Kuliah 12 Unsur unsur iklim yang mempengaruhi pertumbuhan dan produktivitas tanaman

Summary

This lecture on agroclimatology explores the key climate elements that influence plant growth and productivity. It discusses how solar radiation affects photosynthesis and plant respiration, as well as how temperature, day length, and rainfall impact various physiological processes. The lecture also touches on the importance of soil moisture, the effect of light intensity on plant species, and the relationship between temperature and plant development. Emphasis is placed on the varying water needs of different crops and the role of environmental factors in determining plant yields, providing essential insights for improving agricultural productivity.

Takeaways

• 😀 Solar radiation affects plant growth by driving photosynthesis and influencing processes like leaf expansion, chlorophyll formation, and CO2 diffusion.
• 😀 The rate of photosynthesis is influenced by light intensity, CO2 levels, and temperature, with higher temperatures generally increasing photosynthesis rates.
• 😀 Plant respiration rates vary depending on light intensity and other factors, and different plant species have varying photosynthesis efficiency.
• 😀 Plants are categorized based on their light saturation needs: Sun species (requiring high light intensity) and shade species (preferring lower light intensity).
• 😀 The length of the day (photoperiodism) influences flowering times, with plants classified as short-day, long-day, or neutral-day based on their flowering response to light duration.
• 😀 Temperature plays a significant role in plant growth, affecting metabolic processes like photosynthesis, respiration, and germination, with high or low temperatures potentially damaging plants.
• 😀 Plants, such as rice, are sensitive to temperature changes at specific growth stages, and temperatures above certain thresholds can result in issues like flower sterility.
• 😀 The Degree of Growth concept is used to calculate plant growth based on accumulated heat units, where temperature influences plant development and flowering times.
• 😀 Soil moisture is directly influenced by temperature, with higher temperatures leading to faster soil moisture loss through transpiration and evaporation.
• 😀 Rainfall and water availability are critical for plant productivity, with various plants requiring different amounts of water based on climate and soil conditions.
• 😀 Soil properties, such as texture and infiltration, also affect plant growth, and maintaining soil moisture can be managed through techniques like mulching.

Q & A

What are the primary weather elements that affect plant growth and productivity?

The primary weather elements affecting plant growth and productivity are solar radiation, temperature, rainfall, and the length of the day. These elements directly impact various physiological processes of plants.

How does solar radiation influence plant growth?

Solar radiation influences plant growth through processes like photosynthesis, where plants convert CO2 and H2O into sugars and O2 using sunlight. Radiation also affects leaf formation, chlorophyll content, and the rate of photosynthesis.

What is the difference between sun-loving and shade-loving plants in terms of light intensity?

Sun-loving plants require high light intensity, typically around 2,500-3,000 foot candles, while shade-loving plants thrive in lower light intensities, around 1,000 foot candles.

How does the length of the day affect plant growth?

The length of the day, or photoperiodism, affects the flowering time of plants. Short-day plants flower when exposed to less than 12 hours of sunlight, long-day plants flower with more than 12 hours, and neutral-day plants are unaffected by day length.

Can you explain the difference between short-day, long-day, and neutral-day plants?

Short-day plants, like chrysanthemums, flower when exposed to less than 12 hours of sunlight. Long-day plants, like spinach, require more than 12 hours of sunlight to flower. Neutral-day plants, such as tomatoes, are unaffected by day length and flower regardless of sunlight duration.

What role does temperature play in plant growth and development?

Temperature affects plant growth by influencing metabolic processes such as photosynthesis, respiration, and transpiration. Each plant has an optimum temperature range, and deviations can lead to reduced growth or damage, particularly during critical phases like flowering.

How does temperature impact the rate of photosynthesis?

Temperature directly influences the rate of photosynthesis. As temperature increases up to an optimal point, photosynthesis rates rise. However, beyond this point, excessive temperatures can hinder enzyme activity, reducing the efficiency of photosynthesis.

What is the concept of the degree of growth or heat unit in relation to plant growth?

The degree of growth or heat unit concept is based on the total heat required for plant growth. It assumes a linear relationship between plant growth and temperature, helping to predict flowering times and development stages.

How does high temperature affect the soil and plant moisture?

High temperatures increase soil evaporation and transpiration, leading to rapid moisture loss in the soil, which can negatively impact plant growth, particularly in dry conditions. This can be mitigated through practices like mulching to conserve moisture.

What are the water requirements for plants like soybean, corn, and rice?

Soybean plants need 300-350 mm of water per month, corn requires 85-100 mm, and rice fields need 85-100 mm per month. These water needs vary depending on growth stages and environmental conditions.