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<p>Proizvodnja mladog krompira u Srbiji je značajna zbog obezbeđenja ove izuzetno cenjene&nbsp;i delikatesne namirnice u periodu od aprila do juna kada je u ponudi na trži&scaron;tu malo drugog&nbsp;svežeg povrća. Osim toga cena mladog krompira je uglavnom visoka, pa je značaj i po osnovu&nbsp;profitabilnosti ove kulture velik.<br />U periodu 2004-2006. godine ispitivan je efekat malčovanja polietilenskom folijom i<br />neposrednog pokrivanja biljaka sa i bez noseće konstrukcije, kao i kombinacija ovih specifičnih&nbsp;agrotehničkih mera na ranostasnost, prinos i komponente prinosa i kvalitet mladog krompira kod&nbsp;ranih sorti Cleopatra i Riviera. U cilju re&scaron;avanja postavljenog zadatka sprovedeno je istraživanje,&nbsp;na lokalitetu južno bačkog okruga (Begeč), postavljen je dvofaktorijalni ogled po split plot planu&nbsp;u pet ponavljanja.<br />Ispitivane agrotehničke mere i njihove kombinacije značajno su uticale na ranostasnost i&nbsp;prinos mladog krompira. Formiranje trži&scaron;nih krtola (krtole veće od 28 mm) bilo je za 10-15 dana&nbsp;ranije u odnosu na kontrolnu (nepokrivenu) varijantu. Najveći prinos u trogodi&scaron;njem istraživanju&nbsp;postignut je na varijanti agrotekstil+niski tunel (40,07 t/ha). U odnosu na kontrolnu varijantu,&nbsp;prinos je bio veći za 19% (u prvoj godini za 22%, drugoj za 16%, dok je u trećoj godini prinos bio&nbsp;veći za 18%).<br />Najveći broj krtola mladog krompira, u trogodi&scaron;njem istraživanju, ostvaren je na<br />kontrolnoj varijanti (9,43), stim &scaron;to je udeo trži&scaron;nih krtola (krtole veće od 28 mm) na kontroli&nbsp;iznosio 89% naspram 95% ostvaren na pokrivenim varijantama. Riviera je ostvarila veći broj&nbsp;krtola po biljci u odnosu na Cleopatru.<br />Ispitivane agrotehničke mere uticale su na povećanje mase krtola po biljci. Najveća masa&nbsp;krtola po biljci u trogodi&scaron;njem ogledu ostvaren je na tretmanima agrotekstil+niski tunel (853,17&nbsp;g) i malčovanje+agrotekstil+niski tunel (850,17 g), dok je najmanja masa zabeležena na&nbsp;kontrolnoj varijanti (640 g). Sorta Riviera je ostvarila značajno veću masu krtola u odnosu na&nbsp;Cleopatru.<br />Ispitivani tretmani su ostvarili veću prosečnu masu jedne krtole za 52% u odnosu na<br />kontrolnu varijantu.<br />Ispitivani tretmani značajno su uticali i na kvalitet mladog krompira; odnosno na<br />povećanje sadržaja suve materije, skroba, vitamina C, celuloze i pepela u krtolama, a na<br />smanjenje sadržaja &scaron;ećera i nitrata.</p> / <p>Production of early potato in Republic of Serbia is important because it provides this<br />highly valued delicates food during the period from April to June, when there is low offer of other<br />fresh vegetables on the market. Besides, price of early potato is usually high so it is important as<br />profitable crop.<br />During the period 2004-2006 effect of mulching with polyethylene foil and direct<br />coverage of plants with agrotextile and low tunnel, as well as combinations of these specific<br />agricultural measures on earliness, yield and yield components and quality of two early potato<br />varieties Cleopatra and Riviera was examined. In order to achieve given objective research was<br />conducted at the site in South Bačka District (Begeč), it set up the two-factorial experiment at<br />split plot plan in five replications.<br />The tested of agricultural measures and their combinations significantly influenced<br />earliness and yield of early potato. The forming of market tubers (tubers larger than 28 mm) was<br />10-15 days earlier than on the control variant (bare soil and uncover plants). The highest yield of<br />the three-year study has been made on the variant combination of agrotextile and low tunnel<br />(40,07 t/ha). Compared to the control variant, the yield was increased by 19% (in the first year<br />increase of 22%, second year increase was 16%, while in the third year yield increase was 18%).<br />The largest number of tubers of early potatoes, in three-year study, has been on the<br />control variant (9,43), but the share of market tubers (tubers larger than 28 mm) on the control<br />variant was 89% versus 95% achieved in covered variants. Variety Riviera has achieved greater<br />number of tubers per plant compared to variety Cleopatra.<br />The tested agricultural measures affected mass increase of tubers per plant. The<br />maximum weight of tubers per plant in the three-year experiment was realized in the treatment<br />combination of agrotextile and low tunnel (853,17 g) and combination of mulching, agrotextile<br />and low tunnel (850,17 g), while the lowest mass was recorded in the control variant (640 g).<br />Variety Riviera has achieved significantly higher tuber weight relative to Cleopatra.<br />The tested treatments have also achieved a higher average weight of a tuber of 52%<br />compared to the control variant.<br />The tested treatments significantly influenced quality of early potato; i.e. the increase the<br />content of dry matter, starch, vitamin C, cellulose and ash in the tubers and on reduction of sugar<br />and nitrate content.</p>

The growing season for vegetable crops is limited by freezing temperatures in arid high elevation climates such as northern Utah. Logan, Utah (41.73 N, 111.83 W, 1382 m elevation) has a short, variable growing season with an average frost-free period of 135 days. Extending the growing season provides growers with an opportunity to extend revenue into a normally unproductive period and benefit from out-of-season price premiums. High tunnels have been used to effectively extend the growing season for numerous crops by providing cold temperature protection. However, limited high tunnel research has been performed in arid high elevation regions that experience extreme temperature fluctuations. The use of high tunnels was investigated in North Logan, Utah to extend the growing season for tomatoes and lettuce. In 2009 and 2010, supplemental heating under low tunnels within high tunnels was investigated to provide early season cold temperature protection for tomatoes. Sunbrite tomatoes were transplanted into four high tunnels over three planting dates. Tomatoes were subjected to supplemental heating treatments including soil warming cables alone or in conjunction with 40-watt incandescent lights for air heating. The highest early season and overall yield was achieved with the 17 Mar. planting date. Early season yield was significantly less for the latest planting date (7 Apr.) compared to the 17 Mar. and 30 Mar. planting dates. Early season yield was significantly greater for treatment plots with soil plus air heating, and soil heating alone significantly improved total yield. The use of a vertical structure within a high tunnel was investigated to improve productivity for lettuce. Parris Island Cos lettuce was consecutively transplanted from spring 2008 to spring 2010 in a high tunnel at the same site. The vertical growing system allowed for 31 plants*m-2 in south oriented gutters, and 45 plants*m-2 in east/west oriented gutters compared to 25 plants*m-2 in the ground including space for maintenance. Root zone temperatures in the gutters fluctuated widely in response to air temperatures, and super-optimal soil temperatures impeded growth. Productivity (g*m-2) in the gutters was only significantly greater than productivity in the ground soil during the spring and fall months when soil and air temperatures were not frequently below 0 °C or above 24 °C. This thesis includes both research results and extension factsheets intended for growers interested in high tunnel production of tomato and lettuce.

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