scholarly journals Influence of legumes on N cycling in a heathland in northwest Spain

Web Ecology ◽  
2007 ◽  
Vol 7 (1) ◽  
pp. 87-93 ◽  
Author(s):  
A. Rodríguez ◽  
J. Durán ◽  
A. Gallardo
Keyword(s):  
Microbial Biomass ◽  
Nitrogen Availability ◽  
Soil Microbial Biomass ◽  
N Uptake ◽  
Microbial Biomass N ◽  
Natural Ecosystems ◽  
Mixed Stands ◽  
Soil Microbial ◽  
Soil Microbial Biomass N ◽  
Biomass N

Abstract. Nitrogen availability frequently limits plant growth in natural ecosystems. N-fixers should have a substantial competitive advantage in N-limited systems, and as a byproduct of their activity they should increase the quantity and availability of N in the system as a whole. However, this effect has rarely been quantified in natural ecosystems. Heathlands in northwest Spain are frequently occupied by legume scrubs. We tested whether the presence of these legumes affected the N cycle in these communities. Specifically, we addressed the following questions: is nitrogen availability higher beneath legume canopies than beneath non-legume canopies? Is soil microbial biomass acting as a sink of extra N mineralized beneath legume canopies? Does the presence of legume scrubs change the soil pools of labile N and P? Is N plant uptake different under N-fixer scrubs than under non-N-fixer scrubs? To answer these questions, we sampled soil beneath the canopy of randomly selected individuals of Erica umbellata, Ulex gallii, and Genista tridentata twice during the growing season. Soil samples were analyzed for organic matter, NH4-N, NO3-N, DON, PO4-P, N mineralization and nitrification rates, and soil microbial biomass-N. In addition, we estimated N uptake by plants and the N concentration in green tissue to compare internal N cycles between legume and non-legume scrubs. Nitrification rates, DON (dissolved organic nitrogen), soil NO3 concentration, and N uptake were significantly higher beneath legume canopies. However, soil microbial biomass-N and extractable-P were significantly lower under legumes. Our results showed that the presence of legume scrubs modify the size of N pools and the dominant form of available N for plants, increasing spatial heterogeneity in mixed stands.

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.

Effects of different freezing methods on estimates of soil microbial biomass N by fumigation-extraction

2003 ◽  
Vol 166 (3) ◽  
pp. 326-327 ◽  
Author(s):  
Jürgen K. Friedel ◽  
Corinne Kobel ◽  
Michael Pfeffer ◽  
Walter J. Fitz ◽  
Walter W. Wenzel
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Microbial Biomass N ◽  
Soil Microbial ◽  
Soil Microbial Biomass N ◽  
Biomass N ◽  
Fumigation Extraction

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.

scholarly journals Comparison of inorganic nitrogen uptake dynamics following snowmelt and at peak biomass in subalpine grasslands

2013 ◽  
Vol 10 (11) ◽  
pp. 7631-7645 ◽  
Author(s):  
N. Legay ◽  
F. Grassein ◽  
T. M. Robson ◽  
E. Personeni ◽  
M.-P. Bataillé ◽  
...  
Keyword(s):  
Land Use ◽  
Microbial Biomass ◽  
Plant Communities ◽  
Inorganic Nitrogen ◽  
N Uptake ◽  
Microbial Biomass N ◽  
Inorganic N ◽  
Peak Biomass ◽  
Biomass N ◽  
Subalpine Grasslands

Abstract. Subalpine grasslands are highly seasonal environments and likely subject to strong variability in nitrogen (N) dynamics. Plants and microbes typically compete for N acquisition during the growing season and particularly at plant peak biomass. During snowmelt, plants could potentially benefit from a decrease in competition by microbes, leading to greater plant N uptake associated with active growth and freeze-thaw cycles restricting microbial growth. In managed subalpine grasslands, we expect these interactions to be influenced by recent changes in agricultural land use, and associated modifications in plant and microbial communities. At several subalpine grasslands in the French Alps, we added pulses of 15N to the soil at the end of snowmelt, allowing us to compare the dynamics of inorganic N uptake in plants and microbes during this period with that previously reported at the peak biomass in July. In all grasslands, while specific shoot N translocation (per g of biomass) of dissolved inorganic nitrogen (DIN) was two to five times greater at snowmelt than at peak biomass, specific microbial DIN uptakes were similar between the two sampling dates. On an area basis, plant communities took more DIN than microbial communities at the end of snowmelt when aboveground plant biomasses were at least two times lower than at peak biomass. Consequently, inorganic N partitioning after snowmelt switches in favor of plant communities, allowing them to support their growing capacities at this period of the year. Seasonal differences in microbial and plant inorganic N-related dynamics were also affected by past (terraced vs. unterraced) rather than current (mown vs. unmown) land use. In terraced grasslands, microbial biomass N remained similar across seasons, whereas in unterraced grasslands, microbial biomass N was higher and microbial C : N lower at the end of snowmelt as compared to peak biomass. Further investigations on microbial community composition and their organic N uptake dynamics are required to better understand the decrease in microbial DIN uptake.

CHANGES WITH TIME IN SOIL BIOMASS C, N AND P OF MINE SPOILS IN A DRY TROPICAL ENVIRONMENT

1989 ◽  
Vol 69 (4) ◽  
pp. 849-855 ◽  
Author(s):  
S. C. SRIVASTAVA ◽  
A. K. JHA ◽  
J. S. SINGH
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Native Forest ◽  
Soil N ◽  
Mine Spoils ◽  
Soil Microbial ◽  
Total Soil ◽  
Soil Biomass ◽  
Biomass N ◽  
Total Soil N

Soil biomass C, N and P were determined for a native forest site, an unmined deforested site and an age-series of adjacent coal mine spoils (5, 10, 12, 16 and 20 yr). Biomass C ranged from 209 to 867 μg g−1 soil, biomass N from 20 to 75 μg g−1 soil and biomass P from 7 to 29 μg g−1 soil. Biomass C, N and P were linearly related to each other. Biomass C was also related to the root biomass. Biomass N with a mean C:N ratio of 11.8 accounted for 2.2–4.2% of the total soil N and was positively related to the mineral N of soil. Biomass C:P ratio ranged from 27.6 to 31.0%. The biomass P was significantly related to the bicarbonate soluble soil Pi. Soil microbial biomass was characterized by a mean C:N:P ratio of 29:3:1. Soil microbial C, N and P were positively related with the age of mine spoils, the values for the youngest spoil (5 yr old) being about four times lower compared to native forest soil. Total soil N was also positively related with age of spoil. The data suggest that microbial biomass can be taken as a functional index of soil redevelopment. Key words: Surface coal mining, soil microbial biomass C, biomass N, biomass P, mine spoil

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