Use of growth promoting bacteria in São Carlos grass, aiming the reduction of nitrogen fertilization in a production area

• Grant number: 19/06345-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2019
• End date: July 31, 2021
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Marcelo Carvalho Minhoto Teixeira Filho
• Grantee: Castro Alves da Silva Junior
• Host Institution: Faculdade de Engenharia (FEIS). Universidade Estadual Paulista (UNESP). Campus de Ilha Solteira. Ilha Solteira , SP, Brazil

Abstract

The use of lawns for their various purposes (ornamental, sports, highways, protection of degraded areas) has increased the demand for grams in Brazil and its production has grown. The São Carlos grass (Axonopus compressus (Swartz.) Beauv) is the second most cultivated in Brazil, after the emerald grass, being indicated for areas in full sun and also the most recommended for areas with lower luminosity. São Carlos Plus is a variety that results in more homogeneous and more easily maintained lawns than the traditional São Carlos. For the production of grams, the most required nutrient is nitrogen (N). Therefore, the application of plant growth promoting bacteria (PGPBs) can promote relevant results in N2 fixation, leading to greater root development due to the phytohormonal action, thus increasing the water and nutrients absorption by the grass, being more sustainable for the environment. The objective of this study was to evaluate the application of plant growth promoting bacteria (Bacillus subtilis, Pseudomonas fluorescens and Azospirillum brasilense) in commercial production area of the São Carlos Plus grass, in the municipality of Pereira Barreto/SP, aiming at the reduction of fertilization nitrogen and consequently reducing costs for the producer. The experiment will be conducted from January 2019 to December 2019. The randomized block design will be used with 16 treatments arranged in 4 x 4 factorial, with four replications, in 10 m2 per plot. The treatments were: three PGPBs (A. brasiliense, B. subtilis and P. fluorescens) in addition to their absence, combined with three doses of N (100, 75 and 50% of the applied dose in the production area, of 280 kg ha- 1) plus the control (without N). The doses of N, using urea as a source, will be applied manually after carpet cutting and repeated every 2 months until total soil cover by the grass. The application of PGPBs will be done after the cut of the previous grass carpet, on the same day as the first portion of the fertilization, using 200 mL of the inoculant containing the PGPBs diluted in a 400 L ha-1 syrup and sprayed on the soil. They will be evaluated: the rate of soil cover by the grass (TCS) and the intensity of the green coloration of the grass by the digital image analysis of the aerial part; the normalized difference vegetation index (NDVI); dry matter and macronutrient concentrations in the leaves as well as the grass root system (dry matter and macronutrient concentration in the roots). The agronomic efficiency of the treatments will also be evaluated.