scholarly journals Evaluation of Natural Regrowth of Axonopus aureus under rest periods in Roraima´s Savannas

2021 ◽  
Vol 10 (9) ◽  
pp. e56310918536
Author(s):  
Newton de Lucena Costa ◽  
Antônio Neri Azevedo Rodrigues
Keyword(s):  
Dry Matter ◽  
Management Practice ◽  
Structural Characteristics ◽  
Area Index ◽  
Rainy Period ◽  
Rest Periods ◽  
Nutrition Value ◽  
The Dead ◽  
In The Beginning ◽  
Leaf Appearance

The natural regrowth of Axonopus aureus in native pasture of Roraima´s savannas was evaluate, during early rainy period. The experimental design was a completely randomized, with four replications. The treatments consisted of four pasture rest periods (14, 28, 42 and 56 days after beginning of the rainy period). Evaluations were carry out during the period of June to August of 2016. The parameters measured were dry matter (DM) yields and grass morphogenetic and structural characteristics. The green and total DM, number of tillers plant-1, number of axillary tillers plant-1, number of live tillers plant-1, number of live leaves tiller-1 and leaf area index were directly proportional to rest periods. The leaf appearance and elongation rate were negatively affect by rest periods, while the dead DM was not affect by rest periods. Considering the low green DM availability of A. aureus, its recommends the utilization of some management practice, preferentially grazing or mowing, to remove the dead DM with low nutrition value and permit a grass vigorous regrowth in the beginning of the rainy period.

scholarly journals Productivity of Urochloa brizantha ‘Marandu’ influenced by strategic rest periods and nitrogen levels

2017 ◽  
Vol 38 (5) ◽  
pp. 3203 ◽  
Author(s):  
Luan Fernandes Rodrigues ◽  
Antônio Clementino dos Santos ◽  
Otacílio Silveira Junior ◽  
José Geraldo Donizetti dos Santos
Keyword(s):  
Linear Relationship ◽  
Dry Matter ◽  
Rest Period ◽  
Quadratic Model ◽  
Area Index ◽  
Nitrogen Levels ◽  
Rest Periods ◽  
Quadratic Relationship ◽  
Four Blocks ◽  
Urochloa Brizantha

The effects of two strategic rest periods and associated nitrogen levels on the agronomic and productive characteristics of Urochloa brizantha ‘Marandu’ were evaluated. The trial was conducted in a completely randomized 4 × 2 split-plot design, with four blocks. The treatments consisted of associations between two rest periods and four nitrogen levels. The rest periods included one at the end of 28 days (RP28days) and another when the canopy height was 40 cm (RP40cm) and nitrogen levels of 0, 150, 300, and 450 kg N ha-1 year-1 was applied as ammonium sulfate. The following variables were evaluated: rest period (RP) per cycle, total dry matter (TDM), dry matter (kg ha-1) and proportion (%) of leaf blade (LB), stem, and senescent material (SM), tiller mass, forage density, leaf area index, height, leaf:stem ratio, and crop growth rate (CGR). The variables height, TDM, LB dry matter, stem dry matter, CGR, and forage density exhibited a linear relationship with RP28days and a quadratic relationship with RP40cm with increasing N levels. The proportions of LB and stem had linear relationships with N levels for RP28days and RP40cm. The leaf:stem ratio was affected by increasing N levels and it fit the quadratic model for both rest strategies. The SM proportion had a quadratic relationship only with RP28days. The tiller mass had a linear relationship with RP28days, whereas SM dry matter showed a linear relationship for RP40cm. The use of the RP40cm reduced the period needed to begin a new grazing cycle. The level of 450 kg N ha-1 is recommended for RP28days and levels between 380 to 400 kg N ha-1 provided better results for RP40cm.

scholarly journals Effects of postgrazing residue on morphogenetic and structural characteristics of Tifton 85 pastures

2016 ◽  
Vol 37 (4) ◽  
pp. 2043
Author(s):  
Wilton Ladeira Silva ◽  
Ana Cláudia Ruggieri ◽  
Ricardo Andrade Reis ◽  
Américo Garcia Silva Sobrinho ◽  
Euclides Braga Malheiros
Keyword(s):  
Structural Characteristics ◽  
Stem Elongation ◽  
Light Interception ◽  
Climatic Conditions ◽  
Leaf Length ◽  
Elongation Rate ◽  
Area Index ◽  
Structural Variables ◽  
Senescence Rate ◽  
Leaf Appearance

The ideal time to start grazing is when pastures reach 95% light interception. The use of residual leaf area index (rLAI) to time the interruption of grazing under intermittent grazing has recently been studied in forage species in different climatic conditions in Brazil. However, studies evaluating the formation and development of leaves and tillers through morphogenetic and structural variables in functional rLAI are still lacking for Tifton 85 pastures. Therefore, the objective of this study was to evaluate the effects of varying rLAI in successive grazing cycles on morphogenetic and structural characteristics of Tifton 85 pasture grazed intermittently by sheep. Morphogenetic and structural characteristics were evaluated in three grazing cycles under three rLAI conditions (0.8, 1.6, and 2.4). The regrowth interval (time taken to return to 95% light interception) of pastures increased from 21.33 to 29.66 days with decreasing rLAI. The leaf appearance rate increased at a rate of 0.02 leaves tiller-1 day-1 and the number of live leaves per tiller increased by 0.41 with decreasing rLAI. Phyllochron, leaf elongation rate, final leaf length, leaf senescence rate, and stem elongation rate decreased linearly with decreasing rLAI. The number of live leaves per tiller was lower (7.97) in the third grazing cycle, probably owing to the higher senescence rate observed that same cycle, while the other variables had higher values. The 2.4 rLAI condition promotes excessive stem elongation, reduced leaf appearance, lower number of live leaves per tiller, and increased senescence of leaves, while the 0.8 and 1.6 rLAI conditions promote desirable morphogenetic and structural characteristics, which correlate directly with forage quality. In order to avoid excessive forage losses, grazing must occur preferentially by the end of March, when climatic conditions still support the appropriate development of the plants.

scholarly journals Forage yield and morphogenesis of Megathyrsus maximus cultivars in Roraimas’s savannas

2020 ◽  
Vol 9 (8) ◽  
pp. e652986054
Author(s):  
Newton de Lucena Costa ◽  
Liana Jank ◽  
João Avelar Magalhães ◽  
Amaury Burlamaqui Bendahan ◽  
Braz Henrique Nunes Rodrigues ◽  
...  
Keyword(s):  
Leaf Senescence ◽  
Dry Matter ◽  
Management Practices ◽  
Average Length ◽  
Structural Characteristics ◽  
Forage Yield ◽  
Leaf Appearance ◽  
Forage Yields ◽  
Specific Management

In order to evaluate the forage productivity and the morphogenic and structural characteristics of Megathyrsus maximus cultivars (Massai, Mombasa, Kenya, Tamani, Tanzania and Zuri), an experiment was conduct under natural environmental conditions in the savannahs of Roraima. The highest yields of green dry matter (GDM) were found with cultivars Zuri (4,317 kg ha-1) and Mombasa (4,115 kg ha-1), followed by Kenya (3,868 kg ha-1) and Tamani (3,755 kg ha-1), while Massai (3,341 kg ha-1) and Tanzania (3,225 kg ha-1) were the least productive. GDM yield was directly correlated with LAI and inversely proportional to tiller population density (TPD). The cultivars Tanzania and Kenya had the highest number of tiller leaves and leaf appearance rates, while the highest leaf expansion rates were estimate in cultivars Zuri and Kenya. The highest average length of tiller leaves was estimate in the cultivars Zuri and Mombasa. Leaf senescence rates were inversely proportional to TPD and the highest recorded with the cultivars Mombasa and Tamani. The six cultivars of M. maximus showed satisfactory forage yields and can be recommend for cultivation in the edaphoclimatic conditions of the of Roraima’s savannas. The determination of morphogenic and structural characteristics can contribute to the establishment of appropriate and specific management practices for each cultivar, aiming to optimize its productivity and reduce losses due to leaf senescence.

scholarly journals Effect of number of seedlings per hill, rate and time of nitrogen application on the growth and yield of late transplant Aman rice

2017 ◽  
Vol 28 (3) ◽  
pp. 174-183
Author(s):  
NAMY Ali ◽  
MAR Sarkar ◽  
SK Sarkar ◽  
SK Paul
Keyword(s):  
Field Experiment ◽  
Plant Height ◽  
Interaction Effect ◽  
Dry Matter ◽  
Growth Parameters ◽  
Management Practice ◽  
Growth And Yield ◽  
Nitrogen Application ◽  
Area Index ◽  
Nitrogen Rates

A field experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh to examine the influence of number seedlings hill-1, rate and time of nitrogen application on the growth parameters of late transplant Aman rice (cv. BR23). The study, laid out in a RCBD with three replications, was comprised of three levels of number of seedlings hill-1 viz. 2, 4 and 6 seedlings hill-1, three nitrogen rates viz. 0, 60 and 120 kg N ha-1 and three levels of time of nitrogen application viz. nitrogen application in two equal splits at 15 DAT and early tillering stage (ET); nitrogen application in three equal splits at 15 DAT, ET and panicle initiation stages (PI); and nitrogen application in four equal splits at 15 DAT, ET, PI and flowering stages (F). The highest plant height (101.04 cm) was found at 80 DAT from 6 seedlings hill-1. 120 kg N ha-1 nitrogen application produced the tallest (104.08 cm) plant and nitrogen application in two equal splits at 15 DAT and ET gave the highest plant height (99.44 cm) at 80 DAT. The maximum number of tillers hill-1 (19.45) at 60 DAT and the highest leaf area index (3.08) at 40 DAT were found in the interaction effect among 6 seedlings hill-1, 120 kg N ha-1 and three times of nitrogen application at 15 DAT, early tillering and panicle initiation stages. The highest shoot dry matter hill-1 (28 g) was obtained as the interaction effect among  6 seedlings hill-1, 120 kg N ha-1 and nitrogen application in four equal splits at 15 DAT, early tillering, panicle initiation and flowering stages. The grain yield, although statistically non-significant, was numerically highest in seedlings hill-1, 120 kg N ha-1 and nitrogen application in three equal splits at 15 DAT, early tillering and panicle initiation stages. Therefore, transplanting with 6 seedlings hill-1 and application of 120 kg N ha-1 in 3-4 equal splits could be a better management practice for ensuring proper growth of the late transplant Aman rice.Progressive Agriculture 28 (3): 174-183, 2017

scholarly journals Forage yield, chemical composition and morphogenesis of Brachiaria brizantha cv. Piatã under regrowth periods

2020 ◽  
Vol 9 (1) ◽  
pp. e133911801
Author(s):  
Newton de Lucena Costa ◽  
Antônio Neri Azevedo Rodrigues ◽  
João Avelar Magalhães ◽  
Amaury Burlamaqui Bendahan ◽  
Braz Henrique Nunes Rodrigues ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Leaf Blade ◽  
Dry Matter ◽  
Structural Characteristics ◽  
Forage Yield ◽  
Brachiaria Brizantha ◽  
Leaf Lifespan ◽  
Blade Length ◽  
Leaf Appearance ◽  
Nitrogen Phosphorus

With the objective to evaluate the effects of regrowth period (14, 21, 28, 35 and 42 days) on green dry matter yield (GDMY), chemical composition and morphogenetic and structural characteristics of Brachiaria brizantha cv. Piatã, was carried out an experiment under greenhouse with natural conditions of light and temperature. GDMY yields and regrowth, leaf blade length, and leaf lifespan rate increased consistently (P<.05) with regrowth period, however the nitrogen, phosphorus, magnesium and potassium contents decreased as regrowth period, while calcium contents were not affected by regrowth period. Maximum GDMY, leaf appearance and elongation rate, and leaf blade length were obtained with regrowth periods at 38.2; 41.1; 31.3 and 38.9 days, respectively. These data suggest that cutting at 35 to 42 regrowth days were optimal for obtain maximum yields and regrowth of rich forage and pasture persistence.

scholarly journals MORPHOLOGICAL CHARACTERISTICS AND FORAGE PRODUCTIVITY OF IRRIGATED CACTUS PEAR UNDER DIFFERENT CUTTING INTENSITIES

2016 ◽  
Vol 29 (2) ◽  
pp. 481-488 ◽  
Author(s):  
GUILHERME FERREIRA DA COSTA LIMA ◽  
MARGARETH MARIA TELES REGO ◽  
FERNANDA DANIELE GONÇALVES DANTAS ◽  
RAIMUNDO NONATO BRAGA LÔBO ◽  
JOSÉ GERALDO MEDEIROS DA SILVA ◽  
...  
Keyword(s):  
Plant Height ◽  
Irrigation Water ◽  
Significant Interaction ◽  
Dry Matter ◽  
Management Practice ◽  
Morphological Characteristics ◽  
Planting Density ◽  
Cactus Pear ◽  
Area Index ◽  
Length Width

ABSTRACT: This study evaluated the effect of different cutting intensities and years of harvesting on the morphological characteristics and production of fresh (FMP) and dry matter (DMP) of cactus pear cv. Gigante (Opuntia ficus-indica Mill) under conditions of irrigation, high planting density and fertilization, with 12 months of regrowth. The experimental was completely randomized in a factorial design (3 × 2) with 12 replicates. The treatments were three cutting intensities (preserving the mother cladode (PMC), primary cladodes (PPC), or secondary cladodes (PSC)), and two years of harvesting. The soil was classified as Cambisol Haplicum and the irrigation water was classified as C4S1 (EC 5.25 dS.m-1) density of 50,000 plants ha-1. The research evaluated plant height, number of cladodes per plant (NCP), length, width, perimeter and thickness of the cladodes, cladode area (CA), cladode area index (CAI), FMP and DMP. There was no significant interaction between treatments (P > 0.05) for the variables plant height, NCP, CAI and FMP. The variables related to cladode morphology showed a significant interaction (P < 0.05). The treatment PSC resulted in a greater DMP (P < 0.05) with a mean of 27.17 Mg ha-1 yr-1, compared to PPC (18.58 Mg ha-1 yr-1) or PMC (11.78 Mg ha-1 yr-1). The treatment PSC promoted greater NCP and forage productivity at harvest and can be considered as a management practice for the sustainability of cactus pear cv. Gigante under irrigation. The more important morphological characteristics were also influenced by the lower cutting intensities.

scholarly journals Integrating Straw Management and Seeding to Improve Seed Yield and Reduce Environmental Impacts in Soybean Production

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1033
Author(s):  
Cailong Xu ◽  
Ruidong Li ◽  
Wenwen Song ◽  
Tingting Wu ◽  
Shi Sun ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Dry Matter ◽  
Management Practice ◽  
Cropping Systems ◽  
Dry Matter Accumulation ◽  
Multiple Cropping ◽  
Area Index

Multiple cropping systems boost grain yields and have an immense potential to increase land productivity. In such cropping systems in China, soybean is directly seeded after the wheat harvest in early June. After the wheat harvest, the farmland has low amounts of soil moisture and contains large amounts of wheat straw, which negatively affect soybean growth and yields. To address these challenges, an integrated management practice (IMP) than can achieve precise direct seeding and straw mulching return, was developed. In this study, differences in the soil temperature and moisture, seedling quality, dry matter accumulation, soybean yield, and greenhouse gas emissions were investigated between IMP and the farmers’ practices (FP). Compared with the FP treatment, IMP significantly increased the soil moisture and decreased the soil temperature in the topsoil layer. In addition, under the IMP treatment, the rate of emergence and developmental uniformity of soybean plants significantly increased by 21.7% and 99.5%, respectively, thus increasing the leaf area index by 30.0% and dry matter accumulation by 12.0% and, in turn, increasing soybean yields by 24.7%. A principal component analysis showed that the dry matter weight, relative water content, leaf area index, and developmental uniformity were strong sensitivity indices for the IMP treatment. In addition, the intensity of emission of N2O and greenhouse gases under IMP both decreased significantly by 25.1% and 28.9% compared with the FP, respectively. Thus, it was concluded that IMP is a suitable farming practice for sustainable agricultural production, and it has broad prospects for application in wheat–soybean double cropping systems in China and other similar areas globally.

scholarly journals Fixed versus variable rest period effects on herbage accumulation and canopy structure of grazed 'Tifton 85' and 'Jiggs' Bermuda grass

2018 ◽  
Vol 53 (1) ◽  
pp. 113-120 ◽  
Author(s):  
Carlos Guilherme Silveira Pedreira ◽  
Valdson José da Silva ◽  
Murilo Saraiva Guimarães ◽  
Diego Noleto Luz Pequeno ◽  
Felipe Tonato
Keyword(s):  
Structural Characteristics ◽  
Total Yield ◽  
Canopy Structure ◽  
Rest Period ◽  
Canopy Height ◽  
Bermuda Grass ◽  
Production Plant ◽  
Forage Production ◽  
Area Index ◽  
Rest Periods

Abstract: The objective of this work was to evaluate the effects of variable and fixed rest periods on the forage production, plant-part composition, and canopy structural characteristics of 'Tifton 85' and 'Jiggs' Bermuda grass (Cynodon spp.) pastures under rotational stocking. The treatments were two grass cultivars (Jiggs and Tifton 85) and two rest periods (grazing starting whenever the canopy reached 25 cm or every 28 days, regardless of canopy height). A completely randomized experimental design, with a 2×2 factorial arrangement (two grass cultivars and two managements), was used with three replicates. The experiment was carried out during the summer growing season in Piracicaba, SP, Brazil. Pre- and post-grazing forage mass chacteristics were evaluated. 'Jiggs' and 'Tifton 85' canopies had similar light interception (96.8%) at pre-grazing, for fixed and variable rest periods; however, they showed different canopy structural characteristics. 'Jiggs' had greater stem proportion, greater canopy height during pre-grazing, and lower leaf area index. There were no differences between strategies and between grass cultivars for total yield, which averaged 16.8 Mg DM ha-1. Fixed and variable rest periods can be used for 'Tifton 85' and 'Jiggs' Bermuda grass.

scholarly journals MORPHOGENETIC AND STRUCTURAL CHARACTERISTICS OF ALEXANDERGRASS PASTURES UNDER CONTINUOUS STOCKING

2018 ◽  
Vol 19 (0) ◽  
Author(s):  
Francisco Migliorini ◽  
André Brugnara Soares ◽  
Daniel Schmitt ◽  
Laíse da Silveira Pontes ◽  
Tangriani Simioni Assmann
Keyword(s):  
Accumulation Rate ◽  
Structural Characteristics ◽  
Block Design ◽  
Forage Production ◽  
Area Index ◽  
Randomized Block Design ◽  
Number Of Leaves ◽  
Student’S T ◽  
Experimental Treatments ◽  
Leaf Appearance

Abstract The aim of this study was to evaluate some morphogenetic and structural characteristics to explain variations in forage accumulation of Alexandergrass (Urochloa (Syn. Brachiaria) plantaginea) under continuous stocking method. The experimental treatments consisted of four grazing heights (10, 20, 30, and 40 cm), allocated to experimental units following a randomized block design with three replicates. The following variables were analyzed: leaf appearance, elongation, and senescence rates, leaf lamina length, number of leaves per tiller, leaf area index (LAI), and forage accumulation rate. Data were submitted to analysis of variance and means were compared by Student's t-test (P≤0.05). The main results were: i) different grazing heights had different tissue flows; ii) grazing heights between 30-40 cm showed the highest LAI, and produced similar values; iii) forage accumulation rate increased according to grazing height increments, but did not change above 30 cm. In conclusion, Alexandergrass pastures under continuous stocking should not be maintained at grazing heights lower than 30 cm if the objective is to maximize forage production.

scholarly journals The Tissue Flow in Brachiaria brizantha Pasture Under Intermittent Stocking

2020 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Caio Vinicio Vargas de Oliveira ◽  
Rodrigo Amorim Barbosa ◽  
Raísa Turcato de Oliveira ◽  
Emizael Menezes de Almeida ◽  
Francielly Paludo ◽  
...  
Keyword(s):  
Phenotypic Plasticity ◽  
Structural Characteristics ◽  
Abiotic Factors ◽  
Structural Variations ◽  
Brachiaria Brizantha ◽  
Area Index ◽  
Appearance Rate ◽  
Leaf Elongation Rate ◽  
Leaf Appearance Rate ◽  
Leaf Appearance

The present work aims to evaluate the morphological and structural characteristics of Brachiaria brizantha cultivars in the system of grazing in the intermittent stocking. The experiment was conducted at EMBRAPA - Beef Cattle. The experimental delineation used was a randomized block with three treatments and three repetitions. The treatments were constituted by grasses of the same species (Brachiaria brizantha) composed by cv. Xaraés, BRS Paiaguás, and the ecotype B4. On the heights of post-grazing, it was observed an interaction between seasons of the year and cultivars. It was observed that the leaf appearance rate (LAR) was higher in the cv. BRS Paiaguás, in relation to the other pastures. The leaf elongation rate (LER) was higher in perforations of the ecotype B4. In the winter, it was registered the lowest values of leaf area index (LAI), LAR, and LER, and, as a consequence, impact in a higher leaf life duration. Although there were some structural variations between tropical climate pastures, it was possible to verify that the phenotypic plasticity of these pastures presented the same behavior, once it suffered a higher influence of abiotic factors. Therefore, all the pastures of B. brizantha converged to the same LAI indicating high phenotypic plasticity.

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