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United States Department of Agriculture

Agricultural Research Service

Research Project: MODELING PARTICLE FILM EFFECTS ON PHOTOSYNTHESIS
2012 Annual Report


1a.Objectives (from AD-416):
Research has demonstrated that the white, reflective particle film used to repel a wide range of insects also reduces plant temperature and heat stress, while reflecting UV radiation and altering the phytochrome-sensitive wavelengths of visible light. Field studies have documented that the reduction of plant temperature results in increased photosynthesis and often water use efficiency, and the reduction of UV radiation has reduced oxidative stress. Research will identify critical plant growth stages and mechanisms by which the particle film increases photosynthesis, water use efficiency, and improve food quality. This fundamental knowledge will be incorporated with particle film application for insect control in order to effectively apply the particle film materials in a commercial setting. The results will enhance the multi-functionality of particle film technology for use in a broad range of crops.


1b.Approach (from AD-416):
1) Develop leaf and canopy reflectance/transmission models and incorporate them into sophisticated crop gas exchange models. These models will incorporate: a) the reflectance/transmission characteristics of specific minerals and formulations, b) the leaf reflectance/transmission characteristics of different plant species, and c) the reflectance/transmission characteristics of specific formulations on the plant leaf.

2) Develop leaf level gas exchange data for key horticultural and field crops. These data serve as the starting point of the crop modeling process. Data already exist for cotton, soybeans, corn, wheat, and rose. 3) Validate modeling with whole plant gas exchange studies in growth chambers. This work will provide a rational basis for selecting which crops can be expected to respond to a reflection-based treatment in specific environments. In addition, it will provide insight into the necessary characteristics of formulations.


3.Progress Report:

Particle Film Effect Simulations for Multiple Locations and Years using Plant Gas Exchange Simulator (PGES) - We have collected multi-year weather data from key agricultural production locations in the States of Washington and California. These locations include: Chelan, Ellensburg, Kennewick, Moses Lake, Mt. Vernon, Pasco, Prosser, Puyallup, Quincy, Walla Walla, Yakima-Parker, and Yakima-Port of Sunnyside in Washington and Davis, Fresno, Lodi, Modesto, Napa-Carneros, Napa-Oakville, Sacramento, and Visalia in California. Hourly weather data from 2001 to 2010 were obtained from weather databases maintained by each state. Air temperature data from June to September for all 10 years at each site were averaged and categorized into warm (top 30%), moderate (middle 40%) and cool (bottom 30%) years. Weather variables included in this data set are solar radiation, air temperature, relative humidity, precipitation, and wind speed. The Plant Gas Exchange Simulator (PGES) has been modified to read these new weather data sets and run simulations of particle film effects on photosynthesis, biomass gain, water use, and water use efficiency. We are currently analyzing multi-year and multi-location simulations of particle film effects on apple and other fruit and nut crops.

Implementation of whole-plant carbon balance - We have implemented whole-plant carbon balance into PGES for simulating total biomass accumulation. It takes into account carbon allocation to maintenance respiration, and carbon partitioning between different organs as competing sinks. This enhances the model’s ability to account for the effects of particle film on whole-plant biomass accumulation and water use. When linked with phenology modules, the full model will be capable of simulating growth and development of fruit trees under various environmental conditions.


Last Modified: 11/27/2014
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