Impact testing of potato harvesting equipment

Samples of 28 different potato harvester chain links in seven different configurations were evaluated using the MSU-USDA Instrumented Sphere (IS). During the fall of 1989, 23 potato harvesters in Michigan were evaluated using the IS. Besides the IS impact data, each harvester was measured for chain speed relationships, operating ground speed, chain type and drop height. Testing of the harvesters did provide a range of data that represents what is likely to occur when the IS is used to evaluate individual harvesters. Based on the average peak acceleration and velocity change values (and the computed severity rating), air heads had the most severe impacts. The next most severe impacts were the primary chain, where all impacts were on steel. Next were the transitions to the rear cross and the side elevator, both of which involved a change of direction for the IS and the potatoes. Roller tables had the least severe impacts.     

Spray volume and fungicide rates for citrus black spot control based on tree canopy volume

The control of citrus black spot (CBS) caused by Phyllosticta citricarpa relies mainly on fungicide sprays. Generally, high and non-standardized spray volumes are adopted and the sprays are based on litre per tree or per hectare. However, the tree canopy volume may vary with age, density and variety, and this is expected to impact on the spray volume and fungicide rates needed for disease control. This study evaluated the efficacy of different fungicide spray volumes and rates for CBS control based on the tree-row-volume (TRV) concept. Two field trials were carried out during three seasons in São Paulo state, Brazil. Trials were set up in commercial orchards of late-maturing ‘Valencia’ sweet orange grown for juice production. In field trial 1, the volumes tested were 125 (standard), 100 (internal runoff point), 75 (intermediate) and 50 (half the internal runoff point) mL of spray mixture/m³ of the tree canopy. In field trial 2, 100 and 50 mL/m³ were evaluated. The fungicide rates ranged from 40 to 110 mg of metallic copper/m³ and from 1.9 to 4.7 mg of pyraclostrobin/m³. Untreated control trees (UTC) were kept unsprayed. CBS incidence and severity, premature fruit drop, yield, fungicide deposition and spray coverage were evaluated. All spray volumes tested reduced CBS incidence and severity on fruit at 75–95% and resulted in 1.6–3.0-fold higher yields than the UTC. However, a slight trend of more CBS symptoms and fruit drop, and lower yield was observed for trees treated with 50 mL/m³ compared to those treated with higher volumes. Spray volume change, from 125 to 75 mL/m³, irrespective of fungicide rate correction, led to a 40% reduction of CBS spray costs and water usage and increased the financial return of the control by up to 35%. TRV-based sprays may contribute to sustainable citrus production by reducing costs and environment impacts while maintaining efficient CBS control.     

Subcutaneous tissue discoloration in ware potatoes. 2. Impact measured by an instrumented sphere

Summary Potatoes are exposed to mechanical forces which can lead to subcutaneous tissue discoloration resulting in losses. We investigated the number and intensity of impacts in different phases of representative Dutch ware potato handling chains using an instrumented sphere (IS). Other questions we asked were, to which drop height onto a defined surface do measured impacts correspond, and what is the relation between the number of impacts and damage? Close relationships between peak acceleration and velocity change for different drop heights were found for various cushioning materials, thus allowing interpretation of impact measurements in terms of drops. The IS recorded c. 340 impacts exceeding 30g. The contribution to the total number of impacts was 11% for Harvest, 0% for Storage, 10% for Transport and 79% for Packaging. The number and intensity of impacts correlated well with the amount of subcutaneous tissue discoloration. It is concluded that the produce-friendliness of the handling chains can be improved.     

Cost benefits of integrating nitrogen,plant growth regulators and fungicides in winter barley

Data from experiments on winter barley sown in mid-September in south-west England between 1983 and 1985 have shown that fungicide programmes, involving up to three sprays per season, provided increased profits at a market value for barley of £100 per tonne of between £53 and £250/ha, depending on variety and nitrogen timing. On non-fungicide treated crops an overall mean benefit of between £28 and £154/ha was obtained by delaying the main nitrogen dressing from mid-March to mid-April, irrespective of site or season. Responses to a plant growth regulator application at GS 30 were more variable, but overall were more cost effective when applied to March nitrogen crops. Integration of these management variables has identified areas where increased profit can be achieved with similar or even reduced agronomic inputs. Overall, two spring-applied fungicide sprays were consistently profitable irrespective of nitrogen timing, whereas the inclusion of an autumn fungicide spray frequently decreased gross margins. In 1985, the financial impact of management variables was studied in crops that received the main nitrogen dressing either in mid-March or in mid-April. A single fungicide spray, applied when the flag leaf was fully emerged (GS 39) to cvs Igri, Sonja, Halcyon and Tipper that received the main nitrogen dressing in mid-March, increased gross margins by 41%, 21%, 10% and 35% respectively, whereas the same fungicide treatment applied to crops that received the main nitrogen dressing in mid-April further increased the gross margin to 51%, 48%, 21% and 47% respectively compared with crops that received no fungicide and the main nitrogen dressing in mid-March. The addition of an autumn fungicide spray improved gross margins for each variety when the main nitrogen dressing was applied in mid-March but not mid-April. The profitability at a reduced market value for barley of £80/t is discussed.     

Spray deposition assessment using different application techniques in artificial orchard trees

Seven orchard spray application techniques were compared in terms of within-tree deposition quality and off-target losses to the ground and behind the target trees. The studied spray techniques included different sprayer types, fan speeds and air deflector settings. An artificial pear canopy was realized for this purpose. Filter papers and a multiple tracer methodology were used to evaluate deposition. All measurements were conducted indoor and will be used as an input and to validate a CFD orchard spray model.Results showed that spray application technique has an effect on spray deposition. Sprayer design caused major differences in spray distribution and off-target losses. A sprayer with individual spouts gave the highest deposits on the tree (0.15 L), followed by an axial sprayer (0.10–0.12 L). Changing settings on the axial sprayer only caused minor differences, although the high fan gear performed significantly better than the low gear. Lowest tree depositions were found for a cross-flow sprayer (0.08–0.09 L). A significant portion of the spray liquid was lost to the ground and directly behind the trees with all spray techniques. The axial fan sprayer and the sprayer with individual spouts caused higher ground deposits than the cross-flow sprayer. The cross-flow sprayer on the other hand gave higher losses behind the trees, especially when a high fan speed was applied.     

Application of an orcinol-ferric chloride colorimetric assay in barley and wheat accessions for water-extractable and total arabinoxylan

Arabinoxylan is an important hemicellulose potentially affecting wheat baking qualities, barley malt quality, and may impart prebiotic benefits. Water-extractable (WEAX) and total arabinoxylan (TOAX) were characterized in 204 wheat and barley accessions, respectively, using an orcinol-ferric chloride assay. WEAX measurement accuracy was optimum when glucose concentration was greater than 12–13 times pentose concentration. The modified method removed enough excess glucose spectral absorbance to make the corrected and uncorrected lines different, but still significantly correlated (p = 0.009, R = 0.94). Mean WEAX (expressed as percentage WEAX of TOAX) for the wheat accessions was 15.90%, ranging from 8.82% to 24.87%, and for barley accessions WEAX the mean was 7.10%, and ranged from 2.98% to 13.86%. Conclusions are 1) the assay is useful for a breeding program because of its semi-high throughput design for the simultaneous analysis of 16 (WEAX) to 40 (TOAX) barley lines or 24 (WEAX) to 40 (TOAX) wheat lines, 2) the trichromatic measurement reduces the impact of glucose, and 3) the broad range of WEAX measured showed that barley and wheat accessions vary in their extractable and unextractable components.     

Density and relative frequency effects on competitive interactions and resource use in pea–barley intercrops

Intercropping advantages may be influenced by both plant density and relative frequency of the intercrop components. In a field study barley (Hordeum vulgare L.) and pea (Pisum sativum L.) were sole cropped and intercropped at three densities and with two relative frequencies when intercropped.Earlier seedling emergence gave barley an initial growth advantage, assessed using the relative efficiency index (REIc), whereas pea was in general more growth efficient once the initial growth phase had been passed. This reversal in relative growth efficiency along with the observation that early barley dominance did not appear to suppress pea growth indicates that differences in phenology played a role in shaping the prevailing dynamics. Whereas increases in plant density had a positive effect on the growth of pea, the growth of intercropped barley was severely limited by increases in density at the end of the growing period and more so in the pea dominated intercrop. At the final harvest land equivalent ratios (LER) of 0.9–1.2 express resource complementarity in almost all studied intercrops, complementarity that was not directly affected by changes in plant density or relative frequency.Intercropped pea did not increase its reliance on atmospheric nitrogen fixation compared to the pea sole crop. With respect to soil nitrogen uptake there were no effect of plant density but a strong effect of the relative frequency of pea in the intercrop, the greater the proportion the lower the uptake.Changes in the competitive strength of the pea and barley crop over the growing season had a marked effect on the proportion of pea in the final grain yields of the intercrops. At low and recommended density the proportions of pea and barley in the final grain yield was not markedly different from the expected proportions sown; however, at high density the suppression of barley strongly increased the proportion of pea in the final grain yield.Weed infestation levels decreased as density was raised and the suppressing effect of density was clearly stronger the greater the frequency of pea in the crop. Earlier germination and tillering ability of barley are seen as likely explanations of lower weed load in the barley dominated crop treatments.This study points at the potential of employing density and relative crop frequency as “regulators” when specific intercrop objectives such as increased competitiveness towards weeds or specific grain yield composition are wanted.     

Evaluating pea and barley cultivars for complementarity in intercropping at different levels of soil N availability

Two field experiments were carried out on a temperate sandy loam using six pea (Pisum sativum L.) and five spring barley (Hordeum vulgare L.) cultivars to determine cultivar complementarity in the intercrop for grain yield, dry matter production and nitrogen (N) acquisition. Crops were grown with or without the supply of 40 or 50 kg N ha⁻¹ in the two experiments. Cultivars were grown as sole crops (SC) and as mixed intercrops (IC) using a replacement design (50:50). The land equivalent ratio (LER), which is defined as the relative land area under SC that is required to produce the yields achieved in intercropping, were used to compare cultivar performance in intercropping relative to sole cropping.Barley was the stronger competitor in the intercrops and as a result barley grain yield and nitrogen uptake in IC were similar to SC. The per plant pea grain production and aboveground N accumulation in IC were reduced to less than half compared to SC pea plants due to competitive interactions.Application of N caused a dynamic change in the intercrop composition. Competition from barley increased with N application and the pea contribution to the combined intercrop grain yield decreased. The LER values showed that in the intercrop plant growth resources were used on average 20% more efficient without N application and 5–10% more efficient with N application.The choice of pea cultivar in the intercrop influenced the intercrop performance to a larger degree than the choice of barley cultivar. Furthermore, pea cultivar×cropping systems interactions was observed, indicating that cultivars performed differently in sole and intercrops. An indeterminate pea cultivar competed strongly with barley causing a greater proportion of peas in the intercrop yield, but caused a reduced N uptake and yield of barley. Determinate peas with normal leaves caused the highest degree of complementary use of N sources by allowing barley to exploit the soil N sources efficiently, while they contribute with fixed N₂. However, difference in performance among cultivars was observed. Using the indeterminate pea cultivar combined IC grain yield was in general lower than the greatest sole crop yield and vice versa for the determinate pea cultivars. Up to 22% (LER=1.22) greater combined IC grain yield was observed in several mixtures using determinate pea cultivars.From the present study, it is was concluded that there is a need for breeding suitable pea cultivars for intercropping purposes, since cultivars bred for sole cropping may not be the types, which are the most suitable for intercropping. For optimized N-use in pea–barley intercrops it is concluded that important traits for the intercropped pea are: (1) determinate growth, (2) a medium competitive root system for soil inorganic N and other nutrients during early growth, (3) high light absorption capacity by peas growing underneath the canopy of the higher barley component and (4) early establishment of symbiotic N₂ fixation to support a high growth rate during early growth stages.Fertilized pea–barley intercrops gave a 15% higher net income than fertilized barley sole cropping and is regarded as a better safeguard for the farmer’s earnings compared to pea sole cropping known for variable yields and poor competitive ability towards weeds.     

茶多酚微胶囊化的试验研究

采用喷雾干燥法,以生物可降解高分子材料羟丙基甲基纤维素邻苯二甲酸酯（HPMCP）为骨架材料,对茶多酚进行微胶囊化研究。以微球的包封率作为实验指标,用L₉ (3⁴)正交实验设计优化制备茶多酚微球的工艺,得到以下结果：加入少量乳化剂可较大程度提高产品的包封率,十二烷基硫酸钠(SDS)作为乳化剂效果比聚乙烯醇(PVA)好,最佳添加量是芯壁材总重的4％;制备茶多酚缓释微球的最佳条件为：进风温度100℃,进料速度6.25βml/min,芯壁材比为2:1,总固形物含量为3％。采用HPMCP作为壁材,以喷雾干燥法对茶多酚进行微胶囊化是可行的,茶多酚微球有一定的缓释效果。     

THE EFFECT OF SUPPLEMENTARY BARLEY UPON GROWTH AND EFFICIENCY OF FOOD CONVERSION IN CALVES KEPT AT HIGH GRAZING INTENSITY

Three groups of Hereford × Friesian steer calves, bom in early January 1969, were strip-grazed on eqoal areas of a sward of S321 perennial ryegrass from May to September inclusive, and received kibbled barley at the rate of nil, 3/4% or 1 1/2% of liveweight per day. Adjustments were made to the number of animals per group in order to maintain the same high grazing intensity (defined as 8 cm stubble height in grazed areas) on all treatments. The animals receiving supplementary barley gained weight at a rate 17–19% higher than the controls, but there was no significant difference in growth rate between the high and low levels of supplementation. The effficiency of conversion of barley was only 5–12 kg per animal liveweight gain/100 kg barley OM. The high level of supplementation resulted in an increase in stocking rate of 36 % over that of the control group, and an increase in liveweight gain per unit area of land grazed of 63%. The additional liveweight gain due to supplements, expressed per unit area of land grazed, was relatively constant at 21–24 kg liveweight gain/ 100 kg barley OM consumed.     

The ‘Electrodyn’ sprayer: first studies of spray coverage in cotton

A programme of investigation was started in mid-1977 in Spain into the performance of the ‘Electrodyn’ sprayer for the control of insect pests on cotton. The first stages of the programme, reported in this paper, evaluated the effect on spray deposition and distribution of emission height, speed of travel, wind speed, and position of the ‘Electrodyn’ sprayer nozzle relative to the row, in order to define the optimum method of use. In replicated field trials ultra-low-volume low volatile formulations were applied and performance was measured by assessing subjectively fluorescent spray deposition and distribution over samples of all plant structures at two heights in the plant. Plants were sampled from one row upwind and three rows downwind from each single spray run. The overall distribution of fully charged spray from the ‘Electrodyn’ sprayer was, in general, similar to that of discharged spray applied by the ‘Electrodyn’, with more than 80% deposited on ‘top’ leaves. A smaller proportion of the fully charged spray cloud penetrated to the lower half of the crop than did discharged spray. Variability from leaf to leaf was less and, of the total spray recovered, the proportion deposited on the main stem and branches in the top of the plant was four times greater, with charged than discharged spray. Cover of a greater part of the circumference of stems and branches and the only significant underleaf cover (the ‘wrap-around’ effect) was achieved by charged spray in the top of the plant and there was a concentration of spray at the tips and edges of leaves and bracts. Subjective assessments of deposition showed that 2·5 times more spray was recovered in the crop when charged than when discharged In practice the improvement could range from about 1·25 to 5 times depending upon the efficiency of the conventional system. Different speeds of travel, between 0·5 and 1·5 m/s (the highest reported) did not affect pest-control performance. An optimum mode of use was devised to facilitate subsequent comparisons of pest control between the ‘Electrodyn’ sprayer, rotary atomizers, and hydraulic nozzle sprayers. The ‘Electrodyn’ sprayer should be held downwind of the operator. At a nominal walking speed of 1·0 m/s in cotton less than 0·4 m tall, the nozzle is held 0·2 m directly above the row and all rows are sprayed: in taller cotton (0·4–1·5 m) the nozzle is held above the inter-row space and either taken along every inter-row with the nozzle 0·2–0·4 m above the crop, or, for low input/high risk crops (minimum levels of pest control) the nozzle is taken along alternate inter-rows, 0·4–0·5 m above the crop.     

Phenotypic,physiological and malt quality analyses of US barley varieties subjected to short periods of heat and drought stress

Drought and heat are major abiotic stresses that significantly reduce crop yield and seed quality. In this study, we examined the impact of heat, drought and combined effect of heat and drought stress imposed during the grain filling stage in 18 US spring barley varieties. These impacts were assessed based on dry biomass, seed yield and six important malting quality traits, namely, beta-glucan, free amino nitrogen, soluble protein, refractive index, diastatic power and alpha-amylase activity. Singly applied heat or drought stress evoked a diverse set of responses among these varieties with respect to biomass, seed yield and malt quality traits suggesting these varieties can be exploited for enhancing barley production based on local conditions. Majority of the tested varieties performed poorly with reference to seed yield when the stresses were applied in combination, suggesting a lack of genetic diversity in the currently grown spring barley varieties to overcome co-occurring episodic drought and heat regimes, especially during heading stages. In the wake of global climate change, enhancing adaptive capacity of barley varieties by introducing novel germplasm into breeding programs or via new technologies is vital to sustain US barley production and meet the demands of the rapidly growing brewing industry.     

Phytate Reduction in Whole Grains of Wheat,Rye, Barley and Oats after Hydrothermal Treatment

Whole grains of different cereals have traditionally been prepared with water and heat prior to dehulling, but knowledge of the effect on nutritional properties is limited. The aim of the present study was to investigate if phytate reduction occurred during hydrothermal treatment of whole grains. Wheat, rye, hulled and dehulled barley, hulled oats and naked oats were incubated with either water or acetate buffer (pH 4·8) at 55 °C for 24 h with the exception of oats, which were incubated at 37 °C. Phytate in wheat, rye and barley was reduced by 46–77% when water was used and by 84–99% when acetate buffer was used. The phytate reduction in oats was considerably less, 8–26%, but, after grinding and soaking, phytate was reduced by 72–77% in dehulled oats and by 88–94% in naked oats. Citric acid and citrate buffer was used for pH adjustment in some experiments, and their use resulted in less phytate reduction than when acetate and lactic acid were used. Wet-steeping of naked oats and naked barley in water at 53–57 °C for 20–30 min reduced the bacterial counts by 99·97%, and the addition of acid prevented bacterial growth during the incubations. It was concluded that cereals with reduced phytate content and good hygienic quality can be developed and produced using hydrothermal treatment of whole grains.     

Spray drift: impact of requirements to protect the environment

Spray drift studies in the US have evaluated the effects of application, meteorological and tank mix variables on spray drift. The data have been incorporated into models to predict drift from aerial applications, and to evaluate worst-case drift from ground rig (boom) and orchard airblast applications. An atomisation model has also been developed to predict droplet size for applications of tank mixes with user-defined or reasonable worst-case physical properties through a wide range of hydraulic nozzles applicable to aerial applications. The database and models help provide the exposure risk input to risk assessments for developing appropriate labelling based on exposure and toxicity risk to non-target sensitive areas. This needs to be balanced with allowing crop protection using careful risk/benefit assessments. Buffers or no spray zones may be based on spray quality, release height and other variables such as wind speed where necessary for protecting specific sensitive areas. The impact of protection measures aimed at minimising the incidence and impact of spray drift is discussed in the present paper.     

Deposition and biological efficacy of a fungicide applied in charged and uncharged sprays in cereal crops

Barley and wheat crops were both sprayed at growth stages 30 and 61–75 with boom-mounted conventional hydraulic nozzles (250 ?/ha), experimental hydraulic electrostatic nozzles (66 ?/ha), electrically driven spinning discs (2 ?/ha, oil-based sprays and 5 ?/ha, aqueous spray) and ‘Electrodyn’ nozzles (1 and 2 ?/ha, oil). The ULV spray systems (up to 5 ?/haS) were used with or without air assistance. The distribution of both oil and aqueous sprays within the crops was measured with fluorescent tracers on plant parts and on whole plants. An experimental triazole fungicide (mixed with tracer) was applied to the crops by all the spray systems and the degree of control of leaf blotch (scald) caused by Rhynchosporium secalis (Oudem.) J.J. Davis in barley and mildew (Erysiphe graminis DC) in wheat compared with the deposit data. The two highest-volume spray systems gave similar results for disease control and there was no significant difference between the charged and uncharged sprays at 66 ?/ha. The Micron Ulva spinning disc and ‘Electrodyn’ systems with air assistance also performed well. Unassisted ULV sprays were often unevenly distributed within the crops and gave inferior disease control. The ‘Electrodyn’ system often produced large total deposits relative to other spray systems but unassisted sprays were mainly deposited on the upper plant parts. The results indicate that application at volumes as low as 1 ?/h can be as biologically effective as conventional high-volume spraying, when compared at the same dose rate of fungicide (90 g/ha). Relationships between spray distribution within cereals and the sites for pest and disease attack are discussed with regard to different methods of application.     

Cereal–legume rotations in a Mediterranean environment: biomass and yield production

The effects of various crop rotations on the biomass and yield of barley (Hordeum vulgare L.), faba bean (Vicia faba L.), and pea (Pisum sativum L.) grown under Mediterranean conditions were studied during three growing seasons in the semiarid Spanish Central Plateau. The treatments comprised six crop sequences: barley monoculture, fallow–barley (currently used in the area), faba bean–barley, pea–barley, fallow–barley–faba bean, and fallow–barley–pea. The fallow was of 16-month duration. The site is representative of cultivated areas of the Plateau, and the soil has a loam texture. Results concentrate on barley as the main crop. Season distribution of rainfall restricted the effectiveness of the management practices and in consequence there were few differences between rotations. Barley had greater biomass and yield after fallow than after other crops but significant differences were dependent on year. Legumes, an alternative to fallow, increased land use, permitted alternative weed control measures, and reduced the need for fertiliser. The intensification of the fallow–barley cropping system is best achieved by reducing the frequency of fallow and including other crops of relatively small biomass production, thereby minimising the impact on yield of the succeeding barley crop.     

西藏部分青稞主要农艺性状分析

为发掘可提供西藏青稞育种利用的优异品种资源，并为西藏青稞生产提供相应的高产栽培技术，考察了来自6个地区34份青稞的主要农艺性状，结果表明，西藏青稞农艺性状存在丰富的遗传变异，具有矮秆、穗数多和千粒重偏低等特点。相关分析表明西藏青稞各农艺性状间存在复杂的相关性，如穗粒数与株高、单株有效穗数与穗长、总小穗与穗长等呈显著或极显著的正相关和偏相关，单株有效穗数与株高呈极显著的负相关，千粒重与单株有效穗数呈极显著的负偏相关。主成分分析将西藏部分青稞7个农艺性状分为4个主成分，其累积贡献率为91.192%，穗型的贡献率最高，达到46.4338%。供试材料在遗传距离5.18水平上可聚为三大类，分为矮秆短穗少粒型、长穗多粒型、穗多粒重型等三种类型。     

西藏部分青稞主要农艺性状分析

为发掘西藏青稞的优异种质资源,考察了来自西藏6个地区34份青稞的主要农艺性状。结果表明,西藏青稞农艺性状存在丰富的遗传变异,具有矮秆、穗数多、千粒重偏低等特点。相关分析表明,西藏青稞各农艺性状间存在复杂的相关性,如穗粒数与株高、单株有效穗数与穗长、总小穗与穗长等呈显著或极显著的正相关和偏相关,单株有效穗数与株高呈极显著的负相关,千粒重与单株有效穗数呈极显著的负偏相关。主成分分析将参试的34份青稞材料的7个农艺性状分为4个主成分,其累积贡献率为91.192%,穗型的贡献率最高,达到46.4338%。供试材料在遗传距离5.18水平上可聚为三大类型：矮秆短穗少粒型、长穗多粒型、穗多粒重型。     

大麦芒的作用初探

本试验对大麦进行了六种剪芒处理的研究。结果表明，大麦的芒对大麦籽粒产量的贡献卓越，其贡献大小因品种而异，一般来说，长芒大麦＞短芒大麦、多棱大麦＞二棱大麦；芒在从大麦抽穗到成熟的各段时期内的贡献大小不一；二棱大麦麦穗一侧的芒对另一侧的籽粒产量不作贡献；剪芒对大麦结实率无显著影响。