Biofertilizers from wastewater treatment as a potential source of mineral nutrients for growth of amaranth plants

Exploring alternative fertilizers is crucial in agriculture due to the cost and environmental impact of inorganic options. This study investigated the potential of biofertilizers derived from sewage treatment on the growth and physiology of Amaranthus cruentus plants. Various treatments were compared, including control treatments with inorganic fertilizer and treatments with biofertilizers composed of microalgae, biosolids and reclaimed water. The following traits were investigated: photosynthetic pigments, gas exchange, growth, and leaf nutrient concentrations. Results show that the concentrations of N, P, Cu, Fe Zn and Na nutrients, in the dry microalgae and biosolids, were quite high for the needs of the plants. The wet microalgae presented high concentration of Cu, Fe and Zn nutrients while reclaimed water contained high concentration of N, K, Ca and S. Na and Zn nutrients increased in the leaf of plants treated with dry microalgae and biosolid, respectively. At the beginning of the..., The experiment was carried out in the greenhouse at the Department of Biological Sciences at the Sao Paulo State University/Bauru Campus, under natural photoperiodic conditions and minimum and maximum average temperature of 17 and 33 oC, respectively. The seeds were sown in 4 L plastic pots filled with vermiculite. The microalgae were cultivated in a transparent box with 50 L of anaerobically pre-treated sewage with 5 L of inoculum of native microalgae from sanitary wastewater. After the microalgae cultivation the reclaimed water and the sedimented microalgae were collected. The sludge was obtained in the third chamber of the baffled anaerobic reactor, which had three chambers with a total volume of 597 L and HDT of 8 h.  After collecting, the sludge was oven dried at 60 oC. Then, it was crushed and ground in a mill to facilitate the  absorption by the plants. At approximately 7 day intervals, the height (cm), the diameter (mm) of the stem at insertion of cotyledons and the number of vi..., , *Instructions about how the experiment was conducted in a greenhouse to evaluate the potential of biofertilizer on amaranth growth and gas exchange. The data files contain the results of the experiment.*

The experiment was carried out in the greenhouse at the Department of Biological Sciences at the Sao Paulo State University/Bauru Campus, under natural photoperiodic conditions and minimum and maximum average temperature of 17 and 33°C, respectively. The seeds were sown in 4 L plastic pots filled with vermiculite. After one week, the plants were thinned to one per pot. Each pot received 250 mL of 20% or 70% full strength Long Ashton (LA) solution from sowing and continued three times a week.

Three disks were collected (Disk diameter = 14,64 mm) per plant. Measurements were done in a spectrophotometer. nm = wavelength. Total chlorophyll and carotenoids were extracted from leaf discs of known area in 80% aqueous acetone according to Lichtenthaler, 1987, and the concentration expressed o...