Effects of land use on soil total and light fraction organic, and microbial biomass C and N in a semi-arid ecosystem of northwest China

Geoderma ◽  
2009 ◽  
Vol 153 (1-2) ◽  
pp. 285-290 ◽  
Author(s):  
Xiao-Ling Wang ◽  
Yu Jia ◽  
Xiao-Gang Li ◽  
Rui-Jun Long ◽  
Qifu Ma ◽  
...  
Keyword(s):  
Land Use ◽  
Microbial Biomass ◽  
Northwest China ◽  
Light Fraction ◽  
Microbial Biomass C ◽  
Arid Ecosystem ◽  
C And N ◽  
Effects Of Land Use ◽  
Semi Arid

Seasonal trends in selected soil biochemical attributes: Effects of crop rotation in the semiarid prairie

1999 ◽  
Vol 79 (1) ◽  
pp. 73-84 ◽  
Author(s):  
C. A. Campbell ◽  
V. O. Biederbeck ◽  
G. Wen ◽  
R. P. Zentner ◽  
J. Schoenau ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Microbial Biomass ◽  
Microbial Biomass Carbon ◽  
Light Fraction ◽  
Water Soluble ◽  
Microbial Biomass C ◽  
Weather Variables ◽  
Total N ◽  
Organic C ◽  
C And N

Measurements of seasonal changes in soil biochemical attributes can provide valuable information on how crop management and weather variables influence soil quality. We sampled soil from the 0- to 7.5-cm depth of two long-term crop rotations [continuous wheat (Cont W) and both phases of fallow-wheat (F–W)] at Swift Current, Saskatchewan, from early May to mid-October, 11 times in 1995 and 9 times in 1996. The soil is a silt loam, Orthic Brown Chernozem with pH 6.0, in dilute CaCl2. We monitored changes in organic C (OC) and total N (TN), microbial biomass C (MBC), light fraction C and N (LFC and LFN), mineralizable C (Cmin) and N (Nmin), and water-soluble organic C (WSOC). All biochemical attributes, except MBC, showed higher values for Cont W than for F–W, reflecting the historically higher crop residue inputs, less frequent tillage, and drier conditions of Cont W. Based on the seasonal mean values for 1996, we concluded that, after 29 yr, F–W has degraded soil organic C and total N by about 15% compared to Cont W. In the same period it has degraded the labile attributes, except MBC, much more. For example, WSOC is degraded by 22%, Cmin and Nmin by 45% and LFC and LFN by 60–75%. Organic C and TN were constant during the season because one year's C and N inputs are small compared to the total soil C or N. All the labile attributes varied markedly throughout the seasons. We explained most of the seasonal variability in soil biochemical attributes in terms of C and N inputs from crop residues and rhizodeposition, and the influences of soil moisture, precipitation and temperature. Using multiple regression, we related the biochemical attributes to soil moisture and the weather variables, accounting for 20% of the variability in MBC, 27% of that of Nmin, 29% for LFC, 52% for Cmin, and 66% for WSOC. In all cases the biochemical attributes were negatively related to precipitation, soil moisture, temperature and their interactions. We interpreted this to mean that conditions favouring decomposition of organic matter in situ result in decreases in these attributes when they are measured subsequently under laboratory conditions. We concluded that when assessing changes in OC or TN over years, measurements can be made at any time during a year. However, if assessing changes in the labile soil attributes, several measurements should be made during a season or, measurements be made near the same time each year. Key words: Microbial biomass, carbon, nitrogen, mineralization, water-soluble-C, light fraction, weather variables

scholarly journals Changes in Soil Labile Organic Matter as Affected by 50 Years of Fertilization with Increasing Amounts of Nitrogen

Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2026
Author(s):  
Nikola Koković ◽  
Elmira Saljnikov ◽  
Frank Eulenstein ◽  
Dragan Čakmak ◽  
Aneta Buntić ◽  
...  
Keyword(s):  
Organic Matter ◽  
Microbial Biomass ◽  
Quality Parameters ◽  
Light Fraction ◽  
Microbial Biomass C ◽  
Microbial Biomass N ◽  
Sensitivity Index ◽  
Strong Impact ◽  
Labile Organic Matter ◽  
C And N

Microbially mediated soil organic matter is an extremely sensitive pool that indicates subtle changes in the quality parameters responsible for the soil’s ecological and productive functions. Fifty years of mineral fertilization of a wheat-corn cropping system has a strong impact on soil quality parameters. The goal of the research was to study the dynamics and quality of soil biological parameters affected by increasing amounts of mineral nitrogen. Soil respiration, potentially mineralizable C and N, microbial biomass C and N and light-fraction OM on Cambisol were analyzed in the following treatments: (1) Control (without fertilization); (2) NPK (60/51/67); (3) NPK (90/51/67); (4) NPK (120/51/67); (5) NPK (150/51/67 kg ha−1). The parameters studied were significantly affected by the long-term application of mineral fertilizer compared with both the control and the adjacent native soil. The highest amounts of nitrogen (N150) did not significantly differ from N120 and N90 for most of the parameters studied. Potentially mineralizable C represented the largest labile carbon pool, while microbial biomass N was the largest labile nitrogen pool. The mineralization rates for C and N were oppositely distributed over the seasons. The sensitivity index correlated with the amount of light-fraction OM. The results give a deeper insight into the behavior and distribution of different pools of labile SOM in the agro-landscapes and can serve as a reliable basis for further research focused on zero soil degradation.

Variation in soil microbial biomass in the dry tropics: impact of land-use change

Soil Research ◽  
2014 ◽  
Vol 52 (3) ◽  
pp. 299 ◽  
Author(s):  
Mahesh Kumar Singh ◽  
Nandita Ghoshal
Keyword(s):  
Land Use ◽  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Soil Depth ◽  
Natural Forest ◽  
Microbial Biomass C ◽  
Soil Microbial Biomass C ◽  
Soil Microbial ◽  
Land Use Types ◽  
C And N

The impact of land-use change on soil microbial biomass carbon (C) and nitrogen (N) was studied through two annual cycles involving natural forest, degraded forest, agroecosystem and Jatropha curcas plantation. Soil microbial biomass C and N, soil moisture content and soil temperature were analysed at upper (0–10 cm), middle (10–20 cm) and lower (20–30 cm) soil depths during the rainy, winter and summer seasons. The levels of microbial biomass C and N were highest in the natural forest, followed in decreasing order by Jatropha curcas plantation, degraded forest and the agroecosystem. The highest level of soil microbial biomass C and N was observed during summer, decreasing through winter to the minimum during the rainy season. Soil microbial biomass C and N decreased with increasing soil depth for all land-use types, and for all seasons. Seasonal variation in soil microbial biomass was better correlated with the soil moisture content than with soil temperature. The microbial biomass C/N ratio increased with the soil depth for all land-use types, indicating changes in the microbial community with soil depth. It is concluded that the change in land-use pattern, from natural forest to other ecosystems, results in a considerable decrease in soil microbial biomass C and N. Jatropha plantation may be an alternative for the restoration of degraded lands in the dry tropics.

Effects of land-use change from grassland to forest on soil sulfur and arylsulfatase activity in New Zealand

Soil Research ◽  
2001 ◽  
Vol 39 (4) ◽  
pp. 749 ◽  
Author(s):  
C. R. Chen ◽  
L. M. Condron ◽  
M. R. Davis ◽  
R. R. Sherlock
Keyword(s):  
Land Use ◽  
Enzyme Activity ◽  
Microbial Biomass ◽  
Land Use Change ◽  
Water Soluble ◽  
Microbial Biomass C ◽  
Organic S ◽  
Arylsulfatase Activity ◽  
Soil Sulfur ◽  
Effects Of Land Use

The effects of land-use change from grassland to forest on soil sulfur (S) and arylsulfatase enzyme activity were investigated by comparing soils under unimproved grassland and an adjacent 19-year-old exotic forest stand (mixture of Pinus ponderosa and P. nigra). Results showed that concentrations of organic S in topsoil under forest were significantly lower [418 µg/g (0–5 cm), 398 µg/g (5–10 cm)] than corresponding soil depths under grassland [541 µg/g (0–5 cm), 468 µg/g (5–10 cm)]. On the other hand, inorganic S concentrations were significantly higher in soil under forest at all depths compared with grassland. The inorganic S concentration in soil under grassland increased with depth, but there was no significant difference observed at different depths under forest. The decrease in organic S [and organic carbon (C)] in soil under forest was due to the enhanced mineralisation of organic components. The accumulation of inorganic S in the soil profile under forest was mainly attributed to enhanced mineralisation, although decreased leaching, increased sulfate-S adsorption, and increased atmospheric inputs by canopy interception of aerosols could have contributed. Microbial biomass C and S and arylsulfatase activity were higher in topsoil under grassland than forest. Lower arylsulfatase activities under forest compared with grassland at the time of sampling suggest that mineralisation of organic S under forest was not currently mediated primarily by enzyme activity, although enzyme activity may have been important at earlier stages of forest development. Arylsulfatase activity was significantly correlated with soil organic C, water-soluble C, microbial biomass C, total S, organic S, and microbial biomass S in soil under grassland and forest. Significant concentrations of organic S and microbial biomass S were present in the forest floor (litter and fermentation layers). These pools would be important for S cycling and availability in forest ecosystems. S mineralisation, S fractions, microbial biomass S, microbial biomass C.

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