Evaluation of the response of sugarcane (Saccharum officinarum L.) to nitrogen fertilization in farmers' fields in the Central Area of the Department of Santa Cruz (Bolivia)

Evaluation of the response of sugarcane (Saccharum officinarum L.) to nitrogen fertilization in farmers' fields in the Central Area of the Department of Santa Cruz (Bolivia)

INSTITUTION

Centro de Investigación Agrícola Tropical (CIAT) (Center for Tropical Agriculture Research)
Proyecto Suelos (Soils Project)
Av. Ejército Nacional No. 131. Tel. 591 3 337 0000. Santa Cruz, Bolivia

Collaboration by
Centro de Investigación y Transferencia de Tecnología para la Caña de Azúcar (CITTCA) (Center for Research and Transfer Technology for Sugarcane)
Saavedra, Departamento de Santa Cruz, Bolivia

STAFF
Dr. Ernesto Salas Garcia (Executive Director - CIAT)
Ing. M.Sc. Mary Selva Viera V. (Director of Research – CIAT)
Ing. M.Sc. David Ruiz A. (Responsible Soils Project – CIAT)
Ing. Alberto Gutiérrez G. (Researcher Soils Project – CIAT)
Ing. Everth Ríos L. (Responsible GIS – Proyecto Suelos – CIAT)
Ing. M.Sc. Roxana Barba A. (Researcher Soils Project – CIAT)
Ing. Carlos Costas Aguilera (Executive Director – CITTCA)

INTRODUCTION

The cultivation of sugarcane has an important role in the agribusiness sector of the department of Santa Cruz. Currently there are about 150,000 hectares cultivated by small and medium producers with an average yield of 50 t ha^-1, and an output of 9 million quintals of sugar covering 100% of the domestic demand for Bolivia and a surplus for export.

Results of a diagnosis of soil fertility, conducted by the Center for Tropical Agricultural Research (CIAT) showed that most soils used in crop production of sugarcane (Saccharum officinarum L.) in the department of Santa Cruz, have low content of organic matter (OM) and total nitrogen (TN). Approximately 70% of the soils of Warnes, Montero, Portachuelo and Saavedra municipalities have contents of TN lower than 0.1%, an amount that would be insufficient to meet the requirements for an average of 50 t ha^-1.
Regarding the texture, in this area a great diversity of soil occurs; from very light (> 80% sand) to very heavy (> 60% clay). Under these conditions, it is expected that cane yields also present great variability. According to data provided by sugarcane growers in some soils, cane yields can reach up to 80 t ha^-1, decreasing to 40 t ha^-1 in 5 years. On the other hand, there are producers with 10 years of ratoon cane with yields of 80 t ha^-1. In recent years, a steady increase in the use of chemical fertilizers is observed to correct nutritional deficiencies in sugarcane, however, in many cases there are low responses, not economically profitable. These results may be related to the fact that producers do not soil test and use recommendations from other producers, as they do not perform proper management of fertilizers.
Based on this background, we propose to implement this project which will benefit in the first instance to the universe of sugarcane growers in improving yields, the profitability of production and what is very important, will contribute to the sustainability of the soil resource. Also, the project will generate useful information for extensionists providing field assistance

OBJECTIVES

General
· Increase productivity and sustainability of sugarcane cultivation in the department of Santa Cruz.

Specifics
· Identify adequate nitrogen management for sugarcane in different types of soil in the central area of Santa Cruz.
· Validate current recommendations of CIAT on nitrogen fertilization based on soil test results and crop demand.

ACTIVITIES AND METHODOLOGY

For the identification of appropriate rates of nitrogen fertilizer, farmer`s fields would be selected according to soil analysis. As data selection criteria, we would include Organic Matter, Total Nitrogen and toil texture, representing soils of sugarcane Santa Cruz area.

There will be a total of 30 fields, including soils with very low, low and medium total nitrogen, light, medium and heavy textures and cane at different ages. In the 30 fields, treatments will be: Check, 50 kg N ha^-1, 100 kg N ha^-1 and 200 kg N ha^-1. Each treatment will be replicated three times at 15 fields. At the other 15 fields, the treatments would be established without replications, adding to the exploration of contrasting environments. Plots would have an area of ​300 m² (6 m x 50 m). Determinations would include: plant height, stem diameter, yield and sugar content. Statistical analysis would include regression analysis for all 30 fields. Analysis of variance (P <0.05), and comparison of averages by LSD test would be carried in each of the 15 fields with replications. Likewise, an economic analysis of the profitability of nitrogen fertilization in sugar cane will be carried out.

EXPECTED RESULTS

The purpose of the project is to improve the productivity and sustainability of sugarcane production in the department of Santa Cruz, through the proper use of nitrogen fertilizers. The project aims to determine the likelihood of response to the application of nitrogen fertilizers and identify rates of nitrogen to improve the development and performance of sugarcane grown in soils of different texture.

IMPACT OF THE PROJECT

The information generated in the project will be beneficial to technicians and researchers who will be able to develop specific recommendations on the use of nitrogen fertilizer in different soil types. It also will help to increase the efficiency of fertilizer, crop productivity, conservation of soil resources and improving the economy of the sugarcane growers of the department of Santa Cruz.

FUNDING REQUESTED TO IPNI

Main funding and staff will be provided by the Tropical Agricultural Research Center (CIAT) and the Center for Research and Transfer Technology for Sugarcane (CITTCA).
Additional funding requested to IPNI is of US$. 5,000 (five thousand US dollars 00/100). This amount would allow to partially cover costs of purchasing fertilizers, soil analysis, fuel, printing, travel and others.