Biomass and root production of two plant life forms in a semiarid Mexican scrub: responses to soil nitrogen availability

2005 ◽  
Vol 83 (10) ◽  
pp. 1317-1321 ◽  
Author(s):  
Numa P. Pavón

The contribution of cacti and shrubs to root biomass and fine-root production was described in a semiarid Mexican scrub. Both life forms were evaluated for fine-root production variation in relation to changes of nitrogen in the soil, with a fertilization experiment. Cacti represented 78% of the total mean root biomass (660 ± 70 g·m–2 (mean ± SE)) in the complete soil profile (50 cm in depth). In both life forms, root biomass was higher near the surface of the soil. Roots <3 mm in diameter represented 92.5% for cactus root biomass and 69.4% for shrubs. Monthly root biomass varied significantly between months, and significant differences were obtained between plant life forms. Fine and very fine root production was estimated as 3.76 Mg·ha–1·year–1, and cactus contribution to total root production was 81.2%. Significant differences were obtained between life forms. It was clear that a low concentration in the soil nitrogen diminishes fine-root production, supporting the hypothesis that in arid ecosystems nitrogen is a limiting factor for primary production.

1987 ◽  
Vol 17 (8) ◽  
pp. 909-912 ◽  
Author(s):  
W. A. Kurz ◽  
J. P. Kimmins

Fine root production rates are most commonly calculated from periodic measurements of live and dead fine root biomass. The accuracy of production estimates based on this method is very sensitive to violations of the inherent assumptions, particularly the assumption that the processes of fine root production and mortality are temporally separate. A simple model was used to simulate data for a variety of seasonal patterns of live and dead fine root biomass. Fine root production and mortality rates were calculated from these simulated data using two different computational methods. Comparison of the calculated rates with the known rates (the rates used to generate the seasonal patterns) revealed that violations of the above assumptions can result in inaccurate rate estimates. When fine root production and mortality occur simultaneously within a sampling interval, the calculated production rate will greatly underestimate the true value. Additional error in the rate estimates may result from sampling error associated with the fine root biomass data. The model suggested that sampling error can cause either overestimation or underestimation of fine root production.


1993 ◽  
Vol 23 (6) ◽  
pp. 1179-1186 ◽  
Author(s):  
David A. Publicover ◽  
Kristiina A. Vogt

A simulation model approach was used to assess the performance of several methods for calculating fine root production under various conditions that could lead to errors in production estimates. The models included two methods that utilize periodic data on live only or live and dead fine root biomass, plus one method (the compartment-flow model) that also incorporates root decomposition rates. Potential sources of error included long sampling intervals, random sampling error, use of an incorrect decay constant, and sample processing errors (undermeasurement of fine root biomass and inaccuracy in identifying live and dead roots). The compartment-flow method was the most accurate and overcomes the problems of underestimation of production to which the biomass-only methods are subject. The sensitivity of the method to processing errors varies according to the method used to determine decay rates. The measurement of true decay rates is the biggest obstacle to accurate estimation of fine root production when using the compartment-flow method.


Author(s):  
Meimei Sun ◽  
Bo-Chao Zhai ◽  
Qiu-Wen Chen ◽  
Guoqing Li ◽  
Sheng Du

AbstractFine roots are the most active and functional component of root systems and play a significant role in the acquisition of soil resources. Density is an important structural factor in forest plantations but information on changes in fine roots along a density gradient is limited. In this study, plantations of black locust (Robinia pseudoacacia L.) and Chinese pine (Pinus tabuliformis Carr.) with four density classes were analyzed for the influence of soil and leaf traits on fine root growth. Fine root biomass increased with stand density. High fine root biomass was achieved through increases in the fine root production and turnover rate in the high-density black locust plantations and through an increase in fine root production in the pine plantations. In the high-density Chinese pine stand, there was a high fine root turnover which, coupled with high fine root production, contributed to a high fine root biomass. Overall, fine root production and turnover rate were closely related to soil volumetric water content in both kinds of plantations, while fine root biomass, especially the component of necromass, was related to soil nutrient status, which refers to phosphorous content in black locust plantations and nitrogen content in Chinese pine plantations. There was a close linkage between leaf area index and fine root dynamics in the black locust plantations but not in the pine plantations.


2000 ◽  
Vol 11 (1) ◽  
pp. 39-42 ◽  
Author(s):  
Numa P. Pavón ◽  
Humberto Hernández-Trejo ◽  
Víctor Rico-Gray

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Juan Piñeiro ◽  
Raúl Ochoa-Hueso ◽  
Manuel Delgado-Baquerizo ◽  
Silvan Dobrick ◽  
Peter B. Reich ◽  
...  

2017 ◽  
Vol 31 (1) ◽  
pp. 84-92
Author(s):  
Celio M. Lopes ◽  
Flora Misaki ◽  
Karina Santos ◽  
Carlos A. P. Evangelista ◽  
Tatiana T. Carrijo ◽  
...  

2014 ◽  
Vol 59 ◽  
pp. 84-90 ◽  
Author(s):  
A. Montagnoli ◽  
M. Terzaghi ◽  
G.S. Scippa ◽  
D. Chiatante

2019 ◽  
Vol 12 (6) ◽  
pp. 1059-1072
Author(s):  
Lin Wei ◽  
Pengwei Yao ◽  
Guanghua Jing ◽  
Xiefeng Ye ◽  
Jimin Cheng

Abstract Aims Clipping or mowing for hay, as a prevalent land-use practice, is considered to be an important component of global change. Root production and turnover in response to clipping have great implications for the plant survival strategy and grassland ecosystem carbon processes. However, our knowledge about the clipping effect on root dynamics is mainly based on root living biomass, and limited by the lack of spatial and temporal observations. The study aim was to investigate the effect of clipping on seasonal variations in root length production and mortality and their distribution patterns in different soil layers in semiarid grassland on the Loess Plateau. Methods Clipping was performed once a year in June to mimic the local spring livestock grazing beginning from 2014. The minirhizotron technique was used to monitor the root production, mortality and turnover rate at various soil depths (0–10, 10–20, 20–30 and 30–50 cm) in 2014 (from 30 May to 29 October) and 2015 (from 22 April to 25 October). Soil temperature and moisture in different soil layers were also measured during the study period. Important Findings Our results showed that: (i) Clipping significantly decreased the cumulative root production (P < 0.05) and increased the cumulative root mortality and turnover rates of the 0–50 cm soil profile for both years. (ii) Clipping induced an immediate and sharp decrease in root length production and an increase in root length mortality in all soil layers. However, with plant regrowth, root production increased and root mortality decreased gradually, with the root production at a depth of 30–50 cm even exceeding the control in September–October 2014 and April–May 2015. (iii) Clipping mainly reduced root length production and increased root length mortality in the upper 0–20 cm soil profile with rapid root turnover. However, roots at deeper soil layers were either little influenced by clipping or exhibited an opposite trend with slower turnover rate compared with the upper soil profile, leading to the downward transport of root production and living root biomass. These findings indicate that roots in deeper soil layers tend to favour higher root biomass and longer fine root life spans to maximize the water absorption efficiency under environmental stress, and also suggest that short-term clipping would reduce the amount of carbon through fine root litter into the soil, especially in the shallow soil profile.


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