Crop nutrients in plants and the factors influencing the amount of fertiliser required
Overview
This standard covers the principles of integrated crop nutrient management and the various factors which, together with fertiliser and organic nutrient application, can be used to satisfy crop requirements.
You must be able to estimate the nutrient requirements of a particular crop and appraise a range of nutrient sources available to clients, prior to constructing nutrient and fertiliser plans and to make fertiliser recommendations to meet crop requirements and have due regard to the environment.
Performance criteria
You must be able to:
P1 calculate typical rates of uptake and removal of nutrients by different crops
P2 indicate typical symptoms of deficiencies of major and micronutrients
P3 use of soil analysis as a basis for nutrient recommendations
P4 interpret the ‘Law of Limiting Factors’
P5 interpret nutrient response curves and the effect of the ‘Law of Diminishing Returns’
P6 use a response curve to calculate an approximate break-even rate for a major nutrient, e.g. nitrogen in cereals and explain how economic changes can affect the nutrient recommendations
P7 distinguish between ‘economic’ and ‘maximum biological yield’
P8 assess and appraise the effects of crop rotation, farming practices and crop quality specifications on nutrient availability and requirement
P9 interpret situations suitable for ‘maintenance applications’ in maintaining soil nutrient reserves and ensuring effective crop response
P10 ensure that prior to drawing up recommendations soil and tissue analysis and their limitation are interpreted
P11 diagnose nutrient disorders in the context of other crop disorders
Knowledge and Understanding
You need to know and understand:
K1 the role of all plant nutrients
K2 the main units in which advice is given and convert between the different units giving advice in metric with imperial conversions
K3 how to approach diagnosis of nutrient deficiencies, e.g. take soil and plant samples, use pH kits
K4 how to interpret soil and tissue analysis reports and the application of the information to given crop fertiliser regime
K5 the role of organic nutrient sources in crop nutrition and identification of the extent to which a given crop fertiliser regime should be modified to take account of this
K6 how to diagnose nutrient disorders
K7 how to convert between metric and imperial units and, where liquids are used, between weight/weight and weight/volume declaration
K8 market requirements in certain crops and the effect nutrients may have on them