Effect of time of application and nitrate: ammonium ratio on maize grain yield, grain N concentration and soil mineral N concentration in a semi-arid region

Abstract. Chinese grasslands are extensive natural ecosystems that comprise 40 % of the total land area of the country and are sensitive to N deposition. A field experiment with six N rates (0, 30, 60, 120, 240, and 480 kg N ha−1 yr−1) was conducted at Duolun, Inner Mongolia, during 2005 and 2010 to identify some effects of N addition on a temperate steppe ecosystem. The dominant plant species in the plots were divided into two categories, grasses and forbs, on the basis of species life forms. Enhanced N deposition, even as little as 30 kg N ha−1 yr−1 above ambient N deposition (16 kg N ha−1 yr−1), led to a decline in species richness. The cover of grasses increased with N addition rate but their species richness showed a weak change across N treatments. Both species richness and cover of forbs declined strongly with increasing N deposition as shown by linear regression analysis (p < 0.05). Increasing N deposition elevated aboveground production of grasses but lowered aboveground biomass of forbs. Plant N concentration, plant δ15N and soil mineral N increased with N addition, showing positive relationships between plant δ15N and N concentration, soil mineral N and/or applied N rate. The cessation of N application in the 480 kg N ha−1 yr−1 treatment in 2009 and 2010 led to a slight recovery of the forb species richness relative to total cover and aboveground biomass, coinciding with reduced plant N concentration and soil mineral N. The results show N deposition-induced changes in soil N transformations and plant N assimilation that are closely related to changes in species composition and biomass accumulation in this temperate steppe ecosystem.

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Soil mineral N dynamics and maize grain yields following Centrosema macrocarpum and Stylosanthes guianensis: effects of different rotations and varying levels of N fertiliser

Field Crops Research ◽

10.1016/s0378-4290(02)00135-1 ◽

2002 ◽

Vol 78 (2-3) ◽

pp. 197-209 ◽

Cited By ~ 6

Author(s):

L Muhr ◽

S.A Tarawali ◽

M Peters ◽

R Schultze-Kraft

Keyword(s):

Soil Mineral N ◽

Soil Mineral ◽

Mineral N ◽

N Dynamics ◽

Grain Yields ◽

Stylosanthes Guianensis ◽

Maize Grain

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Nitrogen enrichment enhances the dominance of grasses over forbs in a temperate steppe ecosystem

Biogeosciences Discussions ◽

10.5194/bgd-8-5057-2011 ◽

2011 ◽

Vol 8 (3) ◽

pp. 5057-5082 ◽

Cited By ~ 1

Author(s):

L. Song ◽

X. M. Bao ◽

X. J. Liu ◽

Y. Zhang ◽

P. Christie ◽

...

Keyword(s):

Species Richness ◽

Aboveground Biomass ◽

N Deposition ◽

Soil Mineral N ◽

N Addition ◽

Soil Mineral ◽

Temperate Steppe ◽

Mineral N ◽

N Concentration ◽

Steppe Ecosystem

Abstract. Chinese grasslands are extensive natural ecosystems that comprise 40 % of the total land area of the country and are sensitive to N deposition. A field experiment with six N rates (0, 30, 60, 120, 240, and 480 kg N ha−1 yr−1) was conducted at Duolun, Inner Mongolia, during 2005 and 2010 to identify some effects of N addition on a temperature steppe ecosystem. The dominant plant species in the plots were divided into two categories, grasses and forbs, on the basis of species life forms. Enhanced N deposition, even as little as 30 kg N ha−1 yr−1 above ambient N deposition (16 kg N ha−1 yr−1), led to a decline in species richness. The cover of grasses increased with N addition rate but their species richness showed a weak change across N treatments. Both species richness and cover of forbs declined strongly with increasing N deposition as shown by linear regression analysis (p<0.05). Increasing N deposition elevated aboveground production of grasses but lowered aboveground biomass of forbs. Plant N concentration, plant δ15N and soil mineral N increased with N addition, showing positive relationships between plant δ15N and N concentration, soil mineral N and/or applied N rate. The cessation of N application in the 480 kg N ha−1 yr−1 treatment in 2009 and 2010 led to a slight recovery of the forb species richness relative to total cover and aboveground biomass, coinciding with reduced plant N concentration and soil mineral N. The results show that N deposition induced changes in soil N transformations and plant N assimilation that are key to changes in species composition and biomass accumulation in this temperate steppe ecosystem.

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TILLAGE-INDUCED SOIL CHANGES AND RELATED GRAIN YIELD IN A SEMI-ARID REGION

Canadian Journal of Soil Science ◽

10.4141/cjss90-022 ◽

1990 ◽

Vol 70 (2) ◽

pp. 203-214 ◽

Cited By ~ 23

Author(s):

J. M. CAREFOOT ◽

C. W. LINDWALL ◽

M. NYBORG

Keyword(s):

Grain Yield ◽

Soil Water ◽

Arid Region ◽

Inorganic N ◽

Total Soil ◽

N Concentration ◽

Plant Emergence ◽

Semi Arid Region ◽

Soil Changes ◽

Semi Arid

Crop yields are affected by tillage-induced changes in soil chemical and physical parameters. This study was conducted to determine the tillage-induced soil changes and related grain yield and grain N concentration for two crop rotations in a semi-arid region. Soil physical and chemical properties were measured in winter wheat-barley-fallow and continuous wheat rotations under no-till (NT) and conventional till (CT). The field measurements were made in 1983 and 1984 on a Lethbridge loam and a Chin clay loam in a semi-arid region of Alberta. Soil moisture, temperature, bulk density and inorganic N were measured. The effects of tillage-induced soil changes on grain yield and grain N concentration were assessed. In 1983, at Lethbridge, tillage had no effect on grain yield. Grain yield was greater for NT than for CT crops in 1984, a year characterized by early summer drought. At Vauxhall, yield of NT crops was equal to or greater than that of CT crops except for barley in 1983, where volunteer winter wheat growth was a severe problem in the NT treatment. May soil temperatures (2-cm soil depth) for spring-seeded barley averaged 14.7 °C in the CT compared with 13.9 °C in the NT treatment. Inorganic N (0 to 30 cm) was not significantly affected by tillage in 1983, but in 1984 inorganic N was consistently greater in the CT than in the NT treatments at midseason and in the fall. The dominant effect on grain N concentration was an inverse relationship with grain yield. However, when grain yields were similar between tillage systems, greater inorganic N with the CT treatment was reflected in larger grain N concentrations for CT. Greater grain yield with NT than with CT at Lethbridge was associated with greater total soil water and improved seedbed moisture resulting in greater seed imbibition of water and plant emergence. At Vauxhall, tillage treatment did not significantly affect total soil water conservation, but greater grain yields with NT than with CT were attributed to improved plant emergence with NT. Conserving both seedbed moisture and total soil water by reducing tillage had beneficial effects on crop yield in this semi-arid region. Key words: No-till, conventional till, soil water, soil temperature, soil nitrogen

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Release of Ammonium-N (NH4+) and Nitrate-N (NO3-) by Different Leguminous Cover Crops (LCCs) Planted in Peat Soils

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.d5224.118419 ◽

2019 ◽

Vol 8 (4) ◽

pp. 6793-6797

Keyword(s):

Cover Crops ◽

Chemical Properties ◽

Soil Mineral N ◽

Soil Mineral ◽

Peat Soils ◽

Mineral N ◽

Nitrate N ◽

N Concentration ◽

Ammonium N ◽

Vigorous Growth

Peat soils is renowned for the low mineral-N concentration which is crucial for crop’s growth. One of the effective and conserving method to improve the soil mineral-N concentration is by planting leguminous cover crop (LCC) which is common in oil palm plantation area. However, different LCCs was found to release different concentration of mineral-N into the soils. Hence, this study aims to determine the concentration of soil mineral-N in form of soil ammonium-N (NH4 + ) and soil nitrate-N (NO3 - ) by different types of LCCs namely Mucuna bracteata, Calopogonium mucunoides, Pueraria javanica and Centrosema pubescens as well as to evaluate the effects on physico-chemical properties of peat soils. Results showed most of the LCCs can survive in acidic peat condition whilst improving the concentration of mineral-N in the soils. Mucuna bracteata was found to release a significant amount of mineral-N into the soils and shows a vigorous growth compared to others during the study period. However, it should be noted that different LCCs required distinct time to fix N since the maturity for different LCCs is different. Hence, prolonged studies on release of mineral N into the soil by LCCs are recommended.

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Aerosol iron solubility in a semi-arid region: temporal trend and impact of anthropogenic sources

Tellus B ◽

10.3402/tellusb.v62i2.16519 ◽

2010 ◽

Vol 62 (2) ◽

Author(s):

Ashwini Kumar ◽

M. M. Sarin

Keyword(s):

Arid Region ◽

Temporal Trend ◽

Anthropogenic Sources ◽

Iron Solubility ◽

Semi Arid Region ◽

Semi Arid

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The Molecular Characterization and Biological Assessment of the Leaves Extracts of Loofah Reveal their Nutraceutical Potential

Recent Patents on Food Nutrition & Agriculturee ◽

10.2174/2212798411999201110211931 ◽

2020 ◽

Vol 11 ◽

Author(s):

Takoua Ben Hlel ◽

Feten Belhadj ◽

Fatih Gül ◽

Muhammed Altun ◽

Ayşe Şahin Yağlıoğlu ◽

...

Keyword(s):

Fatty Acids ◽

Phenolic Compounds ◽

Hela Cell ◽

Arid Region ◽

Biological Properties ◽

Biological Assessment ◽

Omega 3 ◽

Hela Cell Lines ◽

Semi Arid Region ◽

Semi Arid

Background:: Luffa cylindrica is a plant that is widely distributed in Africa and Asia and it can be grown in regions with tropical or subtropical climates. Few patents dealt with Loofah biological properties, including some functional foods formulated from its leaves. Objective:: This study aimed to structurally and functionally characterize the bioactive compounds of L. cylindrica leaves grown in two different environments. Methods:: The extracts of L. cylindrica leaves collected from two Tunisian locations: Essouasi (LE), a semi-arid region and Medenine (LM) an arid region, were investigated for their phenolic compounds and fatty acids using HPLC/TOF-MS and GCMS techniques respectively. Furthermore, the antioxidant capacity was evaluated with DPPH, Chelating effect, Hydroxyl radical and Superoxide anion scavenging activities while the anticancer activity against HeLa cell lines was assessed using xCELLigence real time cell analyzer and lactate dehydrogenase cytotoxicity assay. Results:: The antiproliferative capacity of both extracts was time and dose-dependent with LE presenting the lowest HeLa cell index (CI = 0.035 ± 0.018, 250 μg/ml). LE also showed the best cytotoxic capacity (56.49 ± 0.8%) and antioxidant potential (IC50 = 54.41 ± 1.12 μg/ml for DPPH and 12.12 ± 0.07 μg/ml for chelating effet). 14 phenolic compounds were detected in LE with ferulic acid being the major compound (5128.5 ± 4.09 μg Phenols/g) while LM had only 6 phenolics. GCMS analysis showed the presence of omega-3 fatty acids in LE. Conclusions:: Our findings suggest that L. cylindrica leaves, especially when collected from semi-arid regions, are promising for formulating nutraceuticals of interest.

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