The use of the ingrowth core method for measuring root production of arable crops – influence of soil and root disturbance during installation of the bags on root ingrowth into the cores

The effects of restorative crops on the amelioration of a degraded soil were investigated in a 6-year field experiment. Treatments included perennial pastures, annual pastures, and arable crops. Improvements in some aspects of chemical, biological, and physical fertility were related to the amount of herbage dry matter returned to the soil and root production. Beneficial effects associated with returned organic matter were partly negated by the degradative effect of tillage. Treatments that returned most organic material to the soil showed the greatest increase in aggregate stability and supported the largest earthworm populations, especially without annual tillage. Differences between treatments in soil organic C content were not generally significant until the sixth year. In contrast, differences between treatments in microbial biomass C were apparent by the third year. Compaction by sheep during grazing appeared to result in a loss of soil macroporosity. In the sixth year, soil macroporosity was greatest in the annually cultivated, ungrazed treatments. The grazed perennial ryegrass and ryegrass/white clover treatments were the most effective in ameliorating degraded soil conditions. The rate of soil amelioration declined with depth, and was mainly confined to the top 10 cm of soil. The rate of amelioration was relatively slow, with, for example, 3 years needed for most of the increase in aggregate stability at 0–5 cm depth.

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Seasonal patterns of fine root dynamics and their contribution to net primary production in hinoki cypress (Chamaecyparis obtusa) and konara oak (Quercus serrata) forests

Trees ◽

10.1007/s00468-020-02030-6 ◽

2020 ◽

Author(s):

Ji Young An ◽

Akira Osawa

Keyword(s):

Fine Root ◽

Chamaecyparis Obtusa ◽

Root Production ◽

Seasonal Patterns ◽

Fine Root Production ◽

Root Dynamics ◽

Fine Root Dynamics ◽

Hinoki Cypress ◽

Core Method ◽

Konara Oak

Abstract Key message Fine root and litterfall are major contributor of NPP and fine root production may reflect forest productivity in a warm-temperate forest in Japan. Abstract Forest ecosystems play an important role as the major carbon sink on land, with fine root dynamics and litterfall representing major carbon fluxes. The objectives of this research were to estimate NPP including annual fine root production values, to investigate fine root dynamics and the relationships between above– and belowground organs in konara oak (Quercus serrata) and hinoki cypress (Chamaecyparis obtusa) forests. Litterfall was collected seasonally for 1 year from June 2013. The ingrowth core method and the sequential soil core method were applied with a root litterbag experiment to estimate fine root (< 2 mm) production (FRP), mortality (FRM), and decomposition (FRD) for 1 year (from 2013 to 2014), using the continuous inflow estimate method and the simplified decision matrix. The total NPP ranged from 8.2 to 13.9 (t ha− 1 yr− 1), and the sum of aboveground litterfall and FRP accounted for 60% of the total NPP on average, confirming the significance of above- and belowground litter for the forest NPP as a source of detritus for the decomposer system. In hinoki cypress stand, fine root biomass peaked in the end of winter while fine root necromass showed the highest peak in late summer. In konara oak stand, only very fine root (< 0.05 mm) biomass and necromass demonstrated significant seasonal patterns. The seasonal patterns of fine root production did not differ between forest types and root diameter classes. We found a possible relationship between above- and belowground production and fine root production tended to be high in productive forests. This study improves our understanding of different patterns of carbon dynamics between temperate broadleaved and coniferous forest ecosystems.

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