Leaf Sampling Procedure

Sampling Procedures for Plant Analysis

Introduction

Plant analysis is the second tool, after soil testing, that is critical to improving crop nutrition and yield. Only plant analysis can identify the actual nutrient status of a plant or crop. While soil testing identifies the nutrients offered to the crop or plants, plant analysis identifies how well the plants utilized the soil and applied nutrients. Plant analysis allows the crop or plant to tell us what nutrients it needs.

It is critical that the correct plant part and stage of growth be sampled, and that the label clearly informed of this.

The normal nutrient concentration differs between the various plant parts. Also, the normal nutrient concentration of each plant part changes as the plant matures. Plant analysis is calibrated to these norms, so correct identification of which nutrients are low or high depends on accurate information. Call our Laboratory if you have a plant not listed.

How to Take Plant Samples

1. Where to Take Samples

A. In Uniform Fields

Where plant grow this uniform over the entire area, one composite sample, taken from at least 10 widely scattered areas in the field. One plant sample is necessary. One soil sample is recommended.

B. In Problem fields

These are where the growth or appearance of one area differs from the rest of the field. Plant analysis can often determine the cause of these differences and indicate the best method to correct the problem. Sample when abnormalities are discovered. Two plant and two soil samples are required. This includes collecting soil and plant samples from the normal area.

All plant samples taken from abnormal areas should be taken from just inside of the abnormal area. Soil  samples should be taken through out the abnormal area.

A separate Plant Analysis History must be completed for each sample taken.

2. When to Take Samples

Crops can be sampled during most of the season. The following tables list the preferred plant parts and growth stages to sample for many crops.

3. Amount of Plant Material

All plant analysis requires at least a rounded double handful(soft ball size) of plant tissue. We find it difficult to analyze a sample that is too small. See the tables on the following pages for the proper number of plant parts to sample.

4. Preparing Samples for Shipping

Use a large, clean paper bag or clean plastic bucket to collect the sample. Remove any dust or residue from the leaf surface with a clean dry soft bristle brush. Do not wash the sample. Improper washing can affect the nutrient content of some elements.

5. Sample Submission Form

Perhaps the most important part of a plant sample is its accompanying Plant Submission Form. This form can be downloaded from submission form. Be sure to indicate if more than one sample is being sent at the same time. 

6. Sending the Sample

Place the collected leaf samples in perforated Cropnuts sample bags, ensuring adequate air circulation to prevent moisture build-up during transit.

Do not send fresh samples or put them into plastic bags. They will decompose during shipment, making them useless for analysis purposes.

IMPORTANT:  Accurate Analysis and meaningful interpretation require properly taken samples.

Follow these and all directions carefully and correctly.

Most Vegetables

Sample uppermost mature leaf.

Tomatoes

Field                                                                       Greenhouse 

Sample uppermost mature leaf or main stem         Sample terminal leaflet or leaf next to most recent fruiting cluster 

Grapes 

(Leaves or Petioles)

Vegetative: Sample youngest fully mature leaf.

Fruiting: Sample leaf opposite basal fruit cluster.

Leaf: for complete nutrient analysis 

Petioles: for nitrate monitoring only

Effective Uses for  Plant Analysis 

1. Confirm visual deficiency symptoms.

2. Reveal hidden nutrient stresses.

3. Check up on the effectiveness of a fertility program.

4. Improve yield goals and fertilizer needs for future crops.

5. Improve quality of plants 

A Complete Plant Analysis from Crop Nutrition Laboratory Ltd includes the total amounts found of the

nutritional elements, N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, Na and Zn. 

The status (Deficient, Low, Normal, High, Very HIgh.) for each nutrient tested is indicated numerically on

the report and a colored bar graph. A complete agronomic interpretation of the analytic results is also

available. 

Some Plant Analysis Do’s and  Don’ts 

DO'S

1. Collect a representative sample. Sample the field as you would if you were sampling the soil (10-20

sampling points.) 

2. Always collect sufficient plant material (see “Quantity” tables).

3. Fill out the plant history questionnaire as completely and accurately as possible. The more complete the 

information the more reliable the interpretation.

4. Always identify the age and growth stage (seedling, bloom, Feekes, V/R, etc.) as accurately as possible.

5. Indicate if foliar fertilizers or fungicides have been recently applied. Identify them and record their 

application rates in the questionnaire. Again, it will make for a more reliable interpretation.

6. Always collect a soil sample from problem areas.

7. When in doubt, Read the Instructions or call or email the lab.

8. Make PLANT ANALYSIS a central part of your agronomic services program. 

DON’TS

1. Sample dead plants.

2. Wash leaf tissue

3. Collect or ship samples in plastic bags or containers.

4. Use galvanized equipment in any way.

5. Sample severely insect damaged plants.

6. Sample severely mechanically injured plants.

7. Sample plants that are too old (see “Growth Stage” tables).

8. Sample during severe drought.

9. Samples covered with dirt/soil particles.

For more information please contact us through:

Crop Nutrition Laboratory Services Ltd.

Limuru, Kenya

Telephone +254 (0) 736 839 933, + 254 (0) 720 839 933

Email support@cropnuts.com