Influence Of Harvest Date Research Articles

Aroma compounds in Ontario Vidal and Riesling icewines. I. Effects of harvest date

Icewine is a sweet dessert wine made from pressing grapes naturally frozen on the vines. It is likely that freeze/thaw cycles endured by icewine grapes change their chemical and sensory profiles due to climatic events. Our objective was to determine the influence of harvest date on icewine must and wine basic chemical variables and aroma compounds. Riesling and Vidal icewines were made from grapes picked between December 2004 and February 2005; Harvest 1 (H1): 19 December; Harvest 2: 29 December; Harvest 3 (H3): 18 January; and Harvest 4 (H4): 11 February (Vidal only). Icewine musts differed in titratable acidity and pH (Vidal only). All basic wine chemical analytes differed across harvest dates. All aroma compounds differed in Vidal and Riesling wines. Highest concentrations for most aroma compounds were in the last harvest date; 16 of 24 for Vidal and 17 of 23 for Riesling. The latest harvest date had highest ethyl isobutyrate, ethyl 3-methylbutyrate, 1-hexanol, 1-octen-3-ol, 1-octanol, cis-rose oxide, nerol oxide, ethyl benzoate, ethyl phenylacetate, γ-nonalactone and β-damascenone. H1 had highest ethyl butyrate, ethyl hexanoate, linalool, 4-vinylguaiacol and ethyl octanoate. Based on odor activity values, the most odor-potent compounds were β-damascenone, cis-rose oxide, 1-octen-3-ol, ethyl octanoate, ethyl hexanoate, and 4-vinylguaiacol across harvest dates. PCA found most aroma compounds associated with the last harvest date, 4-vinylguaicol excepted, which was associated with H1. Harvest date was considered a discriminating dimension using canonical variant analysis for volatile compounds.

Optimizing soybean harvest date using HJ-1 satellite imagery

Satellite imagery provides contiguous spatial coverage of a field and can be used to measure crop and soil attributes. In the last decade, remote sensing has been proved useful in guiding field management such as sowing, irrigation and fertilization, yet its potential in optimizing large-area crop harvest has not been explored. With a limited number of observations from Hongxing Farm in Northeast China, this paper first analyzes the influence of harvest date on yield. Optimal harvest date (OHD) was estimated for 41 sites in total based on maximum yield. Then the indicating ability of seven satellite-derived indices at different maturing stages for OHD was analyzed. These indices included NDVI (normalized difference vegetation index), soil adjusted vegetation index (SAVI), enhanced vegetation index (EVI), green normalized difference vegetation index (GNDVI), visible atmospherically resistant index (VARI), chlorophyll vegetation index (CVI) and normalized difference water index (NDWI). The analysis showed that there was a continuous increase of yield before maximum yields were reached and then a rather fast decrease occurred. All seven indices acquired from HJ-1 satellite are capable of predicting soybean OHD; EVI and NDWI performed better than other indices with higher correlation coefficients. The highest correlation coefficients between remote sensing indices and observed optimal harvest date were 0.723 and 0.720 for EVI and NDWI respectively. The temporal variation of correlation coefficient between seven indices and observed OHD suggests that the best time for OHD prediction is the period 2–3 weeks earlier than the general harvest. Stepwise regression analysis was undertaken and optimum regression expressions were constructed, taking optimal soybean harvest date as the dependent variable and remote sensed indices (EVI, NDWI and NDVI at suitable dates) as independent variables. An optimal soybean harvest date map of Hongxing Farm was produced with average standard error of 1.15 days. This knowledge may be of use when determining the best times to harvest soybean to obtain a higher yield.

Influence of harvest date on fruit yield and return bloom in ‘Marsh’ grapefruit trees (Citrus paradisi Macf.) grown under a tropical climate

SummaryGrapefruit grown in tropical climates reach a suitable fruit size and juice content for fresh consumption during August – October in the northern hemisphere. However, some tropical plantations delay harvesting until November or December, with the fruit then being used for processing. In our experiments, delaying the harvest from October to December reduced the average mature fruit weight by 10% and increased abscission from 29 to 70 fruit per tree. Juice contents decreased slightly, from 44.5% (w/w) to 43.2% (w/w), while total soluble solids (TSS) contents barely changed, from 10.4 ºBrix to 10.2 ºBrix. Delaying the harvest date also reduced return flowering by 20% in the following Spring, and the number of fruit set by 20%. Mature fruit abscission and reduced flowering were not dependent on weather conditions. The former was spontaneous and due to senescence, while the latter was due to fruit remaining on the tree. Over a 4-year period, our results showed an average reduction of 30% in fruit yield per tree when harvest dates were delayed from October (153 kg tree–1) to December (105 kg tree–1). As juice content and TSS content values were suitable for processing in October, there was no reason to delay the harvest date.

Chemical characteristics and biofuels potentials of various plant biomasses: influence of the harvesting date

An optimal valorization of plant biomasses to produce biofuels requires a good knowledge of the available contents and molecular composition of the main chemical components, which changes with the harvesting date. Therefore, we assessed the influence of harvesting date on the chemical characteristics of various energy crops in the context of their conversion to biofuels. We showed that the biomass chemical composition, enzymatic digestible organic matter, bioethanol and thermal energy production potential for each species are impacted by the harvesting date. The proportion of enzymatically digestible organic matter decreases as the harvesting date is delayed. This is related to the increase in cellulose and lignin contents. The suitability of the biomasses for bioethanol production increases with harvest stage, as the total carbohydrates content increases. The suitability of the biomasses as a source of thermal energy increases according to the harvesting date as the proportion of organic matter increases and the content of mineral compounds decreases. For all investigated energy conversions, the best harvesting period is autumn, because the significantly higher crop dry matter yield largely compensates for the sometimes slightly less favorable chemical characteristics. While the biomass composition of energy crops changes with harvest stage, the dry biomass yield per unit area is the main factor that controls the total amount of chemical components, digestible organic matter, bioethanol and thermal energy that can be expected to be harvested per unit area. The biomass compositions presented in this paper are essential to investigate their suitability for bioenergy conversion.

Влияние сроков уборки овса на посевные качества семян при хранении

Влияние сроков уборки овса на посевные качества семян при хранении

Influence of harvesting date on some physicochemical properties of nectarine leaf and fruit

The influence of harvesting date were studied on antioxidant activity and some physicochemical properties of nectarine (cultivar, red gold) leaf and fruit including weight, pigments, carbohydrate and total phenolic and flavonoids contents. Leaves and fruit were harvested in four different stages; two weeks after fruit set (AFS), five weeks AFS or pit hardening (PH), three and six weeks after PH. The results showed that the content of carbohydrates increased gradually as harvesting date delayed. The content of sucrose decreased gradually in the next harvests. The highest carbohydrate contents were observed at the last harvest time. It is suggested that the observed changes may be due to the replacement of sucrose by other kind of carbohydrate like glucose during late stage of ripening. The results showed that although the content of total phenol and flavonoid in fruit were reduced significantly by delaying in harvest time, no significant reduction was observed in antioxidant activity. It is concluded that the other compounds such as anthocyanin, carotenoids and vitamin C have more role in the antioxidant activity of ripened nectarine fruit. Key words: Antioxidant activity, chlorophyll, flavonoids, harvesting time, nectarine, sugar, total phenols, DPPH

Influence of harvest dates on sugar beet quantitative traits

Results of the investigation regarding influence of harvest dates on quantitative traits of sugar beet are presented in this paper. The three-year trial was conducted on five varieties developed by Institute of Field and Vegetable Crops, Novi Sad. Analysis of variance showed significant differences between harvest dates in 2008 and 2010 for all analyzed traits, but in 2009, due to severe drought differences were not found. With the delay of harvest date, root and raw sugar yield increased, while sugar content was dependent on climatic conditions (precipitation) between two harvest dates. There were no differences among the analyzed genotypes for measured traits in 2010. Interaction between genotype and harvest date has not been confirmed. Variety Drena had the highest root and raw sugar yields in 2008 and 2010.

Influence of harvest date and storage conditions on the content of chlorophyll pigments in pear peels

Abstract During each season, pears were harvested on three dates at four-day intervals. The fruit was stored for 150 days in temperatures of 0-0.5°C in common cold storage (NA - normal atmosphere) and also in controlled atmospheres (CA) of different gaseous content: 0.8% CO2 + 2% O2, 2% CO2 + 2% O2 and 3% CO2 + 3% O2. After removing the pears from storage they were additionally stored for seven days in a temperature of 17°C - simulated shelf life. The content of chlorophyll pigments (chlorophyll a + b) was determined after each harvest date, storage time and simulated shelf life. Based on the results, I concluded that the a + b chlorophyll content in the peel of both pear cultivars significantly decreased along with the subsequent harvest date. In addition, the storage conditions had a significant influence on the studied factor. Compared to the normal atmosphere, the controlled atmosphere conditions were more efficient in slowing the yellowing of the fruit due to reduced chlorophyll degradation. The atmosphere consisting of 3% CO2 + 3% O2 or 2% CO2 + 2% O2 was more favourable for the higher content of chlorophyll a + b in the peel of ‘Conference’ pears than 0.8% CO2 + 2% O2. In the case of ‘Concorde’ pears, the influence of particular compositions of CA on the content of chlorophyll a + b changed over the years.

Влияние сроков уборки на урожайность голозёрного овса и посевные качества семян при хранении

Влияние сроков уборки на урожайность голозёрного овса и посевные качества семян при хранении

Harvest Date Influence on Dry Matter Yield and Moisture of Corn and Stover

Harvest date greatly affects the biomass yield, moisture, and quality of corn and stover. Traditionally, corn and stover have been harvested at lower moisture levels. However, corn stover and grain can be more effectively utilized as animal feed and biomass-ethanol feedstock if they are collected before in-field dry down. This study determined dry matter yield, moisture content, and quality of corn and stover before, during, and after grain maturity in central Illinois. The two-year average kernel moisture was 37.4% (w.b.) when reaching physiological maturity. At the same time, the average stover moisture was 67.7% (w.b.). The dry matter yield of grain increased rapidly until reaching grain maturity and remained relatively stable after grain maturity, with an average yield of 11.2 t ha-1 over the two-year study. For corn stover, the two-year average dry matter yield was 14.7 t ha-1 at the beginning of the study (filling stage), and it decreased to 13.2 t ha-1 at grain physiological maturity and further decreased to 11.0 t ha-1 throughout grain dry down. During grain dry down, the moldy kernel percentage increased from 2.1% to 4.1% and the stalk lodging percentage increased from 1.2% to 3.6%. The results of this study showed that early harvest of corn and stover at grain maturity has several advantages: higher dry matter yield of stover, lower moldy kernel percentage, and fewer plant lodgings.

Variations in antioxidant capacity of nectarine fruits (Prunus persica cv. red-gold) affected by harvest date

The influence of harvesting date on some physicochemical properties of nectarine (Prunus persica var. Red gold) fruit including fruit weight, pigment content, total carbohydrate, total phenol and antioxidant activity were studied. Fruits were harvested in four different stages; a) two weeks after fruit set, b) pit hardening, c) three weeks after pit hardening and 6 weeks after pit hardening. Results showed that the heaviest fruit either wet or dry was observed in the last harvesting date. The reduction in sucrose at the final harvest might be due to conversion to monosaccharides like fructose or glucose. On the other hand, although the content of total phenolic and flavonoid content of fruits were significantly reduced in the last harvest, no significant reduction was observed in their antioxidant activity. Generally, it can be concluded that compounds like anthocyanin, carotenoids and vitamin C play important role in antioxidant activity in ripened nectarine fruit and their content differ in different harvest times.

Influence of harvest date of primary growth on microbial flora of grass herbages and haylage, and on fermentation and aerobic stability of haylage conserved in laboratory silos

AbstractThe influence of harvest date of the primary growth of grass herbages on the microbial flora of herbage pre‐conservation and haylage post‐conservation was studied along with fermentation variables and aerobic stability of haylage. The primary growths of two grass swards, one intensely (Int) and one extensively (Ext) managed, were cut at three different harvest dates (May, June, August) and ensiled in laboratory silos for 120 d. Later harvest dates resulted in increased counts of yeast, mould and enterobacteria in the pre‐conserved herbage (P < 0·001). Counts of lactic acid bacteria (LAB) (P < 0·001) and number of mould species (P < 0·001) were highest in the pre‐conserved herbage harvested in August. Later harvest dates resulted in higher yeast (P < 0·001) and LAB (P < 0·001) counts in the haylage while counts of enterobacteria decreased (P < 0·001). Clostridial spore counts were unaffected by harvest date both in herbage and haylage. The haylage harvested in August had the lowest pH and the lowest concentration of ethanol but the concentration of lactic acid was in general low. Aerobic stability was longer (P < 0·01) for haylage from herbage harvested in August compared with haylage from herbage harvested in May and June. Sward type had less influence than harvest date on microbial variables in herbage and haylage and on fermentation variables of haylage, and did not influence the aerobic stability of haylage.

Influence of harvest date on nitrate contents of three potato varieties for off-season production

The influence of potato variety and harvest date was investigated on tuber nitrate content for off-season production in three varieties: Arinda (mid-early), Spunta (mid-late) and Mondial (late). Samples of tubers were harvested at 90, 105 and 120 days after planting in winter–spring crop and at 80, 95 and 110 days after planting in summer–autumn crop. Tuber nitrate content was determined by ion selective electrode (ISE) method. Investigated varieties differed in nitrate content. In both off-season crops, the highest quantities of nitrate were contained in the late Mondial, with respect to the middle early Arinda variety and Spunta. After a delay of the harvest date, nitrate contents in the investigated tuber samples significantly decreased in winter–spring crop, whereas they increased in summer–autumn crop in the three varieties, but to the greatest extent in the case of late Mondial variety. Regardless of variety and harvest time, the content of nitrate in tubers was within the guidelines proposed by some European countries.

Chemical composition and methane yield of maize hybrids with contrasting maturity

Maize ( Zea mays L.) is the most important substrate for biogas production in Germany. This study was conducted to determine the influence of harvest date and hybrid maturity on the yield and quality of maize biomass for anaerobic methane production. In 2004 and 2005, maize hybrids of widely contrasting maturity were grown on a loamy sand soil (Haplic Luvisol) near Braunschweig, Germany. Whole-plant yield was determined several times after female flowering and the biomass analysed for nutrient composition. The specific methane yield (SMY) was measured using 20 l batch digesters. In both experimental years, the late energy maize prototypes had a lower concentration of fat and protein, but higher concentration of ash, detergent fibre, and lignin as compared with the climatically adapted medium-early hybrids. Despite substantially different nutrient concentration among the maize hybrids, no clear-cut association existed between chemical composition and specific methane yield. Contrary to the medium-early hybrids, the late hybrids attained both maximum specific methane yield and maximum methane hectare yields at the final harvest date. In the very long growing season of 2004, the highest individual methane yield of 9370 N m 3 ha −1 was obtained by the hybrid with the latest maturity used in the study. It appears that late energy maize, which can take full advantage of the growing season, is better suited for biogas production, provided that the whole-plant dry matter concentration is high enough to produce good quality silage.

Effect of variety and harvest date on pectin extracted from chicory roots (Cichorium intybus L.)

The influence of harvest date on pectin quality and yield of five varieties of chicory is investigated in this work. The pectin is extracted from the raw material with an acidic treatment at 85°C for an hour after inulin extraction. Main changes due to harvest date are observed in terms of neutral sugar content, average molecular weight, esterification degree and extraction yield. The galacturonic acid content remains relatively constant throughout the harvest period. While no statistically significant differences (p<0.05) in terms of galacturonic acid content and neutral sugar content are observed between the five cultivars studied, average molecular weight, esterification degree and extraction yield are significantly affected by the cultivar type. Depending on the harvest date, a broad range of pectins can easily be extracted from chicory pulps.

Influence of harvest date and hybrid on the mycotoxin content of maize (Zea mays) grain grown in New Zealand

The changes in concentrations of the Fusarium mycotoxins nivalenol (NIV), deoxynivalenol (DON), and zearalenone (ZEN) in harvested maize (Zea mays) grain with time of harvest were determined, as well as how those changes were affected by the hybrid grown. The study used five hybrids in commercial use, three of these resistant to mycotoxin accumulation under New Zealand growth conditions (3902, 3787, 3394) and two less resistant (3751, 3514). The trial was conducted at five well‐maintained long‐term maize research sites over the three major maize‐growing regions of New Zealand. Results showed that apart from seasonal effects, hybrid choice was the major factor affecting the incidence and concentration of mycotoxins in harvested maize grain. Susceptible hybrids were significantly more likely to contain mycotoxins and to have high concentrations. It was determined that harvest date also had an impact on mycotoxin concentrations, with the best indicators of increased mycotoxin risk being either a prolonged time elapsed since the crop first reached 28% kernel moisture, or a very late (late June or July) harvest. The possibility of a site effect was also observed. At one site in the Waikato region, cob and kernel moisture contents were determined over most of the season, and the collected grain measured for infection by Fusarium species, and for contamination by mycotoxins. This showed that once the kernel moisture content fell below 30%, a substantial increase in Fusarium infection is likely. When this occurs, further delays in harvest can compromise grain quality and lead to increased mycotoxin contamination. The level of fungal infection and mycotoxin contamination would have been markedly less if the crops had been harvested earlier than they were, with the most susceptible hybrids being most affected. The study showed that although there may exist a reasonably wide harvest window for resistant hybrids planted at good sites, with more susceptible hybrids it is imperative to harvest as soon as practical, but that even then, mycotoxin contamination can be present.

Influence of harvest date and geographical location on kernel symptoms, fungal infestation and embryo viability of malting barley

This study focused on the influence of harvest timing and geographical location on spring malting barley (potential malting variety) in terms of fungal infestation and seedling viability in symptomatic and asymptomatic kernels. The study was conducted over two consecutive crop years (2003–2004) at four locations in Slovakia. The following categories of the barley kernels were used for the assessment: kernels with black point symptoms (BPK), kernels with black cover on their surface (BCK), pink-colored kernels (PCK) and asymptomatic kernels (AK). The occurrence of various fungi was detected in all kernel categories ranging from 60 to 100%. The most frequent fungal contaminants were members of the genus Alternaria, recovered from BPK in the range of 52.6–69.85%, BCK (62.36–73.28%) and AK (55.35–69.58%). The prevalence of Alternaria spp. was recorded for each harvest time. Other dematiaceous fungi, Epicoccum nigrum and Cochliobolus sativus were found with medium frequency in the same three categories. However, C. sativus was recovered with a higher frequency in BPK (2.6–25.3%). In PCK, the most commonly recovered fungi were species of Fusarium with F. avenaceum (59.2–93.2%) as the most prevalent. The infestation of kernels by fungi from other genera showed only low frequency within all the kernel categories investigated. There was no significant influence of the year and location on the proportion of the symptomatic kernel categories. Kernel germination was inhibited to a greater degree in the wetter and colder year. The strongest inhibition of germination ranging from 2.35 to 22.45% was recorded in PCK in all locations and both years. Germination declined from PCK to BCK (43.2–90.32%), and BPK (45.6–91.61%), while it was highest in AK at all harvest times (63–93.6%). This study found that the black covering symptoms (BCK) caused greater damage to viability of the kernels than black point symptoms (BPK). The delayed harvest time resulted not only in increasing numbers of discolored kernels and undesirable symptomatic kernel fractions but also in lower germination of the kernels tested.

Influence of Different Factors on Firmness and Color Evolution During the Storage of Persimmon cv. ‘Rojo Brillante’

ABSTRACT‘Rojo Brillante’ persimmons were harvested in 2 different dates, early and late, and then submitted to 1‐methylcyclopropene (1‐MCP) treatment (500 nL/L) before stored at 1 or 15 °C up to 50 or 30 d, respectively. The influence of harvest date, 1‐MCP treatment, orchard, storage time, and temperature on firmness loss and color evolution during storage of ‘Rojo Brillante’ persimmon was studied. Statistical models that allowed the prediction of these 2 quality parameters during the storage, as well as the modeling of the behavior of both of them, were also evaluated. The softening, as a consequence of chilling sensitiveness when stored at 1 °C, was more accentuated in the early harvested fruit. In storage at 15 °C, also, the firmness loss was faster in fruit harvested earlier. 1‐MCP treatment drastically reduced chilling injury (CI) symptoms at 1 °C and retarded firmness loss at 15 °C, both of these effects being dependent on harvest date. The model presented to study the firmness and color relationship offers an important tool to predict firmness from fruit color measurements.

Influence of harvest date on ripening and volatile compounds in the scab-resistant apple cultivar ‘Golden Orange’

SummaryThe quality of scab-resistant apple cv. ‘Golden Orange’, as influenced by harvest time, was evaluated in comparison with the scab-susceptible cv. ‘Golden Delicious’ (clone B) (Golden B). Fruits from both cultivars were harvested on three different dates and ripened at 20°C. Quality parameters at harvest [fruit mass, flesh firmness, starch hydrolysis, soluble solids content (SSC), titratable acidity (TA)], colour, ethylene production (EP), development of headspace volatiles during post-harvest ripening, and sugar and organic acid compositions at the end of ripening were measured. At harvest, firmness, SSC, TA, starch hydrolysis and Streif Index indicated that ‘Golden Orange’ apples were less mature than ‘Golden B’ apples, even if their skin colour was more yellow. Generally, during post-harvest ripening, ‘Golden Orange’ apples showed lower EP, lower total volatile production, and their skin turned as yellow as ‘Golden B’. ‘Golden Orange’ apples differed from ‘Golden B’ in their sugar, organic acid and volatile compound compositions. These differences were independent of harvest date and could explain the different sensory descriptions peculiar to this cultivar. Compounds that contributed most to the characteristic aroma were ethyl 2-methylbutanoate and hexyl and 2-methylbutyl acetate in ‘Golden B’ apples, and ethyl and hexyl 2-methylbutanoate, ethyl hexanoate and hexyl acetate in ‘Golden Orange’ fruit, at all harvest times. The concentrations of these volatiles were largely dependent on harvest date and on the length of post-harvest ripening.

Influence of harvest date and crop yield on the fatty acid composition of virgin olive oils from cv. Picual.

In this study was analyzed the effect of crop year and harvesting time on the fatty acid composition of cv. Picual virgin olive oil. The study was carried out during the fruit ripening period for three crop seasons. The mean fatty acid composition of Picual oils was determined. The oils contained palmitic acid (11.9%), oleic acid (79.3%), and linoleic acid (2.95%). The content of palmitic acid and saturated fatty acids decreased during fruit ripening while oleic and linoleic acids increased. The amount of stearic and linolenic acids decreased. The amount of saturated acids, palmitic and stearic, and the polyunsaturated acids linoleic and linolenic was dependent on the time of harvest, whereas the amount of oleic acid varied with the crop year. The differences observed between crop years for both palmitic and linoleic acid may be explained by the differences in the temperature during oil biosynthesis and by the amount of summer rainfall for oleic acid content. A significant relationship was observed between the MUFA/PUFA ratio and the oxidative stability measured by the Rancimat method.