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• High fruit load increased yield and water productivity but reduced fruit quality in each irrigation treatment. • High irrigation levels did not lead to remarkable yield increase in each fruit load group. • Fruit quality and net profits were pronouncedly improved by elevated irrigation levels. • Trees under commercial fruit load intensity and high irrigation level treatment exhibited the highest net profits. An integrated research coupling a field study with an agronomic-economic model (ANSWER-APP) was conducted to investigate the combined effects of irrigation levels and crop loads on fruit quality, water productivity and profitability of mature date palms. The study took place in Israel's hyper-arid Arava Valley, where date palm trees are widely cultivated and rely exclusively on brackish water irrigation. Three fruit load intensities (low, FL1; commercial, FL2; high, FL3) and two irrigation levels (W1 and W2, equal to and higher than the local irrigation regime, respectively) were applied in a 22-year-old date palm orchard in 2018–2019. Irrigation amount, fruit quality and yield were measured. Profitability for each treatment was analyzed with the ANSWER-APP. Higher fruit load resulted in higher yield and water productivity, but on the other hand led to reduced fruit physical properties (size and mass), regardless of the irrigation treatment. The improved fruit physical properties and net profits in W2 compared to W1 treatment in each fruit load group resulted from excess salt leaching in the root zone. Notably, trees under W2FL2 treatment were found to have highest net profits. It is concluded that adequate irrigation amounts contribute to net profits in date palm trees treated with high fruit load intensity under saline irrigation conditions. [ABSTRACT FROM AUTHOR]

• Fanned semi-closed greenhouse presents high vertical microclimate heterogeneity. • Microclimate conditions in fanned semi-closed greenhouse triggered tomato production. • The use of curtains and circulation fans increased the chance of dew formation. • Horizontal air flow does not have the potential to reduce the vertical heterogeneity. The extent of the vertical microclimate heterogeneity inside a greenhouse is mostly unknown, and it can strongly affect plant production and yield quality. Tomato crop was grown in a semi-closed greenhouse equipped with horizontal ventilation and sidewall curtains, which were only opened depending on microclimate conditions; and a naturally ventilated greenhouse equipped with sidewalls curtains that were kept open. Both greenhouses had a 1,000-m2 area and a net size of 50-mesh, and were located in an arid climate zone in Israel. Vertical profiles of CO 2 concentration, actual vapor pressure, air, leaf and soil temperature, net CO 2 assimilation rates, stomatal conductance, and total fruit yield, fresh mass, and quality were monitored in both greenhouses for 13 days, in January 2018; CO 2 concentration, actual vapor pressure, and air and soil temperature were additionally monitored in the semi-closed greenhouse for seven days in December 2016, when the ventilation was inoperative, and in December 2017, with ventilation. The vertical air temperature gradient, along with the colder microclimate inside the naturally ventilated greenhouse, led to a lack of plant uniformity and yield loss. Closing the side curtains in the fanned semi-closed greenhouse had a beneficial effect on yield, however, with mixed results for quality, due to the higher air temperature and lower carbon dioxide levels at the upper canopy. Horizontal air circulation in the semi-closed greenhouse increased transpiration and assimilation, and increased dew occurrence at night, but did not reduce the vertical heterogeneity. Significant vertical gradients affect plant physiology, and closing the curtains in winter cultivation in semi-arid/arid climates has the potential to improve fruit yield and quality. However, it must be coupled with proper air circulation and, preferably, with CO 2 enrichment, or careful management of natural ventilation through side curtains, in order to maximize CO 2 replenishment while minimizing heat losses. [ABSTRACT FROM AUTHOR]