Bibliografias temáticas / Crop load

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Literatura científica selecionada sobre o tema "Crop load"

Autor: Grafiati

Publicado: 4 de junho de 2021

Última modificação: 19 de fevereiro de 2023

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Artigos de revistas sobre o assunto "Crop load"

Peck, Gregory, Megan McGuire, Thomas Boudreau e Amanda Stewart. "Crop Load Density Affects ‘York’ Apple Juice and Hard Cider Quality". HortScience 51, n.º 9 (setembro de 2016): 1098–102. http://dx.doi.org/10.21273/hortsci10962-16.

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To assess the impact crop load has on hard cider chemistry, ‘York’ apple (Malus ×domestica Borkh.) trees were hand thinned to three different crop loads: low [two apples per cm2 branch cross-sectional area (BCSA)], medium (four apples per BCSA), and high (six apples per BCSA). Higher crop loads produced smaller, less acidic fruit that were slightly more mature. In juice made from fruit from these treatments, the total polyphenol content did not differ at harvest, but, after fermentation, the medium crop load had 27% and the high crop load had 37% greater total polyphenol content than the low crop load. Yeast assimilable nitrogen (YAN) concentration in juice made from fruit from the low crop load treatment had 18% and 22% greater than the medium and high crop load, respectively. YAN concentrations in juice from the medium and high crop load treatments were similar. Our results provide apple growers and hard cider producers with a better understanding of how apple crop load impacts YAN concentrations in juice and total polyphenol concentrations in juice and cider.

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Serra, Sara, Rachel Leisso, Luca Giordani, Lee Kalcsits e Stefano Musacchi. "Crop Load Influences Fruit Quality, Nutritional Balance, and Return Bloom in ‘Honeycrisp’ Apple". HortScience 51, n.º 3 (março de 2016): 236–44. http://dx.doi.org/10.21273/hortsci.51.3.236.

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The apple variety, ‘Honeycrisp’ has been extensively planted in North America during the last two decades. However, it suffers from several agronomic problems that limit productivity and postharvest quality. To reduce losses, new information is needed to better describe the impact of crop load on productivity and postharvest fruit quality in a desert environment and the major region where ‘Honeycrisp’ expansion is occurring. Here, 7-year-old ‘Honeycrisp’ trees on the M9-Nic29 rootstock (2.5 × 0.9 m) were hand thinned to five different crop loads [from 4.7 to 16.0 fruit/cm2 of trunk cross-sectional area (TCSA)] to compare fruit quality, maturity, fruit size, elemental concentration, and return bloom. Fruit size distribution was affected by crop load. Trees with the highest crop load (16 fruit/cm2) produced smaller fruit. Index of absorbance difference (IAD) measurements (absorption difference between 670 and 720 nm), a proxy indicator of the chlorophyll content below the skin of fruit measured by a DA-meter, were made shortly after harvest (T0) and after 6 months of storage (T1). Fruit from the trees with the lowest crop load had lower IAD values indicating advanced fruit ripeness. The comparison between the IAD classes at T0 and T1 showed that fruit belonging to the lowest IAD class had significantly higher red-blushed overcolor percentage, firmness, dry matter, and soluble solid content than those in the “most unripe” class (highest IAD readings) regardless of crop load. The percentage of blushed color, firmness, titratable acidity (TA), soluble solids content, and dry matter were all higher in the lowest crop loads at both T0 and T1. Fruit calcium (Ca) concentration was lowest at the lowest crop load. The (K + Mg + N):Ca ratio decreased as crop load increased until a crop load of 11.3 fruit/cm2, which was not significantly different from higher crop loads. For return bloom, the highest number of flower clusters per tree was reported for 4.7 fruit/cm2 crop load, and generally it decreased as crop load increased. Here, we highlight the corresponding changes in fruit quality, storability, and elemental balance with tree crop load. To maintain high fruit quality and consistency in yield, careful crop load management is required to minimize bienniality and improve fruit quality and storability.

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Reginato, Gabino H., Víctor García de Cortázar e Terence L. Robinson. "Predicted Crop Value for Nectarines and Cling Peaches of Different Harvest Season as a Function of Crop Load". HortScience 42, n.º 2 (abril de 2007): 239–45. http://dx.doi.org/10.21273/hortsci.42.2.239.

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Several field experiments to assess the effect of tree size and crop load on fruit size and yield efficiency were conducted in cling peach and nectarine orchards of different harvest seasons in Chile. Trees were randomly selected in each orchard and then hand-thinned at the beginning of pit hardening to a wide range of crop loads. The fraction of above-canopy photosynthetically active radiation (PAR) intercepted by the canopy (PAR i) was determined at harvest. All fruits were counted and weighed and average fruit weight calculated. Crop load and yield were normalized by tree size measured by intercepted PAR i. For each orchard, the relationship between crop load and fruit size or crop load and yield efficiency was assessed by regression analysis. Fruit size distribution was calculated from fruit size adjusted for fruit load assuming a normal fruit size distribution and valued according to shipment date and price obtained from a Chilean export company. Using crop load as a covariate, fruit size adjusted for crop load was compared for nectarine and peach cultivars. Fruit size adjusted for fruit load and yield efficiency was greater with late season cultivars than the early or midseason cultivars. Predicted crop value (PCV), normalized in terms of PAR intercepted, was calculated for all the cultivars. Large differences in predicted crop value were found for early, midseason, and late ripening nectarines. Early and late ripening cultivars had the highest predicted crop value, especially at lower crop loads and larger fruit sizes. The early season cultivars had high crop value as a result of higher fruit prices, whereas the late season cultivar had high crop value as a result of higher production. With cling peaches, the early season cultivar ‘Jungerman’ had a lower predicted crop value than the late season cultivars ‘Ross’ and ‘Davis’. For cling peaches, the highest PCV was achieved at a relatively high crop load with high yield and small fruit size.

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Liu, Xiaoli, Qiuwen Chen e Zhaoxia Zeng. "Study on nitrogen load reduction efficiency of agricultural conservation management in a small agricultural watershed". Water Science and Technology 69, n.º 8 (11 de fevereiro de 2014): 1689–96. http://dx.doi.org/10.2166/wst.2014.076.

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Different crops can generate different non-point source (NPS) loads because of their spatial topography heterogeneity and variable fertilization application rates. The objective of this study was to assess nitrogen NPS load reduction efficiency by spatially adjusting crop plantings as an agricultural conservation management (ACM) measure in a typical small agricultural watershed in the black soil region in northeast China. The assessment was undertaken using the Soil and Water Assessment Tool (SWAT). Results showed that lowland crops produce higher nitrogen NPS loads than those in highlands. It was also found that corn gave a comparatively larger NPS load than soybeans due to its larger fertilization demand. The ACM assessed was the conversion of lowland corn crops into soybean crops and highland soybean crops into corn crops. The verified SWAT model was used to evaluate the impact of the ACM action on nitrogen loads. The results revealed that the ACM could reduce NO3-N and total nitrogen loads by 9.5 and 10.7%, respectively, without changing the area of crops. Spatially optimized regulation of crop planting according to fertilizer demand and geological landscapes can effectively decrease NPS nitrogen exports from agricultural watersheds.

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Inglese, P., T. Caruso, G. Gugliuzza e L. S. Pace. "Crop Load and Rootstock Influence on Dry Matter Partitioning in Trees of Early and Late Ripening Peach Cultivars". Journal of the American Society for Horticultural Science 127, n.º 5 (setembro de 2002): 825–30. http://dx.doi.org/10.21273/jashs.127.5.825.

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Effect of crop load on dry matter partitioning was studied on 3-year-old peach [(Prunus persica (L.) Batsch (Peach Group)] trees of the early ripening `Early May Crest' (EMC) grafted on `GF677' and Penta (Prunus domestica L.) rootstock and the late ripening `Flaminia' grafted on `GF677' rootstock [(Prunus persica × Prunus dulcis (Mill.) D. A. Webb] and grown outdoors in 230-L containers, for 2 years. Fruit thinning was carried out 10 days after fruit set to produce different crop loads. Trees were sampled destructively throughout two growing seasons and divided into above-ground and root components, for dry matter and carbohydrate analysis. At the end of the fruit development period, in the first year, total tree dry matter accumulation was related linearly to crop load even when the increase in crop load greatly decreased vegetative and root growth. Total dry matter accumulation was highest in EMC/`GF 677' at any specific crop load, and EMC trees on `GF677' allocated relatively more dry matter than EMC/`Penta' trees to vegetative and root growth, even under increasing fruit sink demand. Two consecutive years of heavy crops resulted in an inverse relationship between crop load and dry matter accumulation of trees, due to a major reduction of vegetative, root, and fruit growth. The percentage of dry matter partitioned to fruit decreased with the vigor of the rootstock, and EMC/`Penta' trees had the lowest harvest index at each specific crop load. The early ripening EMC/`GF677' trees which had twice the harvest index of `Flaminia'/`GF677' trees for any level of crop load. `Flaminia'/`GF677' trees had the largest canopy size. Starch content in the roots was lowest for cropping trees and depended on the rootstock and on the length of the fruit development period, being highest for the late ripening `Flaminia'/`GF677' trees. Individual fruit weight decreased with crop load, and the reduction of fruit size was related to rootstock and time of ripening.

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Anthony, Brendon, Sara Serra e Stefano Musacchi. "Optimizing Crop Load for New Apple Cultivar: “WA38”". Agronomy 9, n.º 2 (22 de fevereiro de 2019): 107. http://dx.doi.org/10.3390/agronomy9020107.

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Crop load management is growing increasingly important as a factor related to biennial tendencies, post-harvest disorders, and inconsistent fruit quality in apples like “Honeycrisp”. Washington State University released a new apple cultivar, called “WA38”, in 2017. Limited literature is available about the productive characteristics of this new cultivar. An experimental trial evaluating the effect of crop load on leaf area, fruit quality, mineral composition, and return bloom of “WA 38” was conducted for two consecutive years (2017 and 2018) to determine an optimal crop load. Trees were trained as a spindle and grafted on Malling-9 Nic29 (Nic29) rootstocks. Crop loads were adjusted to 2, 4, 6, and 8 fruits/cm2 of trunk cross-sectional area (TCSA). Crop load had a significant effect on production, with yields ranging from 28 to 83 MT/ha in 2017. Fruit quality was impacted by increasing crop load, with a reduction in fruit weight, soluble solid content, firmness, dry matter, titratable acidity, and a delay in maturity. Leaf-to-fruit ratios were higher in lower crop loads. Relatively consistent flower bud formation was seen at the 6 and 8 fruits/cm2 categories. A possible threshold for optimal fruit quality and consistent bloom was identified around 6 fruits/cm2 TCSA.

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Einhorn, Todd C., Debra Laraway e Janet Turner. "Crop Load Management Does Not Consistently Improve Crop Value of ‘Sweetheart’/‘Mazzard’ Sweet Cherry Trees". HortTechnology 21, n.º 5 (outubro de 2011): 546–53. http://dx.doi.org/10.21273/horttech.21.5.546.

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The effect of crop load level on vegetative growth, fruit growth, yield, fruit quality, surface pitting, crop value and return bloom was studied over a 2-year period on 9- and 10-year-old ‘Sweetheart’/‘Mazzard’ sweet cherry (Prunus avium) trees. In early spring, whole-tree crop loads were adjusted to two different levels by removal of reproductive buds (either 50% or all but one) from spurs and compared with an unthinned control. In 2009, heavy crop loads of unthinned trees reduced fruit size by 30 days after full bloom (DAFB). At harvest, fruit diameter of thinned treatments was increased 22% and 27% compared with unthinned fruit. Fruit quality attributes [soluble solids concentration (SS), fruit firmness, and total acids (TA)] were significantly greater for thinned treatments. Thinned treatment yields were reduced 40% to 54% relative to unthinned trees, with greater percentages of fruit in large size classes. Despite significantly fewer fruit per tree, moderately thinned trees had a higher estimated crop value ($142 per tree) than unthinned trees ($125 per tree). Crop value was lowest for the heavily thinned treatment ($107 per tree), reflecting overthinning. In 2010, shoot growth was negatively related to crop load level. Fruit growth of unthinned trees was not significantly affected by higher fruit density until 89 DAFB. Yield of 2010 unthinned trees was 87% of 2009, while thinned tree yields were similar between years. Improved fruit quality and greater percentages of large fruit were observed for thinned treatments in 2010; however, crop value was highest for unthinned trees ($190 per tree), even though 18% of the fruit were too small for fresh market sale. Surface pitting was unaffected by crop load level in either year. Return bloom (flowers per reproductive bud and reproductive buds per spur) was significantly, negatively related to the prior season's crop load in 2010 and 2011. In the current sweet cherry pricing structure, higher crop value is associated with large volumes of medium-sized fruit. Thinning to manage crop load of low-medium density, productive ‘Sweetheart’/‘Mazzard’ trees will not be an annual requirement, though in heavy fruit set years crop load management will improve crop value.

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van Vliet, L. J. P., B. J. Zebarth e G. Derksen. "Effect of fall-applied manure practices on runoff, sediment, and nutrient surface transport from silage corn in south coastal British Columbia". Canadian Journal of Soil Science 82, n.º 4 (1 de novembro de 2002): 445–56. http://dx.doi.org/10.4141/s01-041.

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Runoff from manured cropland during the wet fall and winter season, when 70% of the annual rainfall occurs, is a surface water quality concern in the Lower Fraser Valley of British Columbia. This study compares different fall-manure application strategies on runoff and contaminant transport from silage corn (Zea mays) land. The treatments were (i) a control, which did not receive manure in the fall; (ii) manure broadcast in the fall on corn stubble; and (iii) manure broadcast in the fall on corn stubble with an established relay crop. Runoff, solids, and nutrients loads from natural precipitation were measured on replicated experimental plots (0.0125 ha) from 1996 to 1998. Fall-applied manure on 3–5% sloping silage cornland without a relay crop resulted in a high risk to surface water quality, due to high suspended solid loads of between 7 and 14 Mg ha-1 yr-1 and high nutrient transport with mean annual total Kjeldahl N (TKN) P, and K loads of 98, 21, and 63 kg ha-1, respectively. Compared with no relay crop, intercropping silage corn with a relay crop of Italian ryegrass (Lolium multiflorum) reduced the mean annual runoff and suspended solid load by 53 and 74%, respectively, TKN load by 56%, P load by 42%, K load by 31%, and Cu load by 57%. Even though total nutrient loads were lower with the relay crop treatment, all fall manure treatments including the relay crop resulted in nutrient loads above guidelines for the first three runoff events immediately following application. Key words: Runoff, suspended solids, nutrient loads, relay crop, cover crop, silage corn, manure

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Maas, F. M., e P. A. H. van der Steeg. "CROP LOAD REGULATION IN 'CONFERENCE' PEARS". Acta Horticulturae, n.º 909 (outubro de 2011): 367–79. http://dx.doi.org/10.17660/actahortic.2011.909.41.

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Francescatto, P., J. Lordan e T. L. Robinson. "Precision crop load management in apples". Acta Horticulturae, n.º 1281 (junho de 2020): 399–406. http://dx.doi.org/10.17660/actahortic.2020.1281.53.

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Mais fontes

Teses / dissertações sobre o assunto "Crop load"

Phelan, Patrick G. "INFLUENCE OF CROP LOAD ON FRUIT COMPOSITION USING PINOT NOIR GRAPES". DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/206.

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ABSTRACT Influence of Crop Load on Fruit Composition Using Pinot Noir Grapes Patrick G. Phelan November 2009 The two seasons for this trial were conducted in 2002 and 2003 at Bien Nacido Vineyard in Santa Maria, California. The trial consisted of pinot noir wine grapes clone 2a, grown on 101-14 rootstock. There were eight treatments with a control consisting of 25 vines per treatment, and 50 vines for the control. The primary objective of this research experiment was to conduct different vine balance procedures and compare them to the amount of wine phenolics. The vines were altered with two procedures. First was crop yield; fruit thinning altered the treatments by providing four different crop loads and a control. The treatment levels were signified as one ton, two ton, three ton, four ton, and control. The second procedure was timing of fruit thinning. Four different crop loads were split in half giving rise to eight treatments and a control. With four of the treatments the fruit was dropped post-bloom, and the other four treatments were dropped at seventy five percent veraison. Equal amounts of early and late thinning were combined and made into wine which gave four different crop load wines and a control wine. This process was done in 2002 and repeated in 2003. Additionally, other vine growth parameters were analyzed to determine the role that crop load and timing of thinning had in their development. Seven variables were analyzed from prunings, clusters, juice, and wine samples. They consisted of berry size, cluster weight, titratable acidity, pH, total soluble solids, phenolic profile (consisting of eleven components), and shoot weight. The results indicated that the following were statistically significant: (1) titratable acidity was significantly different between the 2002 and 2003 growing seasons, (2) total soluble solids showed a significant difference between the early fruit thinning versus the late thinning, (3) berry size in 2002 showed a statistically significant effect of drop date on the mean caliper size, (4) in 2002 the berry size also showed a statistically significant interaction between drop level and drop date, (5) berry size in 2003 showed a statistically significant effect of drop level on the mean caliper size, (6) in 2003 there is also a statistically significant effect of drop date on the mean caliper size, (7) again in 2003 there is a statistically significant interaction between drop level and drop date, (8) cluster weights in 2002 showed a statistically significant relationship between drop level and average cluster weight, (9) in 2002 cluster weights also showed an effect of the time of fruit drop on the average cluster weight, (10) cluster weights in 2003 showed a statistically significant relationship between drop level and the average cluster weight, (11) pruning weights in 2002 showed a statistically significant relationship between drop level and average shoot weight, (12) pruning weights in 2003 showed a statistically significant relationship between drop level and average shoot weight and finally, (13) of the eleven phenolic components measured, five differed significantly by year but not across the five treatments. Information derived from this experiment suggests that the site is a high vigour location according to Robinson and Smart’s yield to pruning weight ratio. With this in mind we find that TA and pH were not a significant factor, but soluble solids (brix) ascertained a higher degree of brix with the late drop treatment. We conclude this to be an effect of both the high vigour site and more uniform fruit drop. In 2002 and 2003, we find a significant interaction between drop date and berry size with a late drop producing the smallest berries on average. Cluster weights varied between 2002 and 2003 and the results were inconclusive. Shoot weights along with harvest totals concluded a high vigour site. The one ton level in 2002 had a significantly higher average shoot weight than the three ton level (p<.001), four ton level (p=.006), and no fruit drop control (p<.001). There is also a significant relationship between drop time and average shoot weight in 2002 (p<.001), and 2003 (p=.049) with the late fruit drop being followed by a lower shoot weight. This significant relationship expressed that an early drop increased the shoot weight which contributed only more vigour to an already high vigour site. The ratio of yield to pruning weight for 2002 gave us a range of .39 to 1.78, and in 2003 the range was .32 to 1.36 concluding a high vigour site. The phenolic profile expressed a statistical difference by year, but was most likely caused by a varying fermentation temperature or different climatic conditions in 2002 and 2003.

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Schmidt, Torrance Ray. "Manipulation of crop load with bioregulators to mitigate biennial bearing in apple". Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Fall2006/t_schmidt_120706.pdf.

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Raines, Doug. "A crop load study on 'nittany' apple on two size controlling rootstocks". Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1539.

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Thesis (M.S.)--West Virginia University, 2000.
Title from document title page. Document formatted into pages; contains viii, 52 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 45-51).

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Davis, David Evan. "Inhibition of Flower Bud Initiation and Development in Apple by Defoliation, Gibberellic Acid and Crop Load Manipulation". Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/29739.

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Biennial bearing has been investigated longer and more extensively in apple than in any other fruit tree; however, it remains a serious problem in commercial apple production all over the world. Trees that have become biennial flower profusely and carry a heavy crop in the "on" year, and flower sparsely or not at all and carry little or no crop the following year, the "off" year. Fruit in the "on" year tend to be small, poorly colored, and of low quality, while the few fruit in the "off" year are usually too large, become susceptible to physiological disorders, and also are of poor quality. Without intervention, the crops in both the "on" and "off" years are undesirable and uneconomical. The most common method used by commercial apple growers to try to prevent biennial bearing is chemical fruit thinning, which is an "on" year method of removing a part of the crop before it matures on the tree. In general, growers don't do anything in the "off" year to prevent biennial bearing with the exceptions of fertilizing and pruning lightly. In this study, several experiments were conducted with the cultivars "Braeburn", "Golden Delicious", "Ramey York", and "Fuji" in the "off" year to try and suppress FBI and thus prevent a biennial bearing situation in the following year. The first set of experiments studied the effect of whole-tree and partial-tree defoliation on suppressing spur and lateral flowering and fruit set. Flowering and fruit set were suppressed with defoliation in most cases. Defoliation in early July caused the least amount of flowering the following year and in some cases it was zero. As the defoliation timing and severity was delayed, there was less suppression of flowering and fruit set. Ammonium thiosulfate and Endothal increased flowering but decreased fruit set compared to a control. Gramoxone suppressed flowering and fruit set. In another set of experiments, gibberellic acid (GA) treatments were evaluated to suppress FBI in "off" or light crop years. The GA4+7 treatments suppressed return bloom of both spur and lateral flowers more than the GA3 treatments. The effectiveness of GA declined with delayed application. Both GA treatments reduced lateral flowering the most on the basal 1/3 of the shoot. In a four year study, apple trees were thinned to one fruit per flowering cluster every year from 1997 to 2000. Other trees were thinned to zero fruit or two fruit per flowering cluster in alternate years from 1997 to 2000. Trees thinned to one fruit per flowering cluster had moderate flowering and fruit set the following year. Trees thinned to two fruit per flowering cluster had very little to no flowering the following year. Trees thinned to zero fruit per flowering cluster had a "snowball" bloom the following year. Trees that were alternately thinned to two or zero fruit per flowering cluster were in a biennial bearing situation.
Ph. D.

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Ford, Rebecca Jane. "The effect of shading and crop load on flavour and aroma compounds in Sauvignon blanc grapes and wine". Master's thesis, Lincoln University. Agriculture and Life Sciences Division, 2007. http://theses.lincoln.ac.nz/public/adt-NZLIU20080523.100013/.

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The effects of crop load and berry exposure on the composition of Marlborough Sauvignon blanc grapes and wine from the Brancott vineyard, Blenheim, were explored. Commercially grown, 2-cane and 4-cane Sauvignon blanc vines were used with a row orientation of north-south. Two exposure treatments were imposed in the following manner: complete leaf removal was undertaken in the fruit zone and 50% shade cloth was erected to give a uniform shading treatment to half the trial vines. Weekly thirty-berry and whole bunch samples were taken from each of the 32 plots with the exception of the veraison period when two samples per week were taken. Vine vigour was assessed using pruning and leaf area per vine data. Harvest occurred on different dates for 2-cane and 4-cane pruned vines so that fruit attained from both treatments had similar °Brix. Fruit was processed at the Lincoln University winery. Must analysis and wine analysis were undertaken. As expected, 4-cane vines had almost double the yield of 2-cane vines. Higher crop load significantly reduced leaf area per shoot and shoot thickness. Lower leaf area to fruit ratio for 4-cane berries resulted in delayed onset of veraison and slowed the rate of sugar accumulation. Crop load, which limited leaf area to fruit ratio, appeared to be the dominant factor in determining timing of grape physiological ripeness as expressed by °Brix over other factors such as fruit exposure. Malic acid, tartaric acid, IPMP (iso-propylmethoxypyrazine) and IBMP (iso-butyl-methoxypyrazine) were lower at equivalent °Brix in 4-cane compared with 2-cane berries. Significantly higher concentrations of quercetin were found in exposed compared to shaded berries. Must analysis showed a significant influence of crop load on berry titratable acidity and pH, reflecting berry ripening results. Exposure significantly increased the concentrations of nitrogenous compounds in 4-cane must yet showed no influence on 2-cane must. After wine processing lower malic acid concentrations in wines made from 100% exposed fruit became evident in lower wine titratable acidity but showed no influence on wine pH. Bentonite addition to wines had a small but statistically significant influence on wine by reducing pH, titratable acidity and alcohol. Bound sulphur concentrations were significantly higher in 4-cane versus 2-cane wines. At harvest, methoxypyrazine levels in grapes and wines were very low; IBMP concentrations where significantly lower than those normally found in Sauvignon blanc wines from Marlborough. This was attributed to the absence of basal leaves from the shoots of ripening berries. The results suggest that leaf area to fruit ratio is a powerful determinant of grape and wine quality.

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Ford, R. J. "The effect of shading and crop load on flavour and aroma compounds in Sauvignon blanc grapes and wine". Lincoln University, 2007. http://hdl.handle.net/10182/498.

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Fernandes, Carla Maria Correia. "Monda em macieira Fuji. Comparação entre novas substâncias quimicas e a monda manual". Master's thesis, ISA/UTL, 2010. http://hdl.handle.net/10400.5/5362.

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Mestrado em Engenharia Agronómica - Hortofruticultura e Viticultura - Instituto Superior de Agronomia
The chemical agents, ammonium thiosulphate (ATS) (1%), 6-benzyladenine (BA) (100 ppm) and metamitron (100, 175, and 350 ppm) were evaluated as thinning agents on 3 years old „Fuji‟ grafted on to M9 apples trees. The products were used alone, at single or double application or in combination. There were no differences between treatments regarding yield, mean fruit weight and number of commercial fruits (70 – 85 mm) but there were differences concerning the greater and smaller fruit size classes. The fruit set was reduced by metramitron, but when considering different crop loads its action was independent of the crop load for the 175 and 350 ppm concentrations, however, an over thinning effect was observed at 350 ppm in trees with low crop load. Probably, unfavourable weather conditions during the application period of ATS+BA has jeopardized its effectiveness. Hand thinning, leaving one fruit per cluster spaced of 15 cm, was the best option, but is often impossible because of labor costs and the limited supply of available labor

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Zibordi, Marco <1978&gt. "Crop load control in apple via shading: exploring the potential of carbon unbalances to manage fruit growth and tree performance". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2866/.

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Kamfer, De Witt. "The effect of maturity and crop load on the browning and concentration of phenolic compounds of Thompson Seedless and Regal Seedless". Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95886.

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Thesis (MScAgric)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: Thompson Seedless and Regal Seedless are two white seedless table grape cultivars widely produced in South Africa. Both cultivars are susceptible to berry browning, especially Regal Seedless. Browning leads to annual financial losses for table grape growers. Although a correlation between harvest maturity and the occurrence of browning seems to exist, it is still unclear whether maturity levels are the actual contributing factor. The aim of the study was to establish if harvest maturity and crop load could influence the occurrence of browning of both cultivars. The impact of harvest maturity and crop load on phenolic compound concentration in the berry skin of both cultivars was also investigated. Total external browning of Regal Seedless and Thompson Seedless occurred in much higher percentages than internal browning. Regal Seedless showed a tendency to decreased total external browning with harvest maturity. The main reason for this is that net-like browning, which is the greatest contributor to total external browning, decreased with harvest maturity, in all three seasons. External browning of Thompson Seedless increased with harvest maturity in both seasons. Contact browning was the greatest contributor to total external browning of Thompson Seedless. Crop load did not significantly influence berry browning of Regal Seedless or Thompson Seedless grapes. The flavan-3-ol concentration (catechin, epicatechin, procyanidin B1 and procyanidin B2) in Regal Seedless generally increased with harvest maturity, whereas in Thompson Seedless the general tendency was a decrease in the flavan-3-ol concentration with harvest maturity. The development of phenolic compound concentration with maturity could not be correlated with the occurrence of berry browning. Crop load did not affect flavan-3-ol concentration. When the flavan-3-ol concentration of Regal Seedless and Thompson Seedless were compared at different harvest maturities the concentrations of flavan-3-ols were clearly much higher in the skin of Regal Seedless than in the skin of Thompson Seedless (for both the 2008 & 2009 seasons). Comparison of the browning incidence with harvest maturity for these two cultivars (see above) clearly reveals that external browning of Regal Seedless occurred in much higher percentages than on Thompson Seedless. Regal Seedless had much higher levels of external browning than Thompson Seedless. The concentration of flavan-3-ols in the skin of white seedless cultivars may be an indication of the cultivar’s susceptibility to external browning.
AFRIKAANSE OPSOMMING: Thompson Seedless en Regal Seedless is twee wit pitlose tafeldruif kultivars wat ekstensief in Suid-Afrika verbou word. Verbruining kan ‘n probleem wees by beide kultivars, spesifiek Regal Seedless. Die faktore wat aanleiding gee tot verbruining is nog nie duidelik bepaal nie. Alhoewel dit lyk of daar ‘n korrelasie tussen rypheidsgraad van die oes en verbruining kan wees is dit steeds onduidelik of oesrypheidsvlakke die werklike oorsaak van verbruining is. Die doel van die studie was om vas te stel of die rypheidsgraad van die oes en oeslading verbruining van beide kultivars kan beïnvloed. Die effek van oes rypheidsgraad en oeslading op konsentrasie van fenoliese verbindings in die korrelskil van beide kultivars is ook ondersoek. Totale eksterne verbruining van Regal Seedless en Thompson Seedless het in baie hoër persentasies voorgekom as interne verbruining. Daar was ‘n tendens by Regal Seedless dat totale eksterne verbruining verminder het soos die oes ryper geraak het as gevolg van netagtige verbruining, wat die grootste bydrae tot totale eksterne verbruining veroorsaak het. Netagtige verbruining se voorkoms het verminder oor al drie seisoene. Eksterne verbruining van Thompson Seedless het toegeneem met oes rypheid in beide seisoene. Kontak verbruining het grootste byrdae gelewer tot totale eksterne verbruining van Thompson Seedless. Oeslading het nie ‘n betekenisvolle invloed op verbruining van Regal Seedless en Thompson Seedless gehad nie. Die flavan-3-ol (katesjien, epikatesjien, prosianidien B1 en prosianidien B2) konsentrasie van Regal Seedless het met oes rypheid toegeneem. By Thompson Seedless was daar ‘n afname in die flavan-3-ol konsentrasie met oes rypheid. Daar was geen korrrelasie tussen die konsentrasie van fenoliese verbinding en die voorkoms van verbruining vir beide kultivars. Oeslading het nie ‘n betekenisvolle effek op die konsentrasie van fenoliese verbindings gehad nie. Vergelyking van die flavan-3-ol konsentrasie van Regal Seedless en Thompson Seedless by verskillende rypheidsgrade wys dat die konsentrasie baie hoër in die korrel skil van Regal Seedless as in die van Thompson Seedless (vir beide 2008 & 2009 seisoene). Die vergelyking van die voorkoms van verbruining met oesrypheid van beide kultivars wys duidelik dat eksterne verbruining van Regal Seedless in baie hoër persentasies voorkom as in Thompson Seedless. Flavan-3-ol konsentrasie in die skil van wit pitlose kultivars kan ‘n aanduiding wees van die kultivar se moontlike risiko vir die voorkoms van eksterne verbruining.

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Chalfant, Patricia. "Responses of Grapevines to Timing and Method of Leaf Removal". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1337628161.

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Livros sobre o assunto "Crop load"

Ravichandran, K. Crop loan system and overdues. Rohtak: Spellbound Publications, 2000.

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Miller, Perry Ray. Introducing alternative crops to the brown soil zone. Ottawa, Ont: Agriculture and Agri-Food Canada, Research Branch, 1995.

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Thomas, H. Nigel. How loud can the village cock crow?: And other stories. St-Laurent, Quebec: AFO Entreprises, 1995.

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Westcott, Paul C. Analysis of the U.S. commodity loan program with marketing loan provisions. Washington, D.C: U.S. Dept. of Agriculture, Economic Research Service, 2001.

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Westcott, Paul C. Analysis of the U.S. commodity loan program with marketing loan provisions. Washington, D.C: U.S. Dept. of Agriculture, Economic Research Service, 2001.

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Westcott, Paul C. Analysis of the U.S. commodity loan program with marketing loan provisions. Washington, D.C: U.S. Dept. of Agriculture, Economic Research Service, 2001.

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Westcott, Paul C. Analysis of the U.S. commodity loan program with marketing loan provisions. Washington, D.C: U.S. Dept. of Agriculture, Economic Research Service, 2001.

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Westcott, Paul C. Analysis of the U.S. commodity loan program with marketing loan provisions. Washington, DC: U.S. Dept. of Agriculture, Economic Research Service, 2001.

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Westcott, Paul C. Analysis of the U.S. commodity loan program with marketing loan provisions. Washington, DC: U.S. Dept. of Agriculture, Economic Research Service, 2001.

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United States. Congress. House. Committee on Agriculture. Subcommittee on Wheat, Soybeans, and Feed Grains. 1988 wheat program announcement and county loan rates for the 1987 wheat crop: Hearing before the Subcommittee on Wheat, Soybeans, and Feed Grains of the Committee on Agriculture, House of Representatives, One Hundredth Congress, first session, July 13, 1987. Washington: U.S. G.P.O., 1987.

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Capítulos de livros sobre o assunto "Crop load"

Wünsche, Jens N., e Ian B. Ferguson. "Crop Load Interactions in Apple". In Horticultural Reviews, 231–90. Oxford, UK: John Wiley & Sons, Inc., 2010. http://dx.doi.org/10.1002/9780470650882.ch5.

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Kon, Thomas M., e James R. Schupp. "Apple Crop Load Management with Special Focus on Early Thinning Strategies". In Horticultural Reviews, 255–98. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2018. http://dx.doi.org/10.1002/9781119521082.ch6.

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Vizzari, Marco, Alessandra Santucci, Luca Casagrande, Mariano Pauselli, Paolo Benincasa, Michela Farneselli, Sara Antognelli, Luciano Morbidini, Piero Borghi e Giacomo Bodo. "Potential Nitrogen Load from Crop-Livestock Systems: An Agri-environmental Spatial Database for a Multi-scale Assessment". In Computational Science and Its Applications -- ICCSA 2015, 45–59. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-21404-7_4.

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Máñez Costa, María, e Dmitry V. Kovalevsky. "Weather and Climate Services to Support a Risk-Sharing Mechanism for Adaptation of the Agricultural Sector. A Theoretical Example for Drought-Prone Areas". In Springer Climate, 115–20. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-86211-4_14.

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AbstractSharing the burden of adaptation is key for the agricultural sector in developing countries. For the agricultural sector in developing countries, the losses will go from 3% under 1.5 °C scenario to 7% under 2 °C scenario (Masson-Delmotte et al. 2018). This anticipated information on possible climate change-driven challenges possesses a big load in farmers management that might ex-ante stop investing because of the negative consequences of the scenarios presented. This situation could be even worse in subsistence farming system totally dependent on the yields. Crop insurances can be a good way to overcome some of the losses. In this paper, we present weather-based insurance schemes (WII), which are based on weather index objectively determined for the specific agricultural region, and therefore the individual loss assessment, which makes insurances too expensive, is not necessary. We present the results of decisions based on perfect and imperfect weather forecasts and conclude by offering insights in the difference of decision-making if a perfect forecast might be available or not and the consequences for farmers income.

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Urretavizcaya, I., C. Miranda, J. B. Royo e L. G. Santesteban. "Within-vineyard zone delineation in an area with diversity of training systems and plant spacing using parameters of vegetative growth and crop load". In Precision agriculture '15, 479–86. The Netherlands: Wageningen Academic Publishers, 2015. http://dx.doi.org/10.3920/978-90-8686-814-8_59.

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Padma Lalitha, Mareddy, e Oruganti Hemakesavulu. "Effect of Load Model and Load Level on DG Placement by Crow Search Algorithm". In Lecture Notes in Electrical Engineering, 185–98. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-8942-9_17.

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López-Hernández, Danilo, Diego Sequera, Oswaldo Vallejo e Carmen Infante. "Atmospheric Nitrogen Deposition can Provide Supplementary Fertilization to Sugar Cane Crops in Venezuela". In Nitrogen Deposition, Critical Loads and Biodiversity, 191–97. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-007-7939-6_21.

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Kruger, Erna, Hendrik Smith, Phumzile Ngcobo, Mazwi Dlamini e Temakholo Mathebula. "Conservation agriculture innovation systems build climate resilience for smallholder farmers in South Africa." In Conservation agriculture in Africa: climate smart agricultural development, 345–60. Wallingford: CABI, 2022. http://dx.doi.org/10.1079/9781789245745.0021.

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Abstract Introduction of Conservation Agriculture (CA) and associated climate-resilient agriculture practices within an innovation system approach, and using farmer-level experimentation and learning groups as the primary learning and social empowerment processes, has created a sustainable and expanding farming alternative for smallholders that is improving their resilience to climate change substantially. Through a knowledge co-creation process, smallholder farmers in the programme have adapted and incorporated a wide range of practices into their farming system, including minimum soil disturbance, close spacing, improved varieties, judicious use of fertilizer, pesticides and herbicides, crop diversification, intercropping and crop rotation as well as fodder production and livestock integration. They have organized themselves into learning groups, local savings and loan associations, water committees, farmer centres and cooperatives and in so doing have created innovation platforms for local value chain development. They have built ongoing relationships with other smallholders, NGOs, academic institutions, government extension services and agribusiness suppliers, and have promoted CA tirelessly within their local communities and social networks. To date, this is the most successful model for implementation of CA in smallholder farming in South Africa and, through networking and upscaling activities, is being promoted nationally as a strategic approach to smallholder adaptation and mitigation programming, in line with the Africa climate smart agriculture (CSA) Vision 25×25 (NEPAD, Malabo, June 2014).

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Castle, Katrina, Jonathan Arah e Andrew Vinten. "Measurement and modelling of the effects of crop residues on nitrate loss from clay loam and sandy loam soils". In Progress in Nitrogen Cycling Studies, 401–5. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-011-5450-5_67.

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Cocking, Edward C., e Philip J. Stone. "Mitigating Increases in Nitrogen Deposition: The Challenge of Extending Symbiotic Nitrogen Fixation to Cereals and Other Non-legume Crops". In Nitrogen Deposition, Critical Loads and Biodiversity, 447–52. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-007-7939-6_47.

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Trabalhos de conferências sobre o assunto "Crop load"

Bates, Terence, Jackie Dresser, Rhiann Eckstrom, Golnaz Badr, Thom Betts e James Taylor. "Variable-rate mechanical crop adjustment for crop load balance in ‘Concord’ vineyards". In 2018 IoT Vertical and Topical Summit on Agriculture - Tuscany (IOT Tuscany). IEEE, 2018. http://dx.doi.org/10.1109/iot-tuscany.2018.8373046.

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Qiu, Tian, Lailiang Cheng e Yu Jiang. "3D characterization of tree architecture for apple crop load estimation". In 2022 Houston, Texas July 17-20, 2022. St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2022. http://dx.doi.org/10.13031/aim.202201119.

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Mu, Xinyang, e Long He. "An Advanced Cartesian Robotic System for Precision Apple Crop Load Management". In 2022 Houston, Texas July 17-20, 2022. St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2022. http://dx.doi.org/10.13031/aim.202200228.

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Alina, Dobrei, Dobrei Alin, Nistor Eleonora, Cristea Teodor, Boldea Marius e Sala Florin. "Mathematical and statistical models for determining the crop load in grapevine". In INTERNATIONAL CONFERENCE OF NUMERICAL ANALYSIS AND APPLIED MATHEMATICS 2015 (ICNAAM 2015). Author(s), 2016. http://dx.doi.org/10.1063/1.4952130.

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"Identification of Repetitive Apples for Improved Crop-Load Estimation with Dual-Side Imaging". In 2014 ASABE International Meeting. American Society of Agricultural and Biological Engineers, 2014. http://dx.doi.org/10.13031/aim.20141888882.

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Nwakuba, Nnaemeka Reginald, Collins Osita Chukwuezie, Sabbas Nwabueze Asoegwu e Kevin Nnanye Nwaigwe. "No-Load Performance Testing of an Arduino-Primed Hybrid Solar-Electric Crop Dryer". In 2017 Spokane, Washington July 16 - July 19, 2017. St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2017. http://dx.doi.org/10.13031/aim.201700079.

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Polin, V. D., e A. A. Ananyev. "THE ROLE OF PRECURSORS IN THE DEVELOPMENT OF THE WEED COMPONENT AND THE YIELD OF WINTER WHEAT IN THE CONDITIONS OF THE TULA REGION". In Agrobiotechnology-2021. Publishing house of RGAU - MSHA, 2021. http://dx.doi.org/10.26897/978-5-9675-1855-3-2021-40.

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In conditions of saturation of the structure of crop rotations with winter wheat by more than 50%, the question of selecting high-quality precursors for its cultivation is acute. A properly selected precursor allows you to get higher crop yields while reducing the cost by reducing the pesticide load on the field.

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Yoon, JongHo, Euy-Joon Lee e Moncef Krarti. "Optimization of Korean Crop Storage Insulation Systems". In ASME 2001 Solar Engineering: International Solar Energy Conference (FORUM 2001: Solar Energy — The Power to Choose). American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/sed2001-103.

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Abstract With the increasing concerns with the quality and the safety of foods, several standards and guidelines have been developed to improve the design, construction, and operation of storage warehouses. Several cool storage buildings have been constructed in Korea during the last decade. However, there are no specific standards or guidelines for energy use reduction in refrigerated structures. The main objective of this study to determine the impact of various insulation systems on the total cooling load of the cool storage structures with particular consideration given to the product thermal mass effect to find optimal insulation thickness for each envelope component for various climatic locations in Korea. An energy analysis model was developed using the DOE-2.1E program and over 3500 energy simulations were performed. To determine the optimal configuration for die storage building insulation system, life-cycle cost analysis was conducted. The selection of optimal insulation configuration for each climatic location is based on various criteria including those of crop storage owners and of national energy conservation policy. The results presented in this paper provide easy-to-use design guidelines to select optimal insulation thickness for crop storage facility in Korea.

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L.F., Aslanova. "THE STRUCTURAL STATE OF ORDINARY CHERNOZEM OF THE STEPPE ZONE OF THE ROSTOV REGION AGAINST THE BACKGROUND OF INTENSIVE AGRICULTURAL LOAD". In INTERNATIONAL FORUM "YOUTH IN THE AGRIBUSINESS". DSTU-Print, 2022. http://dx.doi.org/10.23947/young.2022.48-49.

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As a result of the intense anthropogenic load, which manifests itself in the form of a violation of the crop rotation system, the destruction of the agronomically cost structure of ordinary chernozem was noted.

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Baldi, Mauri´cio, e Pable Siqueira Meirelles. "Hydropneumatic Suspension Design". In ASME 2003 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/detc2003/vib-48614.

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This study proposes a robust and cheap hydropneumatic suspension system for agricultural trailers used to spread crop protection. This kind of vehicle has a high dynamic load factor that increases the axles loads when it is in use and require a height control to assure the same spraying efficiency keeping constant the distance between the spray nozzles and the crop. As the tractor has its own hydraulic system, the hydropneumatic suspension conception take in account that height control will be done by the hydraulic fluid, being the mass of gas kept constant. A mathematical model of the hydropneumatic spring stiffness behavior was developed, as well as a methodology to define the suspension parameters. Experimental validation of the mathematical model was carried out through the use of a real agricultural trailer, equipped with a hydropneumatic suspension projected using the procedure presented, and tested in a hydropuls® road simulator.

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Relatórios de organizações sobre o assunto "Crop load"

Katuuramu, Dennis, Gail R. Nonnecke e Paul A. Domoto. Influence of Rootstocks and Crop Load Ratios on Gibson Golden Delicious Apple Yield and Fruit Quality. Ames: Iowa State University, Digital Repository, 2011. http://dx.doi.org/10.31274/farmprogressreports-180814-341.

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Katuuramu, Dennis, Gail R. Nonnecke e Paul A. Domoto. Influence of Crop Load on Tree Growth, Yield, and Fruit Quality of Scab Resistant Apples at Harvest. Ames: Iowa State University, Digital Repository, 2012. http://dx.doi.org/10.31274/farmprogressreports-180814-2351.

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Fuchs, Marcel, Ishaiah Segal, Ehude Dayan e K. Jordan. Improving Greenhouse Microclimate Control with the Help of Plant Temperature Measurements. United States Department of Agriculture, maio de 1995. http://dx.doi.org/10.32747/1995.7604930.bard.

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A model of the energy balance of a transpiring crop in a greenhouse was developed in a format suitable for use in climate control algorithms aimed at dissipating excess heat during the warm periods. The model's parameters use external climatic variables as input. It incorporates radiation and convective transfer functions related to the operation of control devices like shading screens, vents, fans and enhanced evaporative cooling devices. The model identified the leaf boundary-layer resistance and the leaf stomatal and cuticular resistance as critical parameters regulating the temperature of the foliage. Special experiments evaluated these variables and established their relation to environmental factors. The research established that for heat load conditions in Mediterranean and arid climates transpiring crops maintained their foliage temperature within the range allowing high productivity. Results specify that a water supply ensuring minimum leaf resistance to remain below 100 s m-1, and a ventilation rate of 30 air exchanges per hour, are the conditions needed to achieve self cooling. Two vegetable crops, tomato and sweet pepper fulfilled maintained their leaf resistance within the prescribed range at maturity, i.e., during the critical warm season. The research evaluates the effects of additional cooling obtained from wet pad systems and spray wetting of foliage.

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Seginer, Ido, Daniel H. Willits, Michael Raviv e Mary M. Peet. Transpirational Cooling of Greenhouse Crops. United States Department of Agriculture, março de 2000. http://dx.doi.org/10.32747/2000.7573072.bard.

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Background Transplanting vegetable seedlings to final spacing in the greenhouse is common practice. At the time of transplanting, the transpiring leaf area is a small fraction of the ground area and its cooling effect is rather limited. A preliminary modeling study suggested that if water supply from root to canopy is not limiting, a sparse crop could maintain about the same canopy temperature as a mature crop, at the expense of a considerably higher transpiration flux per leaf (and root) area. The objectives of this project were (1) to test the predictions of the model, (2) to select suitable cooling methods, and (3) to compare the drought resistance of differently prepared seedlings. Procedure Plants were grown in several configurations in high heat load environments, which were moderated by various environmental control methods. The difference between the three experimental locations was mainly in terms of scale, age of plants, and environmental control. Young potted plants were tested for a few days in small growth chambers at Technion and Newe Ya'ar. At NCSU, tomato plants of different ages and planting densities were compared over a whole growing season under conditions similar to commercial greenhouses. Results Effect of spacing: Densely spaced plants transpired less per plant and more per unit ground area than sparsely spaced plants. The canopy temperature of the densely spaced plants was lower. Air temperature was lower and humidity higher in the compartments with the densely spaced plants. The difference between species is mainly in the canopy-to-air Bowen ratio, which is positive for pepper and negative for tomato. Effect of cooling methods: Ventilation and evaporative pad cooling were found to be effective and synergitic. Air mixing turned out to be very ineffective, indicating that the canopy-to-air transfer coefficient is not the limiting factor in the ventilation process. Shading and misting, both affecting the leaf temperature directly, proved to be very effective canopy cooling methods. However, in view of their side effects, they should only be considered as emergency measures. On-line measures of stress: Chlorophyll fluorescence was shown to accurately predict photosynthesis. This is potentially useful as a rapid, non-contact way of assessing canopy heat stress. Normalized canopy temperature and transpiration rate were shown to correlate with water stress. Drought resistance of seedlings: Comparison between normal seedlings and partially defoliated ones, all subjected to prolonged drought, indicated that removing about half of the lowermost leaves prior to transplanting, may facilitate adjustment to the more stressful conditions in the greenhouse. Implications The results of this experimental study may lead to: (1) An improved model for a sparse canopy in a greenhouse. (2) A better ventilation design procedure utilizing improved estimates of the evaporation coefficient for different species and plant configurations. (3) A test for the stress resistance of transplants.

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Litaor, Iggy, James Ippolito, Iris Zohar e Michael Massey. Phosphorus capture recycling and utilization for sustainable agriculture using Al/organic composite water treatment residuals. United States Department of Agriculture, janeiro de 2015. http://dx.doi.org/10.32747/2015.7600037.bard.

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Objectives: 1) develop a thorough understanding of the sorption mechanisms of Pi and Po onto the Al/O- WTR; 2) determine the breakthrough range of the composite Al/O-WTR during P capturing from agro- wastewaters; and 3) critically evaluate the performance of the composite Al/O-WTR as a fertilizer using selected plants grown in lysimeters and test-field studies. Instead of lysimeters we used pots (Israel) and one- liter cone-tainers (USA). We conducted one field study but in spite of major pretreatments the soils still exhibited high enough P from previous experiments so no differences between control and P additions were noticeable. Due to time constrains the field study was discontinued. Background: Phosphorous, a non-renewable resource, has been applied extensively in fields to increase crop yield, yet consequently has increased the potential of waterway eutrophication. Our proposal impetus is the need to develop an innovative method of P capturing, recycling and reuse that will sustain agricultural productivity while concurrently reducing the level of P discharge from and to agricultural settings. Major Conclusions & Achievements: An innovative approach was developed for P removal from soil leachate, dairy wastewater (Israel), and swine effluents (USA) using Al-based water treatment residuals (Al- WTR) to create an organic-Al-WTR composite (Al/O-WTR), potentially capable of serving as a P fertilizer source. The Al-WTR removed 95% inorganic-P, 80% to 99.9% organic P, and over 60% dissolved organic carbon from the agro-industrial waste streams. Organic C accumulation on particles surfaces possibly enhanced weak P bonding and facilitated P desorption. Analysis by scanning electron microscope (SEM- EDS), indicated that P was sparsely sorbed on both calcic and Al (hydr)oxide surfaces. Sorption of P onto WW-Al/O-WTR was reversible due to weak Ca-P and Al-P bonds induced by the slight alkaline nature and in the presence of organic moieties. Synchrotron-based microfocused X-ray fluorescence (micro-XRF) spectrometry, bulk P K-edge X-ray absorption near edge structure spectroscopy (XANES), and P K-edge micro-XANES spectroscopy indicated that adsorption was the primary P retention mechanism in the Al- WTR materials. However, distinct apatite- or octocalciumphosphatelike P grains were also observed. Synchrotron micro-XRF mapping further suggested that exposure of the aggregate exteriors to wastewater caused P to diffuse into the porous Al-WTR aggregates. Organic P species were not explicitly identified via P K-edge XANES despite high organic matter content, suggesting that organic P may have been predominantly associated with mineral surfaces. In screen houses experiments (Israel) we showed that the highest additions of Al/O-WTR (5 and 7 g kg⁻¹) produced the highest lettuce (Lactuca sativa L. var. longifolial) yield. Lettuce yield and P concentration were similar across treatments, indicating that Al/O- WTR can provide sufficient P to perform similarly to common fertilizers. A greenhouse study (USA) was utilized to compare increasing rates of swine wastewater derived Al/O-WTR and inorganic P fertilizer (both applied at 33.6, 67.3, and 134.5 kg P₂O₅ ha⁻¹) to supply plant-available P to spring wheat (TriticumaestivumL.) in either sandy loam or sandy clay loam soil. Spring wheat straw and grain P uptake were comparable across all treatments in the sandy loam, while Al/O-WTR application to the sandy clay loam reduced straw and grain P uptake. The Al/O-WTR did not affect soil organic P concentrations, but did increase phosphatase activity in both soils; this suggests that Al/O-WTR application stimulated microorganisms and enhance the extent to which microbial communities can mineralize Al/O-WTR-bound organic P. Implications: Overall, results suggest that creating a new P fertilizer from Al-WTR and agro-industrial waste sources may be a feasible alternative to mining inorganic P fertilizer sources, while protecting the environment from unnecessary waste disposal.

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Aparicio, Gabriela, Vida Bobić, Fernando De Olloqui, María Carmen Fernández Diez, María Paula Gerardino, Oscar A. Mitnik e Sebastian Vargas Macedo. Liquidity or Capital?: The Impacts of Easing Credit Constraints in Rural Mexico. Inter-American Development Bank, junho de 2021. http://dx.doi.org/10.18235/0003336.

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This paper evaluates the effectiveness of easing credit constraints for rural producers in Mexico through loans provided by a national public development finance institution. In contrast to most of the existing literature, the study focuses on the effect of medium-sized loans over a two- to four-year time horizon. This paper looks at the effects of such loans on production and investment decisions, input use, and yields. Using a multiple treatment methodology, it explores the differential impacts of providing liquidity for working capital versus providing credit for investments in fixed assets. It finds that loans increased the likelihood that producers grow and sell certain key annual crops, in particular among recipients of working capital loans. It also finds significant effects on production value and sales (per hectare), with similar impacts for recipients of both types of loans, with gains in yields driven by changes in labor quality and more intensive use of key inputs. There is no evidence of significant effects on the purchase of large machinery, but there are impacts on the acquisition of cattle. Overall, the results reported in this paper suggest that lack of liquidity is at least as important as lack of funding for new investment in capital for rural producers in Mexico. Producers benefit from easing their credit constraints, regardless of the type of loan used for that purpose.

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Lehotay, Steven J., e Aviv Amirav. Fast, practical, and effective approach for the analysis of hazardous chemicals in the food supply. United States Department of Agriculture, abril de 2007. http://dx.doi.org/10.32747/2007.7695587.bard.

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Background to the topic: For food safety and security reasons, hundreds of pesticides, veterinary drugs, and environmental pollutants should be monitored in the food supply, but current methods are too time-consuming, laborious, and expensive. As a result, only a tiny fraction of the food is tested for a limited number of contaminants. Original proposal objectives: Our main original goal was to develop fast, practical, and effective new approaches for the analysis of hazardous chemicals in the food supply. We proposed to extend the QuEChERS approach to more pesticides, veterinary drugs and pollutants, further develop GC-MS and LC-MS with SMB and combine QuEChERS with GC-SMB-MS and LC-SMB-EI-MS to provide the “ultimate” approach for the analysis of hazardous chemicals in food. Major conclusions, solutions and achievements: The original QuEChERS method was validated for more than 200 pesticide residues in a variety of food crops. For the few basic pesticides for which the method gave lower recoveries, an extensive solvent suitability study was conducted, and a buffering modification was made to improve results for difficult analytes. Furthermore, evaluation of the QuEChERS approach for fatty matrices, including olives and its oil, was performed. The QuEChERS concept was also extended to acrylamide analysis in foods. Other advanced techniques to improve speed, ease, and effectiveness of chemical residue analysis were also successfully developed and/or evaluated, which include: a simple and inexpensive solvent-in-silicone-tube extraction approach for highly sensitive detection of nonpolar pesticides in GC; ruggedness testing of low-pressure GC-MS for 3-fold faster separations; optimization and extensive evaluation of analyte protectants in GC-MS; and use of prototypical commercial automated direct sample introduction devices for GC-MS. GC-MS with SMB was further developed and combined with the Varian 1200 GCMS/ MS system, resulting in a new type of GC-MS with advanced capabilities. Careful attention was given to the subject of GC-MS sensitivity and its LOD for difficult to analyze samples such as thermally labile pesticides or those with weak or no molecular ions, and record low LOD were demonstrated and discussed. The new approach of electron ionization LC-MS with SMB was developed, its key components of sample vaporization nozzle and flythrough ion source were improved and was evaluated with a range of samples, including carbamate pesticides. A new method and software based on IAA were developed and tested on a range of pesticides in agricultural matrices. This IAA method and software in combination with GC-MS and SMB provide extremely high confidence in sample identification. A new type of comprehensive GCxGC (based on flow modulation) was uniquely combined with GC-MS with SMB, and we demonstrated improved pesticide separation and identification in complex agricultural matrices using this novel approach. An improved device for aroma sample collection and introduction (SnifProbe) was further developed and favorably compared with SPME for coffee aroma sampling. Implications, both scientific and agricultural: We succeeded in achieving significant improvements in the analysis of hazardous chemicals in the food supply, from easy sample preparation approaches, through sample analysis by advanced new types of GC-MS and LCMS techniques, all the way to improved data analysis by lowering LOD and providing greater confidence in chemical identification. As a result, the combination of the QuEChERS approach, new and superior instrumentation, and the novel monitoring methods that were developed will enable vastly reduced time and cost of analysis, increased analytical scope, and a higher monitoring rate. This provides better enforcement, an added impetus for farmers to use good agricultural practices, improved food safety and security, increased trade, and greater consumer confidence in the food supply.

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