scholarly journals Distribution of organic matter in a desert shrub community /

1972 ◽  
Author(s):  
Ralph C. Holmgren ◽  
Sam F. Brewster

FLORESTA ◽  
2014 ◽  
Vol 44 (3) ◽  
pp. 349
Author(s):  
Daniel Costa de Carvalho ◽  
Marcos Gervasio Pereira ◽  
Luiz Fernando Tavares de Menezes

 O estudo avaliou a quantidade de matéria orgânica e nutrientes foliares aportados ao solo por Allagoptera arenaria em uma comunidade arbustiva de Palmae na restinga de Marambaia, Rio de Janeiro. As coletas foram realizadas em dez parcelas de 10 m x 10 m (100 m²), demarcadas aleatoriamente na formação arbustiva. Foram coletadas 3 (três) folhas de dez indivíduos adultos escolhidos aleatoriamente. Foi possível quantificar um incremento anual de massa seca de 8,2 Mg.ha-1 ano-1 para a área de estudo. Para o N, observou-se um teor de 12,3 g.kg-1, seguido de 5,7 g.kg-1 para o K, os quais representam, respectivamente, um aporte de 303 kg.N.ha-1.ano-1 e 140 kg.K.ha-1.ano-1. Para P, foi verificado teor no material foliar na ordem de 0,31 g.kg-1, com aporte de 7,4 kg.ha-1.ano-1.Palavra-chave: Ciclagem de nutrientes; ecossistemas costeiros; palmáceas; plantas focais. AbstractBiomass and Nutrient input by Allagoptera arenariain in Restinga da Marambaia, Rio de Janeiro, RJ. This research assessed the amount of organic matter and foliar nutrients in the soil from Allagoptera arenaria in a Palmae shrub community of Restinga da Marambaia, Rio de Janeiro. Samples were collected at ten randomly demarcated plots of 10 x 10m (100 m²) in the bush. We collected three (3) leaves of ten randomly chosen adults. It was possible to quantify an annual increase of dry mass of 8,2 Mg ha-1 yr-1 for the focused area. We observed for N an average grade of 12,3 g kg-1 followed by 5,7 g kg-1 for K, which respectively represent an investment of 303 kg N ha-1 year-1 and 140 kg K ha-1 year-1. We observed for P mean levels in leaf material in order of 0,31 g kg-1 with intake of 7,4kg ha-1 year-1.Keywords: Nutrient cycling; coastal ecosystems; palms; nurse plants.







Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1372
Author(s):  
Yan Jiang ◽  
Yun Tian ◽  
Tianshan Zha ◽  
Xin Jia ◽  
Charles P.-A. Bourque ◽  
...  

Understanding plant resource use efficiencies (RUEs) and their tradeoffs in a desert shrub community, particularly as it concerns the usage of water, light, and nitrogen, remains an ecological imperative. Plant RUEs have been widely used as indicators to understand plant acclimation processes to unfavorable environmental conditions. This study aimed to examine seasonal dynamics in RUEs in two widely distributed plant species in a typical desert shrub community (i.e., Artemisia ordosica and Leymus secalinus) based on in-situ measurements of leaf photosynthesis, specific leaf area (SLA), leaf nitrogen concentration (i.e., Nmass + Narea), and several site-related abiotic factors. Both species exhibited significant seasonal variation in RUEs, with a coefficient of variation (CV) > 30% and seasonal divergence among the various RUEs. Seasonal divergence was largely controlled by variation in stomatal conductance (Gs), which was in turn influenced by variation in soil water content (SWC) and water vapor pressure deficit (VPD). RUEs between species converged, being positively correlated, yielding: (i) r2 = 0.40 and p < 0.01 for WUE; (ii) r2 = 0.18 and p < 0.01 for LUE;and (iii) r2 = 0.25 and p < 0.01 for NUE. RUEs for A. ordosica were mostly larger than those for L. secalinus, but less reactive to drought. This suggests A. ordosica was more conservative in its usage of available resources and was, therefore, better able to adapt to arid conditions. Resource use strategies between species differed in response to drought. Desert shrubs are projected to eventually replace grasses, as drought severity and duration increase with sustained regional climate change.



Nature ◽  
2003 ◽  
Author(s):  
Philip Ball
Keyword(s):  


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