thus, altitude-specific land-use management holds significance in the distribution of available soil micronutrients in hilly ecosystems.
Highlights
To sub-optimal plant productivity as well as poor quality of the produce
In the present study, an attempt was made to answer the following key questions: (i) What is the status of plant-available micronutrient (DTPA extractable followed by metal (Fe), Mn, Cu, and Zn) concentrations in the soils of Northeast India; (ii) What is the impact of land use change on plant-available micronutrient concentrations; (iii) How strongly does the altitudinal variation influence the micronutrient concentrations among and across the land uses
We identified seven major land use systems dominant in the region and they are as follows (i) Shifting cultivation (SC: current 0–1 year-old); (ii) Settled agriculture (SA) in upland; (iii) Lowland paddyfallow agriculture (LP); (iv) Natural forest (EF: evergreen/semi-evergreen); (v) Grassland (GL); (vi) Scrubland (SL: including scrub forests, coal mine degraded forests, abandoned degraded jhum); and (vii) Plantation and horticulture (PH) in sloppy uplands
Summary
To sub-optimal plant productivity as well as poor quality of the produce. Plant availability of soil micronutrients is influenced by many factors such as land use change, soil management, and cropping system practices[9,10]. Over the past few decades, deforestation in the form of burning of vegetation due to the prevalence of shifting cultivation (SC), cultivation along the steep slopes in uplands (bun and terrace agriculture), and extensive open cast coal mining converted significant forest areas to degraded scrubland (> 11% GA) This resulted in colossal loss of phytomass and vegetative cover while increased the severity of erosion and soil losses many folds (10 t h a−1 to 155 t h a−1) in undulating u plands[13,15]. The region still lacks detailed information on complex interaction of acidity, soil properties and interaction of LULC and altitudinal gradient on micronutrient’s availability in this vast (> 26 M ha area) hill ecosystem of Eastern Himalaya This has become a major bottleneck for devising location-specific micronutrient management strategies for improvement of crop productivity and quality of the produces while restoring degraded scrublands. (ii) What is the impact of land use change on plant-available micronutrient concentrations; (iii) How strongly does the altitudinal variation influence the micronutrient concentrations among and across the land uses
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
