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
Q
PLACEMENT OF FERTILIZER: TREES
A
- lanzones: 1.5m
- coconut: 1.2m
- papaya: 0.3m
- citrus: 0.6 - 0.9m
- cacao: 0.6 - 0.9m
26
Q
METHODS OF FERTILIZER APPLICATION
A
- broadcast method
- band or trench
- foliar application
- fertigation
27
Q
BROADCAST METHOD
A
- spread uniformly
- lowland rice
- trees (within canopy dripline followed by shallow cultivation)
28
Q
BAND OR TRENCH
A
- applied at bottom of furrows or side of seedlings during plant
- for trees, applied in holes or trenches dug within canopy dripline
29
Q
FOLIAR APPLICATION
A
- sprayed to leaves
- applying of micronutrients and diluted solution of macronutrients
30
Q
FERTIGATION
A
- applied through drip irrigation system
- base of newly transplanted seedlings
31
Q
SITE-SPECIFIC NUTRIENT MANAGEMENT
A
- nutrient omission plots
- plant need-based N management approach
- use of all nutrient sources
