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    Influence of handling at harvest on the softening behaviour of kiwifruit : a thesis presented in partial fulfilment of the requirements for the degree of Master in Horticultural Science at Massey University, New Zealand
    (Massey University, 1992) Davie, Ivan John
    The New Zealand Kiwifruit industry in 1991 lost an estimated $54 million due to premature softening of kiwifruit during postharvest storage. The present study sought to determine if premature softening might be associated with the physical damage resulting from handling at harvest. The influence of physical damage on fruit was investigated on fruit from eleven kiwifruit properties from the Bay of Plenty region in New Zealand. Fruit were harvested and stored at 0°C and 20°C; firmness was destructively assessed. Softening behaviour of fruit sampled immediately after harvest from the vine (no physical damage) were compared with fruit from the same orchard block handled through the normal postharvest handling chain and packed in a packhouse. Analysis of variance and nonlinear regression using two, three and four parameter models were used to help in describing any differences in firmness values for fruit held in cool storage (0°C). The advantages and disadvantages of using analysis of variance and nonlinear regression to describe differences in firmness values between treatments are discussed. Analysis of variance determined that the packhouse and vine fruit on average were of a similar firmness. Nonlinear three parameter model: Firmness = a exp-bt + c (starting values: a = 6, b = 0.01 and c = 0.5) where: a = difference between initial and final asymptotic firmness b = exponent describing rate of decline in firmness c = final asymptotic value for fitted firmness was found to best characterise changing fruit firmness values over time. An analysis of variance was then performed on the resulting parameter values a, b and c which found that vine fruit on average had a slightly faster rate of softening than packhouse fruit. Packhouse fruit were not expected on average to have a similar firmness to vine fruit, as packhouse fruit were thought to have been exposed to potentially damaging impacts during handling. This may have been due to vine fruit being of a smaller size, position of fruit trays in cool storage or the rewarming of fruit during transportation. A non-destructive measure of firmness would help to identify the factors leading to premature softening and help to quantify fruit to fruit variability. A second part of this study therefore involved development and evaluation of a non-destructive instrument for measuring kiwifruit firmness (softness meter) compared with a penetrometer and its ability to repeatedly measure an individual fruit's firmness over time. The non-destructive softness meter characterised fruit firmness by measuring changes in deformation over time. Plots of deformation versus the natural log of time were linear and the gradient of the line was used as the measure of firmness (softness coefficient). Fruit with a range of firmness values were assessed using the softness meter, then penetrometer readings were obtained on the same location of each fruit and the relationship between the two instruments established. Within-fruit variation for both softness coefficients and penetrometer data was strongly related to fruit firmness, with coefficients of variation remaining approximately constant at about 10% for each variable. The softness meter will help to identify how localised treatments applied to fruit affect firmness and help to identify premature softening causes in individual fruit.
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    An economic analysis of a robotic harvest technology in New Zealand fresh apple industry : a dissertation presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Agribusiness, Massey University School of Agriculture and Environment, Manawatu, New Zealand
    (Massey University, 2020) Ghahremani, Morteza
    The New Zealand apple industry is predominately an export-oriented industry relying on manual labour throughout the year. In recent years, however, labour shortages for harvesting have been jeopardising its competitiveness and profitability. Temporary immigration labour programs, such as the Recognised Seasonal Employer (RSE) program have not been able to solve the labour shortages, urging the industry to consider use of harvesting automation, i.e. robotic technology, as a solution. Harvesting robots are still in commercial trial stage and no studies have assessed the economic feasibility of such technology. The present study for the first time develops a bio-economic model to analyse the investment decision for adopting harvesting robots compared to available alternatives, i.e. platform and manual harvesting systems, using net present value (NPV) as the method of analysis; for newly established single-, bi-, and multi-varietal orchards across different orchard sizes, and three apple varieties (Envy, Jazz, and Royal Gala); and implications of orchard canopy transition and associated sensitivities are considered. The results of the analysis identified fruit value and yield as the key drivers for the adoption of harvesting automation. For relatively low value and or yielding varieties such as Jazz or Royal Gala, robots are less profitable in single-varietal orchard compared to bi-varietal orchard planted with relatively low value and yielding varieties. In a multi-varietal orchard, a relatively high value and high yield variety, such as Envy, is crucial to compensate for the costs incurred for harvesting other varieties using robots or platforms. The greatest potential benefit of utilising harvesting robots was reducing pickers required by an average of 54% for Envy and 48% for each of Jazz and Royal Gala across all orchard sizes compared to manual harvesting; and 7% in average for each of Envy, Jazz, and Royal Gala across all orchard sizes compared to platform harvesting system. This study also identified the break-even price for a robotic harvester in a single-varietal orchard, showed that the break-even prices exceeded the assumed price of the robot, and are highly variable depending on the varietal value and yield, where Envy as a relatively higher value and yielding variety returns a break-even price of $2.92 million compared to relatively lower value and yielding varieties, Jazz with $674,895, and Royal Gala with $689,608. Sensitivity analyses showed that both harvesting speed and efficiency are key parameters in the modelled orchard and positively affected the net returns of the investment and must be considered by researchers and manufacturers. However, for developers and potential adopters of robots, it should be more important that robots operate faster, but not necessarily as more efficient in order to generate a high return while substituting the highest number of pickers and leaving less unharvested fruit on trees in the limited harvesting window. Reducing robot price by 12% and 42% can generate an equivalent level of profit similar to manual or platform harvesting, respectively. Increases in labour wages, and decreases in labour availability and efficiency adversely affected the NPV and profitability outlook of the investment, but NPV was more affected by the decreases in labour efficiency and availability than wage increases. This research has important science and policy implications for policy makers, academics, growers, engineers, and manufacturers. From an economic perspective, for late adopters or those growers who may not be financially able to invest in robots or may be uncertain about their performance, platform harvesting system can be utilised as an alternative solution that is commercially available until robotic harvesting technology improves or becomes more affordable, and commercially available. Alternatively, it may be possible for these orchardists to benefit from utilising the robotic harvester in the form of a co-operative or contract-harvesting business model to avoid the capital costs associated with purchasing and operating the robots. Besides the economic factors, robotic harvesters have the potential to be considered as a solution for non-economic factors such as food safety problems. This is more apparent in the post-Covid-19 pandemic era, which has not only made it more difficult for growers to source their required workers due to border closures, but also has led consumers to be more cautious about food safety when they make purchase decisions and prefer to have their fresh fruit touchless from farm to plate. This may not be a problem for packhouses as most are automated, but it may be an issue for harvesting operations, because pickers have to pick apples by hand. Even though robots cannot be the only option for growers to rely on for the foreseeable future as they are not commercially available, in the current situation robot harvesting may be the most ideal solution.
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    A study of the effect of the frequency of spring cutting on the regrowth and resulting yield of lucerne (Medicago sativa L.) : a thesis presented in partial fulfillment of the requirements for the degree of Master of Agricultural Science at Massey University
    (Massey University, 1968) Tsuma, Francis
    There is abundant evidence to show that the yield, stand, chemical composition and the feeding value of lucerne may be materially affected by varying the cutting interval. Therefore, the purpose of the field experiment reported here was to determine the effect of the frequency of spring cutting on the regrowth and resulting yied of a pure stand of New Zealand certified lucerne (Chanticleer) and on weed invasion of the stand and, if possible, the reasons for this effect. It is hoped that this information will add to the existing evidence. Lucerne is cultivated for stock feed in many parts of the world, including New Zealand. In recent years, it has become increasingly important as a forage crop because of its potential for high yields of good quality feed under a wide range of climatic and soil conditions. The long tap root of the plant affords it considerable resistance to drought. Moreover, the plant is rich in phosphates, lime and protein, all of which are essential in animal production. In common with other legumes, it possesses the power to increase the nitrogen content of the soil. [FROM INTRODUCTION]
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    Maturation and ripening of Doyenne du Comice pears : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Horticultural Science at Massey University, Palmerston North, New Zealand
    (Massey University, 1998) Cabrera Bologna, Carlos Danilo
    Characterisation of fruit quality attributes before and at harvest, during coolstorage and during ripening was made using standard and new, non-destructive devices during both the 1996 and 1997 seasons. Fruit firmness was linearly related to time when measured either by 'Kiwifirm' or penetrometer before harvest. Destructive techniques, the penetrometer and the texture analyser, were used to measure firmness and compared with non-destructive devices, the Kiwifirm and the softness meter. It is suggested that expressing rates of softening will be much more straightforward using a device such as the Kiwifirm. This device and the softness meter provided firmness data for pears that were too soft to measure by penetrometer. The effects of harvest date (1,11 and 21 March, 1996) and three crop loads on fruit maturity after a period of 6 weeks in coolstorage were investigated. Fruit size increased considerably during the 20 days before harvest, suggesting that periodical harvests need to be made in order to pick optimum size fruit each time. Maturity at harvest influenced the quality of 'Comice' stored at 0°C in air. Fruit from different harvests behaved differently in terms of softening behaviour and colour changes after 6 weeks in coolstorage. Crop load did not affect fruit quality attributes assessed after coolstorage. The characterisation of the nature and degree of within-tree and between tree fruit variability in harvest maturity and final ripening behaviour of 'Doyenne du Comice' pear was assessed by measuring firmness and colour. These attributes were measured non-destructively on fruit from different positions on the trees, and subsequently measured at harvest and during ripening at 20°C after 7 weeks in coolstorage at 0°C in air. Fruit behaved differently in terms of softening behaviour and colour changes depending on their position on the tree. Fruit maturity was delayed when fruit came from shaded areas, fruit from inner locations were greener than fruit from the outside and top positions. Selective picking and the association of harvest and ripening data may be important in making predictions that could reduce variability in fruit quality in the market place.
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    Plant density and crop establishment studies with tomatoes for mechanical harvest : a thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy in Horticultural Production at Massey University
    (Massey University, 1981) Green, Jacqueline Claire Shelagh
    Using three cultivars, chitting tomato seed and priming tomato seed with P. E. G. was found to have no effect on the early relative growth rate of the seedlings, when compared with untreated seed. However, because chitted seeds emerged earlier than primed seeds, which in turn emerged earlier than untreated seed, at any one time, the plants from chitted seed were larger than those from primed seed, and both were found to be larger than those from untreated seed. The seed treatments along with a high quality transplant treatment were compared in a field study to determine plant weight and fruit yield at four plant densities (62,500, 160,000, 200,000 and 591,716 plants per hectare). Castlong was found to give heavier total fruit yields than either VF 145-B7879 or Fireball. This is attributed to the higher proportion of fruit total plant weight that this variety develops. Castlong also produced a higher proportion of ripe total fruit at all harvests, this is considered to be due to this cultivar's early maturity combined with its excellent field storage characteristics. Transplanted plants in all cases yielded heavier and matured earlier than any of the three seed treatments. The yields and maturity characteristics were not significantly different from any of the three seed treatments. Increasing the plant density from 62,500 plants per hectare to 591,716 plants per hectare increased fruit number and yield per unit area and also tended to increase the proportion of the fruit that was ripe. The number of fruit per plant decreased as plant density increased.
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    Development of an autonomous kiwifruit harvester : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Industrial Automation at Massey University, Manawatu, New Zealand.
    (Massey University, 2012) Scarfe, Alistair John
    The already intensive labour requirements within the New Zealand kiwifruit industry are increasing. Furthermore, ZESPRI Group Limited is targeting a threefold increase in industry return by 2025 (from approximately $NZ1Billion to $NZ3Billion). Development of autonomous mechanised solutions to assist manual labour is emerging as a strategic necessity. The objective of this research was to develop a commercially viable autonomous kiwifruit harvester (AKH). The AKH must be capable of operating within variable and complex on-orchard environments to minimise manual labour requirements. Successful completion required development and integration of autonomous: 1. Fruit identification and localisation 2. Custom robotic arms with soft fruit extraction harvesting hands 3. Custom robotic arm for soft fruit handling 4. Transportation platform with navigational sensing and strategies 5. Storage bin collection and drop-off The AKH has four robotic harvesting arms with hands specifically designed to mimic the human fruit harvesting action. Remotely mounted stereoscopic vision identifies and localises fruit. The fruit locations are mapped into the harvesting arms’ coordinate space allowing fruit extraction. The presented system configuration resolves the slow harvest rates experienced by other systems. Practical on-orchard testing identified additional environmental complexities that present the greatest challenge to consistent fruit identification. These are mainly from natural lighting effects. Stereoscopic machine vision (SMV) was investigated as the primary navigation sensor. However, diverse environmental conditions (lighting and structure appearance) made consistent object detection unreliable. Consequently, a light detection and ranging/SMV combination was used to achieve reliable navigational object detection and fruit storage bin identification. Practical on-orchard testing and analysis verified AKH operational ability (testing was limited due to a vine killing bacterial (Psa-V) outbreak restricting orchard access): 1. Fruit identification (83.6% of crop) with combined localisation and extraction accuracy of 3.6mm in three-dimensional space 2. More gentle fruit harvesting and handling than humans harvesting 3. Reliable object detection and path planning for navigation. Over the twenty metre scanning range 96% of the in-row objects were correctly classified to reliably determine the drive path 4. Reliable fruit storage bin identification and localisation (98% correct classification) 5. Commercially viable manufacture cost less than $130,000 per unit 6. Although full commercial operation was not achieved, modifications are identified to rectify the limitations Key system improvements are presented for: 1. High intensity artificial lighting for increased fruit identification rates. Natural sunlight variations affected identification ability, minimising this affect will increase identification rates 2. Alter the storage bin filling arm geometry to permit complete storage bin filling 3. Sensing the robotic arms’ position to resolve positioning errors