Response of horticultural crops under variable microclimatic conditions of different protected cultivation structures

Protected cultivation structures provide favorable environment for crop growth thereby achieving greater yield and high quality produce. The objective of this work was to evaluate the microclimate parameters such as temperature, relative humidity, solar radiation and light intensity underdifferent protected cultivation structures in comparison with open field condition. Four types of protected cultivation structures (polyhouse, walking tunnel,shadenet house and modified greenhouse) were considered for the study. Meteorological data of seven years (2010-2016), recorded on daily basis were used for micro climate analysis of different protected cultivation structures. FAO-56 Penman Monteith approach was used to estimate the reference crop evapotranspiration under different kind of protected cultivation structures.Study shows that walking tunnel, polyhouse and modified greenhouse structures offers a solar energy saver and enhances temperature inside the structures. The total water requirement of drip irrigated crops in protected cultivation structure is reduced by about 25% to 35% under different protected cultivation structures in comparison to open field cultivation. This paper also presents the difference incrop yield grown under protected cultivation structures and open field condition.

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Summer Production of Lettuce, and Microclimate in High Tunnel and Open Field Plots in Kansas

HortTechnology ◽

10.21273/hortsci.19.1.113 ◽

2009 ◽

Vol 19 (1) ◽

pp. 113-119 ◽

Cited By ~ 12

Author(s):

Xin Zhao ◽

Edward E. Carey

Keyword(s):

Open Field ◽

Air Temperature ◽

Meteorological Data ◽

Marked Change ◽

Daily Basis ◽

Daily Maximum ◽

High Tunnel ◽

Horticultural Crops ◽

High Tunnels ◽

Open Fields

High tunnels have been shown to be a profitable season-extending production tool for many horticultural crops. Production of cool-season vegetables during the hot summer months represents a challenge to market growers in the midwestern United States. Two experiments were conducted to investigate the microclimate and production of eight leaf lettuce (Lactuca sativa) cultivars in high tunnels and open fields, using unshaded and shaded (39% white shadecloth) tunnels in Summer 2002 and 2003, respectively. Wind speed was consistently lower in high tunnels with the sidewalls and endwalls open. An unshaded high tunnel resulted in an increase of daily maximum and minimum air temperatures by ≈0.2 and 0.3 °C, respectively, in comparison with the open field. In contrast, daily maximum air temperature in a shaded high tunnel decreased by 0.4 °C, while the daily minimum air temperature was higher than that in the open field by 0.5 °C. Using high tunnels did not cause a marked change in relative humidity compared with the open field. When using shadecloth, the daily maximum soil temperature was lowered by ≈3.4 °C and the leaf surface temperature was reduced by 1.5 to 2.5 °C. The performance of lettuce during summer trials varied significantly among cultivars. Unshaded high tunnels generally led to more rapid bolting and increased bitterness of lettuce compared with the open field. Lettuce grown in high tunnels covered by shadecloth had a lower bolting rate, but decreased yield relative to the open field. Based on our results, summer lettuce production would not be recommended in high tunnels or open fields in northeastern Kansas, although the potential of shaded high tunnels deserves further studies. Reference crop evapotranspiration (ET0) was estimated from meteorological data on a daily basis using the FAO-56 method. The ET0 was lowest in the shaded high tunnel and was the highest in the open field. Relatively lower ET0 in high tunnels indicated a likely lower water requirement and therefore improved water use efficiency compared with the open field.

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(202) Microclimate and Reference Crop Evapotranspiration in High Tunnels and Open Field during Summer Lettuce Production

HortScience ◽

10.21273/hortsci.40.4.1054d ◽

2005 ◽

Vol 40 (4) ◽

pp. 1054D-1055

Author(s):

Xin Zhao ◽

Edward E. Carey

Keyword(s):

Open Field ◽

Meteorological Data ◽

Daily Basis ◽

Crop Evapotranspiration ◽

Reference Crop Evapotranspiration ◽

Horticultural Crops ◽

High Tunnels ◽

Use Efficiency ◽

Leaf Lettuce ◽

Reference Crop

High tunnels, unheated greenhouses, have been shown to be a profitable season-extending production tool for many horticultural crops. Production of cool-season vegetables during hot summer months can be achieved using shaded high tunnels. Microclimate in high tunnels and open field was monitored during summer trials of leaf lettuce, in which unshaded tunnels and shaded tunnels (39% PAK white shadecloth) were used, respectively, in 2002 and 2003. Wind speed was consistently lower in high tunnels. Compared to open field, daily air temperature was about 0.7 °C higher in unshaded high tunnels, and 0.5 °C lower in shaded high tunnels. Relative humidity was slightly lower in unshaded tunnels, but tended to increase in shaded tunnels, in comparison to the open field. When using shadecloth, soil temperature was lowered by 1∼3 °C and the leaf surface temperature was significantly reduced by 1.5∼2.5 °C. In shaded high tunnels, PAR light dropped by at least 50% relative to the outside, where the maximum PAR light intensity reached 1800 μmol·m-2·s-1. Overall, shaded high tunnels resulted in higher quality lettuce, with less bolting and bitterness. Reference crop evapotranspiration (ET0) was estimated from meteorological data on a daily basis using the FAO-56 method. ET0 was lowest in shaded high tunnels, and highest in the open field. Relatively lower ET0 in high tunnels indicated a likely lower water requirement and therefore improved water use efficiency compared with the open field.

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