Site Specific Nutrient Management for Soft Corn Varieties in the Highlands of Guatemala

IPNI-2009-GTM-6

08 Feb 2010

Project Description


Soft corn varieties for human consumption are grown in extensive areas of the highlands of Guatemala. Farmers own small farms and phase limitations in capital and technology and grain production is generally low. However, high enough sustainable yields can provide adequate income to sustain the household and provide savings to invest in farm improvement.

According to HELPS International, a NGO working in Guatemala in diverse areas of poverty alliviation, the farmer's family in rural Guatemala needs approximately 1,700 kg of corn per year, but  the traditional method of growing corn yields only about 700 pounds of corn per year.  The head of the family has to work outside his community obtain the resources to purchase the additional corn for the year. Increasing the ability of farmers to grow higher yields is one way of helping farmers to obtain a better way of life.  

Yield potential and nutrient needs differ among agro-ecological corn growing zones. This results in different growing conditions which require different nutrient recommendations and management. Knowing that soil testing is rarely used by small farmers, a site specific nutrient management approach, based on the omission plot technique, was developed to study the influence of local agro-ecological conditions on nutrient requirements as a tool to develop fertilizer recommendations to achieve high sustainable yields.


Justification

Soft corn varieties for human consumption are grown in extensive areas of the highlands of Guatemala. Farmers own small farms and phase limitations in capital and technology and grain production is generally low. However, high sustainable yields can provide adequate income to sustain the household and provide savings to invest in farm improvement.

Main limitations of corn producers in the highlands are soil degradation (erosion), declining soil fertility and inadequate technical assistance. Work conducted in the past by IPNI in South America, has demonstrated that plant population and nutrient management can improve and sustain high enough yields satisfy food need and to help farm income.

Fertilizer recommendations used in the soft corn producing areas of the highlands do not satisfy the nutrient needs for high yields. One only nutrient recommendation is used for extensive areas of production, assuming that nutrient needs are constant in time and space. Improvement of corn production in the region needs a more dynamic approach in terms of nutrient management.

Yield potential and nutrient needs differ among agro-ecological zones. This results in different growing conditions which require different nutrient recommendations and management. Knowing that soil testing is rarely used by farmers, a site specific nutrient management approach, based on the omission plot technique, was developed to study the influence of local agro-ecological conditions on nutrient requirements as a tool to develop fertilizer recommendations to achieve high sustainable yields.

Objectives
  1. Determine yield potential, yield goals and yield gaps for the soft corn varieties of corn at the different agro-ecological zones of the highlands of Guatemala.
  2. Build up a set of practical tools for site specific nutrient management.
  3. Develop simplified fertilizer recommendations for the most representative agro-ecological zones of the soft corn growing area located on the highlands of Guatemala.

Methods

A simple experiment was designed to compare a balanced fertilized treatment against plots with individual omission of N and P. All experimental plots were planted with a population of 62,000 plants/ha arranged in rows 0.8 m apart and hills 0.4 m apart. Every hill received two seeds. This is a mayor change in crop management introduced in the experiment to ensure a uniform population. Farmers normally plant 40,000 seeds locating 4-5 seed in each hill, which are unevenly distributed in the field. Competition within the hills leads to only one or two plants producing a good corn ear reducing yield potential. An exploratory complete balanced fertilizer treatment was designed based on local experience.