Sampling Instructions
CROP & PASTURE TISSUE - SAMPLING INSTRUCTIONS
PASTURE SAMPLES
General sampling instructions
• Design your sampling plan similar to the W-sampling plan as detailed in the previous section and try to ensure that samples are representative of what your animals are consuming.
• Exclude dusty or soil contaminated plants and do not sample fields within 3-5
days after being sprayed with pesticides or foliar nutrients.
• Using a pair of clean rust-free shears, take around 15 to 20 small handfuls of
grass (about 5cm from the ground) from sites throughout the sampling area and combine in
the Phosyn sample bag provided. Please avoid contaminating the sample with soil, dirt or
chemical residue (drench etc) as this can lead to erroneous results.
NOTE - The optimum sampling time for pasture samples is generally during the active growing cycle i.e. during the spring or autumn flush.
CROP SAMPLES
Given the diversity of plant types and varieties, it is not intended to outline a sampling guide for every specific crop but a sampling guide is detailed below which provides advice for a broad range of crop types. If your crop is not listed, please contact your local distributor or Phosyn representative for more specific sampling instructions and advice. However, as a general rule you should collect the youngest fully expanded leaves available.
General sampling instructions
• In designing your sampling plan try to select trees/ bushes etc of the same
variety and rootstock along the sampling path. A typical random sampling pattern is
shown below.
• Exclude pollinators and diseased or otherwise abnormal trees and bushes.
• Exclude dusty or soil contaminated plants and do not sample fields within 3-5 days
after being sprayed with pesticides or foliar nutrients.
IMPORTANT - UNLESS OTHERWISE ADVISED, PLEASE ENSURE THAT YOU SEND AT LEAST ABOUT 200 GRAMS (ABOUT TWO HAND FULLS) OF FRESH PLANT MATERIAL FOR EACH SAMPLE REQUIRING LABORATORY ANALYSIS.
Fruits, vines and nut crops
Apple - Collect mid-shoot leaves on current season's extension growth from late January to mid February (i.e. mid summer)
Banana - Select the third youngest fully emerged leaf from medium-sized suckers that can be reached from the ground. Take sample strips of lamina from at least 10 plants per block. Collect 20cm wide strips of leaf blade tissue at about half way along the leaf on each side of the midrib.
Cherry - Collect youngest mature leaf from the mid section of current season's extension growth
Citrus - Collect 5 to 7 month old spring flush leaves from non-fruiting shoots in February.
Coffee - Sample 4th pair of leaves from tip of actively growing fruit branches.
Grapevine - Either the petiole (stem of the leaf) or the leaf blade opposite the bunch at the
base of the shoot can be sampled, depending on the time of the year and your preference.
(a) Leaf petiole
(flowering) - Collect leaf petioles from opposite the basal cluster from exposed shoots
on the outside of the vine during flowering at full bloom (November/ December). Petioles
should be separated from the leaf blade immediately after sampling.
Note - Petioles should only be sampled at flowering.
(b) Leaf (Ripening) - Collect leaf blades only and remove petioles immediately.
Sampling again should be from opposite the basal cluster from exposed shoots on the
outside of the vine.
Note - Leaf blades can be sampled pre-flowering, at flowering or at veraison.
Kiwifruit - Collect the first leaf above the fruit towards the growing point in February in the mid-summer growth stage.
Macadamia - Select mature leaf from the second whorl of current seasons growth, avoiding terminals carrying new flushes.
Mango - Collect the most recently mature leaf in early spring, just prior to flowering.
Nectarine - Collect youngest mature leaf at mid portion of the current seasons non-fruiting laterals (extension growth), taken at shoulder height.
Olives - as for Nectarine.
Passionfruit - Collect the youngest fully expanded leaf from well-developed actively growing laterals.
Peach - as for Nectarine.
Pear - as for Nectarine.
Persimmon - Collect the youngest mature leaf from non-fruiting shoots. Sample during late Feb to early March.
Vegetable crops
Brassica - As a general rule, samples should be collected at mid-growth stage or when the plant is starting to head.
For Cabbage & Cauliflower, sample the youngest mature wrapper leaf from head maturity through to early harvest;
For Brussel sprout, collect upper leaf at mid-growth stage when the plants are beginning to head;
For Broccoli, collect youngest mature leaf at mid-growth stage when the curd is starting to form.
Cucurbits (Cucumber, rockmelon, pumpkin, zucchini, marrow, squash etc) - Collect youngest fully mature leaf with petiole at early flowering.
Garlic - Sample youngest mature leaf (without the white) at the bulbing stage.
Legumes (peas, beans) - Collect the youngest fully expanded leaf (minus petiole) at the early vegetative growth stage prior to flowering. (i.e. 6-8 weeks from seeding)
Lettuce - Collect the wrapper leaf when the head is approximately half its final size.
Onion - Collect youngest mature leaf at the mid-growth stage or 3-4 leaf seedling stage.
Potato - In order to monitor the availability of major nutrients i.e. NP&K during the
growing season, it is recommended that petiole samples are taken at regular intervals
from king tuber length 10ml - 150ml. Trace element analysis can be carried out at any
plant stage, however, it is generally recommended from tuber initiation through to early
bulking stage (refer to individual trace element recommendations for optimum application timings).
NOTE - King tuber size is defined as the distance between the two furthest points on the tuber. For analysis purposes, petioles are usually collected at regular intervals from 10mm - 150mm.
To collect a petiole sample, select the 4th petiole from the growing point and immediately
stripped off the attached leaflets. Each individual sample should be made up of al least
40 individual petioles.
Tomato - Collect the youngest mature leaf including the petiole either when the first
fruit is mature or at peak harvest.
Temperate and tropical crops
Sugarcane - A section of around 20cm long of the TVD (top visible dewlap - this is approximately the third leaf from the shoot apex) should be collected during the boom phase of growth i.e. when stalk elongation is around 2cm per day.
Sunflower - Collect youngest open leaf at early vegetative growth stage (approximately 6 weeks from seeding)
Lucerne / Alfalfa - Sample at vegetative growth stages. Collect plant tops from the top 15cm of the plant.
Lupin - Collect youngest mature blade during the vegetative growth stage prior to flowering.
Cereals (ie Wheat, Sorghum etc) - Sampling can be carried out at any growth stage, but
generally the 4-5-leaf stage is recommended, in order that any desired nutritional
application can be made at the optimum timing. Sampling of either whole plant, or
youngest mature blades can be made, however for the majority of trace element analysis,
i.e. Ca, Mg, Cu, Zn analysis of youngest mature blades is the more accurate method.
Please state clearly on the analysis request form which method of sampling has been used.
Canola - Leaf tissue should be collected at no later then the 6-leaf stage.
Note: If Mo deficiency is suspected (eg historical reasons etc) then it is advised that samples are collected at the 4-leaf stage.
Cotton
Sampling at three main growth stages is recommended; namely At the 4 to 6 leaf stage, at squaring and at flowering
At each stage, collect two separate samples as follows;
(a) Leaf - collect the youngest fully unfolded leaf (100 leaves per sample)
(b) Petiole - Detach petioles from the leaf immediately after sampling (200 petioles per sample).