Soil microbial biomass, CO2 and NH3 emission and nitrogen use efficiency in a sandy soil amended with recycled dairy products

2021 ◽  
Vol 23 ◽  
pp. 101546
Author(s):  
Di Liu ◽  
Marzoq Hadi Al Fahd ◽  
Esmat F. Ali ◽  
Ali Majrashi ◽  
Adel M. Ghoneim ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Sandy Soil ◽  
Nitrogen Use Efficiency ◽  
Dairy Products ◽  
Soil Microbial Biomass ◽  
Nitrogen Use ◽  
Soil Microbial ◽  
Nh3 Emission ◽  
Use Efficiency

scholarly journals 15N Natural Abundance of Soil Microbial Biomass in Alpine and Tundra Ecosystems

2021 ◽  
Vol 54 (6) ◽  
pp. 907-917
Author(s):  
M. I. Makarov ◽  
M. S. Kadulin ◽  
T. I. Malysheva
Keyword(s):  
Microbial Biomass ◽  
Isotopic Composition ◽  
Nitrogen Availability ◽  
Soil Microbial Biomass ◽  
Nitrogen Use ◽  
Soil Microbial ◽  
Use Efficiency ◽  
N Enrichment ◽  
Tundra Ecosystems ◽  
Extractable Nitrogen

Abstract Isotopic composition of nitrogen in soil microbial biomass (δ15Nmicr) is connected with the transformation of nitrogen compounds and with the balance of carbon and nitrogen availability for microorganisms. We have studied the dependence of δ15Nmicr on nitrogen isotopic composition in the substrate (δ15N of total and extractable nitrogen), as well as the dependence of δ15Nmicr and 15N-enrichment of microbial biomass (Δ15Nmicr = δ15Nmicr – δ15Nsubstr) on nitrogen availability parameters (the C/N ratio in soil, the N-mineralization activity, the content of extractable nitrogen, and the nitrogen use efficiency) in soils of four alpine ecosystems in the North Caucasus and four tundra ecosystems in the Khibiny Mountains. It has been shown that δ15Nmiсr varies from –0.2 to +8.4‰ and may be characterized by both 15N-enrichment and depletion (negative Δ15Nmiсr values) relative to the total and extractable soil nitrogen. As a rule, Δ15Nmicr is 1.5–3.1‰ relative to 15Ntotal and 0.6–4.8‰ relative to 15Nextr. However, under the most N-deficiency conditions in soils of mountain tundra lichen and shrub heaths, Nmicr does not accumulate an increased amount of 15N. We have not revealed a close correlation of δ15Nmicr and Δ15Nmicr with the C/N ratio. The accumulation of 15N in microbial biomass is much stronger related to N-mineralization (positively) and the nitrogen use efficiency (negatively). This testifies to the important role of microbial nitrogen dissimilation in controlling the isotopic composition of soil microbial biomass nitrogen.

Nitrogen use efficiency in spring wheat: genotypic variation and grain yield response under sandy soil conditions

2017 ◽  
Vol 155 (9) ◽  
pp. 1407-1423 ◽  
Author(s):  
E. MANSOUR ◽  
A. M. A. MERWAD ◽  
M. A. T. YASIN ◽  
M. I. E. ABDUL-HAMID ◽  
E. E. A. EL-SOBKY ◽  
...  
Keyword(s):  
Grain Yield ◽  
Sandy Soil ◽  
Spring Wheat ◽  
Nitrogen Use Efficiency ◽  
Genotypic Variation ◽  
Utilization Efficiency ◽  
Soil Conditions ◽  
Nitrogen Use ◽  
N Concentration ◽  
Use Efficiency

SUMMARYAgricultural practices are likely to lower nitrogen (N) fertilization inputs for economic and ecological limitation reasons. The objective of the current study was to assess genotypic variation in nitrogen use efficiency (NUE) and related parameters of spring wheat (Triticum aestivumL.) as well as the relative grain yield performance under sandy soil conditions. A sub-set of 16 spring wheat genotypes was studied over 2 years at five N levels (0, 70, 140, 210 and 280 kg N/ha). Results indicated significant differences among genotypes and N levels for grain yield and yield components as well as NUE. Genotypes with high NUE exhibited higher plant biomass, grain and straw N concentration and grain yield than those with medium and low NUE. Utilization efficiency (grain-NUtE) was more important than uptake efficiency (total NUpE) in association with grain yield. Nitrogen supply was found to have a substantial effect on genotype; Line 6052 as well as Shandawel 1, Gemmiza 10, Gemmiza 12, Line 6078 and Line 6083 showed higher net assimilation rate, more productive tillers, increased number of spikes per unit area and grains per spike, extensive N concentration in grain and straw, heavier grains, higher biological yield and consequently maximized grain yield. The relative importance of NUE-associated parameters such as nitrogen agronomic efficiency, nitrogen physiological efficiency and apparent nitrogen recovery as potential targets in breeding programmes for increased NUE genotypes is also mentioned.

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