Soil Science
Chapter 16. Practical nutrient management
(*: important concept)
Zueng-Sang Chen (陳尊賢)
Tel: 2369-8349, soilchen@ccms.ntu.edu.tw; http://Lab.ac.ntu.edu.tw/soilsc/
Printed on Dec 20, 2004
16.1 Goals of nutrient management
 * Four goals: cost-effective production, efficient use and conservation, maintain soil quality, and
protection of environments.
 * Conceptual nutrient management: recycling the nutrient? or losses to the environment?
 * Soil quality
16.2 Environmental quality
 * point industrial point and Nonpoint landscape pollution from agriculture
 * Nutrient management plans: typical component (Table 16.3, p675)
 ** 4 general types of Best management practices (BMP): riparian buffer strips, cover crops, conservation
tillage, and forest stand management (Fig 16.4, 16.5, 16.7, 16.11, and 16.12)
16.7 Inorganic commercial fertilizers
 ** Nutrient contents of fertilizers (Table 16.4, p706-707).
 How much of N, P, and K in a bag of 6-24-24 (6% N, 24% P2O5, and 24% K2O) in 25 kg fertilizer bag
(answer: 1.5kg N, 2.6 kg P, and 5.0 kg K in 25 kg fertilizer bag) (Box 16.3, p708)
 * Law of minimum nutrient (Fig 16.26, p709)
 * Concept of limiting factors: (Fig 16.27, p710)
16.8 Fertilizer application methods
 *broadcast, localized, and foliar application. (Table 16.29, p712)
16.10 Diagnostic tools and methods
 * the relations between plant growth and yield (Fig 16.32, p717)
 * a guide of tissue analysis for selected plant species (Table 16.16, p 718)
 Plant tissues analysis (Representative leaves, and time of sampling)
16.11 Soil analysis
 ** sampling of soil samples, soil chemical (test) analysis, and interpretation.
16.14 Broad aspects of fertilizer practice.
 Profit production should be considered on “fertilizer costs”. (Fig 16.41, p734)
 Response curve (y= a + bx + cx2) (Fig 16.42, p 734)
 Profit production should be considered on the effects of excess inorganic N on the water quality (Fig
16.43, p735)
Discussion:
1. Compare the relative advantages and disadvantages of organic and inorganic nutrient sources.
2. What’s the limiting factor for plant growth and productivity?
3. How to decide the reasonable fertilizer application rates based on the most benefit of productivity, crop
quality and environmental quality.
4. Please make a detail explanation for the best management practices for the production of vegetables or
high economic orchard along the river system? What are the function of riparian buffer strips, cover crop,
and forest management.