Linking rhizosphere respiration rate of three grassland species with root nitrogen concentration

Geoderma ◽  
2019 ◽  
Vol 346 ◽  
pp. 84-90 ◽  
Author(s):  
Mao Tang ◽  
Daniel C. Keck ◽  
Weixin Cheng ◽  
Hui Zeng ◽  
Biao Zhu
Keyword(s):  
Respiration Rate ◽  
Nitrogen Concentration ◽  
Grassland Species ◽  
Rhizosphere Respiration ◽  
Root Nitrogen

Habitat and leaf habit as determinants of growth, nutrient absorption, and nutrient use by Alaskan taiga forest species

1983 ◽  
Vol 13 (5) ◽  
pp. 818-826 ◽  
Author(s):  
F. Stuart Chapin III ◽  
Peter R. Tryon
Keyword(s):  
Seasonal Pattern ◽  
Nitrogen Concentration ◽  
Leaf Nitrogen ◽  
Leaf Biomass ◽  
Deciduous Species ◽  
Nitrogen And Phosphorus ◽  
Leaf Respiration ◽  
Phosphate Absorption ◽  
Leaf Habit ◽  
Root Nitrogen

Four evergreen and four deciduous trees and shrubs were sampled from habitats with differing soil temperature regimes in interior Alaskan forests to examine the relative importance of habitat and leaf habit in determining seasonal patterns of shoot growth, tissue nutrient concentration, respiration rate, and phosphate absorption rate. Leaf habit was the primary determinant of shoot growth, with deciduous species producing leaf area and leaf biomass earlier in the season than evergreens. Deciduous trees produced more biomass per shoot and per unit ground area than did evergreens. The seasonal pattern of leaf nitrogen and phosphorus concentration was correlated closely with patterns of leaf growth, declining through the growing season in deciduous species first as nutrient concentrations were diluted by increasing leaf biomass and later as nutrients were retranslocated from senescing leaves. In evergreens the seasonal decline in nutrient concentration was entirely due to dilution by increasing leaf biomass, and there was no evidence of autumn retranslocation from 1st-year leaves. In contrast to seasonal pattern, the magnitude of leaf phosphorus and root nitrogen and phosphorus concentrations was correlated more closely with habitat than with leaf habit, generally being lower in cold sites. Leaf respiration was highly correlated with leaf nitrogen concentration, so that the seasonal pattern of leaf respiration was determined primarily by leaf habit, whereas the magnitude of respiration was more closely correlated with habitat. Root respiration showed no consistent correlation with either habitat or leaf habit but was lower than leaf respiration, as would be expected from low root nitrogen concentration. Phosphate absorption rate was determined more strongly by habitat than by leaf habit, being lower in cold sites characterized by slow plant growth and consequently low annual nutrient requirement. Evergreen species were more effective at absorbing phosphate at low solution concentrations than were deciduous species. Phosphate absorption was less temperature sensitive than root respiration, so that roots of all species absorbed more phosphorus per unit of carbon respired at low root temperature.

Root nitrogen concentration of sorghum above 2% produces least Striga hermonthica seed stimulation

2006 ◽  
Vol 149 (3) ◽  
pp. 255-262 ◽  
Author(s):  
G.C. Ayongwa ◽  
T.J. Stomph ◽  
A.M. Emechebe ◽  
T.W. Kuyper
Keyword(s):  
Nitrogen Concentration ◽  
Striga Hermonthica ◽  
Root Nitrogen

scholarly journals Botanical Composition and Diet Quality of the Vicuñas (Vicugna vicugna Mol.) in Highland Range of Parinacota, Chile

Animals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1205
Author(s):  
Giorgio Castellaro ◽  
Carla Orellana ◽  
Juan Escanilla ◽  
Camilo Bastías ◽  
Patrich Cerpa ◽  
...  
Keyword(s):  
Nitrogen Concentration ◽  
Mean Value ◽  
Foraging Strategies ◽  
Grass Species ◽  
Botanical Composition ◽  
Diet Diversity ◽  
Grassland Species ◽  
Vicugna Vicugna ◽  
Quality Diet ◽  
High Degree

Understanding the botanical composition of herbivores’ diets and their nutritional quality is an important question in the development of sustainable strategies for the management of natural resources. In Chilean highland vicuña-grazed grasslands, there is little information in this regard and, therefore, this study aimed to determine the year-round profile of the diet’s botanical composition and quality. In highland grasslands, on an area of 21.9 ha, continuously grazed for 3.06 VU/ha/year (18°03′ S, 69°13′ W; 4425 m.o.s.l), twelve feces piles were sampled monthly and were analyzed through microhistology, and the nitrogen concentration [NF, OM basis] was determined. The botanical composition, diversity (J) and selectivity index (Ei) of the main species were estimated. Diets were composed of dry–grassland grasses (37.7%), wet–grassland grasses (36.6%), graminoids (14.3%) and forbs (10.2%). The diet diversity ranged from 0.79 (dry–winter) to 0.87 (wet–summer). The main dominant grassland species obtained negative Ei values. The annual mean value of [NF] was estimated as 1.82%, with a higher value in summer months (2.21%), which coincides with the physiological states of higher nutritional demand. The vicuñas behave like generalist ungulates, having a high degree of selectivity towards grass species, which mostly fulfill a nutritional role in subsistence and a functional role in survival, applying foraging strategies that allow them to obtain a better quality diet during the season of greatest nutritional demand.

Effects of root diameter and root nitrogen concentration on in situ root respiration among different seasons and tree species

2010 ◽  
Vol 25 (5) ◽  
pp. 983-993 ◽  
Author(s):  
Dima Chen ◽  
Lixia Zhou ◽  
Xingquan Rao ◽  
Yongbiao Lin ◽  
Shenglei Fu
Keyword(s):  
Tree Species ◽  
Root Respiration ◽  
Nitrogen Concentration ◽  
Root Diameter ◽  
Different Seasons ◽  
Root Nitrogen
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