Introduction to Crop physiology and it's Importance in Agriculture

Crop :- 

It is a group of plants grown as a community in a specific locality and, for a specific Purpose.

Crop Physiology:-

Crop physiology is the study of the ways in which plant physiological processes are

integrated to cause whole plant responses in communities. The subject matter of crop physiology includes the ways in which the knowledge of plant physiology is applied for better management of crops.

Plant physiology is a study of Vital phenomena in plant. It is the science concerned with Processes and functions, the responses of plants to environment and the growth and development that results from the responses. 

Essentially the overall goal of plant physiology is to evolve a detailed and

comprehensive knowledge of all the natural phenomena that occur in living plants and thus to understand the nature of plant growth, development and productivity. Many aspects of

practical agriculture can benefit from more intensive research in plant physiology.

History of Crop Physiology:-

W.L. Balls (1915): Crop physiology, with the aim of understanding the dynamics of yield

development in crops, really began with the work of W.L. Balls. Along with Holton he

analysed the effects of plant spacing and sowing date on the development and yield of Egyptian Cotton plants within crop stands, not in isolated plants. It was from his work the term ‘crop physiology’ came into existence.

1924- In England- a rapid development of the methods of growth and yield analysis by different investigators (V.H. Blackman, F.G. Gregory, G.E. Briggs etc.) was started.

1947: The concept of LAI (Leaf area index) was developed by D.J. Watson. This index has provided a more meaningful way of analyzing growth in crops, and stimulated renewed interest in crop physiology.

1953: Monsi and Saeki explained about the manner of light interception by the crop canopy with their concept of light interception coefficient.

1963: Hesketh and Moss showed that photosynthesis by leaves of Maize, Sugarcane and related tropical grasses could reach much higher rates, with less marked light saturation, than leaves of other plants. (This was the starting point for research to find other photosynthetic CO2 fixation path ways like C4, and CAM Mechanisms).

Importance of Crop Physiology in agriculture:-

Many aspects of Agriculture and Horticulture can be benefitted from more

intensive research in plant physiology to provide practical solutions in agriculture and horticulture. Understanding the physiological aspects of seed germination, seedling growth, crop establishment, vegetative development, flowering, fruit and seed setting and crop maturity, plant hormone interaction, nutrientphysiology, stress (biotic/abiotic) physiology etc., provides a reasonable scientific base for effective monitoring and beneficial

manipulation of these phenomenon’s. Since in agriculture we are interested in economic yield which is the output of these phenomenons and well beingness of plants, Plant Physiology provides a platform for getting better yield of crops.

1. Seed physiology:- 

Seed is the most important input in agriculture. Germination of seed and proper establishment of seedling depends upon various internal and external factors.

Knowledge of Seed physiology helps in understanding of different physiological and morphological changes that occur during germination. Any deviation in these

processes causes Seed dormancy. 

Example: When ever Paddy is used as a seed material in the very next season it is recommended to treat the seed either with HNO3 or with GA.

2. Optimum seedling growth and plant population:-

By knowing the process of radicle and plumule emergence and their function we can achieve best plant health, which is the outcome of best plant physiology. By knowing the different inputs requirement of plants (water, nutrients, sunlight) we can easily manage the plant population to get highest yield.

3. Growth Measurements of crops:-

The first prerequisite for higher yields in crops is high total dry matter production per unit area. High dry matter production is a function of optimum leaf area (Optimum

leaf area Index) and Net Assimilation rate. (CGR = LAI X NAR).

Example: Pruning operation in horticultural crops like Mango is done based on this principle of proper canopy management for better photosynthesis.

4. Harvest Index:- 

The difference between total amount of dry matter produced and the photosynthates

used in respiration is the net product of photosynthesis. Economic yield depends on

how the dry matter is distributed among different organs of the plant. 

Example: excessive vegetative growth period in Ground nut produces less number of Pods as the reproductive period gets constricted. Thus, groundnut varieties with relatively extended period of reproductive growth are desirable.

5. Nutriophysiology:- 

Nutriophysiology is yet another important area to under stand crop physiology. For the

healthy growth of a crop around 17 essential elements are required. Knowledge of nutriophysiology has helped in identification of essential nutrients, ion uptake mechanisms, their deficiency symptoms and corrective measures. It also helps to check the toxicity symptoms of various nutrients.