# Presentation: 041336

## Cotton Modeling to Assess Climate Change and Crop Management

- December  2005

- V. R. Reddy1 and K. R. Reddy2

- 1USDA-ARS, Crop Systems and Global Change Laboratory, BARC-West, Beltsville, MD 20705, USA
- 2Department of Plant and Soil Sciences, Mississippi State University, Mississippi State, MS 39762, USA

## Why Do We Need Models?

- Help pinpoint knowledge gaps.
- Design critical experiments.
- Synthesize knowledge about different componentsof a system.
- Summarize data.
- Transfer research results to users.

## Demand for Models

- Resource management (e.g. several Govt. agencies and private comp. use).
- Policy analysis.
- Production forecasts (e.g. global, regional and local forecasts).
- Research and development (e.g. research priorities and guide fund allocations).
- Turning information into knowledge (e.g. information overflow in every area including agricultural research).

## Timeline for Information Flow

## SPAR – Database for Modeling

## SPAR – Database for Modeling

## GOSSYM: Model Structure

- For more details on model structure: Hodges et al., 1998

## GOSSYM: Model Validation

- United States

- Greece

- China

- Israel

- Continuous evolution of the model by extensive testing across diverse environments, soil conditions and cultural practices.
- Information feedback from scientists, farmers and farm managers.

## Climate Change Effects

## Climate Change – Cotton Yield

- Extreme Years Lint yield

## Tillage and Erosion Studies

- GOSSYM was used to evaluate the effects of erosion and erosion-related activities on lint yields.
- GOSSYM was also used to investigate the effects of simulated tillage and wheel traffic on growth and yield.

## Insect Damage Assessment

- RbWHIMS: Rule-based Wholistic Insect Management System.
- Provides information to the user for determining pesticide management strategies.
- Recommendations include: extent of pest control,timing of pesticide application/no application and when to observe the field for future management strategies.

## Genetics Improvement Research

- GOSSYM – a tool to predict the effect and economic benefit of various genetic combinations.
- Photosynthesis was found to be the limiting factor in the okra leaf-type cottons which have more number of bolls/plant and less lint yield than normal leaf-type cottons.

## GOSSYM: Educational Applications

- As a tool for learning: principles of crop and soil management.
- As a classroom teaching tool: graphically presents the changes in plant growth and development.
- Educating farm managers to improve their crop productivity.
- Assist crop consultants in the decision making process.
- 22 (15 Ph.D and 7 MS) theses on GOSSYM were accepted since 1979 at MSU.
- GOSSYM served as a template to other crop models (melons, soybean, corn, wheat, rice and potato) at USDA.

## GOSSYM: Model Applications

- Field Scale

## Pre-season and In-season Decisions

- Timely decisions can be taken by predictions with GOSSYM.
- Helps in decision-making regarding leasing of farms.
- Estimations before hand – fertilization and irrigation costs.
- GOSSYM – for determining crop termination, nitrogen application, irrigation management.

## Growth Regulator Applications 

## Growth Regulator Applications 

## GOSSYM: Reap Profits 

- In another study, GOSSYM plots had a profit of $100 - $350 ha-1 (McKinion et al., 1989).
- GOSSYM plots had a profit of $80 ha-1 than farmer plots (Ladewig and Powell, 1992).

- GOSSYM Plots

- Farmer Plots

## GOSSYM

- Deficiencies and
- Future Development Needs

## Deficiencies and Future Needs

- Fiber quality?

- Nutrients other than
- C and N?

- Extreme weather,
-  Hail? Winds?

- Modern/transgenic
- cottons?

- Damage due to
- UV-B/pests/herbicides?

- GOSSYM

## Thank You

- Shall We Discuss!