Agricultural Science

Effects of Different Soil Moisture Contents on Photosynthesis of Lettuce

Xiao Kong — 2023-07-22

In order to explore the photosynthetic physiological response characteristics of lettuce under different soil moisture conditions, the photosynthetic indexes and chlorophyll fluorescence parameters of lettuce under different soil moisture gradients were determined by pot water control experiment. The results showed that with the decrease of soil moisture content, Pn, Tr, Gs, Ci, Fv/Fm, ΦPSII and qP of lettuce leaves all showed a downward trend, while NPQ increased with the decrease of soil moisture content. Among them, the water holding capacity in the field was 55~60%, and the net photosynthetic rate of lettuce was the highest, indicating that mild drought promoted photosynthesis of lettuce.

The Effectiveness of Two Hydroponically Fodder Production of Alfalfa (Medicago sativa L.) as Compared to Open Field System in Mount Lebanon

Edouard Tabet — 2024-12-31

This work aims to study the effect on the productivity and quality variation of alfalfa using the two different fertilization recipes: F1 and F2 along with two different cultivation method in soilless: coconut fiber bag CF, Nutrient Film Technique (NFT) and in soil So. Number of leaves, stem length, number of flowers, crude protein, fiber and ash content of alfalfa plants were measured during the three cuttings time of the production cycle. In the productivity phase, results showed that during the three cuttings repetition, the number of leaves, stem length and number of flowers of alfalfa were in favor of the treatment of coconut fiber bags and the F1 fertilization recipe (CF1) followed by NFT with a good interaction noticeable at this combination level (CF1) with the cutting 1. As for the quality variation phase, the results showed that the crude protein and ash content are in favor of alfalfa grown in soilless CF2; CF1; NFTF1 and NFTF2. As for fiber content, F1 was the most favorable and NFTF1 reported higher fiber content than coconut fiber bags. Concerning the cutting system, cut 1 had a large impact on chemical composition. In summary, alfalfa grown in soilless is more productive and succeeded in the production cycle and the quality variation of alfalfa.

Use Of Micronized Calcium Carbonate-Based Sunscreen on Young European Hazelnut (Corylus Avellana L.) in Commercial Nursery Under Environmental Stress Conditions During the Summer Period

Ignacio Errazuriz Montanares — 2023-12-31

Chile has become one of the main exporters of European hazelnuts in the world, mainly due to favorable edaphoclimatic conditions. Currently, due to the negative effects of climate change, Chile has been suffering recurrent heat waves and droughts, which are damaging the productive efficiency of the European hazelnut. The present research proposes to evaluate the use of a sunscreen composed of micronized calcium carbonate, pinolene and lignosulfonate on young European hazelnut plants growing in a commercial nursery. In this study, the environmental conditions of heat stress observed during the summer months were evaluated. The results show statistically significant differences between treatments, in favor of plants treated with the sunscreen in at least one of the three months of evaluation. Thus, stomatal conductance (g_s) showed increases of up to 29% compared to the control treatment, transpiration rate (T_r) increased by up to 25% and the net assimilation rate (a_n) increased by up to 18% compared to the control treatment without application. The use of sunscreen would increase the gas exchange of young European hazelnut plants, thus providing greater tolerance to conditions of high environmental temperature, promoting an increase in the production of photo-assimilates compared to untreated plants.