poster - International Conference of Agricultural Engineering

Irrigation of Brachiaria brizantha pasture with wastewater of
cassava industry
Altair Bertonha 1 *, Daiane de C. Mariano 2 , Paulo S. L. de Freitas 1
1
Professor, University of Maringá, Av. Colombo 5790, Maringá, PR, 870200.900, Brasil
2 University of Maringá, Av. Colombo 5790, Maringá, PR, 870200.900, Brasil
*abertonha@uem.br
Abstrat
The water reuse from food industries of vegetable origin, as source of water, nutritious and
organic matter for the soil and plants is a practice traditionally used in the agriculture and
may be treated as the fertirration is. At this research, it was evaluated the cassava waste
water application effects in Brachiaria brizantha cv. MG-5, being employed a hydraulic
sprinkler, having as treatments all the waste water depth accumulated during the crop cycle,
which are 0, 100, 275, 290, 328 and 366, applied during 10 weeks, for 4 continuous hours of
irrigation a week, totaling 40 hours of irrigation that occurred from November 20, 2008 to
January 30, 2009, when the pasture was cut. Soil and tissue plant were analyzed before and
at the end of the experiment. Biomass and dry matter were analyzed at the end of the
experiment. It was conclude that there is no restriction in the use of cassava waste water in
the fertigation of the evaluated grass for these waste water depths; that the plant’s height
isn’t a good reference to estimate the dry matter productivity of this grass when irrigated with
waste water; that the waste water application caused an organic matter level increasing at
the layer from 20 to 40 cm of depth, and an Al level increasing at the layer from 0 to 20 cm of
depth; and that, in function of waste water depth (L), the absorbing efficiency of N and P
related to the witness was adjusted by a quadratic function, and for the K, it was adjusted
linearly.
Key words: waste water, irrigation, dry mass
1. Introduction
In the process of industrialization of cassava starch, each ton of processed roots can
produce up to 2.5 m 3 of wastewater (Cereda 2001) composed of formation water from the
roots, washing and process.
The application of this waste, according to Saraiva et al (2007) increases the levels of
organic matter, nitrogen, phosphorus and potassium in the soil. On the other hand its
indiscriminate use can change the balance of cations and pollute the soil and groundwater,
presenting itself as a residue favourable for fertilization and unfavourable to pollution of soil
and water, depending on the management practices used in your application.
The quantity of nitrogen (N) and potassium (K) of this wastewater can meet crop demand
(Anami et al., 2008 and Pelissari et al., 2009), but their applications must be monitored
because the mobility of these ions on the ground in various stages of plant growth
(Santos et al., 2009) and soil management (Pearson and Ison, 1997).
In addition to nutrients this residue is an important source of water for irrigation in the border
of the cassava industry, reaching estimated values of 10.000.000m 3 a year in the
northwest of Paraná State.
The acclimation of Brachiaria brizantha Stapf in the northeaster state of Paraná, this
allows grass to produce up to 18 Mg DM ha -1 yr -1 (Souza 2002), often pastured 30-35 days
(Correa 1999), presenting in its nutritional composition, 11 to 18, 0,6 to 1.2; 11 to18, 2 to
4 and 1.2 to 2.3 gKg -1 respectively of N, P, K, Ca and Mg.
The objective of this study was to take the wastewater from the cassava industry as a source
of water and nutrients applied on Brachiaria brizantha cv. MG-5.