Nutritional comparison between hydroponically grown leguminous and non-leguminous fodder to identify the adaptability and best harvesting time for sustainable hydroponic grass production

Two types of fodder crops were evaluated in this study, maize (Zia maize) and black gram (BG) (Vigna mungo) and in maize, non-descriptive local maize (LM) and hybrid maize (HM) verity were used. LM was considered as control and changes of the nutritional composition according to the type of fodder (leguminous and non-leguminous) and the day was evaluated. For comparative nutritional analysis, dry matter (DM), crude protein (CP), ether extract (EE), crude fibre (CF), acid detergent fibre (ADF), neutral detergent fibre (NDF), and total ash were analyzed and the biomass yield was measured using weight balance and root and shoot length of experimental fodders. Results revealed that among three types of forages total DM was significantly (P<0.01) higher in HM and significantly (P<0.01) lower in BG. Considering total CP and NDF, it was significantly (P<0.01) higher in BG and HM than LM. The highest biomass yield and shoot length were observed in BG and the lowest biomass yield was observed in HM. Moreover, with the increment of days, all fodder sprouts DM% was constantly decreasing, however, CP% maintained the same level from day 1 to 5. Although from day 6 to 9, CP% increased moderately for HM and BG, CP% decreased slightly for LM. Therefore, farmer can use BG and HM for maximum utilization of nutrients and considering DM and CP% for LM day 6 was the best time for harvesting; however, for HM and BG, day 9 or more than 9 was the best time for harvesting. Res. Agric., Livest. Fish.8(3): 321-328, December 2021

Deep Learning Models to Determine Nutrient Concentration in Hydroponically Grown Lettuce Cultivars (Lactuca sativa L.)

Deep learning (DL) and computer vision applications in precision agriculture have great potential to identify and classify plant and vegetation species. This study presents the applicability of DL modeling with computer vision techniques to analyze the nutrient levels of hydroponically grown four lettuce cultivars (Lactuca sativa L.), namely Black Seed, Flandria, Rex, and Tacitus. Four different nutrient concentrations (0, 50, 200, 300 ppm nitrogen solutions) were prepared and utilized to grow these lettuce cultivars in the greenhouse. RGB images of lettuce leaves were captured. The results showed that the developed DL’s visual geometry group 16 (VGG16) and VGG19 architectures identified the nutrient levels of lettuces with 87.5 to 100% accuracy for four lettuce cultivars, respectively. Convolution neural network models were also implemented to identify the nutrient levels of the studied lettuces for comparison purposes. The developed modeling techniques can be applied not only to collect real-time nutrient data from other lettuce type cultivars grown in greenhouses but also in fields. Moreover, these modeling approaches can be applied for remote sensing purposes to various lettuce crops. To the best knowledge of the authors, this is a novel study applying the DL technique to determine the nutrient concentrations in lettuce cultivars.

Environmental Amelioration Through Nutrient Calibration: Maximizing Carbon Sequestration in Hydroponic Greenhouse Production of Lactuca Sativa in Lahore’s Spring

This study explores the applicability of internationally prescribed nutrient recipes to greenhouse hydroponic production in Lahore. Lactuca sativa was hydroponically grown at different nutrient concentrations to uncover optimum nutrition for maximum foliage cover. Conclusions were based on visual analysis of foliage cover, as laboratory analysis of trial plants was beyond the scope of this environmental study. Nutrient levels that displayed the best foliage cover in Lahore-based greenhouse during spring weather were different from concentrations kept in US- or Europe-based hydroponic greenhouses. Plant trials conducted for this article explain the adjustments that must be made to hydroponic recipes discussed in international literature; if they are to be used in polyhouse hydroponic production in Lahore’s warmer climate.

Physiological and Morphological Responses of Hydroponically Grown Pear Rootstock Under Phosphorus Treatment

Phosphorus (P) is an essential macronutrient for the growth and development of fruit trees, playing an important role in photosynthesis, nucleic acid synthesis, and enzyme activity regulation. The plasticity of plant phenotypic has been investigated in diverse species under conditions of P-deficiency or P-excess. Based on these researches, P level fluctuations in different species result in different characteristics of the response. Nevertheless, little is known about the response of pear seedling rootstock (Pyrus betulifolia Bunge) to the changing of P levels. To explore the effects of different levels of P on the growth of pear seedling rootstock, we performed the hydroponic assays to determine and analyze the biological indexes including growth parameters, photosynthetic rate, root and shoot morphological traits, and concentrations of macro- and micronutrients. The results show that either deficiency or excess of P inhibited the growth and development of pear seedling rootstock. Root growth (down 44.8%), photosynthetic rate (down 59.8%), and acid phosphatase (ACP) activity (down 44.4%) were inhibited under the P-deficiency conditions (0mM), compared with normal P conditions (1mM). On the other hand, dark green leaves, suppression of root elongation (down 18.8%), and photosynthetic rate (down 25%) were observed under regimes of excessive P, compared with normal P conditions (1mM). Furthermore, the root concentration of not only P, but also those of other mineral nutrients were affected by either P treatment. In brief, these results indicated that a careful choice of P fertilizer supply is crucial to ensuring normal growth and development of pear seedling rootstock.

Selenium Enrichment of Green and Red Lettuce and the Induction of Radical Scavenging Potential

Selenium (Se)-enriched vegetables are promising dietary sources of Se, which provides beneficial biological effects in humans. In this study, we investigated the effects of foliar application of Se on hydroponically grown multi-leaf green (V1) and red (V2) lettuce plants. Three selenate (SeIV) amendment levels were evaluated for their influence on plant growth, elemental composition and radical scavenging capacity. Lettuce heads biofortified with 0.598 mg Se plant−1 accumulated 19.6–23.6 and 14.9–17.6 μg Se g−1 DM in the multi-leaf green (V1) and red (V2) lettuce plants, respectively. The accumulated Se levels can contribute significantly to the recommended dietary allowance of 70 µg day−1 for adult men and 60 µg day−1 for adult women. Accordingly, both V1 and V2 lettuce cultivars grown under the Se3 foliar application condition can cover the daily requirement for adult men by approximately 100% and 85% to 100%, respectively, by consuming 75–90 g or 100 g fresh weight from V1 or V2, respectively. The ABTS radical scavenging potential of green lettuce was induced at Se2 and Se3 foliar application levels, where the IC50 was 1.124 ± 0.09 μg mL−1 at Se0 and improved to 0.795 ± 0.03 and 0.697 ± 0.01 μg mL−1, respectively. There was no cytotoxicity against Vero kidney cells among all treated lettuce plants at the highest concentration tested of 1 mg/mL. Finally, a further focused investigation of the metabolic profile of lettuce plants under varied Se levels needs to be investigated in future studies.