Lecture 8: Soil and Nutrient Management Practices Flashcards
1
Q
PROCESSES CAUSING NUTRIENT LOSS
A
- leaching
- volatilization
- erosion
- crop nutrient removal
2
Q
LEACHING
A
- through percolation
- minimized by timely application of fertilizer; improvement of WHC
3
Q
VOLATILIZATION
A
- nutrients in gaseous form
- ammonium forming fertilizers (ammonium sulfate; urea)
- minimized by covering the fertilizer with soil
4
Q
EROSION
A
- through loss of topsoil
- minimized by adopting soil and water conservation practices
5
Q
CROP NUTRIENT REMOVAL
A
- through uptake by plants
- minimized by applying fertilizers corresponding to nutrient removed by plants
6
Q
FERTILIZATION
A
- application of fertilizer
- affected by crop species, age, and existing nutrient level in soil
7
Q
APPLICATION OF HIGHER PROPORTION OF N
A
- early vegetative stage
- after harvest (perennials)
8
Q
APPLICATION OF HIGHER PROPORTION OF K
A
- reproductive stage
9
Q
COMPLETE FERTILIZER
A
- NPK
10
Q
METHODS OF DETERMINING FERTILIZER REQUIREMENT
A
- field fertilizer trial
- nutrient deficiency symptoms
- soil analysis
- tissue analysis
- crop nutrient removal
11
Q
FIELD FERTILIZER TRIAL
A
- effect of various levels of fertilizer
- interaction of fertilizer with existing external factors in given site
12
Q
DISADVANTAGE OF FIELD FERTILIZER TRIAL
A
- reliable but expensive
- long period
- valid only on specific site
13
Q
SOIL ANALYSIS
A
- chemical analysis of representative soil sample
14
Q
ORGANIC MATTER
A
- native source of N in soil
- low: < 2%
- medium: 2-3%
- high: 3.5%
15
Q
P DEFICIENCY
A
- P < 10 ppm
16
Q
K DEFICIENCY
A
- K < 0.4 m.e./100 g soil
17
Q
TISSUE ANALYSIS
A
- chemical analysis of plant tissue
18
Q
TISSUE ANALYSIS: CRITICAL NUTRIENT LEVELS
A
- N: 2.2 - 2.4%
- P: 0.04 - 0.11%
- K: 0.7 - 1.1%
19
Q
CROP NUTRIENT REMOVAL: PINEAPPLE (36000 plants/ha)
A
- N: 200kg
- P2O5: 47kg
- K2O: 71kg
20
Q
CROP NUTRIENT REMOVAL: GINGER (40 tons/ha)
A
- N: 127kg
- P2O5: 66kg
- K2O: 167kg
21
Q
SYNTHETIC FERTILIZER
A
- mostly inorganic
- readily soluble
- immediate effect
- high concentration of particular nutrients
- caused increased acidity
22
Q
NATURAL FERTILIZER
A
- mostly organic
- slow nutrient release
- low amount of various nutrients
- promote good soil physical characteristics
23
Q
SOURCES OF NATURAL FERTILIZERS
A
- animal manure
- crop residue
- green manure
- compost
24
Q
PLACEMENT OF FERTILIZER
A
- as close to the root
- direct seeded crops: small amount; bottom or beside furrow/hill
- transplanted: dissolved fertilizer; drenched at base of seedlings
- trees: area of greatest concentration of roots; within canopy dripline
25
PLACEMENT OF FERTILIZER: TREES
1. lanzones: 1.5m
2. coconut: 1.2m
3. papaya: 0.3m
4. citrus: 0.6 - 0.9m
5. cacao: 0.6 - 0.9m
26
METHODS OF FERTILIZER APPLICATION
1. broadcast method
2. band or trench
3. foliar application
4. fertigation
27
BROADCAST METHOD
1. spread uniformly
2. lowland rice
3. trees (within canopy dripline followed by shallow cultivation)
28
BAND OR TRENCH
1. applied at bottom of furrows or side of seedlings during plant
2. for trees, applied in holes or trenches dug within canopy dripline
29
FOLIAR APPLICATION
1. sprayed to leaves
2. applying of micronutrients and diluted solution of macronutrients
30
FERTIGATION
1. applied through drip irrigation system
2. base of newly transplanted seedlings
31
SITE-SPECIFIC NUTRIENT MANAGEMENT
1. nutrient omission plots
2. plant need-based N management approach
3. use of all nutrient sources
