Latest Research on Horticultural Crops : Dec 2020

Modelling biomass production and yield of horticultural crops: a review

Descriptive and explanatory modelling of biomass production and yield of horticultural crops is reviewed with special reference to the simulation of leaf area, light interception, dry matter (DM) production, DM partitioning and DM content. Most models for prediction of harvest date (timing of production) are descriptive. For DM production many descriptive and explanatory models have been developed. Most explanatory models are photosynthesis-based models. Important components of photosynthesis-based models are leaf area development, light interception, photosynthesis and respiration. Leaf area is predominantly simulated as a function of plant developmental stage or of simulated leaf dry weight. Crop photosynthesis can be calculated as a function of intercepted radiation or more accurately by considering radiation absorption of different leaf layers in combination with a submodel for leaf photosynthesis. In most crop growth models respiration is subdivided into two components: growth and maintenance. There is reasonable consensus concerning the simulation of growth respiration, but the simulation of maintenance respiration is still an area of great uncertainty, which is especially important for large crops grown under winter conditions at relatively high greenhouse temperatures. DM partitioning can be simulated by descriptive allometry, functional equilibrium or sink regulation. The most suitable approach depends on the type of crop studied and the aim of the model. As opposed to most agricultural crops, the DM content of the harvestable product is of great importance to the yield of most horticultural crops. More attention should be paid to the simulation of DM content. It is concluded that the strong features of explanatory crop growth models are the simulation of light interception and gross photosynthesis, while the weak features are the simulation of leaf area development, maintenance respiration, organ abortion, DM content and product quality. [1]

Texture evaluation of horticultural crops.

Methods and instruments used for texture evaluation are described. For sensory measurement of texture, relevant characteristics of temperate fruits are listed. [2]

 

USING PLANT PHYSIOLOGY TO IMPROVE THE WATER USE EFFICIENCY OF HORTICULTURAL CROPS

A study of water and hormone relations in a range of horticultural plants, conducted over a number of years, resulted in the development of a model which described the physiological mechanisms operating in these crops which control transpiration. The model relied heavily on information relating stomatal function to the ability of the roots to supply abscisic acid via the transpiration stream. Published work by other groups, which utilised split root experimental systems also lent support to this idea. Using this knowledge, we have been able to develop a commercially viable irrigation system for grapevines which has been designed to reduce vegetative vigour and improve water use efficiency. We have called the technique Partial Rootzone Drying (PRD) and it requires that the roots are simultaneously exposed to both wet and dry zones. This results in the stimulation of some of the responses normally associated with water stress such as reduced vigour and transpiration but does not result in changes in plant water status. Crop yield is relatively unaffected. Implementation of the PRD technique is simple, requiring only that irrigation systems are modified to allow alternate wetting and drying of part of the rootzone. Commercial-scale trials are currently being evaluated and further studies on the physiological mechanisms involved in modifying water use efficiency in a range of horticultural plants is continuing. [3]

Environmental Impact Assessment of Diversification of Horticultural Crops: A Case Study of Ethiopia

Recently adopted horticultural crops under the policy of diversification of agriculture in Ethiopia will possibly have an impact on bio-physical, social-economic environment. This study was conducted to assess the potential impact of under construction horticultural project, for different crops of horticulture. Impacts were computed on soil and water resources, air quality, flora and fauna, local socio-economic aspects and human health in the peripheries of the Tana Lake, Ethiopia. Environmental quality index and range methods were used for impact assessment. The analysis shows that high level impact may be on soil and water resources, medium level impact on ecosystem and human health and low level of impact on the air quality and socio-economic conditions of surrounding population [4]

Development and Performance Evaluation of Manually Operated Seedling Planter for Horticultural Crops

A low cost manually operated single row vegetable seedling planter was developed for transplanting of plug and pot type vegetable seedlings on ridges and mulch beds. It consisted of jaw assembly, delivery pipe, lever, handle and spacing marker. Operating principle of the developed transplanter involves the raising the transplanter up to one feet height and allow to free fall in the soil, dropping the seedling in the seedling delivery tube, pressing the lever in upward direction which enable the jaw to open the soil and seedling was placed in the soil by gravity and lifting the transplanter with open jaw and close the after raising the transplanter by one feet height. It was evaluated for inter and intra-row spacings of 45×45 cm. Manual transplanting on plastic mulch beds (MPMB) was compared with developed transplanter on plastic mulch beds (TPMB). The transplanting rate using single labour was found to be 5 and 12 seedlings /min for MPMB and TPMB respectively. The field capacity was calculated as 0.0031 and 0.0166 for MPMB and TPMB. Similarly, field efficiency was 21-28% and 42-57%. Moreover, cost of operation (Rs/ha) in was found to be 9218 and 1753Rs/ha. The time saving over manual transplanting is 80.96% by using seedling planter. The weight of developed transplanter is 2.4 kg and cost is Rs. 500. It is completely made up of stainless steel Developed vegetable transplanter found more suitable for vegetable transplanting as compare to traditional method of manual transplanting. The aim of this study is to reduce the human effort, to increase the field efficiency, to reduce the cost of operation and to increase the field capacity while planting horticultural crops. [5]

Reference

[1] Marcelis, L.F., Heuvelink, E. and Goudriaan, J., 1998. Modelling biomass production and yield of horticultural crops: a review. Scientia Horticulturae, 74(1-2), pp.83-111.

[2] Bourne, M.C., 1980. Texture evaluation of horticultural crops. HortScience, 15, pp.51-57.

[3] Dry, P.R., Stoll, M., Mc Carthy, M.G. and Loveys, B.R., 1999, June. Using plant physiology to improve the water use efficiency of horticultural crops. In III International Symposium on Irrigation of Horticultural Crops 537 (pp. 187-197).

[4] Ali, M. (2013) “Environmental Impact Assessment of Diversification of Horticultural Crops: A Case Study of Ethiopia”, Journal of Experimental Agriculture International, 4(1), pp. 90-100. doi: 10.9734/AJEA/2014/3787.

[5] Harshavardhan, K. and Shrivastava, A. (2018) “Development and Performance Evaluation of Manually Operated Seedling Planter for Horticultural Crops”, Current Journal of Applied Science and Technology, 29(1), pp. 1-8. doi: 10.9734/CJAST/2018/43833.

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