Practical Skills and Field/Laboratory Work
What the domain tests
Practical Skills and Field/Laboratory Work tests safe, accurate field and lab procedures: soil sampling, seed testing, moisture determination, pH/EC measurement, fertilizer calculations, plot layout and record keeping.
Core rules
- Collect a representative soil sample in a zig-zag pattern from several spots, mix, quarter and send a composite sample with correct labelling.
- Seed testing includes purity, germination and moisture. Germination percentage = (number of normal seedlings/total seeds tested) x 100.
- Adjust seed rate for germination and purity: seed rate = recommended rate/(germination fraction x purity fraction).
- Calibrate pH and EC meters with standard solutions before use; rinse the electrode between samples.
- Use clean glassware, correct units and replicate measurements. Record raw data immediately.
- Follow safety rules for pesticides, acids, glassware and field machinery.
Worked example
The recommended seed rate is 100 kg/ha, germination is 80% and purity is 90%. Adjusted seed rate = 100/(0.80 x 0.90) = 100/0.72 = 138.9 kg/ha. Reasoning: only 72% of the seed lot is pure and viable, so more seed must be sown to establish the target population. Round to about 139 kg/ha.
Traps
Do not take a single spot sample as representative. Do not calculate germination from abnormal seedlings. Do not use uncalibrated meters. Do not confuse fresh weight with dry weight. Do not record data after the practical from memory.