Effect of cultivation on physical speciation of humic substances and plant nutrients in aggregate fractions of crusting soil from Zimbabwe

Pardo, M. T.; Giampaolo, S.; Almendros, G.

doi:10.1007/s003740050287

Cited by 11 publications

(6 citation statements)

References 19 publications

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“…1995). A decrease in humus as a result of cultivation was also found for a crusting soil in Zimbabwe by Pardo et al . (1997), who used a mixture of 0.1 m NaOH and 0.1 m Na 4 P 2 O 7 to extract the humus.…”

Section: Resultssupporting

confidence: 73%

Humus composition of soils under forest, coffee and arable cultivation in hilly areas of south Sumatra, Indonesia

Watanabe

Sarno

Rumbanraja

et al. 2001

European J Soil Science

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Summary To understand the effect of land use changes on the composition of humus in tropical soils, samples from land under primary forest, secondary forest, coffee plantation, and arable crops were investigated at three sites in south Sumatra, Indonesia. Total carbon and total nitrogen contents were 1.7 to 4.3 times and 1.1 to 2.8 times greater in the topsoil under primary forest than under the other types of land use. Following change from primary forest to other uses, the proportion of humic acids in the organic matter of the topsoils decreased while that of the fulvic acid fraction increased. Within the range of land uses, differences in the yields of humic acids and fulvic acid fractions were, respectively, larger and smaller than those in total carbon content. The humic acids were classified into the low and middle classes in the degree of humification. Absorption due to the green fraction of humic acids, Pg, was detected in the UV‐visible spectra of almost all the humic acids. No relation was observed between the degree of humification of humic acids or the strength of Pg absorption in their spectra and land use change. The fulvic acid fractions were fractionated on insoluble polyvinylpyrrolidone (PVP) into the adsorbed fractions consisting of humic substances and the non‐adsorbed fractions consisting of non‐humic substances. A positive correlation between the amount of the fulvic acid fraction and the percentage of the PVP‐adsorbed fraction within it indicated that the variation in the amount of the fulvic acid fraction was attributable to acid‐soluble humic substances. The ionization difference spectra of solutions between pH 12 and pH 7 suggested that the chemical structures of the PVP‐adsorbed fulvic acids have been altered by land use change.

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Section: Resultssupporting

confidence: 73%

Humus composition of soils under forest, coffee and arable cultivation in hilly areas of south Sumatra, Indonesia

Watanabe

Sarno

Rumbanraja

et al. 2001

European J Soil Science

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“…However, through the action of stabilizing force, biochar combined with soil minerals to form aggregates, whose physical protection could reduce the decomposition of soil organic carbon in aggregates of 1-2, 0.25-1 and <0.25 mm size ranges by microorganism. At the same time, colloidal components with high degree of humification such as humic acid and fulvic acid became relatively enriched in micro-aggregates, and new carbon with high degree of humification or aromatic carbon, which was difficult to be utilized by microorganisms was stably stored by wrapping effect of powdery minerals [31].…”

Section: Effect Of Biochar and Nitrogen Fertilizer On Total Organic Cmentioning

confidence: 99%

Effects of Biochar Combined with Nitrogen Fertilizer Reduction on Rapeseed Yield and Soil Aggregate Stability in Upland of Purple Soils

Tian

Wang

et al. 2019

IJERPH

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Reduction of soil fertility and production efficiency resulting from excessive application of chemical fertilizers is universal in rapeseed-growing fields. The main objective of our study was to assess the effects of biochar combined with nitrogen fertilizer reduction on soil aggregate stability and rapeseed yield and to identify the relationship between yield and soil aggregate stability. A two-factor field experiment (2017–2019) was conducted with biochar (0 (C0), 10 (C10), 20 (C20) and 40 t·ha−1 (C40)) and nitrogen fertilizer (180 (N100), 144 (N80) and 108 kg N·ha−1 (N60)). Experimental results indicated that under N100 and N80 treatments, C10 significantly increased the macro-aggregates (R0.25), mean weight diameter (MWD) and geometric mean diameter (GMD) of soil water stable aggregate by 14.28%–15.85%, 14.88%–17.08% and 36.26%–42.22%, respectively, compared with C0. Besides, the overall difference of the soil water-stable aggregate content in 2–5 mm size range among nitrogen treatments was significant under the application of C10, which increased by 17.04%–33.04% compared with C0. Total organic carbon (TOC) in R0.25 of soil mechanical-stable aggregates was basically all increased after biochar application, especially in 0.25–1 mm and 1–2 mm aggregates, and had an increasing trend with biochar increase. C10 significantly increased rapeseed yield by 22.08%–45.65% in 2019, compared with C0. However, the reduction of nitrogen fertilizer reduced the two-year average rapeseed yield, which decreased by 11.67%–31.67% compared with N100. The highest yield of rapeseed was obtained by N100C10 in two consecutive years, which had no statistical difference with N80C10. However, the two-year yields of N80C10 were all higher than those of N100C0 with increase rate of 16.11%, and which would reduce 35.43% nitrogen fertilizer in the case of small yield difference, compared with the highest yield (2.67 t·ha−1) calculated by multi-dimensional nonlinear regression models. The regression analysis indicated R0.25, MWD and GMD had the strong positive associations with rapeseed yield, whereas percentage of aggregate destruction (PAD0.25) had a significant negative correlation with rapeseed yield. This study suggests that the application of biochar into upland purple soil could improve soil structure, increase the content of TOC in macro-aggregates under nitrogen fertilizer reduction as well as replace part of nitrogen fertilizer to achieve relatively high rapeseed yield.

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“…On the other hand, SOM levels largely depend on the management systems applied by farmers, and most of them use practices that reduce rather than build up SOM concentration. Thus, severe losses of soil carbon (C) as a result of cultivation in southern African soils are well documented (Pardo, Giampaolo, and Almendros 1997;Solomon, Lehmann, and Zech 2000;Nandwa 2001; Zingore et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Cultivation-Induced Effects on the Organic Matter in Degraded Southern African Soils

Pardo

Almendros

Zancada

et al. 2012

Communications in Soil Science and Plant Analysis

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We studied quantitative and qualitative changes in soil organic matter (SOM) due to different land uses (reference woodland versus cultivated) on six soils from Tanzania (Mkindo and Mafiga), Zimbabwe (Domboshawa and Chikwaka), and South Africa (Hertzog and Guquka). Structural characteristics of the humic acids (HAs) were measured by Curie-point pyrolysis-gas chromatography/mass spectrometry (P y-GC/MS) and solid-state 13 C nuclear magnetic resonance (CPMAS 13 C NMR) spectroscopy. Significant changes in concentration and composition of SOM were observed between land uses. Losses of organic carbon after cultivation ranged from 35% to 50%. Virgin soils showed large proportions of colloidal humus fractions: humic acids (HAs) and fulvic acids (FAs) but negligible amounts of not-yet decomposed organic residues. The change in land use produced a contrasting effect on the composition of the HAs: a noteworthy "alkyl enhancement" in Mkindo soil and "alkyl depletion" in Chikwaka and to a lesser extent in Dom oshawa. The remaining soils displayed only minor alterations.

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Effect of cultivation on physical speciation of humic substances and plant nutrients in aggregate fractions of crusting soil from Zimbabwe

Cited by 11 publications

References 19 publications

Humus composition of soils under forest, coffee and arable cultivation in hilly areas of south Sumatra, Indonesia

Humus composition of soils under forest, coffee and arable cultivation in hilly areas of south Sumatra, Indonesia

Effects of Biochar Combined with Nitrogen Fertilizer Reduction on Rapeseed Yield and Soil Aggregate Stability in Upland of Purple Soils

Cultivation-Induced Effects on the Organic Matter in Degraded Southern African Soils

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