Effect of Differently Matured Composts from Willow on Growth and Development of Lettuce

Soil amendments from peats, brown coals and composts produced from segregated biodegradable waste or biomass from fallow land can increase soil fertility and improve soil productivity. The aim of the study was to determine the possibility of using willow (Salix viminalis L.) biomass composts as a substrate component in horticulture. The objects of the research were composts produced from willow carried out in a pile under aerobic conditions. The addition of hay and mineral nitrogen (Nmin) was used to improve process efficiency. In order to verify the type and determine fertilizing value, basic chemical parameters were analyzed (pH, total contents of C, N and P) and a pot experiment was established to analyze the germination and growth of lettuce (Lactuca sativa L.). Changes in pH, an increase in total nitrogen content (TN), phosphorus (TP) and a decrease in TOC was observed in the investigated samples. Results of the experiment showed that the highest yield was obtained from the pots with the mixture of willow, hay and Nmin. Matured composts significantly stimulated the germination and growth of the test plants. It can be concluded that the addition of hay and Nmin significantly improved composting process and increased the fertilizing value of the investigated composts.

Selenium Biofortification of Lettuce Plants (Lactuca sativa L.) as Affected by Se Species, Se Rate, and a Biochar Co-Application in a Calcareous Soil

Selenium biofortification of lettuce plants was studied for two rates (5 and 10 mg kg−1 soil) of either selenate or selenite and for the effect of 5% w/w biochar addition. Lettuce seedlings were grown in pots containing 1 kg of a calcareous soil. Twelve weeks later, the plants were harvested and selenium (Se), phosphorus (P), and sulfur (S) concentrations were determined in heads and roots. Plant growth characteristics were measured and plant biometrics were assessed by NDVI, NDRE, and SPAD measurements. The highest Se concentration of 315.19 mg kg−1 D.W. and the highest amount of Se taken up by plants (950.5 μg/pot) were observed for the low selenate rate with biochar. The corresponding values for selenite treatments were an order of magnitude lower. Although in general, minor to severe toxicity symptoms occurred with selenium application in no biochar treatments (except selenite low rate), the addition of biochar secured plant growth and increased S and P concentrations in plants, regulating Se uptake by plants at high selenite rate and allowing maximum plant uptake at the low selenate rate. To propose an appropriate Se fertilization rate, the fate of excess selenates in the soil environment should be examined and experimentation under soil conditions is necessary.

Growth and yield assessment of lettuce (Lactuca sativa L.): an economic feasibility and performance evaluation of capillary wick irrigation system

The study assessed the growth and yield of lettuce (Lactuca sativa L.) in order to evaluate the performance and economic feasibility of capillary wick irrigation system. Unlike any other capillary rise-based systems that uses the matric potential of the soil to dictate the amount of water to be drawn, this system aimed to continuously supply water imitating a full-time drip irrigation system but cheaper in terms of materials and operating cost. A 5 mm-width, cotton fabric strip was used as a wick material based from the results of the preliminary testing to verify several literature claims. In order to determine number of wicks to optimally supply the water demand of lettuce, treatments namely, T1= 1 wick, T2 = 2 wicks, T3 = 3 wicks and a control treatment T4 which uses manual irrigation method, were tested and compared against each other. Significant results were in terms of the volume of water applied, and the water use efficiency in which T1 showed a better performance among other treatments. However, it does not imply that T1 had produced a supreme yield output. Instead, this can be attributed to the efficient application of irrigation water to an optimal level. This means that T1 or the use of 1 wick material minimizes irrigation water losses through evaporation and percolation. An economic analysis was performed and has resulted to a return on investment of 41.92% or 41.92% of the investment cost will be returned after three cropping, which is an attribute of the particular set-up cost of the study.

Detection of enteropathogens and research of pesticide residues in Lactuca sativa from traditional and agroecological fairs

Agroecological production represents a new reality in vegetable farming. Thus, the study aimed to search for the presence of pesticides in agroecological samples and microbiological and parasitological contamination in Lactuca sativa L. of agroecological and conventional fairs in Alagoas. Thirty-two samples were collected, a hygienic-sanitary checklist was performed, along with coliform, Salmonella spp., Staphylococcus aureus research and Gas Chromatography with Mass Spectrometer (GC-MS) for pesticide research; using two methodologies for parasitological studies. Thirty-two samples were analyzed, with a sanitary adequacy level at 45% and 38% for fairs (agroecological and conventional) respectively, with three samples (9.4%) in total, being adequate to the microbiological pattern according to RDC no. 12/2001. Among the 23 samples which were tested positive for parasites, 69.5% originated from samples extracted at conventional fairs, and 53% of every positive samples presented Entamoeba coli as the main contaminant. All together, no traces of deltamethrin were detected, but in two of the samples a peak retention for diphenoconazole was detected. In conclusion, the fairs represent an adequate environment for human pathogens and indicators. Therefore greater hygiene training of vegetable traders and consumers in the state of Alagoas is required, especially in conventional fairs, which presented more critical microbiological and parasitological indexes comparing to fairs with agroecological products; however, the presence of difenoconazole in two samples of agricultural fairs suggests accidental contamination or indiscriminate use of this chemical in the production of Lactuca sativa, however, products with agroecological origin represents a better choice for the consumers.

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.

The effect of combination of AB-mix nutrition with liquid organic fertilizer of tofu liquid waste on hydroponical growth and production of lettage (Lactuca sativa L.)

This study aims to determine the effect of the combination of AB mix nutrients with liquid organic fertilizer (LOF) of tofu liquid waste on the growth and yield of lettuce plants and to obtain the best combination for the growth and yield of lettuce hydroponically. This study used a non-factorial Randomized Block Design (RBD), consisting of a comparison of nutritional treatments, namely: N1 = 100% AB mix + 0% LOF of liquid waste tofu, N2= 75% AB mix + 25% LOF of tofu liquid waste, N3= 50% AB mix + 50% LOF of tofu liquid waste, N4= 25% AB mix + 75 % LOF of tofu liquid waste, N5= 100% LOF of waste liquid tofu which consists of 4 replications. Parameters observed were plant height, number of leaves, leaf length, leaf width, root length, fresh weight, root volume and weight fit for consumption. The results showed that the administration of 50% AB mix + 50% LOF of tofu liquid waste and 25% AB mix + 75% LOF of tofu liquid waste showed results that tended to be the same but the results of the combination of 75% AB mix + 25% LOF of tofu liquid waste were higher. On the parameters of the number of leaves is 11.12 strands, fresh weight is 66.40 g and suitable weight for consumption is 58.31 g.