Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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    We will mail you new results for this query: keywords==light penetration
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Less at the top, more gain at the bottom : better light penetration leads to higher production
Heuvelink, E. ; Kierkels, T. - \ 2016
In Greenhouses : the international magazine for greenhouse growers 5 (2016)4. - ISSN 2215-0633 - p. 18 - 19.
greenhouse horticulture - greenhouses - light penetration - crop production - farm management - diffused glass - glastuinbouw - kassen - lichtpenetratie - gewasproductie - agrarische bedrijfsvoering - diffuus glas
If light penetrates the crop better, it results in higher production. This is because the leaves that are deeper in the crop are a long way from their light saturation point. Diffuse glass or coatings and the distribution of the crop are the most applicable ways to achieve better light penetration. Other methods are usually beyond the reach of the grower
Algenteeltsystemen voor de tuinbouw - leren van huidige systemen bij telers - voorlopige samenvatting resultaten en aanbevelingen
Hemming, Silke - \ 2011
algae culture - cropping systems - greenhouse horticulture - light penetration - temperature - energy consumption - multiple cropping - biobased economy
On the photosynthetic responses of crops to intracanopy lighting with light emitting diodes
Trouwborst, G. - \ 2011
University. Promotor(en): Olaf van Kooten, co-promotor(en): Wim van Ieperen; Jeremy Harbinson. - [S.l.] : S.n. - ISBN 9789085858621 - 154
kasgewassen - fotosynthese - fotosynthese van het kroondak - kunstmatige verlichting - lichtgevende dioden - lichtpenetratie - glastuinbouw - lichtverdeling - greenhouse crops - photosynthesis - canopy photosynthesis - artificial lighting - light emitting diodes - light penetration - greenhouse horticulture - light distribution

Key words: Cucumis sativus, intracanopy lighting, light-emitting diodes (LEDs), light distribution, light interception, light quality, photosynthesis, photosynthetic acclimation

Assimilation lighting is a production factor of increasing importance in Dutch greenhouse horticulture. Assimilation lighting increases production levels, improves product quality and opens possibilities for year round production. As a drawback, this use of assimilation lighting increases energy inputs and CO2-emission.
Intracanopy lighting (with LEDs) is a technique to enhance the light use efficiency by changing the position of (a part of ) the lamps from above to within the canopy of greenhouse grown crops. Intracanopy lighting (IL) firstly reduces reflection and transmission losses of the supplemental lighting on crop level. These losses are high in traditional top-lighting systems, hence IL yields a higher light absorption on crop level. Secondly, IL creates a more homogenous vertical light distribution which can result in higher light use efficiencies. The aim of present study was to obtain insights in photosynthetic acclimation in response to irradiance level and spectrum in the framework of the applicability of LEDs as light source for intracanopy lighting in indeterminate growing vegetable crops. Intracanopy lighting may vary in (1) position within the crop, in (2) irradiance level and in (3) spectrum.
Leaves deeper in the canopy are older. If leaf age negatively affects the photosynthetic capacity (Amax), then potential positions of IL-lamps reduce. By growing tomato plants horizontally so that irradiance was similar for all leaves from 0-70 days old, it is concluded that during the normal life-span of tomato leaves in cultivation, irradiance and not ageing is the most important factor affecting Amax.
In winter, natural irradiances are low so that new developing leaves acclimate to low irradiances. Later on in their life time these leaves could be exposed to higher irradiances owing to IL. The question arose if cucumber leaves which develop under low irradiance can acclimate to a moderate irradiance. Acclimation of photosynthesis occurred within 7 days but photosynthesis at moderate irradiance and Amax did not reach to that of leaves developed under moderate irradiance. This reveals the importance of photosynthetic acclimation during the leaf developmental phase for crop productivity in scenarios with realistic, moderate fluctuations in irradiance that leaves can be exposed to.
By growing plants under seven different combinations of red and blue light, blue light is shown to have both a qualitative and a quantitative effect on leaf development. Only leaves developed under red light (0% blue) displayed a dysfunctional photosynthetic operation (“red light syndrome”), which was largely alleviated by only 7% blue. Quantitatively, leaf responses to an increasing blue light percentage resembled responses associated with an increase in irradiance.
Leaves developed under red light exposed to a mixture of red and blue (RB) completely recovered within 4 days after exposure to RB-light but remained limited in other leaf parameters, showing limitations in plasticity due to constraints arising from the prior leaf development. Leaves developed under RB also revealed the “red light syndrome” within 7 days of red illumination.
Lastly, the effects of intracanopy lighting with LEDs on the production and development of a cucumber crop was investigated in winter. In the IL-treatment, LEDs supplied 38% of the supplemental irradiance within the canopy; the remaining 62% was supplied as top lighting by High-Pressure Sodium (HPS) lamps. The control was 100% top lighting (HPS lamps). Intracanopy lighting resulted in a greater Amax for leaves at deeper canopy layers but did not increase total biomass or fruit production. This was partly due to a reduced light interception caused by extreme leaf curling, which counteracted the expected higher light absorption by the crop, and partly to a lower dry matter partitioning to the fruits, and thus a greater dry matter partitioning to the leaves compared to the control. The effect of these factors on fruit yield was quantified using a explanatory crop model. Model calculations revealed a large negative effect on the fruit yield due to the greater partitioning to the leaves, whereas the negative effect of leaf curling was small. The effect of a greater Amax at deeper canopy layers was slightly positive. The last however might have indirectly caused the greater partitioning to the leaves as the greater Amax was associated with a preserved leaf mass per area.

Understanding growth of East Africa highland banana: experiments and simulation
Nyombi, K. - \ 2010
University. Promotor(en): Ken Giller, co-promotor(en): Peter Leffelaar; P.J.A. van Asten. - [S.l. : S.n. - ISBN 9789085855507 - 196
musa - bananen - bladoppervlakte-index - lichtpenetratie - straling - simulatiemodellen - kunstmeststoffen - gebruiksefficiëntie - plantenvoeding - middelgebergte - uganda - oost-afrika - bananas - leaf area index - light penetration - radiation - simulation models - fertilizers - use efficiency - plant nutrition - upland areas - east africa
Key words: leaf area; radiation interception; QUEFTS model; fertilizer recovery fractions; nutrient mass fractions; crop growth; calibration; validation; radiation use efficiency; sensitivity analysis

East Africa Highland banana yields on smallholder farms in the Great Lakes region are small (11−26 Mg ha−1 cycle−1 in Uganda, 21−43 Mg ha−1 cycle−1 in Burundi and 25−53 Mg ha−1 cycle−1 in Rwanda). The major causes of poor yields are declining soil fertility and soil moisture stress. In order to improve production, knowledge on highland banana physiology, growth patterns and response to fertilization is important, to establish the potential yield of the crop, to quantify the yield gaps between potential and actual yield, and to explore options for closing the yield gaps.
Measurements of plant morphological characteristics, radiation interception and biomass (by destructive harvesting) were taken in experimental fields in central and southwest Uganda. Results showed that total leaf area can be estimated by using height and girth (used to estimate middle leaf area) and number of functional leaves. The light extinction coefficient, k determined from photosynthetically active radiation (PAR) measurements over the entire day was 0.7. Banana plants partitioned more dry matter (DM) to the leaves during first phase of vegetative growth, with the pseudostem becoming the dominant sink later with 58% of total DM at flowering, and the bunch at harvest with 53% of the total DM. Changes in dry matter partitioning influenced the allometric relationships between above-ground biomass (AGB in kg DM) and girth (cm), the relationship following a power function during the vegetative phase (AGB = 0.0001 (girth)2.35), and exponential functions at flowering (AGB = 0.325 e0.036 (girth)) and at harvest (AGB = 0.069 e0.068 (girth)). This thesis shows that allometric relationships can be derived and used to estimate biomass and bunch weights.
In fertilizer trials, yield increases above the control (13.0 Mg ha−1 yr−1) ranged from 2.2−11.2 Mg ha−1 yr−1 at Kawanda, to more than double at Ntungamo, 7.0−29.5 Mg ha−1 yr−1 (control 7.9 Mg ha−1 yr−1). The limiting nutrients at both sites were in the order K>P>N. Differences in soil moisture availability and texture resulted in higher yields and total nutrient uptakes (K>N>P) at Ntungamo, compared with Kawanda. Per unit dry matter yield, highland bananas take up a similar amount of N (49.2 kg finger DM kg−1 N), half the amount of P (587 kg finger DM kg−1 P), and five times the amount of K (10.8 kg finger DM kg−1 K), when compared with cereal grain. Calibration results of the static nutrient response model QUEFTS using data from Ntungamo were fair (R2 = 0.57, RMSE = 648 kg ha−1). The calibrated QUEFTS model predicted yields well using data from Mbarara southwest Uganda (R2 = 0.68, RMSE = 562 kg ha−1).
A new dynamic radiation and temperature-driven growth model, LINTUL BANANA 1 was developed to the compute potential yields of East Africa highland banana. The model considers (i) the physiology of the highland banana crop; (ii) the plant dynamics (i.e. three plant generations, Plant 1, 2 and 3 at different stages of growth constituting a mat); and (iii) three canopy levels formed by the leaves of the three plants. Average computed potential bunch dry and fresh matter were slightly higher at Ntungamo (20 Mg ha−1 DW; 111 Mg ha−1 FW), compared with Kawanda (18.25 Mg ha−1 DW; 100 Mg ha−1 FW), and values compared well with banana yields under optimal situations at comparable leaf area index values (20.3 Mg ha−1 DW; 113 Mg ha−1 FW). Sensitivity analysis was done to assess the effects of changes in parameters (light use efficiency, LUE; the light extinction coefficient, k; specific leaf area, SLA; the relative death rate of leaves, rd; relative growth rate of leaf area, RGRL; and the initial dry matter values) on bunch dry matter, leaf dry matter and leaf area index (L) at flowering. Sensitivity results for Kawanda and Ntungamo showed that changes in LUE1 resulted in more than proportional increase in bunch DM (1.30 and 1.36), a higher leaf DM (0.60 and 0.67) and L at flowering (0.60 and 0.67). Changes in rd1 values reduced bunch dry matter, leaf dry matter and L at flowering. Changes in SLA1 reduced only leaf DM, whereas both leaf DM and L at flowering were reduced by changes in k1 at both sites. Initial dry matter values had a small effect (sensitivity < 0.0263) for bunch DM, leaf DM and L at flowering. Based on the model results, it is clear that the potential yield of East Africa highland bananas is more than 18 Mg ha−1 DW. Management options that increase LUE and reduce the relative death rate of leaves, and improvements in parameters related to light interception (SLA and k) are important to increase yield.

Diffuus licht heeft positief effect op opbrengst
Hemming, S. - \ 2007
Onder Glas 4 (2007)4. - p. 34 - 35.
kassen - bekleding, bouw - beglazing - diffuus glas - lichtpenetratie - cucumis sativus - bereikt resultaat - productiegroei - glastuinbouw - groenten - greenhouses - cladding - glazing - diffused glass - light penetration - achievement - production growth - greenhouse horticulture - vegetables
Wageningen UR Glastuinbouw onderzoekt het effect van diffuus licht op de plantengroei. Afgelope zomer is een proef uitgevoerd met een zomerteelt van komkommer. De resultaten zijn veelbelovend. Door het licht diffuus te maken wordt het natuurlijke licht beter benut en de gewasopbrengst verhoogd. Dat is voor de energie-efficiëntie in Nederlandse kassen voordelig
Diffuus licht verhoogt opbrengst komkommer
Hemming, S. ; Dueck, T.A. - \ 2007
Groenten en Fruit. Algemeen 1 (2007). - ISSN 0925-9694 - p. 18 - 19.
tuinbouw - onderzoek - experimenten - cucumis sativus - kasgewassen - teelt onder bescherming - bekleding, bouw - doorschijnendheid - lichtpenetratie - horticulture - research - experiments - greenhouse crops - protected cultivation - cladding - translucence - light penetration
Diffuse kasdekmaterialen hebben voordelen voor Nederlandse telers volgens onderzoek van Wageningen UR, net zoals voor telers uit zuidelijke landen. Het kan productie verhogen en schade aan planten tegengaan, die voordelen zijn nu bevestigd door een proef met komkommer
Toepassingsmogelijkheden pigmentfolie: Materiaaleigenschappen van de fotoselectieve pigmentfolie van Floralum en teelteffecten op roos en tomaat
Rijssel, E. van; Romashev, Y. - \ 2005
Aalsmeer : PPO Glastuinbouw (Rapporten PPO B.U. Glastuinbouw ) - 27
folie - lichtpenetratie - impact - groenteteelt - kosten-batenanalyse - solanum lycopersicum - tomaten - rosa - rozen - nederland - foil - light penetration - vegetable growing - cost benefit analysis - tomatoes - roses - netherlands
De fotoselectieve pigmentfolie is een folie die pigmenten bevat die delen van de UV en infrarode straling uit het zonlicht absorberen en onder invloed van de geabsorbeerde straling fluoresceren met blauw, resp. rood licht. Een neveneffect van de pigmentkorrels is dat het niet geabsorbeerde licht wordt verstrooid, de folie is dus niet helder maar zorgt voor een diffuse doorlating. Toepassing van de folie in de glastuinbouw wordt gezien als een plakfolie op het kasdek. Een gunstig neveneffect daarbij is dat het glas bij glasbreuk wordt vastgehouden en niet op het gewas valt. Bij het plakken van de folie wordt het glas vochtig gemaakt, het vocht wordt naar buiten weggestreken bij het gladstrijken van de folie. Een restant van het vocht zorgt bij zonnig weer voor het ontstaan van blaasjes tussen glas en folie. Om dit te voorkomen is het restant van de folie geperforeerd, doch het effect ervan is nog niet getoetst.
Licht onder water : pilot-onderzoek naar het doorzicht voor duikers in recreatieplas De Berendonck
Zaal, L.Z. - \ 2003
Wageningen : Wetenschapswinkel Wageningen UR (Rapport / Wetenschapswinkel Wageningen UR nr. 184) - 50 p.
lichtpenetratie - duiken - nederland - oppervlaktewater - meren - fysische eigenschappen - waterrecreatie - gelderland - surface water - lakes - physical properties - light penetration - water recreation - diving - netherlands
The goal of this pilot-project is to gain insight into the causes of the poor sight. The secondary goal is to draft initial improvement proposals. The research questions are: - to which degree is there a case of bad sight and in which water layers is it present ? - what are the possible causes of this lesser sight, in view of determining matter in the water and determining events in the history of the lake ? - which proposals can be made to improve the sight ?
The attenuation of ultraviolet and visible radiation in Dutch inland waters
Lange, H.J. de - \ 2000
Aquatic Ecology 34 (2000). - ISSN 1386-2588 - p. 215 - 226.
absorptiegraad - chlorofyl - organische verbindingen - koolstof - humuszuren - ultraviolette straling - lichtpenetratie - oppervlaktewater - binnenwateren - absorbance - chlorophyll - organic compounds - carbon - humic acids - ultraviolet radiation - light penetration - surface water - inland waters
Manipulating the physiological quality of in vitro plantlets and transplants of potato
Mehari, T. - \ 2000
Agricultural University. Promotor(en): Paul Struik; W.J.M. Lommen. - S.l. : S.n. - ISBN 9789058083302 - 230
solanum tuberosum - aardappelen - in vitro kweek - microvermeerdering - zaadproductie - transplantaten - groei - groeianalyse - bladoppervlakte-index - bladoppervlakte - lichtpenetratie - ophoping van drogestof - stikstof - temperatuur - acclimatisatie - potatoes - in vitro culture - micropropagation - seed production - transplants - growth - growth analysis - leaf area index - leaf area - light penetration - dry matter accumulation - nitrogen - temperature - acclimatization
<p><em>In vitro</em> techniques have been introduced in potato seed production systems in recent years. This research project aimed at studying the morphological and physiological changes in plants and crops in the last three phases of a seed production system that included an <em>in vitro</em> multiplication, an <em>in vitro</em> normalisation (growing cuttings to rooted plantlets), a transplant production, and a tuber production (field) phase.</p><p>Leaf area was identified as an important plant parameter for plant growth in the normalisation and transplant production phases. Explants and plantlets with larger initial leaf area performed better than those with smaller initial leaf area. <em>In vitro</em> treatments mainly affected leaf area of transplants through their effects on early above-ground leaf area. Leaf area increase was better described by logistic than by exponential or expolinear curves in all phases of growth, suggesting restriction of leaf area increase in all phases.</p><p>Low temperature decreased leaf and stem dry weights in all phases, and increased tuber fresh and dry yields, average tuber weight, leaf/stem ratio, specific leaf area and harvest index in the tuber production phase. Growing <em>in vitro</em> plants at low normalisation temperatures increased leaf and total plant dry weights early in the transplant production and tuber production phases. It resulted in higher tuber yields, heavier individual tubers and higher harvest index.</p><p>Fertilising plants with higher nitrogen (40 versus 10 mg N per plant) during transplant production resulted in plants with higher groundcover in the field. This led to higher interception of solar radiation and higher tuber yield in one of the two experiments. Growing plants at higher temperature (26/20 versus 12/18 °C) during transplant production increased leaf area at the end of the transplant production phase. After transplanting to the field, it resulted in crops with higher groundcover, which intercepted more incoming solar radiation. Yield tended to be higher, but differences could not be assessed as statistically significant. A glasshouse experiment showed that high temperature during transplant production increased leaf and stem dry weights in the tuber production phase, but reduced tuber dry weights and harvest index when temperatures during tuber production were high. Thus, high temperature during transplant production may favour haulm growth and light interception in the field, but may also reduce dry matter partitioning to tubers.</p><p>Conditions in the tuber production phase were found to be of greater importance for final yield than conditions and treatments in earlier phases.</p><p>Strategies to optimise the production and use of propagules and transplants should focus on achieving leafy starting material, reducing stress during changes in environment and optimising conditions during tuber production. Production of transplants should be adjusted to the expected growth conditions in the tuber production phase.</p><p><strong>Key words:</strong><em>Solanum tuberosum</em> L., <em>in vitro</em> plantlet, seed production, normalisation, transplant production, tuber production, acclimatisation, leaf area, groundcover, logistic growth, temperature, nitrogen, dry matter production, specific leaf area, harvest index, radiation interception, radiation use efficiency.</p>
Photosynthesis of leaf canopies
Wit, C.T. de - \ 1965
Wageningen : Pudoc (Agricultural research reports 663) - 57
bladeren - fotosynthese - fotosynthese van het kroondak - lichtpenetratie - bladoppervlakte-index - leaves - photosynthesis - canopy photosynthesis - light penetration - leaf area index
The development of a procedure to calculate the effect of certain environmental factors on the rate of photo-synthesis imposed mainly geometrical problems, which were solved in such a way that the actual calculation could be carried out by means of a computer. The calculation procedures have been used to study the. relative importance of the variables under various conditions. The results for a standard set of conditions, have been summarized in order to make it possible to estimate the daily photosynthesis at any time and place for a wide range of photosynthesis functions without a computer.
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