Contents of macronutrients and growth of ‘BRS Marataoã’ cowpea fertigated with yellow water and cassava wastewater

Narcísio Cabral De Araújo,Vera Lucia Antunes Lima,Elysson Marcks Gonçalves Andrade,Suenildo Jósemo Costa Oliveira,Jailton Garcia Ramos,Geovani Soares De Lima

doi:10.4136/ambi-agua.2309

Narcísio Cabral De Araújo, Vera Lucia Antunes Lima + Show 4 more

Open Access

https://doi.org/10.4136/ambi-agua.2309

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Abstract

Agricultural utilization of yellow waters associated with cassava wastewater is a sustainable technique, since it allows reduction of costs related to acquisition of industrialized fertilizers and minimizes the environmental pollution caused by the inadequate disposal of these effluents. In this context, this study evaluated the macronutrient macronutrient content and growth of cowpea fertigated with yellow water associated with cassava wastewater and NPK as source of nutrients. The experiment was set up in a greenhouse located at Campus I of the Federal University of Campina Grande. The experimental design was completely randomized, composed of five treatments characterized by: fertigation with mineral fertilizers, in the form of NPK; organic fertigation composed of human urine, cassava wastewater, human urine plus cassava wastewater; and organo-mineral fertigation composed of urine, cassava wastewater and mineral phosphorus, with four replicates. At 36 days after sowing, the following parameters were determined: contents of nitrogen, phosphorus, potassium, sulfur and the variables number of leaves, plant height, stem diameter, leaf area, shoot fresh matter and shoot dry matter. The use of yellow waters promotes significant increases for growth and production variables for nitrogen and potassium contents mainly, as well as for growth and production variables. The contents of nitrogen, phosphorus and potassium were higher than the levels considered as adequate for the cowpea crop. The use of human urine and cassava wastewater have potential to meet the needs for the main macronutrients required by cowpea and the irrigation via fertigation with these biofertilizers positively influences the development of cowpea.

Highlights

Cowpea (Vigna unguiculata (L.) Walp.), known as ‘feijão-fradinho’, ‘feijãomacassar’ or ‘feijão-de-corda’, is a source of income and food for many regions, especially the Brazilian Northeast (Benett et al, 2013)
Human urine has been used as a source of urea and cassava wastewater as a source of potassium since the concentration of these substitute mineral fertilizers (Ranasinghe et al, 2016)
Considering the lack of studies using yellow water and cassava wastewater in cowpea cultivation, the present study evaluated the contents of nitrogen (N), phosphorus (P), potassium (K) and sulfur (S) and the growth of Vigna unguiculata (L.) Walp., cultivar ‘BRS Marataoã’, fertigated with human urine combined with cassava wastewater as source of nutrients

Summary

Introduction

Cowpea (Vigna unguiculata (L.) Walp.), known as ‘feijão-fradinho’, ‘feijãomacassar’ or ‘feijão-de-corda’, is a source of income and food for many regions, especially the Brazilian Northeast (Benett et al, 2013). In Brazil, cowpea has undergone great changes, in both the production sector, with expansion of its cultivation to other regions, and in the commercial sector, with the standardization of the best product, beginning of industrial processing and product entry in new markets in the country and abroad (Freire Filho et al, 2011). The recycling of nutrients contained in biodegradable wastes is a sustainable technique because it minimizes the use of synthetic mineral fertilizers and the negative impacts resulting from lack of environmental management in the exploitation of natural resources to produce fertilizers and pollution of waters due to uncontrolled disposal of wastes in the environment. The increased costs of mineral fertilizers and increasing environmental pollution make the use of organic wastes in agriculture an attractive alternative from an economic point of view, due to the cycling of C (carbon) and nutrients (Silva et al, 2010). Human urine has been used as a source of urea and cassava wastewater as a source of potassium since the concentration of these substitute mineral fertilizers (Ranasinghe et al, 2016)

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