Corn and Sorghum - Soil Management

Corn and Sorghum Soil Management

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Nutrient Budget Calculator

The Nutrient Budget Tool is a resource for growers who are interested in adequately providing the correct amount of nutrients for their crops for the optimal yields. This tool allows growers to choose crop type and yield goals into a spreadsheet that will then output the needed fertilizer levels of N, P, K needed to meet projected yield goals. Soil test, irrigation water test, and manure nutrient test analysis results can also be input to calculate the overall results of a crop’s nutrient/fertilizer needs. This tool is designed to help promote soil testing and analysis and to help growers be more cost and nutrient efficient. We plan to expand the Nutrient Budget Tool in the future to incorporate soil salinity levels (EC) and pH to better service the nutrient budget users and provide greater information.

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Nutrient Budget Tool

1. Choose the crop from the list of tabs at the bottom of the screen.

2. Fill in the “Plan Area” field in acres and “Yield Area” field in lbs/acre or tons/acre. Doing this will provide the needed N, P, and K requirements of the specified plan area.

3. Additional numbers from irrigation water analysis, soil analysis and fertilizer analysis from a plan area can be input to factor in to the overall needed requirements for N, P, and K in lbs/plan area.

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Planting Configuration

Grain sorghum can be planted in row spacing ranging from 6 to 40 inches apart or in twin rows in a variety of configurations. Grain sorghum will generally yield more when planted in 20 or 30 inch rows compared to 40 inch rows or in twin rows spaced 12-14 inches apart on 38-40 inch beds. Grain sorghum can be planted on beds or on flat ground.

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Seeding Rate

The optimum seeding rate for grain sorghum is about 10 pounds of seed per acre assuming a seed size of 14,000 seeds per pound and 70% emergence. Seed size varies from about 13,000 to 16,0000 seeds per pound depending on the hybrid, so seeding rate on a pound per acre basis should be decreased for smaller seed and increased for larger seed. The goal is to achieve a plant density of 100,000 plants per acre. Seeding rate can be increased by 20% if row spacing is 30 inches or less, with a non-tillering or short season hybrid or if planting in twin rows.

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Seeding Depth

The optimum depth of seeding is 1 to 2 inches. Seed deeper on lighter soils or if seeding into moisture rather than irrigating up.

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Fertilizer

At the 6000 lb/acre yield level, the grain sorghum plant will take up about 150 pounds of nitrogen per acre. The actual nitrogen fertilizer requirement depends on grain yield, nitrogen contained in the soil (Table 2) irrigation water, previous crop, and other factors. For example, more nitrogen fertilizer may be necessary following a small grain crop in order to break down the straw, compared to low residue crops or soil nitrogen building crops such as alfalfa. Phosphorus fertilizer is generally not required except when planting in the cooler part of the spring and the soil phosphorus level is less than 5 ppm. A need for potassium fertilizer is not expected in Arizona for most soils. Iron deficiency can occur on highly alkaline soils and zinc deficiency can occur where topsoil has been removed by land leveling.

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Soil Management Publications

Feb 2014

Diagnosing Nutrient Deficiencies Quick-Reference

Publication (PDF, 429KB)

Authors: Shawna Loper

Nutrient deficiencies can be identified in field through visual observations. However, additional analysis, either plant or soil testing is often necessary to confirm nutrient stress. The following is a quick-reference flow chart that can be used in field to identify potential nutrient deficiencies. Each nutrient has unique deficiency symptoms. Deficiencies will appear in many ways. It can be confused with other plant problems like pathogens or spray damage. But nutrient deficiencies can often be recognized because they tend to form symmetrical patterns, where both sides of leaf or plant parts show the same pattern.
Jun 2009

Growing Grain Sorghum in Arizona

Publication (PDF, 398KB)

Grain sorghum (milo) is a warm season, annual grain crop. It is more resistant to salt, drought, and heat stress than most other crops. Nevertheless, highest yields are obtained when stresses are minimized. This Article give some suggestion on planting, fertilizing, irrigation and other aspects of growing.
May 1991

Nitrogen Management Guide for Field Corn

Publication (PDF, 378KB)

Authors: Thomas A. Doerge, Robert L. Roth, Bryant R. Gardner

The level of nitrogen fertility has more influence on the growth and yield of Field Corn than any other single plant nutrient because it is the nutrient most often deficient in Arizona soils.
May 1991

Nitrogen Management Guide for Grain Sorghum

Publication (PDF, 320KB)

Authors: Thomas A. Doerge, Robert L. Roth, Bryant R. Gardner

The level of nitrogen fertility has more influence on the growth and yield of Grain Sorghum than any other single plant nutrient because it is the nutrient most often deficient in Arizona soils.
May 1991

Nitrogen Management Guide for Sweet Corn

Publication (PDF, 615KB)

Authors: Thomas A. Doerge, Robert L. Roth, Bryant R. Gardner

The level of nitrogen fertility has more influence on the growth and yield of sweet corn than any other single plant nutrient because it is the nutrient most often deficient in Arizona soils.

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Soil Management Presentations

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ARIZONA PEST MANAGEMENT CENTER