scholarly journals Integrating Rowcovers and Soil Amendments for Organic Cucumber Production: Implications on Crop Growth, Yield, and Microclimate

HortScience ◽  
2010 ◽  
Vol 45 (4) ◽  
pp. 566-574 ◽  
Author(s):  
Ajay Nair ◽  
Mathieu Ngouajio
Keyword(s):  
Plant Growth ◽  
Soil Temperature ◽  
Light Transmission ◽  
Ambient Air ◽  
Crop Growth ◽  
Organic Production ◽  
Growth Characteristics ◽  
Temperate Climate ◽  
The Impact ◽  
Plant Growth Characteristics

The area of organic production has registered a steady increase over past recent years. Transitioning to organic production is not straightforward and often includes a steep learning curve. Organic growers have to develop strategies to best manage nutrients, pests, and crop growth and yield. Additionally, in regions with temperate climate like the Great Lakes region, weather (especially temperature and solar radiation) plays an important role in crop productivity. Growers routinely use compost for nutrient provisioning and rowcovers for insect exclusion and growth enhancement. The objective of this work was to study the combined effect of rowcovers (with different light transmission) and compost organic cucumber (Cucumis sativus L.) growth and microclimate. Plots were assigned to three rowcover treatments (60% light transmission, 85% light transmission, and uncovered) and two amendment treatments (compost and no compost) in a split-plot factorial design. Data were collected for ambient air and soil temperature, photosynthetically active radiation (PAR), relative humidity, plant growth characteristics, and yield. Rowcovers modified crop microclimate by increasing air and soil temperature and decreasing PAR. There was a marked increase in the growing degree-day accumulations under rowcovers when compared with uncovered treatment. The impact of rowcovers on plant growth was significant. Use of rowcovers increased vine length, flower count, leaf area, leaf count, plant biomass, and total marketable yield. Use of compost in conjunction with rowcovers enhanced the rowcover effect. With the use of compost, there were not many significant differences in plant growth characteristics between rowcover materials; however, as expected, rowcover with 60% transmission was able to trap more heat and reduce light transmission when compared with rowcover with 85% transmission. This study clearly shows the importance of organic amendments, especially compost, in organic vegetable production. Applications of compost enhanced crop growth and also led to higher marketable yields. Results of this study suggest additive effects of rowcover and compost application on organic cucumber production.

The impact of increased temperatures on germination patterns of semi-aquatic plants

2019 ◽  
Vol 29 (3) ◽  
pp. 204-209
Author(s):  
Jade Dessent ◽  
Susan Lawler ◽  
Daryl Nielsen
Keyword(s):  
Soil Temperature ◽  
Air Temperature ◽  
Soil Seed Bank ◽  
Ambient Air ◽  
Future Climate Change ◽  
Ambient Air Temperature ◽  
Threshold Temperatures ◽  
Soil Temperatures ◽  
The Impact ◽  
Number Of Seeds

AbstractFuture climate change predictions indicate that there will be an increase in ambient air temperature. Increases in ambient air temperature will result in a corresponding increase in soil temperature. The consequences of further increases in soil temperature will potentially be detrimental for the soil seed bank of plants in terms of length of dormancy and viability of seeds. This experiment investigated the effect of different exposure temperatures and duration of exposure on the germination of semi-aquatic plant species. Seeds of four species (Alternanthera denticulata, Juncus usitatus, Persicaria lapathifolia and Persicaria prostrata) were exposed to temperatures ranging from 25 to 100°C for durations between 1 and 14 days, before being germinated in an incubator for 6 weeks. Germination occurred in all four species after exposure to temperatures ranging from 25 to 60°C. These temperatures appeared to promote germination as the temperature and duration of exposure increased. However, in P. lapathifolia and P. prostrata, the number of seeds germinating declined when exposed to 70°C and there was no germination for temperatures exceeding this. In contrast, A. denticulata and J. usitatus only began to decline when exposed to 80°C, with no germination at higher temperatures. These results suggest that soil temperatures exceeding potential threshold temperatures of 70 and 80°C will result in a decline in the number of seeds germinating and may potentially see a change in species distributions. As such soil temperatures are already being experienced throughout Australia, some species may already be close to their thermal threshold.

scholarly journals OH reactivity and concentrations of biogenic volatile organic compounds in a Mediterranean forest of downy oak trees

2016 ◽  
Vol 16 (3) ◽  
pp. 1619-1636 ◽  
Author(s):  
N. Zannoni ◽  
V. Gros ◽  
M. Lanza ◽  
R. Sarda ◽  
B. Bonsang ◽  
...  
Keyword(s):  
Degradation Products ◽  
Ambient Air ◽  
Oxidation Products ◽  
Temperate Climate ◽  
Air Masses ◽  
Mixing Ratios ◽  
Oak Trees ◽  
Biogenic Compounds ◽  
Reactive Gases ◽  
The Impact

Abstract. Total OH reactivity, defined as the total loss frequency of the hydroxyl radical in the atmosphere, has proved to be an excellent tool to identify the total loading of reactive species in ambient air. High levels of unknown reactivity were found in several forests worldwide and were often higher than at urban sites.Our study presents atmospheric mixing ratios of biogenic compounds and total OH reactivity measured during late spring 2014 at the forest of downy oak trees of the Observatoire de Haute Provence (OHP), France. Air masses were sampled at two heights: 2 m, i.e., inside the canopy, and 10 m, i.e., above the canopy, where the mean canopy height is 5 m.We found that the OH reactivity at the site mainly depended on the main primary biogenic species emitted by the forest, which was isoprene and to a lesser extent by its degradation products and long-lived atmospheric compounds (up to 26 % during daytime). During daytime, no significant missing OH reactivity was reported at the site, either inside or above the canopy. However, during two nights we determined a missing fraction of OH reactivity up to 50 %, possibly due to unmeasured oxidation products. We confirmed that no significant oxidation of the primary species occurred within the canopy; primary compounds emitted by the forest were fast transported to the atmosphere. Finally, the OH reactivity at this site was maximum 69 s−1, which is a high value for a forest characterized by a temperate climate. Observations in various and diverse forests in the Mediterranean region are therefore needed to better constrain the impact of reactive gases over this area.

scholarly journals The Impact of Multi-Sensor Data Assimilation on Plant Parameter Retrieval and Yield Estimation for Sugar Beet

2015 ◽  
Vol XL-7/W3 ◽  
pp. 19-25 ◽  
Author(s):  
M. Hodrius ◽  
S. Migdall ◽  
H. Bach ◽  
T. Hank
Keyword(s):  
Data Assimilation ◽  
Plant Growth ◽  
Sugar Beet ◽  
Leaf Area ◽  
Satellite Imagery ◽  
Crop Growth ◽  
Sensor Data ◽  
Landsat 8 ◽  
Yield Estimation ◽  
The Impact

Yield Maps are a basic information source for site-specific farming. For sugar beet they are not available as in-situ measurements. This gap of information can be filled with Earth Observation (EO) data in combination with a plant growth model (PROMET) to improve farming and harvest management. The estimation of yield based on optical satellite imagery and crop growth modelling is more challenging for sugar beet than for other crop types since the plants’ roots are harvested. These are not directly visible from EO. In this study, the impact of multi-sensor data assimilation on the yield estimation for sugar beet is evaluated. Yield and plant growth are modelled with PROMET. This multi-physics, raster-based model calculates photosynthesis and crop growth based on the physiological processes in the plant, including the distribution of biomass into the different plant organs (roots, stem, leaves and fruit) at different phenological stages. <br><br> The crop variable used in the assimilation is the green (photosynthetically active) leaf area, which is derived as spatially heterogeneous input from optical satellite imagery with the radiative transfer model SLC (Soil-Leaf-Canopy). Leaf area index was retrieved from RapidEye, Landsat 8 OLI and Landsat 7 ETM+ data. It could be shown that the used methods are very suitable to derive plant parameters time-series with different sensors. The LAI retrievals from different sensors are quantitatively compared to each other. Results for sugar beet yield estimation are shown for a test-site in Southern Germany. The validation of the yield estimation for the years 2012 to 2014 shows that the approach reproduced the measured yield on field level with high accuracy. Finally, it is demonstrated through comparison of different spatial resolutions that small-scale in-field variety is modelled with adequate results at 20 m raster size, but the results could be improved by recalculating the assimilation at a finer spatial resolution of 5 m.

scholarly journals 623 Does the Aquadome Ameliorate Diural Fluctuations

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 555A-555
Author(s):  
Kimberly Swenson ◽  
Albert H. Markhart
Keyword(s):  
Plant Growth ◽  
Soil Temperature ◽  
Plant Protection ◽  
Soil Surface ◽  
Ambient Air ◽  
Controlled Environment ◽  
Apparent Effect ◽  
Cold Night ◽  
Data Loggers ◽  
Protection Systems

A major limitation to plant growth in spring is low night temperatures. A variety of plant protection systems have been developed to keep the temperatures around the plant warmer than the ambient air. One system that has been developed for use with individual plants is a double walled stiff plastic tent. The space between the walls can be either filled with water or air. The top of the tent can be either open or closed. The objective of this investigation is to quantify the effect of these protection systems under controlled environmental conditions. Two wash-tubs filled with wet soil were placed in a controlled environment growth chamber. One tent was placed on the soil surface of each tub. The chamber was programmed to simulate a cold night. Temperatures started at 20 °C and then decreased to –5 °C at a rate of about 4 °C/h. During this time, ambient air temperature, jacket temperature, soil temperature, and air inside the tent was measured continuously with self-contained data loggers. Water filled tents delayed the time it took for the inside temperature to reach the outside temperature by 2 hours. There was not apparent effect on soil temperature. The effect of water vs. air-filled jackets and the effect of capping the top will also be presented.

scholarly journals Growth Characteristics and Response to Nitrogen Fertilizer of Some Morphotypes of Jute Marlow (Corchorus olitorius Linn.)

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 612f-612
Author(s):  
M.J. Makinde ◽  
S.A. Ayanlaja
Keyword(s):  
Genetic Diversity ◽  
Plant Growth ◽  
Root Growth ◽  
Nitrogen Fertilizer ◽  
Growth Characteristics ◽  
Corchorus Olitorius ◽  
Seed Rate ◽  
Fertilizer Rates ◽  
Plant Growth Characteristics

Plant growth characteristics were observed for 12 morphotypes of Corchorus olitorius planted in the field. Two commonly used varieties in Nigeria were subjected to increasing nitrogen fertilizer rates. Extensive variations in measured leaf, stem, and root growth confirmed genetic diversity among morphotypes. Thus, fresh shoot harvest l00 kg N/ha at 3 kg/ha seed rate for the lanceolate was 17.44 t·ha–1, the serrate-type at the same seed rate required N at 200 kg·ha–1 to produce 18.19-ha harvest.

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