scholarly journals Studies on the Seedling Emergence in Crops : Effects of soil moisture content, cultural temperature and seed size on the strength of plumule-elongation in naked barley plants

1970 ◽  
Vol 39 (1) ◽  
pp. 41-46
Author(s):  
Jun INOUYE ◽  
Hidefumi SEKO ◽  
Kenji ITO
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Seed Size ◽  
Soil Moisture Content ◽  
Seedling Emergence ◽  
Naked Barley

The influence of seed pre-treatments and soil conditions on the emergence of sesame seedlings

2000 ◽  
Vol 40 (6) ◽  
pp. 843 ◽  
Author(s):  
J. S. Day
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Gibberellic Acid ◽  
Soil Moisture Content ◽  
Seedling Emergence ◽  
Sesamum Indicum ◽  
Soil Conditions ◽  
Sesame Seeds ◽  
Pre Treatment ◽  
Gibberellic Acid Treatment

Poor and uneven emergence of seedlings decreases the efficiency of sesame (Sesamum indicum) seed production. In a glasshouse study, seedling emergence was reduced by low soil moisture content (less than 20%, w/v) and by waterlogging (common in soils with small soil particles). Watering events that failed to raise soil moisture content above 20% caused most seeds to germinate (more than than 80%), but only some of these seeds emerged from the soil (less than 50%). Gibberellic acid pre-treatment of seeds (50 or 1000 mg/L) failed to improve emergence of seeds from soils with an initial soil moisture content less than 20%. This result supports previous reports suggesting that gibberellic acid treatment does not influence seedling emergence, and may only be useful to overcome seed dormancy in those sesame varieties where dormancy is a problem. For maximum emergence it is recommended that sesame seeds be sown in non-waterlogged soils and that soil moisture content be maintained above 20% for a number of days after sowing.

Effects of fluid drilling germinating onion seeds on seedling emergence and subsequent plant growth

1984 ◽  
Vol 102 (2) ◽  
pp. 461-468 ◽  
Author(s):  
W. E. Finch-Savage
Keyword(s):  
Soil Moisture ◽  
Plant Growth ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Seedling Emergence ◽  
Emergence Time ◽  
Sowing Dates ◽  
Germinating Seeds ◽  
Germinated Seeds ◽  
Fluid Drilling

SummaryThe seedling emergence from fluid-drilled germinating and natural onion seeds was compared at five sowing dates between 10 February and 18 May on irrigated and unirrigated plots in two experiments. In the second experiment fluid-drilled seeds selected for uniform germination were also included. There were few significant differences between the emergence of seedlings from germinating and natural seeds in the field sowings of Expt 1. However, a reduction in mean emergence time at the earliest sowing led to an increase in bulb weight while a reduction in the spread of emergence at sowing 3 led to a reduced coefficient of variation of bulb diameter at harvest. Under the less variable conditions on the irrigated plots of Expt 2 germinating seeds reduced mean emergence time and increased percentage emergence compared with natural seed at some sowings. Fluid-drilled selected germinated seeds, however, reduced mean emergence time and increased percentage emergence at every sowing and reduced the spread of emergence at all but the first sowing compared with natural seed.Low soil moisture content made seedling emergence more unpredictable and reduced the benefits gained by sowing germinated seeds. The results presented suggest that techniques to increase the proportion of germinated seeds at the point of sowing and economical methods of applying water during periods of low soil moisture following sowing are needed if the full benefits of fluid drilling are to be realized.

The influence of sowing depth and seed press wheel weighting on seedling emergence of crisp lettuce

1985 ◽  
Vol 104 (3) ◽  
pp. 631-636 ◽  
Author(s):  
D. C. E. Wurr ◽  
Jane R. Fellows
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Seedling Emergence ◽  
Field Capacity ◽  
Considerable Effect ◽  
Wide Spread ◽  
Sowing Depth ◽  
Variable Weight ◽  
Different Depths

SummaryThe effects on emergence and growth of crisp lettuce seedlings as a result of sowing seeds at different depths and pressing them into the furrow bottom with a weighted seed press wheel were examined in three similar experiments in 1982, 1983 and 1984. Sowing depth had a considerable effect on percentage seedling emergence and the spread of emergence times but the pattern of response varied from year to year and appeared to be related to differences in soil moisture content. The most uniform emergence and the highest level of emergence were achieved by sowing shallowly (< 10 mm) with rainfall almost immediately after sowing then keeping the soil moisture content close to field capacity for 2 days. When rainfall or irrigation were delayed, drilling 15–20 mm deep gave more consistent results. Effects on seedling weight and variability of weight were associated with the time and uniformity of seedling emergence. Later emerging seedlings were lighter and a wide spread of emergence times gave seedlings of variable weight. There was virtually no effect on emergence of using additional weights on a seed press wheel.

scholarly journals Forest canopy gaps offer a window into the future The case of subtropical coastal forests within an urban matrix in South Africa

2021 ◽  
Vol 30 (1) ◽  
pp. e003
Author(s):  
Astika Bhugeloo ◽  
Syd Ramdhani ◽  
Kabir Peerbhay ◽  
Olivier Kambol Kambaj ◽  
Sershen
Keyword(s):  
South Africa ◽  
Species Richness ◽  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Seedling Emergence ◽  
Canopy Gaps ◽  
Coastal Forests ◽  
Disturbed Forest ◽  
Primary Forests

Aim of the study: Alien and indigenous species emergence patterns within canopy gaps in urban subtropical forests are poorly understood. This study compared canopy gap floristics in relation to abiotic and physical characteristics across three subtropical urban forests differing in disturbance history.Area of study: Three Northern Coastal Forests of varying disturbance histories found in coastal subtropical urban KwaZulu-Natal (KZN), South Africa (SA).Materials and methods: Closed canopy ( n = 15 quadrats per forest ) and four gaps from three size classes (‘small’ < 25 m2, ‘medium’ 25 - 45 m2; ‘large’ > 45 m2) were surveyed for each forest using classical vegetation sampling techniques. Soil moisture content and air temperature were measured within each gap.Main results: Cumulatively all forests hosted 198 species. Species richness was highest in the primary highly disturbed forest followed by the primary least disturbed forest and lowest in the transitional highly disturbed forest. Alien taxa cover within gaps was correlated with higher indigenous seedling emergence in the primary forests. Species richness was positively correlated with gap size and soil moisture content, and negatively correlated with air temperature.Research highlights: Gap floristic patterns are influenced by size, abiotic factors, disturbance and forest successional status. Alien taxa may facilitate indigenous seedling emergence within gaps in primary forests. Floristic, abiotic and physical characteristics of canopy gaps should be monitored within urban forests as they can influence gap infilling regarding species composition and rate. This can inform management strategies including species reintroduction and enrichment planting.

Analysis on Soil Moisture Content in the Middle Reaches of the Yellow River

2011 ◽  
Vol 28 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Run-chun LI ◽  
Xiu-zhi ZHANG ◽  
Li-hua WANG ◽  
Xin-yan LV ◽  
Yuan GAO
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Yellow River ◽  
The Yellow River

Distribution of soil moisture content and its effect on the potential growth of the over-story species in North-East Chalkidiki

2001 ◽  
Vol 66 ◽  
Author(s):  
M. Aslanidou ◽  
P. Smiris
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Soil Depth ◽  
Moisture Distribution ◽  
Taxus Baccata ◽  
Mixed Stands ◽  
Potential Growth ◽  
North East ◽  
Soil Moisture Distribution

This  study deals with the soil moisture distribution and its effect on the  potential growth and    adaptation of the over-story species in north-east Chalkidiki. These  species are: Quercus    dalechampii Ten, Quercus  conferta Kit, Quercus  pubescens Willd, Castanea  sativa Mill, Fagus    moesiaca Maly-Domin and also Taxus baccata L. in mixed stands  with Fagus moesiaca.    Samples of soil, 1-2 kg per 20cm depth, were taken and the moisture content  of each sample    was measured in order to determine soil moisture distribution and its  contribution to the growth    of the forest species. The most important results are: i) available water  is influenced by the soil    depth. During the summer, at a soil depth of 10 cm a significant  restriction was observed. ii) the    large duration of the dry period in the deep soil layers has less adverse  effect on stands growth than in the case of the soil surface layers, due to the fact that the root system mainly spreads out    at a soil depth of 40 cm iii) in the beginning of the growing season, the  soil moisture content is    greater than 30 % at a soil depth of 60 cm, in beech and mixed beech-yew  stands, is 10-15 % in    the Q. pubescens  stands and it's more than 30 % at a soil depth of 60 cm in Q. dalechampii    stands.

scholarly journals Mapping barrier island soil moisture using a radiative transfer model of hyperspectral imagery from an unmanned aerial system

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rehman S. Eon ◽  
Charles M. Bachmann
Keyword(s):  
Soil Moisture ◽  
Radiative Transfer ◽  
Moisture Content ◽  
Layer Thickness ◽  
Soil Moisture Content ◽  
Hyperspectral Imagery ◽  
Barrier Island ◽  
Water Layer ◽  
Radiative Transfer Model ◽  
Transfer Model

AbstractThe advent of remote sensing from unmanned aerial systems (UAS) has opened the door to more affordable and effective methods of imaging and mapping of surface geophysical properties with many important applications in areas such as coastal zone management, ecology, agriculture, and defense. We describe a study to validate and improve soil moisture content retrieval and mapping from hyperspectral imagery collected by a UAS system. Our approach uses a recently developed model known as the multilayer radiative transfer model of soil reflectance (MARMIT). MARMIT partitions contributions due to water and the sediment surface into equivalent but separate layers and describes these layers using an equivalent slab model formalism. The model water layer thickness along with the fraction of wet surface become parameters that must be optimized in a calibration step, with extinction due to water absorption being applied in the model based on equivalent water layer thickness, while transmission and reflection coefficients follow the Fresnel formalism. In this work, we evaluate the model in both field settings, using UAS hyperspectral imagery, and laboratory settings, using hyperspectral spectra obtained with a goniometer. Sediment samples obtained from four different field sites representing disparate environmental settings comprised the laboratory analysis while field validation used hyperspectral UAS imagery and coordinated ground truth obtained on a barrier island shore during field campaigns in 2018 and 2019. Analysis of the most significant wavelengths for retrieval indicate a number of different wavelengths in the short-wave infra-red (SWIR) that provide accurate fits to measured soil moisture content in the laboratory with normalized root mean square error (NRMSE)< 0.145, while independent evaluation from sequestered test data from the hyperspectral UAS imagery obtained during the field campaign obtained an average NRMSE = 0.169 and median NRMSE = 0.152 in a bootstrap analysis.

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