Effects of tree cover and season on soil nitrogen dynamics and microbial biomass in an African savanna woodland dominated by Colophospermum mopane

2007 ◽  
Vol 23 (4) ◽  
pp. 437-448 ◽  
Author(s):  
Donald Mlambo ◽  
Eddie Mwenje ◽  
Petros Nyathi
Keyword(s):  
Microbial Biomass ◽  
Accumulation Rate ◽  
Tree Cover ◽  
Microbial Biomass N ◽  
Nitrate Accumulation ◽  
Mineral N ◽  
N Transformations ◽  
Crown Diameter ◽  
Large Trees ◽  
Biomass N

The objective of this study was to investigate the effects of tree cover and season on soil N dynamics and microbial biomass in a semi-arid southern African savanna in Zimbabwe. We used a randomized complete block design with five blocks of 100 × 100 m, demarcated in a 10-ha pocket of Colophospermum mopane-dominated woodland protected from grazing and fire. In each block, we randomly selected three mopane trees with large canopies (8.3 m crown diameter) and another three with small canopies (2.7 m crown diameter). We determined soil organic carbon and nutrient concentrations, litterfall N and C inputs, microbial biomass and N transformations beneath large and small mopane trees as well as in the intercanopy areas. Soil organic carbon, microbial biomass, N, P and K were more than twice those beneath large trees than in the intercanopy areas. Rainy-season net mineral N accumulation rate in the surface soil (0–10 cm) ranged from 3.71 μg g−1 mo−1 in the intercanopy areas to 8.80 μg g−1 mo−1 beneath large trees; correspondingly, net nitrate accumulation rate ranged from 1.33 to 3.60 μg g−1 mo−1. Dry-season net mineral N and net nitrate accumulation rates were similar across sampling sites and did not exceed 2 and 0.4 μg g−1 mo−1, respectively. Litterfall N inputs were positively and significantly correlated with soil N availability, microbial biomass N and N transformations. At all sampling sites, microbial biomass and mineral N pools in the dry season were maximum when soil moisture (∼5%) and N transformations were minimum. In contrast, when soil moisture (9–13%) and N transformations were maximum in the rainy season, microbial biomass and mineral N pools were minimum. It is concluded that the improved soil conditions beneath isolated trees in semi-arid savannas may enhance herbaceous biomass yield especially of canopy shade-tolerant species.

Soil-plant nitrogen dynamics following incorporation of a mature rye cover crop in a lettuce production system

1995 ◽  
Vol 124 (1) ◽  
pp. 17-25 ◽  
Author(s):  
L. J. Wyland ◽  
L. E. Jackson ◽  
K. F. Schulbach
Keyword(s):  
Microbial Biomass ◽  
Cover Crop ◽  
Microbial Biomass N ◽  
N Availability ◽  
N Content ◽  
N Transformations ◽  
Total N ◽  
Mineralizable N ◽  
Biomass N ◽  
Bare Soils

SUMMARYWinter non-leguminous cover crops are included in crop rotations to decrease nitrate (NO3-N) leaching and increase soil organic matter. This study examined the effect of incorporating a mature cover crop on subsequent N transformations. A field trial containing a winter cover crop of Merced rye and a fallow control was established in December 1991 in Salinas, California. The rye was grown for 16 weeks, so that plants had headed and were senescing, resulting in residue which was difficult to incorporate and slow to decompose. Frequent sampling of the surface soil (0–15 cm) showed that net mineralizable N (anaerobic incubation) rapidly increased, then decreased shortly after tillage in both treatments, but that sustained increases in net mineralizable N and microbial biomass N in the cover-cropped soils did not occur until after irrigation, 20 days after incorporation. Soil NO3-N was significantly reduced compared to winter-fallow soil at that time. A 15N experiment examined the fate of N fertilizer, applied in cylinders at a rate of 12 kg 15N/ha at lettuce planting, and measured in the soil, microbial biomass and lettuce plants after 32 days. In the cover-cropped soil, 59% of the 15N was recovered in the microbial biomass, compared to 21% in the winter-bare soil. The dry weight, total N and 15N content of the lettuce in the cover-cropped cylinders were significantly lower; 28 v. 39% of applied 15N was recovered in the lettuce in the cover-cropped and winter-bare soils, respectively. At harvest, the N content of the lettuce in the cover-cropped soil remained lower, and microbial biomass N was higher than in winter-bare soils. These data indicate that delayed cover crop incorporation resulted in net microbial immobilization which extended into the period of high crop demand and reduced N availability to the crop.

scholarly journals Assessing the Response of Tomato Yield, Fruit Composition, Nitrogen Absorption, and Soil Nitrogen Fractions to Different Fertilization Management Strategies in the Greenhouse

HortScience ◽  
2019 ◽  
Vol 54 (3) ◽  
pp. 537-546
Author(s):  
Pengpeng Duan ◽  
Ying Sun ◽  
Yuling Zhang ◽  
Qingfeng Fan ◽  
Na Yu ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Organic N ◽  
Microbial Biomass N ◽  
Mineral N ◽  
Soil Microbial ◽  
Tomato Yield ◽  
Fruit Composition ◽  
Soil Microbial Biomass N ◽  
Biomass N

A greenhouse field experiment involving tomato (Solanum lycopersicum) was performed using different nitrogen (N) management regimes: sole application of differing rates of chemical N fertilizer (SC) (SC treatments: N0, N1, N2, and N3) and combined application of manure and chemical N fertilizer (MC) (MC treatments: MN0, MN1, MN2, and MN3). These were used to understand the relationship between comprehensive fruit composition, yield, and N fractions (soil mineral N; soil soluble organic N; soil microbial biomass N, and soil fixed ammonium) under greenhouse conditions. The results showed that the MC treatments significantly increased vitamin C and soluble sugar content compared with SC treatments. In addition, the MN2 treatment produced a high yield and had a positive effect on fruit composition. The N3 (563 kg N/ha) and MN3 (796 kg N/ha) treatments resulted in a high loss of N below the root zone (0–30 cm), consequently reducing N use efficiency. Soil mineral N, soil soluble organic N, and soil fixed ammonium tended to be higher during the first fruiting period, whereas soil microbial biomass N tended to be higher during the second fruiting period. MC treatments significantly increased the N fraction in the 0- to 30-cm soil layer; N fractions tended to be higher with the MN2 treatment. According to an optimum regression equation, soil fixed ammonium during the first fruiting period and soil microbial biomass N during the second fruiting period had a more significant influence on tomato yield and fruit composition. Overall, application MC at an appropriate rate (MN2: 608 kg N/ha) is a promising approach to achieving high yields and optimum taste, and it offers a more sustainable fertilizer management strategy compared with chemical N fertilization.

Factors influencing the availability of mineral nitrogen in clay soils of the brigalow (Acacia harpophylla) region of Central Queensland

1992 ◽  
Vol 43 (5) ◽  
pp. 1197
Author(s):  
PR Grace ◽  
IC MacRae ◽  
RJK Myers
Keyword(s):  
Microbial Biomass ◽  
Clay Soils ◽  
Microbial Biomass C ◽  
Microbial Biomass N ◽  
Mineral N ◽  
Available N ◽  
Soil Microbial ◽  
Biomass N ◽  
Chloris Gayana ◽  
Highly Correlated

Microbiological and chemical assays were performed on clay soils from woodland (Acacia harpophylla-Casuarina cristata), grassland (Panicurn maximum var trichoglume-Chloris gayana) and cropland (Vigna mungo) in the brigalow region of Central Queensland. Over a 15 month period, the microbial biomass C in the top 3.5 cm of native brigalow woodland soil was on average 3630 8g C g-l, 50% more than an associated perennial pasture and over 400% more than an annually cropped soil. Microbial biomass N (575 8g N g-l) in woodland soil was on average 41% and 270% higher than in pasture and cropped soils respectively and highly correlated with seasonal soil moisture content. Viable counts of bacteria were consistently lower (average 69.2%) in the 0-3.5 cm and 3.5-7.5 cm strata of woodland soil compared with pasture and annual crop sites. Soil NO-3- N levels increased two fold in the upper 3.5 cm of the woodland site during low rainfall periods. This increase may be attributed to a more efficient distribution of mineral N mediated by the increased presence of a fungal population in this community. Leaching may also play a significant role in the distribution of plant available N in the brigalow region as suggested by the inverse relationship N = 54.11-0.67 R (P<0.01), where N is soil NO-3-N (8g N g-l) and R is rainfall in the preceding 3 month period (mm month-1).

scholarly journals Nitrogen Immobilisation and Microbial Biomass Build-Up Induced by Miscanthus x giganteus L. Based Fertilisers

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1386
Author(s):  
Michael Stotter ◽  
Florian Wichern ◽  
Ralf Pude ◽  
Martin Hamer
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Microbial Biomass ◽  
Triticum Aestivum L ◽  
Microbial Biomass C ◽  
Microbial Biomass N ◽  
Miscanthus X Giganteus ◽  
Organic Fertilisers ◽  
Biomass N ◽  
Set Up

Cultivation of Miscanthus x giganteus L. (Mis) with annual harvest of biomass could provide an additional C source for farmers. To test the potential of Mis-C for immobilizing inorganic N from slurry or manure and as a C source for soil organic matter build-up in comparison to wheat (Triticum aestivum L.) straw (WS), a greenhouse experiment was performed. Pot experiments with ryegrass (Lolium perenne L.) were set up to investigate the N dynamics of two organic fertilisers based on Mis at Campus Klein-Altendorf, Germany. The two fertilisers, a mixture of cattle slurry and Mis as well as cattle manure from Mis-bedding material resulted in a slightly higher N immobilisation. Especially at the 1st and 2nd harvest, they were partly significantly different compared with the WS treatments. The fertilisers based on Mis resulted in a slightly higher microbial biomass C and microbial biomass N and thus can be identified as an additional C source to prevent nitrogen losses and for the build-up of soil organic matter (SOM) in the long-term.

scholarly journals Maturity indices of composting plant materials with Trichoderma asperellum as activator

2020 ◽  
Vol 53 (1) ◽  
pp. 19-27
Author(s):  
Adenike Fisayo Komolafe ◽  
Christopher Olu Adejuyigbe ◽  
Adeniyi Adebowale Soretire ◽  
Isaac OreOluwa Olatokunbo Aiyelaagbe
Keyword(s):  
Microbial Biomass ◽  
Microbial Biomass N ◽  
Cow Dung ◽  
Trichoderma Asperellum ◽  
Plant Materials ◽  
Total N ◽  
Compost Maturity ◽  
Randomized Design ◽  
Maturity Indices ◽  
Biomass N

AbstractCompost maturity is a major factor in its use for nutrient supply without adverse effect on crop germination. Composting may be accelerated with inclusion of some microorganisms as activators. This study was conducted to determine the effect of Trichoderma asperellum and length of composting of different plant materials and cattle manure on compost maturity in Ibadan, Nigeria. Composting of two plant materials with cow dung at ratio 3:1 was done in triplicate with or without Trichoderma activation to obtain twelve heaps of four different types of composts; Panicum-based compost with Trichoderma, Tridax-based compost with Trichoderma, Panicum-based compost without Trichoderma and Tridax-based compost without Trichoderma. The process was a 2×2 factorial experiment, laid out a completely randomized design. The Trichoderma activated compost (TAC) at four weeks of composting (4WC) had 56% total N, 21% organic matter, 38% total K, 51% total P and 66.6% microbial biomass N increase over non-activated compost (NAC). Carbon to nitrogen ratio was within the ideal range (10–20) in TAC while it was greater than it in NAC. Microbial biomass and lignin contents had a 56% and 41% increase, respectively, in NAC over TAC. Trichorderma-activated compost has a potential to hasten maturation and makes the compost ready for field on or before four weeks without posing a threat to crop germination.

Short‐term effects of organic and inorganic fertilizer applications on soil microbial properties

2011 ◽  
Vol 1 (4) ◽  
pp. 202-207
Author(s):  
N. Ewusi‐Mensah ◽  
V. Logah ◽  
J. O. Fening
Keyword(s):  
Microbial Biomass ◽  
Deciduous Forest ◽  
Block Design ◽  
Mean Value ◽  
Cattle Manure ◽  
Microbial Biomass C ◽  
Microbial Biomass N ◽  
Forest Zone ◽  
Soil Microbial ◽  
Biomass N

This paper reports the short Ã¢â‚¬Â term effects of organic and inorganic fertilizerapplications on the culturable resident bacterial and fungal properties of aFerric Acrisol in the semi Ã¢â‚¬Âdeciduous forest zone of Ghana after three continuouscropping seasons. The treatments were two compost types (i.e. 1:1compost comprising 1 part made up of Chromolaena, Stylosanthes, maizestover mixture and 1 part of cattle manure, 2:1 compost comprising 2 partsof Chromolaena, Stylosanthes, maize stover mixture and 1 part of cattle manure),cowdung, 100% NPK and a control replicated three times in a randomizedcomplete block design. The results showed that total microbial load on alogarithmic scale ranged from 4.6 cfu/g in the control to 5.4 on cowdungtreated plots. Bacterial counts on 2:1 compost applied at 5 t/ha treatedplots recorded 5% more bacteria than the 1:1 compost applied at 5 t/ha.Fungal counts in the control and inorganic treated plots were higher than theorganically amended plots. The highest and lowest microbial biomass C contentswere recorded on cowdung and 1:1 compost at 5 t/ha treated plotsrespectively. Microbial biomass N content ranged from 1.4 Ã¢â‚¬Â 8.2 mg N kg‐1soil with a mean value of 6.2 mg N kg Ã¢â‚¬Â1 soil. Microbial biomass P contentranged from 3.6 Ã¢â‚¬Â 6.3 mg P kg‐1 soil with a mean value of 5 mg P kg‐1 soil.Microbial biomass carbon to organic carbon ratio varied from 18.37 to 85.63.

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