scholarly journals Evaluation of the growth and quality of lettuce (Lactuca sativa L.) in a closed recirculating hydroponic system

2017 ◽  
Vol 35 (2) ◽  
pp. 216-222 ◽  
Author(s):  
Rafael David Fraile-Robayo ◽  
Javier Giovanni Álvarez-Herrera ◽  
Andrea Johana Reyes M. ◽  
Omar Ferney Álvarez-Herrera ◽  
Ana Lucía Fraile-Robayo
Keyword(s):  
Growth Rate ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Calcium Nitrate ◽  
Potassium Nitrate ◽  
Area Index ◽  
Hydroponic System ◽  
Physiological Variables ◽  
Over Time

The production of lettuce in hydroponic systems with a recirculating nutrient solution has been growing, so it is necessary to evaluate the growth and quality of production under this system. Two harvest cycles were evaluated, comparing the behavior of physiological variables and growth rates on lettuce plants in a hydroponic system with a plastic cover. Lettuce plants were planted at 30 days after germination in an NFT hydroponic system. Nutrient solutions were prepared with sources of potassium nitrate, calcium nitrate, urea phosphate, magnesium sulfate and a source of minor nutrifeed. The second cycle had the highest total dry mass and leaf area index (LAI) at 43 days after transplant (dat). The relative growth rate (RGR) declined over time. The absolute growth rate (AGR) presented a sigmoid behavior as a gaussian bell shape; the leaf area index (LAI) increased until 43 dat, with the second cycle presenting the highest value; the net assimilation rate (NAR) decreased over time, with the second cycle having the highest value at 22 dat. The chlorophyll content for this variety was low, with a yellow pigmentation in the plant. The stomatal conductance (SC) in the two cycles at transplant time presented low values caused by the stress leaded by an imbalance in the pH of the solution, when the plants adapted to the system, this value increased.

scholarly journals Growth and yield of wheat at different dates of sowing under chrland ecosystem of Bangladesh

2017 ◽  
Vol 14 (2) ◽  
pp. 147-154 ◽  
Author(s):  
MM Kamrozzaman ◽  
MAH Khan ◽  
S Ahmed ◽  
N Sultana
Keyword(s):  
Growth Rate ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Dry Matter ◽  
Block Design ◽  
Grain Filling ◽  
Crop Growth ◽  
Growth And Yield ◽  
Area Index ◽  
Crop Growth Rate

An experiment was conducted at Sadipur charland under Farming System Research and Development Site, Hatgobindapur, Faridpur, during rabi season of 2012-13 and 2013-14 to study the growth and yield performance of cv. BARI Gom-24 as affected by different dates of sowing under Agro-ecological Zone-12 (AEZ-12) of Bangladesh. The experiment was laid out in randomized complete block design with six replications, comprising five different dates of sowing viz. November 5, November 15, November 25, December 5 and December 15. Results reveal that the tallest plant, leaf area index, total dry matter, and crop growth rate were observed in November 25 sown crop and leaf area index, total dry matter and crop growth rate were higher at booting, grain filling, and tillering stages of the crop. Maximum effective tillers hill-1 (3.49), spikes m-2, (311), number of grains spike-1 (42.20) and 1000-grain weight (52.10 g) were produced by November 25 sown crop exhibited the highest grain (4.30 t ha-1) and straw yield (4.94 t ha-1) as well as harvest index (46.88%) of the crop. Lowest performance was observed both in early (November 5) and late sown crop (December 15). The overall results indicated that November 25 sown crop showed better performance in respect of growth and yield of wheat under charland ecosystem of Bangladesh.J. Bangladesh Agril. Univ. 14(2): 147-154, December 2016

The effect of planting date and nitrogen management on yield and quality of aromatic rice (Oryza sativa)

2004 ◽  
Vol 142 (2) ◽  
pp. 183-191 ◽  
Author(s):  
M. GHOSH ◽  
B. K. MANDAL ◽  
B. B. MANDAL ◽  
S. B. LODH ◽  
A. K. DASH
Keyword(s):  
Oryza Sativa ◽  
Grain Yield ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Amylose Content ◽  
Aromatic Rice ◽  
Area Index ◽  
Growth Environment ◽  
Yield And Quality

Growth environment and plant nutrition are two important factors influencing growth, yield and quality of aromatic rice (Oryza sativa L.). The present study was conducted at Kalyani, India to determine the effect of two planting dates and four fertilizer levels on different aromatic rice cultivars during the dry seasons of 1995/96 and 1996/97, while nine cultivars were evaluated during the wet seasons of 1996 and 1997. Thermal and photoperiodic conditions significantly influenced the vegetative (leaf area index and light extinction co-efficient) and reproductive (filled spikelets/panicle) growth of the crop. Delayed planting (23 February) significantly reduced the grain yield by 0·88 t/ha, amylose content by 0·5% and duration by 10 days; but increased the summed heliothermal units (17806 v. 18505). Thus, the cultivars became less efficient (27%) in heat use with delay in planting from 2 to 23 February. Relative availability of NH4+-N from urea and Azolla influenced the crop growth (leaf area index [LAI], tiller production and leaf chlorophyll content) and nutrient uptake. Supply of inorganic N either alone or in conjunction with Azolla significantly increased grain yield (18–41%) and protein content (0·1–0·7%) over 15 t/ha of Azolla alone. However, combined application of Azolla and urea lowered the amylose content below that achieved by application of either substance alone. Correlation studies among quality attributes indicated that long-grained varieties had lower head rice recovery (r=−0·69) due to more breakage during milling and greater test weight (r=0·93).

scholarly journals Effect Of Planting Geometry On Growth Of Rice Varieties

2017 ◽  
Vol 5 (4) ◽  
pp. 423-429 ◽  
Author(s):  
Mohan Mahato ◽  
Bishnu Bilas Adhikari
Keyword(s):  
Growth Rate ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Plant Height ◽  
Dry Matter ◽  
Dry Matter Accumulation ◽  
Rice Varieties ◽  
Area Index ◽  
Crop Growth Rate ◽  
Planting Geometry

A field experiment was conducted under humid subtropical agro-climatic condition of Nepal during rainy season of 2014. The experiment was laid out in to two factor Randomized Complete Block Design with  three replications consisting three drought tolerant rice varieties (Sukhadhan-4, Sukhadhan-5 and Radha-4) and four planting geometry (15 cm × 10 cm, 15 cm × 15 cm, 20 cm × 15 cm and 20 cm × 20 cm). The results revealed that the highest plant height and maximum leaf area index was recorded in planting geometry 15 cm × 10 cm in all growth stages. Whereas, planting geometry 20 cm × 15 cm produced the maximum number of tiller m-2 in all growth stage.  While planting geometry 20 cm × 15 cm and 20 cm × 20 cm produced statistically similar crop growth rate and dry matter accumulation in all stage of growth. Regarding the varieties, Sukhadhan- 4 showed highest plant height up to 75 DAT and plant height was statistically similar to Radha - 4 in 60 and 75 DAT. But maximum number of tiller m-2, leaf area index, crop growth rate and dry matter accumulation were recorded in Sukhadhan – 5 varieties. Int. J. Appl. Sci. Biotechnol. Vol 5(4): 423-429

The influence of leaf area and radiation on the growth of clover in swards

1962 ◽  
Vol 13 (4) ◽  
pp. 615 ◽  
Author(s):  
WR Stern ◽  
CM Donald
Keyword(s):  
Growth Rate ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Crop Growth ◽  
Light Regime ◽  
Agricultural Practice ◽  
Area Index ◽  
Crop Growth Rate

A study was made of the light regime and the growth of clover: (a) in mixed swards with varying proportions of grass; (b) in specially designed cultures in which grass and clover competed for light alone. The growth of the clover showed direct dependence on the level of radiation at the surface of the clover leaf canopy; it was positive when radiation values were above about 60–80 cal/cm²/day but fell to zero or negative rates at lower radiation levels. A relationship is presented between the level of radiation, the leaf area index, and the crop growth rate. It is shown that the optimum leaf area index increases with increasing levels of radiation; and further that as the leaf area index increases, the level of radiation required for maximum growth rate also rises. The implications in agricultural practice are discussed briefly.

The quality of short-wave radiation within plant canopies

1969 ◽  
Vol 47 (12) ◽  
pp. 1989-1994 ◽  
Author(s):  
T. B. Daynard
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Plant Communities ◽  
Short Wave ◽  
Wave Radiation ◽  
Leaf Angle ◽  
Visible Radiation ◽  
Area Index ◽  
Plant Canopies

In this paper, a mathematical attempt is made to predict the effects of leaf area index, leaf angle, and leaf spectral properties on changes in the relative composition of short-wave radiant fluxes as they penetrate plant canopies. Results of this theoretical analysis indicate that a sizeable change in the quality of visible radiation will only occur if the canopy is sufficiently dense to intercept at least 98% of the incident flux one or more times. By contrast, a significant increase in the proportion of infrared radiation is predicted within plant communities, even those of a low effective leaf area index. For natural plant communities, the results would indicate a minimal change in the composition of penetrating radiation at solar noon and a maximal change at sunrise or sunset.The implications of these phenomena to plant morphogenesis and to radiation-measuring techniques are discussed.

scholarly journals Pasture damage and regrowth from cattle treading

2000 ◽  
pp. 155-160 ◽  
Author(s):  
T.N. Pande ◽  
I. Valentine ◽  
K. Betteridge ◽  
A. Mackay ◽  
D. Horne
Keyword(s):  
Growth Rate ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Canopy Cover ◽  
Control Treatment ◽  
Research Station ◽  
Area Index ◽  
Hill Country ◽  
Grazed Pasture ◽  
Tiller Density

Two experiments were conducted to describe the damage and regrowth of pasture after a single, severe cattle treading event during winter. One experiment was conducted on hill country at AgResearch's Ballantrae Hill Country Research Station, and the other on the No. 4 Dairy Unit at Massey University. Herbage growth rate, canopy cover, tiller density and leaf area index were studied and compared in grazed, cattle-trodden and untrodden (control) pastures. At Ballantrae, the control treatment was sheep-grazed pasture, and at Massey University, it was cattle-grazed, but untrodden pasture under the electric fence. A single cattle treading event on winter-wet soils reduced hill pasture growth rates in spring to 11 kg DM/ha/day compared to 18 kg DM/ha/day in undamaged pasture on slopes, and to 21 kg DM/ ha/day compared to 39 kg DM/ha/day on tracks. Spring dairy pasture growth rate to 7 weeks after treading was 33 kg DM/ha/day compared to 51 kg DM/ha/day in undamaged pasture. Damage reduced canopy cover to 60% on hill pasture tracks and to 43% in dairy pasture, compared to covers of 95% and 90% in undamaged pastures, respectively. It was concluded that the low spring herbage growth rate following a single, severe winter treading of pasture on wet soil was due mainly to significantly reduced tiller numbers, and a decrease in leaf area index and canopy cover. Treading had no significant effect on the size of individual tillers. Keywords: cattle treading, hill country, pasture, pugging

Derivation of Leaf-Area Index from Quality of Light on the Forest Floor

Ecology ◽  
1969 ◽  
Vol 50 (4) ◽  
pp. 663-666 ◽  
Author(s):  
Carl F. Jordan
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Forest Floor ◽  
Area Index
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