10 May 2013

Developing Quick Guides for fertilizing hybrid maize in large areas

What is a Quick Guide?

A Quick Guide (QG) is a one-page summary of plant nutrition and crop management guidelines for larger areas (i.e. district, municipality). Quick Guides are designed to provide farmers with location-specific guidelines based on the principles of site-specific nutrient management (SSNM) by capturing the most important factors that affect fertilizer recommendations in a given region.

Quick Guides are developed in a consultative fashion by local maize experts (i.e. researchers and extension from government and private agencies, crop advisors, farmer leaders) with the aid of the software Nutrient Expert for Hybrid Maize. Quick Guides aim to facilitate the dissemination of SSNM by reaching out to a large number of maize farmers in extension campaigns. Each Quick Guide presents fertilizer and crop management recommendations for the most relevant maize-growing scenarios (i.e. maize areas with common growing environments, farming practices, and yield levels) within the given area. Farmers then select the recommendation that best matches the location-specific conditions of their maize fields (e.g. irrigated or rainfed, crop rotation, soil type, crop residue management, etc). Quick Guides are best complemented by other extension tools and approaches such as videos on best management practices for maize, farmers’ meetings, and guidelines for on-farm evaluation of the suggested recommendations.

Information required in developing Quick Guides

The following set of information is required to develop a Quick Guide for a specific area:

• Characteristics of the growing environment
o availability of water (i.e. irrigated or rainfed)
o soil texture
o soil color or organic matter content
o other soil-related constraints, if any (e.g. acidity);

• Crop rotation (e.g. maize-maize, rice-maize);

• Common practices for managing crop residues;

• Maize yields obtained for specific growing seasons; and

• Fertilizer application history and use of organic amendments (if any)

Developing a Quick Guide: Step-by-step procedure

The development of a Quick Guide requires the active participation of a team of local maize experts (i.e. researchers and extension agents from government and/or private agencies, crop advisors, farmer leaders). Members of the local team need to sit together and ensure that reliable data (i.e. from farm surveys, maps, reports) are available on which to base the following steps:

Step 1. Identify the maize farming conditions and/or practices within a site (e.g. municipality) and determine the extent (area) covered by each condition/practice.

% of total maize area
Water availabilityIrrigated1
Favorable rainfed2
Less favorable rainfed3
Soil typeLight (e.g. sandy loam)
Medium to heavy (e.g. clay loam, clayey)
Cropping systemMaize – maize
Rice – maize
Maize – other crop
Crop residue managementAll aboveground residue removed
All aboveground residue returned
All aboveground residue retained and burned
1Irrigated: irrigation water is available as needed during the maize growing season
2Favorable rainfed: rainfall is evenly distributed throughout the maize growing period and sufficient for the moisture requirement of maize crop; drought occurrence is 0 to 1 in a 5-year period.
3Less favorable rainfed: the maize crop depends on rainfall, but rainfall distribution during the growing period might be erratic or less favorable; and drought is likely to occur 2 to 3 times in a 5-year period.

Step 2. Identify the most relevant maize growing scenarios in the area and determine the number of fertilizer recommendations

• Identify the field characteristics or farming practice/s (listed in Step 1) that represent a substantial portion (in terms of area or production level) of the maize fields and/or farming situations

• The total number of scenarios to be included in the QG must cover majority (at least 50% of the total area) of the maize farming situations. A scenario is determined by the variability of a set of factors (i.e. see list in Step 1) that affect the fertilizer requirement of the maize crop (see examples below). A maize growing area with homogeneous field characteristics and farming practices can be represented by a single scenario (i.e. one recommendation for the entire municipality).

• For easier comprehension of the QG, limit the number of scenarios per QG to not more than three scenarios, with each scenario having only one or two options (e.g. with or without Bio-N use, use of single element fertilizers or compound fertilizers, etc).

• Limit the number of recommendations in one QG to six (i.e. 3 scenarios x 2 options).

Example 1:
Water availability: Favorable rainfed = 70% (of total maize area), Irrigated = 30%
Soil type: sandy loam = 90%
Cropping system: maize – maize (100%)
Crop residue management: all aboveground residue retained and incorporated (100%)

Possible number of scenarios: two
(1) Rainfed
(2) Irrigated

Example 2:
Water availability: Favorable rainfed = 100%
Soil type: sandy loam = 60%, clayey soils = 40%
Cropping system: maize – maize (60%), rice – maize (40%)

Possible number of scenarios: two
(1) sandy soils with maize – maize cropping
(2) clayey soils with rice – maize cropping

Example 3:
Water availability: Less favorable rainfed without supplemental irrigation (70%); Rainfed with supplemental irrigation (30%)
Soil type: sandy soils (40%); loamy to clayey soils (60%)
Cropping system: maize – maize (100%)

Possible number of scenarios: three
(1) loamy to clayey soils without supplemental irrigation
(2) sandy soils without supplemental irrigation
(3) loamy to clayey soils with supplemental irrigation

Note: In less favorable rainfed environments, it would be useful to provide two fertilizer guidelines depending on rainfall or soil moisture condition (i.e. Plan A – for situations with sufficient rainfall and soil moisture during planned dates for fertilizer application; Plan B – for situations of delayed rainfall at V6 or V8, where fertilizer application rates and timing are adjusted as a result of the delayed availability of soil moisture). Plan A and Plan B guidelines are provided by the Nutrient Expert TM for Hybrid Maize software when the growing environment is “less favorable rainfed”.

Step 3. Run the Nutrient Expert for Hybrid Maize software to develop a fertilizer recommendation for each maize-growing scenario. The input data for the software (i.e. growing environment, current farmer’s practice, yield, and fertilizer use) can be based on (1) individual farms/farmers who are representative of the maize-growing scenario, or (2) data gathered from farm surveys, maps, and reports that represent each maize-growing scenario. The following output from the software is required:

(a) estimate of attainable yield (yield goal)
(b) fertilizer N, P2O5, and K2O requirements
(c) fertilizer application strategy or guideline, with
- right sources of nutrients (fertilizer)
- right timing of application
- right rate of fertilizer to apply

Note: Print or save the “Report” of the “Sources and Splitting” module (i.e. fertilizer guideline) for your reference

Step 4. Compile the recommendations into one prototype QG

Step 5. Evaluate the newly-developed fertilizer guidelines with farmers.

Step 6. Revise (if necessary) and finalize Quick Guide for reproduction.

Example of Quick Guide developed for one municipality in the Philippines
(Click on the image to enlarge)

Mirasol Pampolino and Julie Mae Pasuquin

More about: Best Management Practices