Differential effects of rotation, plant residue and nitrogen fertilizer on microbial biomass and organic matter in an Australian alfisol

Ladd, J.N.; Amato, M.; Zhou, Liqin; Schultz, Juliana

doi:10.1016/0038-0717(94)90298-4

Cited by 126 publications

(37 citation statements)

References 19 publications

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“…Our results indicate that microbial biomass C values were significantly affected by soil N contents and organic-matter contents (Figure 3). In general, studies on the influence of N fertilizer inputs on soil biological properties have produced contradictory results, with some showing increases in the size of the microbial biomass (Fraser, Haynes, and Williams 1994;Omay et al 1997) and others reporting the opposite trend (Ladd et al 1994;Bardgett, Wardle, and Yeates 1998). Similar significant positive linear correlations have been reported between microbial biomass C and soil organic-matter content in 13 diverse soils differing in management practices (Witter, Martensson, and Garcia 1993).…”

Section: Discussionmentioning

confidence: 87%

Excessive Nitrogen Inputs in Intensive Greenhouse Cultivation May Influence Soil Microbial Biomass and Community Composition

Hao

Christie

Fang

et al. 2009

Communications in Soil Science and Plant Analysis

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Intensive greenhouse vegetable-production systems commonly utilize excessive fertilizer inputs that are inconsistent with sustainable production and may affect soil quality. Soil samples were collected from 15 commercial greenhouses used for tomato production and from neighboring fields used for wheat cropping to determine the effects of intensive vegetable cultivation on soil microbial biomass and community structure. Soil total nitrogen (N) and organicmatter contents were greater in the intensive greenhouse tomato soils than the open-field wheat soils. Soil microbial carbon (C) contents were greater in the greenhouse soils, and soil microbial biomass N showed a similar trend but with high variation. The two cropping systems were not significantly different. Soil microbial biomass C was significantly correlated with both soil total N and soil organic matter, but the relationships among soil microbial biomass N, soil total N, and organic-matter content were not significant. The Biolog substrate 2323 utilization potential of the soil microbial communities showed that greenhouse soils were significantly higher (by 14%) than wheat soils. Principal component (PC) analysis of soil microbial communities showed that the wheat sites were significantly correlated with PC1, whereas the greenhouse soils were variable. The results indicate that changes in soil microbiological properties may be useful indicators for the evaluation of soil degradation in intensive agricultural systems.

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Section: Discussionmentioning

confidence: 87%

Excessive Nitrogen Inputs in Intensive Greenhouse Cultivation May Influence Soil Microbial Biomass and Community Composition

Hao

Christie

Fang

et al. 2009

Communications in Soil Science and Plant Analysis

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“…There is, however, a second plausible explanation. The decrease in microbial biomass with increasing N could be due to an artifact of the biomass assay technique, because of its known pH dependence, especially when the fumigation-incubation procedure is used (Ladd et al 1994 (Table 3). These results may be related to the greater crop residues with high N contents obtained with fertilization (Ukrainetz et al 1995).…”

Section: Canadian Journal Of Soil Sciencementioning

confidence: 99%

Soil microbial and biochemical properties after ten years of fertilization with urea and anhydrous ammonia

Biederbeck¹,

Curtin²,

Bouman³

et al. 1996

Can. J. Soil. Sci.

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O. T. 1996. Soit microbial and biochemical properties after ten years of fertilization with urea and anhydrous ammonia. Can. J. Soil Sci. 76: 7-l4.The influence of nitrogen (N) fertilizers, eipecially anhydrous ammonia, on soil quility has been qr:estioned frequently by pro_ponents of organic farming uoO to* input sustainabie agriculture. A 10-yr experiment wis conducted on an Orthic Dark Brown Chernozemic loam, at Scott, Saskatchewan, to examine ih. influ.n.. of uiea and anhydrous ammonia, at rates of N up to I 80 kg ha-l' on yields of cer-eals and oilseeds. In the 10th yr, we sampled soil from the 0-to 7.5-and 7.5-to l5-cm depths of each treatment 3 d before and 6 and 26 d after fertilization to'aisess the impact of applied N on microbial populations and soil biochemical properties. The^long-term residual effects ofN fertilization on ioil properiies were evident prioitothe 1Oth annual N application. The short-term effects were most pronounced 6 d after the 1gth N application. Generally, effects were greater in the7.5-to 15-cm depth, where N was.placed. the s'oit, which was already acidic (pH ='5.2 in 0.01 M CaCl2), decreased in pH in proportion to N_rate and more so for anhydrous ammonia than urea. Geneially, fungal and bacterial populations (plate counts) were positively related to N rate and were greater in soil treated with anhydrouj imm6nia than in urea-treated soil. In contrast, the actinomycete population was inversely related to N rate and was less for anhydrous ammonia than for urea. Nitrifier counts were increased by low rates of N (added substrate) but were similar to the check at high N rates (high acidity). There were no significant effects of N treatment on denitrifiers or yeasts. In contrast to the plate coun-t results, *i.t6bial biomass decreased with increasing rates of N and was lower for anhydrous ammonia than for ur.u. fio*.u.., the authenticity of this response is questionable because the fumigation-incubation method of biomass determination is compromised under acid conditioni. Carbon mineralization was unaffected but N mineralization and nitrification tended to decrease at the 1 80 kg N ha-l rate of anhydrous ammonia. Significant nitriflication occurred at pH < 5.0 suggesting possible adaptation of nitrifiers in this acid soil. Wet aggregate stability (WAS) was ulgffecled by N treatments. We conItua"ittrut, if producers in the Dark Brown soil zone apply fertilizirs at rates less than 90 kg N hr', deterioration of soil quality should be minimal.

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“…Rickerl et al (1989) found that populations of this organism were 29% larger in soils under minimum tillage as compared to soils under conventional tillage. Ladd et al (1994) verified that the C biomass of microbial populations was greater in soils under crop rotation than in soils under continuous monoculture; greater in soils where plant residues were incorporated or remained on the soil surface than where they were removed; and smaller in a nitrogen-fertilized soil than in non-fertilized ones. This information is important because these are characteristics that contribute to soil biological equilibrium, nutrient mineralization and suppressive capacity toward plant pathogens, among others, making the system less dependent on external input.…”

Section: Introductionmentioning

confidence: 73%

Soil Organisms in Organic and Conventional Cropping Systems

Bettiol¹,

Ghini²,

Galvao³

et al. 2014

Organic Agricultural Practices

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Despite the recent interest in organic agriculture, little research has been carried out in this area. Thus, the objective of this study was to compare, in a dystrophic Ultisol, the effects of organic and conventional agricultures on soil organism populations, for the tomato (Lycopersicum esculentum) and corn (Zea mays) crops. In general, it was found that fungus, bacterium and actinomycet populations counted by the number of colonies in the media, were similar for the two cropping systems. CO 2 evolution during the cropping season was higher, up to the double for the organic agriculture system as compared to the conventional. The number of earthworms was about ten times higher in the organic system. There was no difference in the decomposition rate of organic matter of the two systems. In general, the number of microartropods was always higher in the organic plots in relation to the conventional ones, reflectining on the Shannon index diversity. The higher insect population belonged to the Collembola order, and in the case of mites, to the superfamily Oribatuloidea. Individuals of the groups Aranae, Chilopoda, Dyplopoda, Pauropoda, Protura and Symphyla were occasionally collected in similar number in both cropping systems. Key words: soil microorganisms, organic agriculture, microartropods, cropping systems, environmental impacts ORGANISMOS DO SOLO EM SISTEMAS DE CULTIVO ORGÂNICO E CONVENCIONALRESUMO: Apesar do crescente interesse pela agricultura orgânica, são poucas as informações de pesquisa disponíveis sobre o assunto. Assim, num Argissolo Vermelho-Amarelo distrófico foram comparados os efeitos de sistemas de cultivo orgânico e convencional, para as culturas do tomate (Lycopersicum esculentum) e do milho (Zea mays), sobre a comunidade de organismos do solo e suas atividades. As populações de fungos, bactérias e actinomicetos, determinadas pela contagem de colônias em meio de cultura, foram semelhantes para os dois sistemas de produção. A atividade microbiana, avaliada pela evolução de CO 2, manteve-se superior no sistema orgânico, sendo que em determinadas avaliações foi o dobro da evolução verificada no sistema convencional. O número de espécimes de minhoca foi praticamente dez vezes maior no sistema orgânico. Não foi observada diferença na taxa de decomposição de matéria orgânica entre os dois sistemas. De modo geral, o número de indivíduos de microartrópodos foi superior no sistema orgânico do que no sistema convencional, refletindo no maior índice de diversidade de Shannon. As maiores populações de insetos foram as da ordem Collembola, enquanto para os ácaros a maior população foi a da superfamília Oribatuloidea. Indivíduos dos grupos Aranae, Chilopoda, Dyplopoda, Pauropoda, Protura e Symphyla foram ocasionalmente coletados e de forma similar entre os sistemas. Palavras-chave: microbiota do solo, agricultura orgânica, microartrópodos, sistemas de cultivo, impacto ambiental

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Differential effects of rotation, plant residue and nitrogen fertilizer on microbial biomass and organic matter in an Australian alfisol

Cited by 126 publications

References 19 publications

Excessive Nitrogen Inputs in Intensive Greenhouse Cultivation May Influence Soil Microbial Biomass and Community Composition

Excessive Nitrogen Inputs in Intensive Greenhouse Cultivation May Influence Soil Microbial Biomass and Community Composition

Soil microbial and biochemical properties after ten years of fertilization with urea and anhydrous ammonia

Soil Organisms in Organic and Conventional Cropping Systems

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