Fate of Organic and Inorganic Nitrogen in Crusted and Non‐Crusted <i>Kobresia</i> Grasslands

Zhang, Li; Unteregelsbacher, Sebastian; Hafner, Silke; Xu, Xingliang; Schleuß, Per-Marten; Miehe, Georg; Kuzyakov, Yakov

doi:10.1002/ldr.2582

Cited by 33 publications

(16 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Crop residue return is frequently increased by nitrogen (N) fertilization; however, the effect of the N-fertilizationtriggered increase of C addition is not always certain (Dou et al, 2016;Zhang et al, 2016). This is because the stable SOM fraction (mineral-associated HF) is not mainly inputdriven but also depends on residue decomposability (Barbera et al, 2010;García-Orenes et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Decadal Nitrogen Fertilization Decreases Mineral‐Associated and Subsoil Carbon: A 32‐Year Study

et al. 2017

Self Cite

View full text Add to dashboard Cite

Crop residues and manure are important sources of carbon (C) for soil organic matter (SOM) formation. Crop residue return increases by nitrogen (N) fertilization because of higher plant productivity, but this often results only in minor increases of SOM. In our study, we show how N fertilization and organic C additions affected SOM and its fractions within a 32‐year‐long field‐experiment at Puch, Germany. Five organic additions, no‐addition (control), manure, slurry, straw and straw + slurry, were combined with three mineral N fertilization rates (no, medium and high fertilization), which resulted in 1·17–4·86 Mg C‐input ha‐1 y‐1. Topsoil (0–25 cm) SOM content increased with N fertilization, mainly because of the C in free light fraction (f‐LF). In contrast, subsoil (25–60 cm) SOM decreased with N fertilization, probably because of roots' relocation in Ap horizon with N fertilization at the surface. Despite high inputs, straw contributed little to f‐LF but prevented C losses from the mineral‐associated SOM fraction (ρ > 1·6 g cm‐3) with N fertilization, which was observed without straw addition. Above (straw) and belowground (roots) residues had opposite effects on SOM fractions. Root C retained longer in the light‐fractions and was responsible for SOM increase with N fertilization. Straw decomposed rapidly (from f‐LF) and fueled the mineral‐associated SOM fraction. We conclude that SOM content and composition depended not only on residue quantity, which can be managed by the additions and N fertilization, but also on the quality of organics. This should be considered for maintaining the SOM level, C sequestration, and soil fertility. Copyright © 2016 John Wiley & Sons, Ltd.

show abstract

Section: Introductionmentioning

confidence: 99%

Decadal Nitrogen Fertilization Decreases Mineral‐Associated and Subsoil Carbon: A 32‐Year Study

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…In contrast, the dying root mats were unable to assimilate C and began the initial stages of degradation. The primary causes of death in Kobresia root mats are overgrazing and natural mortality of single Kobresia clones (Unteregelsbacher et al, 2012;Zhang et al, 2016). Over time, intensified root and soil organic carbon decomposition as well as increasing leaching losses result in altered soil properties.…”

Section: Sampling Preparation and Experimental Set-upmentioning

confidence: 99%

“…The fate of added N in Kobresia pasture ecosystems was also investigated using a 15 N-labelling technique (Xu et al, 2003(Xu et al, , 2004. A recent study determined the 15 N recovery in soil and plant of non-crust and crust patches of Kobresia pastures, in which the crust patches were considered to be degraded (Zhang et al, 2016). They observed lower total recovery from inorganic N but higher recovery from organic N in crust patches, concluding that crusts changed the fate of added N. However, these 15 N-labelling studies only added very low levels of N as a tracer and did not consider the impact of increasing N addition (from increasing N deposition or fertilizer inputs to reverse degradation) on the fate of N in intact and degraded Kobresia pastures.…”

Section: Introductionmentioning

confidence: 99%

Responses of Degraded Tibetan Kobresia Pastures to N Addition

2017

Self Cite

View full text Add to dashboard Cite

Kobresia pastures on the Tibetan Plateau are the largest alpine pastoral ecosystems. Kobresia pastures have experienced severe degradation in recent decades, inducing large nitrogen (N) losses from these ecosystems. This is particularly problematic, as it intensifies prevailing N limitation in these regions. Simultaneously, anthropogenic N deposition has increased across these ecosystems, but the fate of added N on variously degraded Kobresia pastures remains unclear. Kobresia pastures of three degradation stages were investigated: living, dying and dead root mats. High and very low (as a tracer) amounts of 15N‐labelled ammonium nitrate (NH4NO3) were applied to root mats under controlled conditions. Leaching was simulated over 3 months, and 15N recovery was measured in the plant–soil system. N addition promoted aboveground biomass and foliar N content of Kobresia during the early growth period, indicating a short‐term offset of N limitation. After 7–8 weeks, plant growth and 15N uptake were reduced in plants with initial N addition, reflecting a transition to N limitation induced by N uptake and leaching from soil. This limitation was also indicated by the strong decline of NO3− in leachates from living root mats compared with degraded root mats. Leaching N losses from dying and dead root mats increased 2⋅2 and 6⋅3 times, respectively, compared with those of living root mats. We conclude that N addition can facilitate plant growth in living root mats but contributes to N leaching in degraded pastures. This contribution to N leaching may weaken ecosystem recovery, increase NO3− loading of adjacent lower landscape parts and cause eutrophication of aquatic ecosystems. Copyright © 2017 John Wiley & Sons, Ltd.

show abstract

“…Apart from the crucial role of soil microbial community structure (abundance of Gram-negative and Gram-positive bacterial, and fungal biomarkers), the decomposition of plant residues also depends on biochemical composition, that is, lignin contents and C/N ratio (Bray et al, 2012;Diedhiou et al, 2009;Franco-Andreu et al, 2017;Samahadthai, Vityakon, & Saenjan, 2010;Singh, 2016;Taylor & Middleton, 2004). However, most of the studies were carried out for agricultural crops and forestry plants due to their potential economic benefits linked with nutrient mineralization and their availability to subsequent crops rather than halophytes, which have potential economic and environmental benefits for coastal ecosystem (Hueso-González, Martínez-Murillo, & Ruiz-Sinoga, 2014;Junior et al, 2018;Qadir et al, 2008;Srivastava, Gupta, Shikha, Singh, & Tewari, 2016;Tejada & Benítez, 2014;Zhang et al, 2017), calls for continued investigations of the subject. To our knowledge, very few reports are available on impact of halophyte decomposition on microbial community on Indian saltmarshes, compared with other saltmarshes of the North America and Europe (Bouchard & Lefeuvre, 2000;Buth & de Wolf, 1985;Goodfriend et al, 1998;Menendez & Sanmarti, 2007;Simões et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Halophyte residue decomposition and microbial community structure in coastal soil

2019

View full text Add to dashboard Cite

Saltmarshes are known for higher primary productivity and play a crucial role in carbon‐sequestration, nutrient‐cycling, and ecological services; however, scarce information are available on halophyte residue mineralization and microbial community structure during decomposition. Soil microcosms with residues (1% w/w) of three dominant halophytes (Aeluropus lagopoides, Arthrocnemum indicum, and Suaeda nudiflora) and one control were incubated under laboratory conditions and sampled at 1, 5, 10, 20, 40, and 90 days to link the microbial community structure and residues decomposition in degraded coastal soil. Samples were subjected to identification of active microbial groups and residue mineralization using fatty acid methyl ester (FAME) and CO2 evolution methods, respectively. Biochemical composition of residues was also analyzed. Cumulative CO2 evolution was elevated in residue‐amended soils compared with control, and it was highest in Arthrocnemum followed by Suaeda, Aeluropus, and control soil. The Aeluropus residue decomposed slower than others due to its high C/N ratio and low protein content. The contents of total FAME and biomarker FAMEs of microbial groups (bacterial, fungal, and actinomycetes) responded positively to the residue amendments compared with control, which indicate the improvement in soil microbial biomass. Soils amended with Suaeda had the highest amount of total (76.8 nmol/g) and fungal FAMEs (6.7 nmol/g), and bacterial (28.6 nmol/g) and actinomycete (3.0 nmol/g) FAMEs were elevated in Arthrocnemum amended soil. At the same time, soils amended with Suaeda (6.2%), Arthrocnemum (28.4%), and control (15.4%) had the greatest abundance of fungal, Gram‐negative and Gram‐positive FAME biomarkers, respectively. The present study suggests that residue of halophyte species affected the abundance of fungal and bacterial biomarkers, and the microbial community structure.

show abstract

Fate of Organic and Inorganic Nitrogen in Crusted and Non‐Crusted Kobresia Grasslands

Cited by 33 publications

References 64 publications

Decadal Nitrogen Fertilization Decreases Mineral‐Associated and Subsoil Carbon: A 32‐Year Study

Decadal Nitrogen Fertilization Decreases Mineral‐Associated and Subsoil Carbon: A 32‐Year Study

Responses of Degraded Tibetan Kobresia Pastures to N Addition

Halophyte residue decomposition and microbial community structure in coastal soil

Contact Info

Product

Resources

About