scholarly journals Seasonal variations in available N and N-mineralization in relation to fine roots in landslide damaged sites in the sal forest ecosystem of Nepal Himalaya

2013 ◽  
Vol 1 ◽  
pp. 114-124
Author(s):  
Tej Narayan Mandal

Seasonal dynamics of available nitrogen and N-mineralization in relation to fine root biomass was studied in five landslide damaged (1 to 58 years old) sites in the moist tropical sal (Shorea robusta) forest ecosystem of Nepal Himalaya. Comparisons were made with an undisturbed mature sal forest site located in the same region. Concentrations of soil available-N (NH4+ and NO3-) increased with the age of site till 40-year old sites and then declined. However, the proportion of NH4+ in total available N increased distinctly with increase in the age of sites. The NH4+: NO3- ratio increased considerably from 1.15 in 1-year site to 2.4 in mature sal forest. On the other hand, the net N-mineralization rate increased consistently until 58 years of age but the proportion of nitrification rate relative to ammonification rate distinctly decreased beyond 40 years indicating the dominance of ammonification over nitrification in the older sites. Fine root biomass and N- mineralization rate both increased but available-N decreased during rainy season. On the other hand fine root biomass and N-mineralization rate both decreased and available N increased during summer season. During the summer season, fine root biomass decreased by 57 - 68% indicating a rapid turnover. High turnover of fine root at the younger sites (1 to 15 yrs old) add more organic matter for the developing vegetation. Fine root biomass was positively correlated with the concentration of available-N and N-mineralization rate. It is concluded that fine root development was facilitated by higher amounts of available-N. DOI: http://dx.doi.org/10.3126/njbs.v1i0.7478 Nepalese Journal of Biosciences 1: 114-124 (2011)

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1236
Author(s):  
Dipendra Singha ◽  
Francis Q. Brearley ◽  
Shri Kant Tripathi

Nitrogen (N) dynamics during changes in land use patterns in tropical forests may profoundly affect fine root dynamics and nutrient cycling processes. Variations in fine root biomass and soil N dynamics were assessed in developing stands of increasing ages following shifting agriculture in Mizoram, Northeast India, and comparisons were made with a natural forest stand. Concentrations of soil available N (NH4-N and NO3-N) and the proportion of NH4-N in total available N increased with stand age. The N-mineralization rate also increased with stand age whilst the proportion of nitrification relative to ammonification declined during succession. Fine root biomass and N-mineralization increased, and available N decreased during the monsoon season while this pattern was reversed during the winter season. A greater proportion of fine roots were <0.5 mm diameter in the younger sites, and turnover of fine roots was more rapid in the developing stands compared to the natural forest. Fine root biomass was correlated positively with N-mineralization rate and soil water content. Thus, it can be concluded that the fine root growth was aided by rapid N-mineralization, and both fine root growth and N-mineralization increase as stands redevelop following shifting cultivation disturbance.


2020 ◽  
Vol 25 (1) ◽  
pp. 24-29
Author(s):  
Krishna Prasad Bhattarai ◽  
Tej Narayan Mandal ◽  
Tilak Prasad Gautam

The present study was conducted to understand the effect of altitude on the nutrient concentration, nutrient stock, and uptake in the fine root of the Terai Sal forest (TSF) and Hill Sal forest (HSF) in eastern Nepal. Annual mean fine root biomass in 0-30 cm soil depth was found higher in HSF (6.27 Mg ha-1) than TSF (5.05 Mg ha-1). Conversely, fine root production was higher in TSF (4.8 Mg ha-1 y-1) than HSF (4.12 Mg ha-1 y-1). Nitrogen, phosphorus, and potassium content in fine roots were slightly higher in TSF than HSF. Nutrient concentration in fine roots of smaller size (<2 mm diameter) was nearly 1.2 times greater than that of larger size (2–5 mm diameter) in both forests. In HSF total stock of different nutrients (kg ha-1) in fine root was 55.62 N, 4.99 P, and 20.15 K whereas, these values were 49.49 N, 4.14 P, and 19.27 K only in TSF. However, total nutrient uptake (kg ha-1y-1) by fine root (both size classes) was greater in TSF (48.5 N, 4.3 P, and 18.6 K) than HSF (36.9 N, 3.3 P, and 13.5 K). The variability in fine root nutrient dynamics between these two forests was explained by the differences in fine root biomass and production which were influenced by the combined effect of varied altitude and season. The fine root, as being a greater source of organic matter, the information on its nutrient dynamics is inevitable for the management of soil nutrients in the forest ecosystem.


2013 ◽  
Vol 2 ◽  
pp. 80-87
Author(s):  
Krishna Prasad Bhattarai ◽  
Tej Narayan Mandal

Soil microbial biomass in relation to fine root was studied in Kiteni hill Sal (Shorea robusta) forest of Ilam during summer season. The forest had sandy loam type of soil texture. Organic carbon was higher in 0-15 cm depth (2.09%) than in 15-30 cm depth (1.53%). Total nitrogen of 0- 15 cm depth was 0.173% and in 15-30 cm depth was 0.124%. Soil microbial biomass of carbon of Kiteni hill sal forest was (445.14 ?g g-1) and microbial biomass of nitrogen was (49.07 ?g g-1). Fine root biomass of this forest was 2.34 t ha-1 (<2 mm diameter) and 0.93 t ha-1 (2-5 mm diameter) in 0-15 cm depth and 0.73 t ha-1 (<2 mm diameter) and 0.46 t ha-1 (2-5 mm diameter) in 15-30 cm depth. Organic carbon, total nitrogen, soil microbial biomass carbon and nitrogen of upper layer soil were negatively correlated with fine root biomass of forest. DOI: http://dx.doi.org/10.3126/njbs.v2i0.7493 Nepalese Journal of Biosciences 2 : 80-87 (2012)


2013 ◽  
Vol 36 (7) ◽  
pp. 645-654 ◽  
Author(s):  
Yun-Ke LIU ◽  
Chuan FAN ◽  
Xian-Wei LI ◽  
Yin-Hua LING ◽  
Yi-Gui ZHOU ◽  
...  

2021 ◽  
Vol 130 ◽  
pp. 108031
Author(s):  
Wen Li ◽  
Yifei Shi ◽  
Dandan Zhu ◽  
Wenqian Wang ◽  
Haowei Liu ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tina Unuk Nahberger ◽  
Gian Maria Niccolò Benucci ◽  
Hojka Kraigher ◽  
Tine Grebenc

AbstractSpecies of the genus Tuber have gained a lot of attention in recent decades due to their aromatic hypogenous fruitbodies, which can bring high prices on the market. The tendency in truffle production is to infect oak, hazel, beech, etc. in greenhouse conditions. We aimed to show whether silver fir (Abies alba Mill.) can be an appropriate host partner for commercial mycorrhization with truffles, and how earthworms in the inoculation substrate would affect the mycorrhization dynamics. Silver fir seedlings inoculated with Tuber. aestivum were analyzed for root system parameters and mycorrhization, how earthworms affect the bare root system, and if mycorrhization parameters change when earthworms are added to the inoculation substrate. Seedlings were analyzed 6 and 12 months after spore inoculation. Mycorrhization with or without earthworms revealed contrasting effects on fine root biomass and morphology of silver fir seedlings. Only a few of the assessed fine root parameters showed statistically significant response, namely higher fine root biomass and fine root tip density in inoculated seedlings without earthworms 6 months after inoculation, lower fine root tip density when earthworms were added, the specific root tip density increased in inoculated seedlings without earthworms 12 months after inoculation, and general negative effect of earthworm on branching density. Silver fir was confirmed as a suitable host partner for commercial mycorrhization with truffles, with 6% and 35% mycorrhization 6 months after inoculation and between 36% and 55% mycorrhization 12 months after inoculation. The effect of earthworms on mycorrhization of silver fir with Tuber aestivum was positive only after 6 months of mycorrhization, while this effect disappeared and turned insignificantly negative after 12 months due to the secondary effect of grazing on ectomycorrhizal root tips.


Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 823
Author(s):  
Anna Zielonka ◽  
Marek Drewnik ◽  
Łukasz Musielok ◽  
Marcin K. Dyderski ◽  
Dariusz Struzik ◽  
...  

Forest ecosystems significantly contribute to the global organic carbon (OC) pool, exhibiting high spatial heterogeneity in this respect. Some of the components of the OC pool in a forest (woody aboveground biomass (wAGB), coarse root biomass (CRB)) can be relatively easily estimated using readily available data from land observation and forest inventories, while some of the components of the OC pool are very difficult to determine (fine root biomass (FRB) and soil organic matter (SOM) stock). The main objectives of our study were to: (1) estimate the SOM stock; (2) estimate FRB; and (3) assess the relationship between both biotic (wAGB, forest age, foliage, stand density) and abiotic factors (climatic conditions, relief, soil properties) and SOM stocks and FRB in temperate forests in the Western Carpathians consisting of European beech, Norway spruce, and silver fir (32 forest inventory plots in total). We uncovered the highest wAGB in beech forests and highest SOM stocks under beech forest. FRB was the highest under fir forest. We noted a considerable impact of stand density on SOM stocks, particularly in beech and spruce forests. FRB content was mostly impacted by stand density only in beech forests without any discernible effects on other forest characteristics. We discovered significant impacts of relief-dependent factors and SOM stocks at all the studied sites. Our biomass and carbon models informed by more detailed environmental data led to reduce the uncertainty in over- and underestimation in Cambisols under beech, spruce, and fir forests for mountain temperate forest carbon pools.


2003 ◽  
Vol 33 (5) ◽  
pp. 847-853 ◽  
Author(s):  
Sylvia E Welke ◽  
Graeme D Hope ◽  
Gary A Hunt

The effect of timber harvesting on the biomass, nutrient standing crop, and decomposition of fine roots (<2 mm) was studied in a high elevation, Engelmann spruce (Picea engelmannii Parry ex Engelm.) – subalpine fir (Abies lasiocarpa (Hook.) Nutt.) forest. Root dynamics were compared in openings of different sizes. The sequential core method was used to collect fine root samples over 4 years. Differences in fine root biomass between opening sizes were most significant for the active fine root portion and were most pronounced in the fall compared with the spring. Active fine root biomass was significantly lower in the 10-ha clearcuts (164 kg/ha) compared with control plots (275 kg/ha). Furthermore, active fine root biomass was often lower in the 1.0-ha opening than in the 0.1-ha and control plots. A similar trend was established for inactive fine root biomass, although this was not consistent over sampling years. Nutrient concentrations of K, but no other elements, were higher in control plots. Nutrient standing crops, however, followed trends observed in fine root biomass. In the 10-ha clearcuts, the largest changes in fine root biomass occurred at the edge of the opening. The findings suggest that small (<10 ha) cutblocks may maintain greater fine root longevity.


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