scholarly journals Long-term litter type treatments alter soil carbon composition but not microbial carbon utilization in a mixed pine-oak forest

2021 ◽  
Vol 152 (2-3) ◽  
pp. 327-343
Author(s):  
Xiaowei Guo ◽  
Zhongkui Luo ◽  
Osbert Jianxin Sun

AbstractChanges in litter and nutrient inputs into soil could have significant consequences on forest carbon (C) dynamics via controls on the structure and microbial utilization of soil organic C (SOC). In this study, we assessed changes in physical fractions (250–2000 μm, 53–250 μm, and < 53 μm soil aggregates) and chemical fractions (labile, intermediate and recalcitrant pools) of SOC in the top 20 cm mineral soil layer and their influences on microbial substrate utilization after eight years of experiment in a mixed pine-oak forest. The litter treatments included: control (Lcon), litter removal (Lnil), fine woody litter addition (Lwoody), leaf litter addition (Lleaf) and a mix of leaf and fine woody litter (Lmix). Nitrogen (N) addition (application rates of 0, 5 and 10 g N m−2 year−1, respectively) was also applied. We found that complete removal of forest-floor litter (Lnil) significantly reduced the pool sizes of all SOC fractions in both the physical and chemical fractions compared with treatments that retained either leaf litter (Lleaf) or mixture of leaves and fine woody materials (Lmix). The type of litter was more important in affecting SOC fractions than the quantity of inputs; neither the level of N addition rate nor its interaction with litter treatment had significant effects on both physical and chemical SOC fractions. Microbial respiration differed significantly among the treatments of varying litter types. However, the effectiveness of microbial C utilization inferred by microbial C use efficiency and biomass-specific respiration was not affected by either the litter treatments or N addition. These results suggest that despite significant changes in SOC composition due to long-term treatments of forest-floor litter and N addition in this mixed pine-oak forest of temperate climate, microbial C utilization strategies remain unaffected.

1999 ◽  
Vol 29 (5) ◽  
pp. 609-620 ◽  
Author(s):  
William S Currie ◽  
John D Aber ◽  
Charles T Driscoll

Nitrogen saturation results in greater mobility of nitrate, which in turn is often correlated with concentrations of nutrient cations in soil solution and streamwater. At the Harvard Forest, U.S.A., under long-term NH4NO3 inputs, a Pinus resinosa Ait. forest has exhibited signs of N saturation more rapidly than a mixed-Quercus forest. We test the hypothesis that increased nitrate leaching causes increased concentrations of nutrient cations in soil solution. Over 2 years (years 6 and 7 of treatment) we measured SO42-, NO3-, Cl-, Ca2+, K+, Mg2+, Na+, H+, and NH4+ in throughfall solution and in forest-floor (Oa) leachate. Concentrations of NO3- in forest-floor leachate increased with rates of N amendment and correlated positively with cation concentrations, with stronger overall correlations in the pine forest: r2 values were 0.51 (pine forest) and 0.39 (oak forest) for Ca2+, 0.45 (pine) and 0.16 (oak) for K+, and 0.62 (pine) and 0.50 (oak) for Mg2+. In summer and fall, the oak forest showed some negative relationships between nutrient cation leaching and rate of N amendment. These contrasts showed retention of cations and N to occur together in an N-limited system, whereas increased nitrate mobility occurred with increased cation losses in an N-saturated system.


2017 ◽  
Vol 2 (1) ◽  
pp. 1 ◽  
Author(s):  
Ng. Lamnganbi Devi ◽  
E. Jadu Singh

Litterfall and its nutrient return in five oak species were studied in the mixed Oak forest in Senapati District, Manipur .Litter production was measured by litter trap method. The total annual litterfall was 958.9 g m-2yr-1.Leaf and non leaf litterfall comprises 76.7 % and 23.3 % of the total litterfall. Maximum litterfall was found in the month of April (193.5 g m-2) and minimum in the month of July (23.7 g m-2).About 70% of the forest floor was replaced each year with turnover time of 1.42 yr.The amount of nutrient return through leaf litter was found to be maximum in Q.polystachya and minimum in C.indica. Nutrients (NPK) concentration of leaf litter of five different tree species was varied among different tree species.


2015 ◽  
Vol 63 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Karsten Schacht ◽  
Bernd Marschner

Abstract The use of treated wastewater (TWW) for agricultural irrigation becomes increasingly important in water stressed regions like the Middle East for substituting fresh water (FW) resources. Due to elevated salt concentrations and organic compounds in TWW this practice has potential adverse effects on soil quality, such as the reduction of hydraulic conductivity (HC) and soil aggregate stability (SAS). To assess the impact of TWW irrigation in comparison to FW irrigation on HC, in-situ infiltration measurements using mini disk infiltrometer were deployed in four different long-term experimental orchard test sites in Israel. Topsoil samples (0-10 cm) were collected for analyzing SAS and determination of selected soil chemical and physical characteristics. The mean HC values decreased at all TWW sites by 42.9% up to 50.8% compared to FW sites. The SAS was 11.3% to 32.4% lower at all TWW sites. Soil electrical conductivity (EC) and exchangeable sodium percentage (ESP) were generally higher at TWW sites. These results indicate the use of TWW for irrigation is a viable, but potentially deleterious option, as it influences soil physical and chemical properties.


2016 ◽  
Vol 5 (3) ◽  
Author(s):  
Swim SL ◽  
Walker RF ◽  
Johnson DW ◽  
Fecko RM ◽  
Miller WW

2007 ◽  
Vol 7 ◽  
pp. 192-197 ◽  
Author(s):  
M. F. Hovmand ◽  
Kaare Kemp

Atmospheric bulk deposition of heavy metals (HM) was measured from 1972/73 to the present time at five to ten forest sites in rural areas of Denmark. From 1979, HM in aerosols were measured at one to four forest sites. On the basis of these long-term continuous measurements, the atmospheric inputs to the forest floor have been calculated. Yearly HM emission estimates to the European atmosphere seems to correlate well with yearly average values of HM deposition, as well as with HM concentrations in the ambient atmosphere. HM emissions have been estimated since the 1950s. Using the correlation between emission and deposition, HM deposition values maybe extrapolated in reverse chronological order. The accumulated atmospheric HM deposition has been estimated in this way over a period of 50 years.


Forests ◽  
2014 ◽  
Vol 5 (10) ◽  
pp. 2561-2580 ◽  
Author(s):  
Jaeeun Sohng ◽  
Ah Han ◽  
Mi-Ae Jeong ◽  
Yunmi Park ◽  
Byung Park ◽  
...  

Author(s):  
A. V. Moshkin ◽  
A. T. Vasyukova ◽  
A. E. Alexeyev

The basic information about functional mixtures is outlined, options for compositions and recommendations for use in baking in mass production are proposed. The characteristic of microbiological, physical and chemical indicators is given, and the results of toxicological studies of dry functional mixtures with fruit and berry powders are given. High-calorie, medium-calorie, and low-calorie composite mixtures have been developed for the centralized production of yeast dough. Dry functional mixtures can be produced according to regulatory documents: TU 9161-004-51926638-11 and TI to TU 9161-004-51926638-11. A patent of the Russian Federation No. 2602629 was obtained for dry functional mixtures with fruit and berry powders. The technological scheme for obtaining a dry functional mixture consists of the following operations: sifting, dosing of prescription components in predetermined proportions: dry egg-milk mixture in the amount of 56.2-61.6% sugar – 20.0-24.3% and salt – 14.1-17.2%. Xanthan (1.06-2.43%) or guar (4.25-5.30%) and fruit and berry powders (1.0-1.5%) are introduced as additional raw materials. Then mixing is carried out, preparation for implementation. The resulting mixture is portioned and packaged in paper bags. Fruit and berry powders were prepared from rose hips, aronia, nettle, bananas, apples and carrots. According to microbiological studies, the degree of contamination during storage during the year corresponds to SanPiN 2.3.2.1078-01, which makes it possible to produce dry functional mixtures with fruit and berry powders for long-term storage. They can be stored in a dry, well-ventilated room in compliance with sanitary rules, with a relative humidity of 65-70% and a temperature of 18-20 °C from 0 to 12 months. It was found that during storage for 12 months. in hermetically sealed paper bags, no powder quality changes were observed. Bakery products made using these mixtures can be recommended for medical, preventive and gerontological nutrition.


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