Late Harvest Research Articles

BRS 420: Early maturity cassava cultivar for production of flour and starch, adapted to no-till planting and mechanization

The cultivar BRS 420 has superior starch yields in early and late harvest, moderate resistance to the main diseases of the crop, adaptation to mechanized planting and to the no-till system, as well as rapid formation of soil cover (which assists in weed control). It represents an alternative for cassava growers in Paraná and Mato Grosso do Sul.

Seeding rate affects the performance of oat and black oat

AbstractBasic management practices, including ideal seeding rates, are still lacking for black oat (Avena strigosa Schreb.) in the southeastern United States. This study evaluated the performance of five seeding rates (15, 30, 60, 120, and 240 lb acre−1) on ‘Legend 567’ oat (Avena sativa L.) and ‘UF‐10’ black oat at three harvest dates (early, mid‐season, and late) per year. Seeding rates of 60, 120, and 240 lb acre−1 tended (P = .07) to increase total herbage accumulation [4,760 lb dry matter (DM) acre−1] compared with 15 lb acre−1 (3,945 lb DM acre−1). Tiller density was usually greater for black oat than for oat. Seeding rate was positively associated with tiller density and explained 84 to 98% and 96 to 98% of the variation for black oat and oat, respectively. Tiller mass was greater for oat (0.045 oz tiller−1) than black oat (0.034 oz tiller−1), and greater for the mid‐season harvest (0.043 oz tiller−1), compared with the early and late harvests (0.037 oz tiller−1 on average). There was a negative effect (P < .001) of seeding rate on tiller mass. Increasing the seeding rate had a negative effect on leaf length at the early and middle harvests (P < .05), and decreased leaf width from 0.56 to 0.39 inches in oat, and from 0.32 to 0.29 inches in black oat when changing from 15 to 240 lb acre−1. To maximize herbage accumulation at a lower seeding rate, we recommend 60 lb acre−1 for both oat and black oat for multiple harvests.

Detekcija gubitaka semena uljane repice pre berbe analizom slike u okviru Fog računarstva

Losses in the production of oilseed rape can occur before harvest, caused by the spontaneous opening of mature pods and the fall of seeds on the ground. Different seed pods, among other things, ripen on the same plant at different times. So, in the cultivation of similar crops, one of the most critical moments is determining the right time for harvesting, because late harvest implies overripeness and opening of the shell, which leads to seed spoilage, losses and mechanical damage during threshing. One way of monitoring seed shedding and thus potential losses is by placing a container between rows of oilseed rape plants and monitor the number of seeds that fall from open shells. The presented model of the system, which consists of sensor devices with associated cameras, positioned above the position, has a function to transmit images of the current state. Central to this paper is an image analysis application that can be performed near sites on computer-aided devices within Fog Computing. In this way, the results of the analysis of images on the number of seeds in the container are obtained almost immediately and can be forwarded to the Cloud platform or directly to the user who will take appropriate action. By obtaining timely information on the number of scattered seeds, it is possible to organize the harvest in an optimal way in order to avoid losses and prevent over-ripeness of oilseed rape.

STUDYING OF THE USE OF A WHEELED TRACTOR AND THE UPGRADED DISC HARROW

Timely preparation of the soil for the future harvest is one of the main tasks facing agricultural producers in the Amur region. There are a number of reasons related to the features of the natural production conditions of the region: late harvesting of branded legumes (soybeans) and abundant precipitation during the spring and autumn field and harvesting operations. (Research purpose) The research purpose is increasing the efficiency of using machine-tractor units during harrowing by improving the design and technological parameters of disc harrows. (Materials and methods) The article presents the device that allows adjusting the coupling weight in the scheme of a machine-tractor unit, for which RF patent No. 196181 was applied. The article also presents photos of the general types of connection of the device with the disk harrow frame, the processing depth was measured. (Results and discussion) All fields suitable for agricultural activity in the region have been developed and used by large agricultural producers, the remaining land reserves consist of slope and small-contour fields, small in size, operated by peasant farms. In small farms, the machine-tractor fleet consists of several units of tractors and a small set of agricultural machines for completing machine-tractor units. (Conclusions) The issue of increasing the efficiency of using machine-tractor units for peasant farms in the Amur region is relevant and requires a modern solution. The article presents the results of research on improving the efficiency of using a tractor unit consisting of a class 1.4 tractor and a BDT-3 disc harrow by increasing traction properties and improving the quality of soil preparation.

The effects of different harvest maturity and methods on fruit and oil quality of olive (Olea europea L. cv. Ayvalık Yağlık)

Objective: This study was conducted to determine the effects of harvest time and method on fruit and oil characteristics of ‘Ayvalık Yağlık’, a major olive cultivar in Turkey. 
 Material and Methods: Early, optimum and late harvests were made by hitting with a wood stick (control), pneumatic beater, and branch shaker in a conventional olive grove located in Edremit district of Balıkesir province in western Turkey. Harvested olive fruits were stored at 18-20°C for 3 days, and physical, biochemical attributes, free acidity, and fatty acid composition, and mechanical damage caused by tested harvest methods were evaluated. 
 Results: Mechanical damage index and free fatty acidity were lower in olive fruits harvested by branch shakers compared to those dropped down by stick. Fruit weight, maturity index, oil content and linoleic acid content increased with the progress of harvest date, while color, moisture content, free fatty acids, total phenolics, and palmitic, stearic, and linolenic acid ratio decreased at the last harvest date. 
 Conclusion: The results showed that significant changes in some physical and chemical properties of the olive fruit occur with the progression of maturity, and using branch shakers and harvesting on the 2nd and 3rd harvest dates are recommended for Ayvalık variety under the experimental site conditions.

The occurrence of Fusarium species in white spears of Asparagus officinalis

The aim of the study was to determine the species composition of fungi of the Fusarium genus found on white Asparagus officinalis spears, depending on the presence or absence of disease symptoms, age of the plantation, date of harvest and the place from which samples were collected for mycological analysis. Additionally, the pathogenicity of selected Fusarium spp. isolates was determined. A. officinalis L. was cultivated for white spears. The research was conducted on the German dioecious cultivar ‘Eposs’. Samples of A. officinalis spears for tests were collected from two plantations. Six species of fungi of the Fusarium genus were identified in the asparagus spears: F. culmorum, F. equiseti, F. oxysporum, F. proliferatum, F. solani, and F. fujikuroi. Among the Fusarium species colonizing Asparagus officinalis the greatest threat is F. oxysporum. Always there are more isolates in the spears with the symptoms, in epidermis. The late harvest date favors the development of fusariosis. This means that the spears harvested at the latest date (late June) are the most heavily colonised by fungi. The isolates of fungi of the Fusarium genus collected from the spears exhibit pathogenicity against A. officinalis plants.

Proximate and Mineral Nutrition of Common Bean Genotypes as Influenced by Harvesting Time

Common bean is the most consumed legume by humans and hence significant for global food security and nutritive value mainly iron (Fe) and zinc (Zn). The objective of the study was to evaluate the effect of harvesting time and genotypes on proximate and mineral composition of common bean. Two field experiments were carried out in Sebele (24o33′S, 25o54′E, 994 m above sea level) horticultural fields during summer 2018/2019. Treatments included two common bean genotypes DAB 564 (white) or 520 (red) and three harvesting stages as the early, mid and late season harvest. In both seasons, genotype and harvesting time significantly (P < 0.05) influenced proximate, macro and micro mineral composition of common bean seeds. Generally genotypes studied had a sufficient amount of proximate and mineral content with crude protein, iron (Fe) and zinc (Zn) content as the most abundant minerals at a range between 20-22%, 33-101 mg g-1 and 41-45 mg g-1, respectively across harvesting times. Genotype DAB 564 (white coloured) significantly (P < 0.05) produced seeds with the highest concentration of proximate and mineral contents especially zinc (45 mg g-1) and iron (70 mg g-1) content irrespective of season. Harvesting common bean seed early or mid-stage produced high seed concentration of proximate, micro and macro mineral content across genotype or season.

Pre-harvest sprouting on high-level seed dormancy of bambara groundnut (Vigna subterranea) landraces

Abstract. Sari M, Ilyas S, Suhartanto MR, Qadir A. 2021. Pre-harvest sprouting on high-level seed dormancy of bambara groundnut (Vigna subterranea) landraces. Biodiversitas 22: 5617-5623. Bambara groundnut (Vigna subterranea (L.) Verdc.) is an underutilized crop. Therefore, its seed quality is not guaranteed. Pre-harvest sprouting (PHS) on bambara groundnut seeds can be found either due to the unpredictable rainfall or the late harvesting and plants are still in the field when rainfall. Conversely, seed dormancy causes a problem for planting. The objective of this research was to identify seed dormancy and PHS of four bambara groundnut landraces and other related seed characters. Four landraces (Madura, Sukabumi, Brown Sumedang and Tasikmalaya) were planted at the end of May 2017. Seeds were harvested at physiological maturity (130 days after planting) during the beginning of the wet season (early October 2017). The result showed that there were variations of PHS among landraces from 1% to 12%, and variations of seed dormancy rates from 62% to 82%. There were differences in seed color, seed size, tannin content, seed hardness, and imbibition rate. However, these characters could not clearly explain the diversities in PHS and seed dormancy. There was a high genetic diversity within Tasikmalaya landrace because this landrace had the highest PHS (12%) and the highest dormancy rate (82%) as well, although both characters are contradictory. This diversity needs further research, mainly to avoid the disadvantages due to PHS.

Prioritization of olive breeding objectives in Spain: Analysis of a producers and researchers survey

Aim of study: Trait prioritization of potential olive (Olea europaea L.) breeding objectives has been evaluated in this work from two surveys to researchers working on olive and olive producers / orchard managers. Area of study: Olive growing area in Andalusia (South of Spain) Material and methods: Twenty-five breeding objectives were associated to plant growth, fructification, oil content and composition, resistance to pest and disease and tolerance to soil and climatic conditions. Two assessment methods were applied (ranking and rating), showing similar results in both the researchers and producers surveys. Main results: Higher productivity was the objective with the highest score, followed by Verticillium wilt resistance and higher oil content. After them, tolerance to water stress and resistance to Xylella fastidiosa were among the preferred objectives. Conversely, the least preferred objectives were late harvesting, high fruit size and tolerance to water lodging and calcareous soils. In the producers’ survey, results have been consistent among the different types of orchards and farmers’ characteristics. It is also interesting to notice that more than 50% of the producers expressed their willingness to orchard enlargement or renewal in the three coming years and 25% of them would change the olive cultivar. They would be willing to pay an average 43% overprice for new cultivar fulfilling their requirements and 75% would support the use of genetic modified olives. Research highlights: These results should be considered to analyze the scope of current breeding programs and define the main criteria to be considered for future works aiming at developing new olive cultivars.

Phytochemistry and Inflorescences Morphometry of Invasive Solidago L. (Goldenrods) Species – Valuable Late Autumn Mellifers

In Europe, two invasive North American species of Solidago L. have been detected: S. canadensis L. and S. gigantea Ait. Both species provide a stable late harvest and are valued by beekeepers for their ability to produce pollen and nectar in late fall. There is a significant correlation between the chemical components of flowers and goldenrod honey, so the study of the phytochemical composition of inflorescences (heads) seems to be very actual. The work aims to determine the total content of saccharides, phenolic compounds, and flavonoids in the heads of S. canadensis and S. gigantea for comparative evaluation of bee production quality, and also to specify morphometric differences in the heads of both species and to reveal the amplitude of their variability. The material was collected in the Moscow and Pskov Regions (Russia). The total content of the saccharides in S. canadensis heads was 27.33 ±0.54 %, with monosaccharides ~44–46 %. In S. gigantea’s heads total content of the saccharides was 1.5 times lower – 18.07 ±0.73 %, the content of monosaccharides was 7.39 ±0.15 %. The total content of phenolic compounds in the heads of S. canadensis was 105.36 ±1.45 mg GAE/100 g and in S. gigantea’s heads was 98.41 ±1.71 mg GAE/100 g. The total flavonoid content as quercetin equivalents was 58.23 ±0.17 mg QE/100 g in the heads of S. canadensis and 41.97 ±0.34 mg QE/100 g in S. gigantea’s heads. Thus, in S. canadensis heads the content of the total content of saccharides is 1.5 times higher, the content of phenolic compounds is 1.3 times higher, and the content of flavonoids is 1.4 times higher than in S. gigantea. A feature allowing the diagnosis of these species is the size of the heads: S. canadensis has smaller heads than S. gigantea (4.4×1.8 vs. 6.4×2.3 mm).

Genetic Variability and Character Association Studies in Indian Mustard (Brassica juncea L.)

India is a nation which has got huge scope for modernization. The pace of increasing modernization in India coupled with its ever increasing human population is posing a very serious impact on environment mainly due to global warming. Abrupt rainfall conditions coupled with drought conditions prevailing during the Kharif season often hampers paddy transplantation in eastern parts of India. It results in late harvesting of paddy which in turn leads to late sowing of mustard crop in the fields during Rabi season. Hence, the need of the hour is to develop Indian mustard varieties having high yield potential as well as suitable for late sown conditions in Eastern India. An investigation was carried out to study the genetic variability, correlation and path analysis of ten quantitative traits in 33 genotypes of Indian mustard procured from diverse agro-climatic zones of the country. Analyses of variance were found to be highly significant for all the characters studied. Genotypic Coefficient of Variability as well as Phenotypic Coefficient of Variability were found high for number of primary branches, number of secondary branches, number of siliqua and seed yield per plot. High heritability coupled with higher genetic advance was found for plant height, number of siliqua per plant and seed yield per plot suggesting due importance of these traits for selection in breeding program.The phenotypic and genotypic correlation studies revealed that seed yield per plot exhibited significant positive correlation with plant height, number of primary branches per plant, number of secondary branches per plant, number of siliqua per plant, siliqua length, seeds per siliqua and 1000 seed-weight. Path coefficient analysis revealed that seed yield per plot, days to maturity, plant height, number of primary branch, number of secondary branch, number of siliqua per plant had positive direct effect on seed yield per plot suggesting that direct selection for these triats can be practiced for yield improvement in Indian mustard.

Grain yield response to cultivar and harvest time of the first crop in rice ratooning in southwestern Japan

AbstractRice (Oryza sativa L.) ratooning has attracted attention due to its higher yield potential compared with conventional methods. Here, field experiments were conducted in southwestern Japan in 2019 and 2020 to determine the effects of cultivar (‘Takanari’, an indica cultivar, and ‘Koshihikari’, a japonica cultivar) and harvest time of the first crop (early and late) on the grain yields of the first and second crops in rice ratooning. For Koshihikari in 2019, grain yield of the second crop did not differ between harvest times. However, Takanari produced a lower grain yield at late harvest. Takanari had fewer spikelets, fewer filled spikelets, and a lower 1,000‐grain weight at late harvest. However, for Takanari in 2020, grain yield did not differ between harvest times. In 2019, the stubble nonstructural carbohydrate (NSC) content did not increase from early to late harvest, whereas the stubble leaf area index (LAI) decreased between harvest times; this difference was more apparent in Takanari than in Koshihikari. Contrastingly, in 2020, the NSC content increased from early to late harvest, but the stubble LAI did not differ between harvest times. Thus, the lower grain yield of late‐harvested Takanari in 2019 might be attributed to the lower stubble LAI resulting in fewer spikelets. In contrast, the maintained grain yield from early to late harvest in 2020 might be attributed to the maintenance of spikelet numbers via the higher stubble NSC content. Therefore, the sufficient stubble LAI and NSC could be essential for improving grain yield of the second crop.

Improving hydration and vase life of cut Zinnia

Zinnia (Zinnia elegans Jacq.) is a commercially important species in the cut flower industry that has several postharvest challenges including hydration, cold storage, and seasonality. The purpose of this work was to increase vase life of cut zinnia by assessing hydration, chilling sensitivity and storage temperatures, and environmental impacts incurred by harvest date. The negative effects of allowing zinnia ‘Benary Giant Deep Red’ stems to dry up to 4 h after hydrating were negated by recutting stems and removing 2.5 cm of the stem. However, if zinnia stems did not dry out, then recutting had either no effect or a negative impact. Zinnia stems did not rehydrate if allowed to dry for 24 h or more and recutting various amounts from stem ends before placing in vases demonstrated no significant effect on vase life, nor did varying the number of stems per vase. Vase life increased by 2.2 d when stems were stored in a 0.01845 mL L−1 sodium hypochlorite solution versus tap water. Postharvest quality of zinnia was affected by storage temperature such that the longest vase life of 13.0 d occurred when stems were stored for 5 h at 5 °C followed by 2 d storage at 1 °C. As storage temperature increased, zinnia vase life decreased, with the shortest vase life of 6.5 d occurring when stems were stored for 48 h at 20 °C. Vase life continually declined when zinnia stems were harvested every 2 wks from 27 July to 19 Oct. The use of floral preservatives increased vase life late in the harvest season but was not comparable to the extended vase life obtained earlier in the season. Zinnia vase life increased by 2.1 d with the use of a floral preservative (Floralife® Professional) as a 20 h pulse solution in lieu of tap water only. The main findings of this research show that zinnia stems can tolerate a short period of desiccation, while storing stems in a floral preservative and incorporating a brief cold storage period of 1–3 d at 1–5 °C increased vase life. Chilling sensitivity was not observed. Conversely, vase life was observed to be negatively correlated with late season harvesting.

321 Extrusion of Grass Silage Increase Intake and Milk Yield in Dairy Cows

Abstract This research evaluated effects of grass silage extrusion on dairy cow performance. A grass dominated (70% timothy, 26% meadow fescue, 3% red clover and 1% undefined) first cut ley was harvested on June 13, 2019, and 10 days later near Uppsala, Sweden (58°83′ N, 17°82′ E). Crops were wilted (45% DM for early cut, 50% DM for late cut), round baled and wrapped into plastic film for ensiling. At feeding out, bales were chopped in a TMR feeder, and a portion was processed in an extruder, where screws shear the material under pressure, for further particle size reduction and cell wall break up. Eight Swedish Red cows in two blocks (4 ruminally fistulated, 143 ± 38 DIM and 4 intact, 68 ± 10 DIM) were used in a Latin square design experiment with 4 periods of three weeks each and 4 treatments. The 2x2 factorial arrangement of treatments included silage from early or late harvest that was chopped or extruded. Silage was fed separately ad libitum and supplemented (daily amounts on an as fed basis) with 2 kg of soybean meal, a compound feed (6 kg for fistulated and 8 kg for intact cows), and 120 g of a mineral mix. Extrusion increased silage DMI (1.8 kg/d, P < 0.001) with greater effect at late harvest (P = 0.021 for interaction between processing and harvest) and milk yield (1.8 kg ECM/d, P = 0.004) with a tendency to greater effect at late harvest (P = 0.055). Extrusion depressed total tract OM digestibility (2.3 percentage points, P < 0.001), eating time (0.5 h/d, P = 0.014), rumination time (2.0 h/d, P < 0.001) and rumen pH (0.1 units, P = 0.008). Extrusion improves intake and milk production in dairy cows, despite depressed digestibility.

Prioritization of olive breeding objectives in Spain: Analysis of a producers and researchers survey

Aim of study: Trait prioritization of potential olive (Olea europaea L.) breeding objectives has been evaluated in this work from two surveys to researchers working on olive and olive producers / orchard managers.Area of study: Olive growing area in Andalusia (South of Spain)Material and methods: Twenty-five breeding objectives were associated to plant growth, fructification, oil content and composition, resistance to pest and disease and tolerance to soil and climatic conditions. Two assessment methods were applied (ranking and rating), showing similar results in both the researchers and producers surveys.Main results: Higher productivity was the objective with the highest score, followed by Verticillium wilt resistance and higher oil content. After them, tolerance to water stress and resistance to Xylella fastidiosa were among the preferred objectives. Conversely, the least preferred objectives were late harvesting, high fruit size and tolerance to water lodging and calcareous soils. In the producers’ survey, results have been consistent among the different types of orchards and farmers’ characteristics. It is also interesting to notice that more than 50% of the producers expressed their willingness to orchard enlargement or renewal in the three coming years and 25% of them would change the olive cultivar. They would be willing to pay an average 43% overprice for new cultivar fulfilling their requirements and 75% would support the use of genetic modified olives.Research highlights: These results should be considered to analyze the scope of current breeding programs and define the main criteria to be considered for future works aiming at developing new olive cultivars.

Oxidative stability, fatty-acid and phenolic composition of Cypriot monovarietal virgin olive oils with progressive fruit maturity

Oil content, extractability, chemical composition and oxidative stability of three monovarietal (‘Ladoelia’, ‘Kato Drys’ and ‘Korakou’) virgin olive oils (VOOs) were examined at progressive stages of fruit maturity. Oxidative stability was assessed on a Rancimat System, phenols and tocopherols by HPLC-DAD and fatty acid (FA) profiles by GC-FID. Oil extractability was highly cultivar-specific and unaffected by maturity stage. ‘Ladoelia’ exhibited excellent extractability and satisfactory VOO composition and oxidative stability, with moderate phenolic and diverse tocopherol content. ‘Kato Drys’ was rich in monounsaturated FA that imparted superior oxidative stability and poor in polyunsaturated and saturated FA. Monovarietal VOOs exhibited higher correlation of oxidative stability with the C18:1/C18:2 ratio (r = 0.80, p < 0.0001) than with the total phenolic content (TPC; r = 0.436, p < 0.05), suggesting that phenolic association with oxidative stability might be specific to individual phenolic compounds than to TPC. Late harvest of ‘Ladoelia’ and ‘Kato Drys’ was liable to drastic rise in free acidity. Poor extractability, low oil and oleic acid contents undermined the suitability of ‘Korakou’ for VOO production. The current findings contribute towards the establishment of typicity for monovarietal VOOs.

Nitrogen reduction in high plant density cotton is feasible due to quicker biomass accumulation

Cotton (Gossypium hirustum L.) as well as other crops are asking for an effective production with cost reduction and environment stewardship globally, especially in the developing countries. A new cotton planting strategy should be possible by shortening the growth season (less than six months rather than seven to eight months by late sowing and early harvesting) with low nitrogen (N) and high density. Therefore, a two-year (2018–2019) field experiment was conducted with a split plot design, two planting densities (D1, 6 plants m−2; D2, 8 plants m−2) as the main plot and three N rates (150, 180 and 210 kg ha-1 referred as N1, N2, and N3, respectively) as the subplot, to determine the effects of planting density and N rate on cotton yield and biomass accumulation. Results showed that, averaged across years, cotton yield was greater for treatment D2 as compared with that in D1, and N3 did not differ from that in N2 but was greater than that in N1. The highest lint yield (1271.2 kg ha-1) was achieved in D2N2 which no differ from that in D2N3 and D1N3. The maximal biomass (K) was achieved in treatment D2N2 (1032.4 g m−2) with the average speed (VT) of 21.2 g m−2 d-1 during the fast accumulation period, and the maximal growth rate (Rm, 20.5 g m−2 d-1) of sink during the cotton growth and development. Seedcotton yield was positively correlated (r = 0.72) to the plant biomass during flowering and boll-setting period, and the yield was contributed directly by sink with a coefficient as high as 0.70, while it was contributed indirectly by flow and source with coefficients of 0.63 and 0.59, respectively. The results suggest that N reduction is feasible due to a quicker bulk sink biomass accumulation under a higher planting density, which benefits efficient cotton production in the Yangtze River Valley, China, and areas with similar ecology.

Ethyl Methane Sulfonate (EMS) Effect on Mutagenesis in Balinese Red Rice (Oryza sativa cv. Barak Cenana)

“Barak Cenana” is one of the local red rice (Oryza sativa) with high economic value due to its nutrient content. Some of the agronomic characters such as tall shoot, low number of tiller, and late harvesting are drawbacks to improving production. Ethyl Methyl Sulphonate (EMS) is a chemical mutagen widely used to improve rice characters by mutation breeding. The present research aims to investigate the EMS concentration suitable to induce mutation in Barak Cenana and observe the mutagenesis effect of EMS on some agronomic characters of Barak Cenana. For those purposes, mature seeds of Barak Cenana were treated with various concentrations of EMS (0.25, 0.5, 0.75, 1.0, and 1.1 %) for 24 hours. Seed germination, plant growth, some agronomic character related to productivity were compared to untreated rice. EMS reduced and delayed seed germination and inhibit shoot and root growth in early vegetative stage. The ability of EMS to reduce and delay seed germination and inhibit shoot and root growth were doses dependent. EMS concentration of more than 1.0% was lethal for Barak cenana and EMS concentration at 0.75% was able to reduce rice productivity by increasing seed sterility. EMS concentrations between 0.25 and 0.5% with 24 h of soaking are suitable for inducing mutagenesis in Barak Cenana. Additionally, some mutants with distinct morphology such as sterile plant, semi-dwarf, high tillering capacity, and high chlorophyll contents were produced in this research.

Combined Effects of Ventilation and Irrigation on Temperature, Humidity, Tomato Yield, and Quality in the Greenhouse

Ventilation and soil moisture influence greenhouse cultivation. Experiments were conducted at Xinxiang Irrigation Research Base of the Chinese Academy of Agricultural Sciences, Henan Province, China, to identify how ventilation and irrigation affected the greenhouse microenvironment. To develop ventilation and irrigation protocols that increase crop yield and improve the quality of drip-irrigated tomatoes grown in the greenhouse, three ventilation modes (T1, T2, and T3) were developed by opening vents in different locations in a completely randomized pattern. T1 had open vents on the north wall and roof of the greenhouse. T2 had open vents on the north and south walls and the roof. T3 had open vents on the north and south walls. Three irrigation treatments (W1, W2, and W3) were designed based on the accumulated water surface evaporation (Ep) of a standard 20-cm evaporation pan. The irrigation quantities were 0.9×Ep (W1), 0.7×Ep (W2), and 0.5×Ep (W3). The spatial and temporal distributions of temperature and humidity were analyzed for different combinations of ventilation and irrigation to identify their effects on tomato yield and fruit quality. Major results were as follows: 1) In addition to solar radiation, ventilation had an important influence on Ep and, on a daily scale, ventilation had a significant effect on Ep (P &lt; 0.05). 2) Ventilation had a significant effect on indoor wind speed, but the effect varied during different growth stages. During the flowering and fruit setting stage, wind speed for T2 significantly differed from those of T1 and T3 (P &lt; 0.01). During the harvest stage, the three ventilation treatments had significantly different effects (P &lt; 0.01). A correlation analysis showed high correlation between T2 wind speed and T3 wind speed (R = 0.831), but low correlation between T2 wind speed and T1 wind speed (R = 0.467). 3) The effect of ventilation on greenhouse humidity and temperature was greater than the effect of irrigation. The differences in air temperature among various combined treatments of ventilation and irrigation were significant for the flowering and fruiting stages (P &lt; 0.05), but they were not significant for the late harvest stage (P &gt; 0.05). There were significant differences in humidity on sunny days (P &lt; 0.01), but no significant differences on cloudy or rainy days (P &gt; 0.05). Air temperature at 2 m was greater than canopy temperature, but humidity at 2 m was less than that at canopy level. 4) Irrigation water quantity was positively correlated with tomato yield and negatively correlated with the fruit quality indicators total soluble solids, vitamin C content, organic acid content, and soluble sugars content. Ventilation had an effect primarily during the harvest period; it had no significant effect on yield (P &gt; 0.05). However, it had a significant effect on vitamin C content and the sugar:acid ratio (P &lt; 0.01). The combination treatment of T2W2 is recommended as the optimal treatment for greenhouse tomatoes using drip irrigation to produce an optimal combination of crop yield and fruit quality. This study provides theoretical and technical support for the improvement of greenhouse climate control by optimizing greenhouse ventilation and irrigation techniques to promote tomato yield and improve fruit quality.

Winter Forage Crop Harvest Time Impacts Regeneration of the Annual Weeds Barley Grass, Annual Ryegrass and Wild Radish

Barley grass (Hordeum spp.) is a short-lived annual weed which competes with preferred crop and pasture species and frequently contaminates wool and carcasses, and irritates the ears, eyes and noses of sheep. Barley grass, annual ryegrass (Lolium rigidum L.) and wild radish (Raphanus raphanistrum L.) are annual winter crop weeds which reduce grain yield through competition. In three consecutive years (2015 to 2017) cereal, legume and cereal/legume forage crops were grown and harvested in early October, late October or early November consistent with an early silage harvest (ES), late silage harvest (LS) or hay cut (H). A spring wheat cultivar was sown over each site in the following year (2016 to 2018). Weed density was recorded during the forage crop and wheat phases. Forage crop weed populations varied between years. Late paddock preparation for sowing in 2015 effectively eradicated barley grass from all forage crops; however, the competitiveness of legume and cereal/legume crops against annual ryegrass was reduced. In contrast, legume and cereal/legume mixtures tended to have higher barley grass densities than cereal crops in 2016 and 2017, when paddock preparation was earlier. Cutting in October 2015 reduced annual ryegrass and wild radish populations in 2016 wheat by 92.0% and 86.7%, respectively. In 2017 and 2018, regrowth and subsequent seed set following cutting appeared to negate cutting time effects for all crop and crop/legume combinations. Late paddock preparation, an early October forage harvest and effective regrowth control provided the best opportunity for barley grass, annual ryegrass and wild radish control in a single year.