Agronomy Important Table Part-1

Agronomy Important Table

Subject:- Agronomy

1. Special Purpose Crops — Important 25 Terminologies

2. Optimum Temperature and Water Requirement of Crops

Important Terminology

3.Critical stage & IW/CPE ratio of different crops

Climatologically approach or IW/CPE approach:-

• Known as soil moisture index approach.
• The ratio IW/CPE serve as soil moisture stress index.
• Lower the ratio will be more stress.
• It is scientific approach but not practical utility.

Critical stage approach:-The stage of growth when plants are most sensitive to shortage of water and most responsive to correction of deficiency

Important Terminology

IW/CPE Ratio:-

IW = Irrigation Water
CPE = Cumulative Pan Evaporation

The IW/CPE ratio is used to decide when to irrigate a crop.

Formula:

IW/CPE Ratio = Depth of Irrigation Water ÷ Cumulative Pan Evaporation

Example:
If the IW/CPE ratio is 0.6 and the irrigation water depth is 6 cm, irrigation should be given when CPE reaches 10 cm.

Calculation:
6 ÷ 0.6 = 10 cm CPE

Exam-Oriented Points

• Highest IW/CPE ratio → Rice = 1.2
• Lowest IW/CPE ratio → Safflower = 0.4
• Wheat → CRI stage is the most critical stage for irrigation
• Maize → Tasseling and silking are highly critical stages
• Groundnut → Pegging and pod development/filling are critical
• Cotton → Flowering and boll formation are critical
• Gram → Pre-flowering and pod development are important
• Pigeonpea → Flower initiation and pod formation are critical

4.Water use efficiency (WUE):-

• It is the yield of a marketable crop produced per unit of water used in evapo-transpiration. OR
• WUE- the dry matter produced per unit of water used and it expressed as kg/ha-mm

Water use efficiency are of two types:-

i. Crop water use efficiency:- It is the ratio of crop yield (y) to the amount of water depleted by the crop in the process of evapo-transpiration (ET).
WUE (Crop)=Y/ET

ii. Field water use efficiency:- It is the ratio of crop yield (y) to the total amount of water used in the field (WR).
WUE (Field)=Y/WR

Water use efficiency of major field crops:-

5.Classification of Crops According To Root Depth, Rooting Characteristic:-

Important Terminology

Shallow-Rooted Crops
Crops whose roots mainly grow in the upper layer of the soil and do not penetrate very deeply.

Moderately Deep-Rooted Crops
Crops whose roots grow to a moderate depth and can obtain water from deeper soil layers than shallow-rooted crops.

Deep-Rooted Crops
Crops having roots that penetrate deep into the soil, allowing them to use moisture from deeper layers.

Very Deep-Rooted Crops
Crops with a very extensive and deep root system that can access water from considerable soil depth.

Root-depth classification

6.Plants and their conditions

Easy Memory Trick

• Halophytes → Salt
• Sciophytes → Shade
• Lithophytes → Rocks
• Psammophytes → Sand
• Calciphytes → Calcium
• Xerophytes → Dry
• Acidophiles → Acid
• Hydrophytes → Water

Agronomy Important Table