ISSUE 3   May 28, 2009

EARLY GROWTH STAGING SMALL GRAINS

Early planted spring wheat and barley have now emerged and are adding some green to the countryside. Winter wheat fields are filling-in nicely. In fact, the more developed winter wheat fields are beyond the 4 to 5 leaf stage and will soon begin jointing. The optimum and/or the legal timing of a number of management practices (i.e. nitrogen, herbicide and fungicide applications) is frequently determined by the growth stage of the crop. Therefore, correctly "growth staging" a crop is important in the crop management process. Though there are a number of different scales (i.e. Feekes, Haun and Zadok) that have been developed to classify the growth stages of small grains, typically early management recommendations are based on leaf numbers or other visible characteristics of the plants. The following is a brief description of how to growth a small grain crop that I have previously published, but I think will be useful as a review as we approach key stages in developing small grain crops.

When growth staging your crop you should begin by obtaining a representative sample of plants from the field or part of the field of interest. To give you a good feel for an "average" plant, use ten plants selected at random away from the edges of the field. Remove any soil attached to the plant so that you are able to observe the roots and crown. Leaf stage is the most common physical feature used to describe early development of small grain crops. Leaf stage is defined by the number of leaves that have visible collars on the main stem. Care must be taken to ensure that the earliest leaves are included when counting. The first leaf is small and is frequently lost from the plant during normal growth. It has a characteristically blunt tip. Look for the sheath remnants at the crown of the plant if you suspect that the first leaf (or second for that matter) is missing. Count only the leaves on the main stem, which is the tallest and most leafy of the stems. Include only those leaves that have a collar. When staging plants include all leaves, even those that have been damaged by hail or frost. The total number of leaves that a plant will developed is more or less fixed for a given variety; leaves that are striped from the plant will not be replaced by additional new leaves.

The North Dakota Agricultural Weather Network (NDAWN) can also be used to give you a rough estimate of the growth stage of your crop. Go to the application section of the NDAWN home page http://ndawn.ndsu.nodak.edu/ and select wheat degree days/growth stage, then enter your planting date and select the NDAWN station nearest your farm. Data on the number of wheat degree days and the approximate growth stage of your crop will be provided as output. This tool can be particularly useful if leaves have been lost to frost or hail damage.

Joel Ransom
Extension Agronomist for Cereal Crops
joel.ransom@ndsu.edu

 

SUNFLOWER

High sunflower yields require detailed management decisions. Sunflower is a warm season crop and fits well into a crop rotation with small grains. Planting sunflower in rotation with small grains provides a biological break to reduce certain diseases in small grains such as tan spot, septoria, and certain root rots.

Sunflower management starts with the selection of an appropriate field. Producers have a major decision to make in the selection of which hybrid(s) to use. It is always a good strategy to use proven hybrids and make a selection based on field research data over multiple locations and years. Select hybrids with high yield potential, disease resistance, and high oil content. For information about hybrids tested in North and South Dakota see

 http://www.ag.ndsu.edu/pubs/plantsci/rowcrops/a652.pdf.  

Yield results from private seed companies can also be incorporated into the decision making process. Good quality seed is important. The germination percent should be high. Seed should be of uniform size, without cracking and free of disease.

Sunflowers should be planted in May when the field conditions are ready. The recommended planting dates for North Dakota are from May 20th to June 5th. Planting date research at several locations and multiple years indicated that plantings in early May can increase insect problems in the crop later during the growing season. In general, yield potential has been higher with the mid-May to late-May planting dates when compared with June planting dates in most locations in North Dakota. Some June plantings in the research plots had lower yield, oil percent, and test weight compared to the May planting dates. Sunflower will mature in about 95-110 days after emergence. There are genetic differences in the time it takes the crop to mature.

Plant populations depend on soil type and anticipated soil moisture conditions. On heavier soils 20,000 to 22,000 plants per acre are recommended for oil type sunflower hybrids. On lighter sandier soils, and low rainfall areas, the recommended population is in the 16,000 to 18,000 range. For confectionary sunflower the population should be lower than for oil type sunflower with a range of 15,000 to 18,000 plants per acre. To obtain the desired plant populations it is to recommend to compensate for germination percentage and overplant by about 15 percent as not all seeds will make it to an established plant. It is very important to get an even distribution of the plants in the field.

Each summer extension specialists and university and USDA researchers survey a number of North Dakota sunflower fields and determine the production problems. In 2008 16% of the 77 fields surveyed had less than optimal plant spacing identified as the factor most limiting to sunflower yield. There may be a number of reasons why plant spacing at the end of the season was limiting but starting the season with a proper and well distributed plant population is essential to maximize yield.

Planters need to be adjusted so proper seed distribution will take place. Increased planting speed may cause larger gaps between plants. Seed should be placed at a depth of 1.5 to 2 inches when soil moisture is good. Deeper depths may be necessary under drier conditions but not more than 2.5 to 3 inches. Larger seed size is better suited for deep planting. When two seeds are dropped close together there might be excessive plant competition often resulting in smaller sunflower heads.

Hans Kandel
Extension Agronomist, Broadleaf crops
hans.kandel@ndsu.edu


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