Productivity and nutrient extraction by Brachiaria brizantha fertigated with treated sewage effluent

Abstract

The present study was performed to evaluate the responses in productivity and nutrient extraction in dry biomass of Brachiaria brizantha ‘Marandu’ fertigated with treated sewage effluent (TSE) from 2013 to 2014, in Jaboticabal, São Paulo, Brazil. A triple line source sprinkler system was used to perform uniform but gradual irrigation of TSE and mineral fertilization in five treatments, with the following TSE fractions in water: 1.0 (E5); 0.87 (E4); 0.6 (E3); 0.31 (E2), and 0.11 (E1). In addition to fertigation, all treatments were supplemented with P and K. TSE was applied at depths of 1,853 and 2,253 mm year-1 in 2013 and 2014, respectively. This provided E5 with the following amounts of N, P, K, and Na (kg ha-1): 931, 27, 314, and 894, in 2013, and 1,132, 21, 463, and 1,428, in 2014. The most relevant effects on B. brizantha dry biomass yield and nutrient extraction were obtained with higher doses of TSE. The extract of macronutrients was higher for K and N, followed by K, Ca, Mg, and Na. Based on the responses in productivity and nutrient extraction of soil by the crop as a function of TSE fertilization without soil contamination, we propose that increased fertilizer application be studied further.

Agronomic performance of Urochloa brizantha cv. Marandu cultivated in clayey and sandy soil submitted to water and nutritional management

“…In springsummer, it accounted for 83% of dry matter production. Similar results were obtained by Dantas et al (2020), Santos et al (2019), and Dantas et al (2016) using the same forage and using increasing doses of fertigation, also obtained a reduction in fresh and dry mass in winter and an increase in dry and fresh mass in the spring-summer period.…”

“…In addition, the Brachiaria forage coefficient (kc) equal to 1.0 was used (SANTOS et al, 2019) to obtain the maximum crop evapotranspiration (ETo = ETc).…”

“…Dry matter (yield) was defined with the execution of cuts every 28 days, simulating a direct grazing system. The forage was manually harvested and cut at a height of 15 cm from the ground with the aid of a pot-shaped steel jig, following the guidelines of Santos et al (2019). Samples were taken from the cut forage to be weighed in fresh form and taken to the oven with forced air circulation and constant temperature of 65°C for 72 hours, for dry mass determination (LACERDA et al, 2009).…”

Physiological quality and seed chemical composition of soybean seeds under different altitude

“…The higher TN concentration in the surface layer for treatments with higher TSE levels was due to the nutrient supply by TSE fertigation, in which TN effluent average content was 50.2 mg•dm -3 . Santos et al (2019) observed that one of the factors that promoted an increase in U. brizantha yield in treatments with a higher TSE level (E3 and E5) was the great availability of N in the soil. The authors observed that the amount of N extracted by U. brizantha in the E5 treatment were 1,045 kg•ha -1 in 2013 and 1.501 kg•ha -1 in 2014, while for the E1 treatment the extraction was only 491 and 404 kg•ha -1 , respectively.…”

“…If the amount of effluent to meet the nitrogen demand by the U. brizantha were greater than the amount of water required by the crop in a period of 28 days, the application of effluent would be based on nutritional demand, otherwise the water demand was used. For further details, check the studies by Santos et al (2017) and Santos et al (2019).…”