Tomato Crop Production Research Articles

SE—Structures and Environment: A Strategy for Greenhouse Climate Control, Part I: Model Development

This paper presents an algorithm developed to predict the dynamic ambient greenhouse air conditions which optimize net profits for the production of a greenhouse tomato crop. Profits are equated to the crop yield value less the energy costs for heating and dehumidification and the CO2injection cost. The climatic conditions considered are CO2level, temperature, relative humidity and incident radiation. These are varied dynamically for every time interval spanning the harvesting period.The algorithm has two sub-programs. For sets of selected internal climatic parameters, the first calculates crop yield, and the second calculates energy costs (heating and dehumidification) with reference to predicted exterior climatic conditions (solar radiation, temperature, wind velocity and relative humidity). These two algorithms are then used to predict the particular set of climatic parameters, adjusted for each time interval over the harvesting period, that will maximize the crop yield value less the energy costs.

Regulation of leaf and fruit growth in plants growing in drying soil: exploitation of the plants' chemical signalling system and hydraulic architecture to increase the efficiency of water use in agriculture.

In this paper the nature of root-to-shoot signals in plants growing in drying soil is considered in the context of their commercial exploitation in tomato (Lycopersicon esculentum L.) and other crops. Recent findings are presented on the effects of partial root drying (PRD) in the production of a glasshouse tomato crop. These findings show how an understanding of both root-to-shoot signalling mechanisms and fruit hydraulic architecture may explain observed increases in fruit quality, the differential effects of PRD on vegetative and reproductive production and the incidence of blossom end rot. Evidence is provided to support the hypothesis that the success of PRD may lie, at least in part, in the relative chemical and hydraulic isolation of the tomato fruit.

Comparison of Classical and Optimal Control of Greenhouse Tomato Crop Production

Through simulation, the optimal control of tomato crop production in a greenhouse based on an economic criterion, is compared with the result obtained with a conventional classical controller. The result is 6 % increase in profit and 43 % increase in energy efficiency over a characteristic autumn day. The solution of the optimal control problem is not at all straightforward. The greenhouse-tomato system is stiff. Singular perturbation theory is usually applied to cope with stiffness in optimal control problems, but in this case direct application is problematic due to the rapid external disturbances. In this paper the problem is solved by adapting a method proposed earlier by Van Henten (1994).

Intensive land preparation emits respirable dust

Respirable dust (RD), defined as particles smaller than 4 ?m diameter, was collected at the implement from 29 farming operations performed for furrow-irrigated tomato, corn, and wheat crop production over a 2-year period. Land preparation, such as land planing, ripping, plowing, and disking, produced significantly higher concentrations of RD than most other cultivation operations. Land preparation accounted for 67% of all farming operations, but produced 82% of the RD. The number of operations and the timing of land preparation were responsible for the difference in RD concentrations among the seven 2-year crop rotations. Of the studied crops, tomato and corn were the most intensively cultivated and yielded the highest RD amounts. Soil moisture was an important environmental variable that influenced the amount of dust and the variability in dust concentration from sample to sample. Among the cropping systems studied, those that required more tillage or land preparation to be performed when the soil was driest produced the most RD.

Movable Row Tomato Production System for the Greenhouse

MORE effective utilization of the greenhouse floor area for tomato crop production was possible with a movable growing system that increased row-to-row distances as the seedlings matured. With proper timing of successive crop plantings a potential increase of total yearly fruit production per unit floor area and a more continuous yearly harvest rate could be realized. Maximum yields of 1.5 kg per four cluster plants were less than the expected 2 kg/plant, thus projected yearly productivity was not attained. More detailed study with the plant cultural procedure is necessary in this modified NFT system before final conclusions on system productivity can be made.