Investigating the Optimal Day for Nitrogen Fertilization on Piatã palisadegrass and Quênia guineagrass after Defoliation

Author(s):  
Dayana Aparecida De Faria ◽  
Anne Caroline Dallabrida Avelino ◽  
Carlos Eduardo Avelino Cabral ◽  
Joadil Gonçalves De Abreu ◽  
Lívia Vieira De Barros ◽  
...  

Considering that nitrogen is the main macronutrient limiting pasture productivity, the aim of this study was to investigate the most appropriate day for nitrogen fertilization of the grasses Brachiaria brizantha BRS Piatã and Panicum maximum BRS Quênia. The experiment was conducted in a greenhouse in the city of Rondonópolis, located in the state of Mato Grosso, Brazil, using a completely randomized design. The treatments consisted of five nitrogen fertilization periods: 0; 2; 4; 6 and 8 days after defoliation. The dry mass of the leaf blade (DMLB), dry mass of stem + sheath (DMSS), dry mass of residue (DMRES) and root dry mass (RDM) were evaluated. The non-structural carbohydrate of the grass roots was also quantified. The later nitrogen fertilization after defoliation reduced DMLB (P< .01) and DMSS (P< .01) of the BRS Piatã palisadegrass, and DMRES of both grasses (P< .01). Higher levels of water soluble carbohydrates were observed when nitrogen fertilization was performed on grass cutting (day 0). Nitrogen fertilization of the BRS Piatã palisadegrass close the time of defoliation is recommended. For Quênia guineagrass, nitrogen can be applied between the cutting day and the eighth day after defoliation. For the root system, there is a higher content of water soluble carbohydrates in the BRS Piatã palisadegrass and greater accumulation of starch in the BRS Quênia guineagrass.

1982 ◽  
Vol 9 (1) ◽  
pp. 113 ◽  
Author(s):  
J Kigel ◽  
A Dotan

The effect of water stress on the regrowth potential of Rhodes grass was studied in plants grown under controlled conditions at 27/22°C and 16-h photoperiods, and subjected to different periods of water withholding. After water was withheld, the levels of water-soluble carbohydrates (WSC) in the roots and basal parts of the leaves gradually increased from 2-4% to 8-9%, while the level of starch in the leaves remained stable below 1%. Regrowth and elongation of leaves that took place after cutting was increased markedly by withholding water for 6-10 days before cutting. A positive linear correlation was shown between initial leaf regrowth and the total amount of WSC present at cutting time. However, this initial advantage of the stressed plants gradually disappeared during the regrowth period, and no significant differences in leaf length and weight were found at later stages between the watered and stressed plants.


Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2058
Author(s):  
Iván P. Ordóñez ◽  
Ignacio F. López ◽  
Peter D. Kemp ◽  
Daniel J. Donaghy ◽  
Yongmei Zhang ◽  
...  

The increase in drought events due to climate change have enhanced the relevance of species with greater tolerance or avoidance traits to water restriction periods, such as Bromus valdivianus Phil. (B. valdivianus). In southern Chile, B. valdivianus and Lolium perenne L. (L. perenne) coexist; however, the pasture defoliation criterion is based on the physiological growth and development of L. perenne. It is hypothesised that B. valdivianus needs a lower defoliation frequency than L. perenne to enhance its regrowth and energy reserves. Defoliation frequencies tested were based on B. valdivianus leaf stage 2 (LS-2), leaf stage 3 (LS-3), leaf stage 4 (LS-4) and leaf stage 5 (LS-5). The leaf stage development of Lolium perenne was monitored and contrasted with that of B. valdivianus. The study was conducted in a glasshouse and used a randomised complete block design. For Bromus valdivianus, the lamina length, photosynthetic rate, stomatal conductance, tiller number per plant, leaf area, leaf weights, root growth rate, water-soluble carbohydrates (WSCs) and starch were evaluated. Bromus valdivianus maintained six live leaves with three leaves growing simultaneously. When an individual tiller started developing its seventh leaf, senescence began for the second leaf (the first relevant leaf for photosynthesis). Plant herbage mass, the root growth rate and tiller growth were maximised at LS-4 onwards. The highest leaf elongation rate, evaluated through the slope of the lamina elongation curve of a fully expanded leaf, was verified at LS-4. The water-soluble carbohydrates (WSCs) increased at LS-5; however, no statistical differences were found in LS-4. The LS-3 and LS-2 treatments showed a detrimental effect on WSCs and regrowth. The leaf photosynthetic rate and stomatal conductance diminished while the leaf age increased. In conclusion, B. valdivianus is a ‘six-leaf’ species with leaf senescence beginning at LS-4.25. Defoliation at LS-4 and LS-5 was optimum for plant regrowth, maximising the aboveground plant parameters and total WSC accumulation. The LS-4 for B. valdivianus was equivalent to LS-3.5 for L. perenne. No differences related to tiller population in B. valdivianus were found in the different defoliation frequencies.


2019 ◽  
Vol 17 (4) ◽  
pp. 539-544
Author(s):  
Md Juiceball Hassan ◽  
Md Masudul Karim ◽  
Md Amirul Islam ◽  
Md Habibur Rahman Pramanik ◽  
Md Alamgir Hossain

Submergence stress at early vegetative stage is one of the most important constraints in the productivity of rice in Bangladesh. Submergence causes yield loss of rice at Aman season in Bangladesh and therefore, it is necessary to develop submergence tolerant rice cultivars. A pot experiment was conducted at the net house of Department of Crop Botany, Bangladesh Agricultural University, during Aman season from July to December, 2017 to evaluate the changes in root porosity and water soluble carbohydrates (WSCs) associated with submergence tolerance in rice. The experiment consisted of two factors—(i) Rice cultivars (Binadhan-11, Binadhan-12, BRRI dhan51 and BRRI dhan52 as tolerant and BRRI dhan49 as susceptible) and(ii) Submergence stress: Submergence for 14 days at vegetative stage and control. Submergence stress was imposed by dipping of pots into a water tank with about 90 cm depth of water while the control plants are maintained in the pot house of the field laboratory. The plants were sampled at seven days interval during submergence to determine the changes in root porosity and to examine the contribution of shoot reserves for their survival. The root porosity was measured by pycnometer method and water soluble carbohydrate was measured by the anthrone method. Tolerant cultivars showed greater root porosity development in both control and stress condition but the susceptible cultivar showed significantly lower root development in stress condition. Higher root porosity might help tolerant cultivars to survive in submergence stress more efficiently. Tolerant rice cultivars had high initial soluble carbohydrate than the susceptible one. Under submergedcondition, the tolerant cultivars showed slow depletion of water soluble carbohydrate compared to susceptible cultivar. Higher carbohydrate contents in tolerant cultivars might act as buffer stock during submergence for their better survival and growth. J Bangladesh Agril Univ 17(4): 539–544, 2019


2020 ◽  
Vol 206 (5) ◽  
pp. 619-629 ◽  
Author(s):  
Meredith L. Mitchell ◽  
Stephen G. Clark ◽  
Kym L. Butler ◽  
Zhongnan Nie ◽  
Vivianne F. Burnett ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document