Continuous Monoculture of Alfalfa and Annual Crops Influence Soil Organic Matter and Microbial Communities in the Rainfed Loess Plateau of China

Cropping systems are structured to maximize crop yields and increase sustainability in agricultural production. A field study was conducted to investigate different long-term cropping systems on soil organic matter and microbial communities. The cropping systems studied were: (i) a 14-year continuous alfalfa (Medicago sativa L.) (CA), (ii) a 9-year alfalfa removed and rotated with 4–5 years continuous annual crops (spring wheat (Triticum aestivum L.), maize (Zea mays L.), potato (Solanum tuberosum L.), and millet (Panicum miliaceum L.)), and (iii) a 5-year field fallow after alfalfa. Results showed that continued annual crops decreased total organic C and labile organic C by 10 to 20% and 17 to 34% in the topsoil (0–30 cm), and by 15 to 35% and 20 to 46% in the subsoil (30–60 cm), respectively, compared with CA. Similar trends were found in soil total N concentration, which decreased by 7 to 20% in the topsoil. Highest microbial biomass C was found in CA. Shannon-Wiener diversity and substrate richness of soil microbes measured by Biolog EcoPlates was significantly affected by cropping system with CA exhibiting a higher degree of soil microbial functional diversity in the topsoil, while the lowest values were found in the alfalfa-potato system. The higher soil organic matter content and functional diversity of soil microbe in CA indicates that soil nutrition and microbial activity did not limit alfalfa development and growth in the dryland area. The lower microbial activity and functional diversity observed in the potato field indicates the importance of crop selection in cropping systems.

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Changes in soil carbon under long-term maize in monoculture and legume-based rotation

Canadian Journal of Soil Science ◽

10.4141/s00-041 ◽

2001 ◽

Vol 81 (1) ◽

pp. 21-31 ◽

Cited By ~ 142

Author(s):

E G Gregorich ◽

C F Drury ◽

J A Baldock

Keyword(s):

Nuclear Magnetic Resonance ◽

Organic Matter ◽

Soil Organic Matter ◽

Magnetic Resonance ◽

Soil Carbon ◽

Crop Residues ◽

Cropping Systems ◽

Natural Abundance ◽

Organic C ◽

Soil C

Legume-based cropping systems could help to increase crop productivity and soil organic matter levels, thereby enhancing soil quality, as well as having the additional benefit of sequestering atmospheric C. To evaluate the effects of 35 yr of maize monoculture and legume-based cropping on soil C levels and residue retention, we measured organic C and 13C natural abundance in soils under: fertilized and unfertilized maize (Zea mays L.), both in monoculture and legume-based [maize-oat (Avena sativa L.)-alfalfa (Medicago sativa L.)-alfalfa] rotations; fertilized and unfertilized systems of continuous grass (Poa pratensis L.); and under forest. Solid state 13C nuclear magnetic resonance (NMR) was used to chemically characterize the organic matter in plant residues and soils. Soils (70-cm depth) under maize cropping had about 30-40% less C, and those under continuous grass had about 16% less C, than those under adjacent forest. Qualitative differences in crop residues were important in these systems, because quantitative differences in net primary productivity and C inputs in the different agroecosystems did not account for observed differences in total soil C. Cropping sequence (i.e., rotation or monoculture) had a greater effect on soil C levels than application of fertilizer. The difference in soil C levels between rotation and monoculture maize systems was about 20 Mg C ha-1. The effects of fertilization on soil C were small (~6 Mg C ha-1), and differences were observed only in the monoculture system. The NMR results suggest that the chemical composition of organic matter was little affected by the nature of crop residues returned to the soil. The total quantity of maize-derived soil C was different in each system, because the quantity of maize residue returned to the soil was different; hence the maize-derived soil C ranged from 23 Mg ha-1 in the fertilized and 14 Mg ha-1 in the unfertilized monoculture soils (i.e., after 35 maize crops) to 6-7 Mg ha-1 in both the fertilized and unfertilized legume-based rotation soils (i.e., after eight maize crops). The proportion of maize residue C returned to the soil and retained as soil organic C (i.e., Mg maize-derived soil C/Mg maize residue) was about 14% for all maize cropping systems. The quantity of C3-C below the plow layer in legume-based rotation was 40% greater than that in monoculture and about the same as that under either continuous grass or forest. The soil organic matter below the plow layer in soil under the legume-based rotation appeared to be in a more biologically resistant form (i.e., higher aromatic C content) compared with that under monoculture. The retention of maize residue C as soil organic matter was four to five times greater below the plow layer than that within the plow layer. We conclude that residue quality plays a key role in increasing the retention of soil C in agroecosystems and that soils under legume-based rotation tend to be more “preservative” of residue C inputs, particularly from root inputs, than soils under monoculture. Key words: Soil carbon, 13C natural abundance, 13C nuclear magnetic resonance, maize cropping, legumes, root carbon

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Soil organic carbon fractions in a Vertisol under irrigated cotton production as affected by burning and incorporating cotton stubble

Soil Research ◽

10.1071/s97117 ◽

1998 ◽

Vol 36 (4) ◽

pp. 655 ◽

Cited By ~ 31

Author(s):

A. Conteh ◽

G. J. Blair ◽

I. J. Rochester

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Organic Matter Content ◽

Matter Content ◽

Total Carbon ◽

Cotton Production ◽

Labile Carbon ◽

Total N ◽

The Difference ◽

Organic Matter Fractions

The contribution of cotton stubble to the soil organic matter content of Vertisols under cotton production is not well understood. A 3-year experiment was conducted at the Australian Cotton Research Institute to study the effects of burning and incorporating cotton stubble on the recovery of fertiliser nitrogen (N), lint yield, and organic matter levels. This study reports on the changes in soil organic matter fractions as affected by burning and incorporating cotton stubble into the soil. Soil samples collected at the start and end of the 3-year experiment were analysed for total carbon (CT), total N (NT), and δ13C (a measure of 13C/12C isotopic ratios). Labile carbon (CL) was determined by ease of oxidation and non-labile carbon (CNL) was calculated as the difference between CT and CL. Based on the changes in CT, CL, and CNL, a carbon management index (CMI) was calculated. Further analyses were made for total polysaccharides (PT), labile polysaccharides (PL), and light fraction C (LF-C). Stubble management did not significantly affect the NT content of the soil. After 3 years, the stubble-incorporated plots had a significantly higher content of CT, CL, and polysaccharides. Incorporation of stubble into the soil increased the CMI by 41%, whereas burning decreased the CMI by 6%. The amount of LF-C obtained after 3 years in the stubble-incorporated soil was almost double that obtained in the stubble-burnt soil. It was concluded that for sustainable management of soil organic matter in the Vertisols used for cotton production, stubble produced in the system should be incorporated instead of burnt.

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Sulfur forms in bulk soils and alkaline soil extracts of tropical mountain ecosystems in northern Thailand

Soil Research ◽

10.1071/sr01001 ◽

2002 ◽

Vol 40 (1) ◽

pp. 161 ◽

Cited By ~ 9

Author(s):

A. Möller ◽

K. Kaiser ◽

N. Kanchanakool ◽

C. Anecksamphant ◽

W. Jirasuktaveekul ◽

...

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Tropical Soils ◽

Forest Site ◽

Alkaline Soil ◽

Northern Thailand ◽

Total N ◽

Soil Extracts ◽

Organic C ◽

Organic S

Sulfur, besides phosphorus, is crucial for the nutrition of plants on tropical soils. Its availability is closely related to the turnover of soil organic matter. To get a better insight into transformation of soil S forms during the decomposition of organic matter, we studied inorganic and organic S pools in bulk samples and alkaline extracts of soils under different land uses representative of the tropical highlands of northern Thailand. Samples were taken from a cabbage cultivation, a Pinus reforestation, a secondary forest, and a primary forest. Total S ranged from 483 549 mg/kg in the subsoil to 1909 376 mg/kg in the organic layers, which is relatively high for tropical soils. The major S component in soil was organic S, comprising 75–99&percnt; of total S. Organic S was significantly correlated with total S, organic C, and total N, indicating that there is a close relationship between C, N, and S cycling in soil. C-bonded S was the predominant form in the topsoils (35–99&percnt; of total S) but its presence decreased with soil depth. The maximum concentrations of ester SO4-S were found in the A horizons (128 49 mg/kg), whereas the concentrations of inorganic SO4-S were small in all horizons. Compared with the forest site, the cabbage cultivation site was strongly depleted in S. C-bonded S was more depleted than ester SO4-S. A comparison of the S forms in NaOH extracts with S forms in bulk soil and C forms as indicated by 13C-NMR spectroscopy showed (i) that the extracts were very representative of soil organic S fractions and (ii) that ester SO4-S was mainly associated with O-substituted aliphatic C. In contrast, C-bonded S seemed to be connected to more-or-less all C binding types. transformation of soil organic matter, sulfate.

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Effect of crop rotations and fertilization on soil organic matter and some biochemical properties of a thick Black Chernozem

Canadian Journal of Soil Science ◽

10.4141/cjss91-036 ◽

1991 ◽

Vol 71 (3) ◽

pp. 377-387 ◽

Cited By ~ 115

Author(s):

C. A. Campbell ◽

R. P. Zentner ◽

K. E. Bowren ◽

L. Townley-Smith ◽

M. Schnitzer

Keyword(s):

Amino Acids ◽

Organic Matter ◽

Soil Organic Matter ◽

Crop Residues ◽

Cultural Practices ◽

Organic Matter Content ◽

Biochemical Properties ◽

Matter Content ◽

Organic C ◽

Cropping Frequency

The effects of crop rotation and various cultural practices on soil organic matter and some biochemical characteristics of a heavy-textured, Orthic Black Chernozem with a thick A horizon were determined after 31 yr at Melfort, Saskatchewan. Treatments investigated included: fertilization, cropping frequency, green manuring, and inclusion of grass-legume hay crops in predominantly spring wheat (Triticum aestivum L.) systems. The results showed that neither soil organic C nor N in the top 15 cm of soil, nor hydrolyzable amino acids, nor C mineralized in 14 d at 20 °C were influenced by fertilization. However, the relative molar distribution (RMD) of the amino acids reflected the influence of fertilization and the phase (Rot-yr) of the legume green manure rotation sampled. Some characteristics assessed increased marginally with increasing cropping frequency but differences were less marked than results obtained earlier in a heavy-textured Black Chernozem with a thin A horizon at Indian Head, Saskatchewan. The relationship between soil organic matter or C mineralization versus estimated crop residues, residue C, or residue N returned to the land over the 31-yr period, were not significant in the Melfort soil. This contrasts with our findings for the thin Black soil. We speculate that the lack of soil organic matter response in the Melfort soil was due to its very high organic matter content (about 64 t ha−1C and 6.5 t ha−1N in the top 15 cm). We also hypothesized that the amino acid RMD results, which differed from most of those reported in the literature, may be reflecting the more recent cropping history of the soil. This aspect requires further research into the composition and distribution of the humic materials in this soil. Key words: Amino acids, relative molar distribution, C respiration, green manures, fertilization

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Free light fraction carbon and nitrogen, a physically uncomplexed soil organic matter distribution within subtropical grass and leucaena–grass pastures

Soil Research ◽

10.1071/sr18162 ◽

2018 ◽

Vol 56 (8) ◽

pp. 820 ◽

Cited By ~ 2

Author(s):

K. A. Conrad ◽

R. C. Dalal ◽

D. E. Allen ◽

R. Fujinuma ◽

Neal W. Menzies

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Soil Depth ◽

Light Fraction ◽

Grass Species ◽

Pasture Grass ◽

Total N ◽

Δ13c And Δ15n ◽

Organic C ◽

C And N

Quantifying the size and turnover of physically uncomplexed soil organic matter (SOM) is crucial for the understanding of nutrient cycling and storage of soil organic carbon (SOC). However, the C and nitrogen (N) dynamics of SOM fractions in leucaena (Leucaena leucocephala)–grass pastures remains unclear. We assessed the potential of leucaena to sequester labile, free light fraction (fLF) C and N in soil by estimating the origin, quantity and vertical distribution of physically unprotected SOM. The soil from a chronosequence of seasonally grazed leucaena stands (0–40 years) was sampled to a depth of 0.2m and soil and fLF were analysed for organic C, N and δ13C and δ15N. On average, the fLF formed 20% of SOC and 14% of total N stocks in the upper 0.1m of soil from leucaena rows and showed a peak of fLF-C and fLF-N stocks in the 22-year-stand. The fLF δ13C and fLF δ15N values indicated that leucaena produced 37% of fLF-C and 28% of fLF-N in the upper 0.1m of soil from leucaena rows. Irrespective of pasture type or soil depth, the majority of fLF-C originated from the accompanying C4 pasture-grass species. This study suggests that fLF-C and fLF-N, the labile SOM, can form a significant portion of total SOM, especially in leucaena–grass pastures.

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Salinity affects microbial activity and soil organic matter content in tidal wetlands

Global Change Biology ◽

10.1111/gcb.12431 ◽

2014 ◽

Vol 20 (4) ◽

pp. 1351-1362 ◽

Cited By ~ 160

Author(s):

Ember M. Morrissey ◽

Jaimie L. Gillespie ◽

Joseph C. Morina ◽

Rima B. Franklin

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Microbial Activity ◽

Organic Matter Content ◽

Matter Content ◽

Tidal Wetlands ◽

Soil Organic Matter Content

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Labile and stable fractions of soil organic matter under management systems and native cerrado

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832010000300032 ◽

2010 ◽

Vol 34 (3) ◽

pp. 907-916 ◽

Cited By ~ 34

Author(s):

Cícero Célio de Figueiredo ◽

Dimas Vital Siqueira Resck ◽

Marco Aurélio Carbone Carneiro

Keyword(s):

Land Use ◽

Organic Matter ◽

Soil Organic Matter ◽

Particulate Organic Matter ◽

Block Design ◽

Management Systems ◽

Total N ◽

Organic C ◽

Randomized Block Design ◽

Stable Organic Matter

Soil organic matter can be analyzed on the basis of the different fractions. Changes in the levels of organic matter, caused by land use, can be better understood by alterations in the different compartments. The aim of this study was to evaluate the effect of different management systems on the labile and stable organic matter of a dystrophic Red Latosol (Oxisol). The following properties were determined: total organic C and total N (TOC and TN), particulate organic C and particulate N (POC and PN), organic C and N mineral-associated (MOC and NM) and particulate organic C associated with aggregate classes (POCA). Eight treatments were used: seven with soil management systems and one with native Cerrado as a reference. The experiment was designed to study the dynamics of systems of tillage and crop rotation, alternating in time and space. The experimental design was a randomized block design with three replications. The soil samples were collected from five depths: 0-5, 5-10, 10-20, 20-30 and 30-40 cm. Changes in organic C by land use occurred mainly in the fraction of particulate organic matter (> 53 mm). Proper management of grazing promoted increased levels of particulate organic matter by association with larger aggregates (2-8 mm), demonstrating the importance of the formation of this aggregate class for C protection in pasture.

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Simulation of soil organic carbon and nitrogen changes in cereal and pasture systems of southern Australia

Soil Research ◽

10.1071/sr9930481 ◽

1993 ◽

Vol 31 (4) ◽

pp. 481 ◽

Cited By ~ 30

Author(s):

MR Carter ◽

WJ Parton ◽

IC Rowland ◽

JE Schultz ◽

GR Steed

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Plant Biomass ◽

Subterranean Clover ◽

Farming Systems ◽

Triticum Aestivum L ◽

Soil Organic C ◽

Total N ◽

Organic C

Maintenance and improvement of soil organic matter levels is an important concern in dryland farming systems of temperate regions. The Century soil organic matter model was used to simulate changes in soil organic C and total N under long-term wheat (Triticum aestivum L.) and pasture rotations at five sites in southern Australia. Average declines in soil organic C and total N of 14 and 10%, respectively, in continuous and wheat-fallow systems over a 10 to 20 year period were closely simulated by the model at each site. Additions of N fertilizer (80 kg N ha-1), which prevented soil organic matter decline in continuous wheat systems, was also well represented by the model. Trends in soil organic matter under long-term legume pasture were not adequately simulated by the model, probably due to the 'annual' nature of subterranean clover (Trifolium subterranean L.) in dry seasons and subsequent changes in the ratio of live to dead plant biomass and shoot to root ratios. Overall, the study emphasizes the importance of adequate total plant C production to prevent a decline in soil organic C.

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PENGARUH PENANAMAN SENGON (Paraserianthes falcataria) TERHADAP KANDUNGAN C DAN N TANAH DI DESA RESAPOMBO, DOKO, BLITAR

VIABEL Jurnal Ilmiah Ilmu-Ilmu Pertanian ◽

10.30957/viabel.v12i1.424 ◽

2018 ◽

Vol 12 (1) ◽

pp. 49-59

Author(s):

Ulyan Khalif

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Soil Fertility ◽

Soil Quality ◽

Organic Matter Content ◽

Matter Content ◽

Total N ◽

Available N ◽

Soil Organic Matter Content ◽

Organic Matter Input

Landuse change are suspected to be one responsible to soil fertility decline on Resapombo, Doko, Blitar. Efforts done by local farmers to deal with these problems are plantation of P. falcataria trough a reforestation program around 2011-2012. The benefits of the program are still need to be assessed so that this research was done (1) to compare the soil quality between P. falcataria-planted field and no P.falcataria field by the parameters of soil organic matter content and available N, (2) to study the relationship between organic matter input and soil organic matter content and available N, and (3) to identify factors affecting N availability post-P. falcatariaplantation. This research used randomized block design with 5 treatments (annual crop field, 3 and 6 years P. falcaria plantation field, agroforestry field with P. falcataria + coffee + talas plantation, and ex-P. falcataria-planted field. Soil were sampled compositely by 3 replication from 0-20 cm depth. Litter were sampled from a 0.5m2 sub-plot of each treatment. Results showed that P. falcataria plantations enhance soil fertility indicated by increased soil organic matter input to 10.6 times (monoculture) and 17.6 times (agroforestry) control, increased soil organic matter content by 1.5 times (monoculture) and 2.3 times(agroforestry) control, increased total N of 1.6 times (monoculture) and 2.4 times (agroforestry) control, increased ammonium by 1.7 times (monoculture) and 3.2 times (agroforestry) control, and increased nitrate by 2.4 times (monoculture) and 3.9 times(agroforestry) control.The increased soil N content of P. falcataria-planted field were caused by higher soil organic inputs compared to those with no P. falcataria plantation. Nitrogen availability affected by soil texture but have no relationship with soil pH. However, agroforestry fields showed higher pH, organic C, total N, and available N than monoculture P. falcataria fields. Measured soil chemical properties showed no significant change by the increase of P. falcataria age, moreover, they declined down towards control on ex-P. falcatariaplantation. This indicates that reforestation would only give a temporary soil quality enhancement.

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