Non Technical Summary
Water management in unirrigated hill farming is challenging because farmers have no control over rainfall and limited control of runoff. Runoff not only wastes valuable resources (soil erosion and nutrients), but also adversely impacts agriculture and the environment; including causing scarcity of water and nutrients on hilltops, creating waterlogged condition in hill bottoms, and promoting eutrophication of downstream lakes, streams, and estuaries.Our preliminary research shows that selective application of biochar is an economically viable technology to mitigate this problem while improving long-term soil health and sequestering carbon for centuries. Biochar increased moisture retention and plant availabe water throughout dry summer months onto much wider than application area. We propose expanding our preliminary findings incorporating the impact of climate change on a larger scale.The objectives of this research are:1. Characterize biochar from commonly available raw materials including deciduous tree wood waste, dairy waste, and other forestry/agricultural processes for optimum impacts on hill top amendment.2. Develop a more advanced high resolution, farm-scale modeling tool that includes snowmelt, slope orientation, subsurface hard panes, and climate change forecast using Falcon Supercomputer.3. Validate the model predictions for moisture, nutrient retention, runoff, groundwater recharge, and biological activities.4. Develop a software plugin (App) for farmers to use the model.This proposal addresses funding priorities A1551 by developing a novel engineering tool that uses complex computational methods for site-specific management. Use of this tool will increase crop productivity, reduces greenhouse gas emissions, and improves the long-term soil health.

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
111	0110	2020	80%
102	0199	3100	20%

Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships; 111 - Conservation and Efficient Use of Water;

Subject Of Investigation
0110 - Soil; 0199 - Soil and land, general;

Field Of Science
2020 - Engineering; 3100 - Management;

Goals / Objectives
The goal of this project is to quantify the economic and environmental benefits from selective application of biochar. We will develop a software tool for farmers to use to quantify benefits and get most return on thier biochar investiment . The software tool developed in this project will use an advanced computation model that incorporates field topography, soil properties, crop management practices, meteorological data, and targeted outcome to predict how farmers should apply biochar to achieve the highest return on investment.The specific project objectives are:Characterize biochar produced from commonly available raw materials including deciduous tree wood waste, dairy waste, and other forestry/agricultural processes.Expand current model to include snowmelt, slope orientation, subsurface hard panes, and climate change forecast and implement a high resolution, farm scale model using Falcon Supercomputer.Validate the model predictions for moisture, nutrient (N, P, K and S) retention, transport, runoff, groundwater recharge, and biological activities.Develop a software plugin for farmers to use the model.

Project Methods
Biochar CharacterizationWe will use two types of biochar as parent material. These two biochars will have distinct physical characteristics, are locally produced and commercially available.Physical properties that are not measured by the vendor and related to soil-biochar interactions will be measured in the laboratory. Biochar and soil samples will be characterized before and after incubation in the field. Pre- and post-treatment soil pH and electrical conductivity (EC) will be determined on a 2:1 water:soil slurry. Soil texture will be determined by the hydrometer method. Cation exchange capacity (CEC) will be measured using the ammonium acetate method.Functional group acidities of the biochar will be characterized using Boehm titrations, specific surface area measurements using BET surface analysis, and scanning electron microscopy to characterize surface morphology as well as imaging how soil particles are interacting with the biochar. Hydrophobicity and water infiltration will be measured on amended soil using sessile-drop contact angle measurement method. Soil moisture content and water holding capacity will be measured by oven-dry method after saturating the soil in a funnel with a filter paper and allowing water to drain. Field capacity and permanent wilting point will be measured as water retention by pressure plate extraction. Water retention at 0.3 MPa and 1.5 MPa will be determined for each pressure to calculate plant available water (PAW). Elemental content of the soil and biochar will be measured by incineration and acid extraction (Ca, Mg, P, Fe, and Al), or combustion analysis (nitrogen and sulfur) using an auto analyzer. Nutrient availability for leaching or plant uptake will be measured using KCl extractions for nitrogen availability and formic acid for P availability. Soil aggregate stability will be measured to evaluate erosion potential using a slaking method.The effects of biochar amendment on nutrient leaching will be assessed by measuring how the biochar amendment changes the adsorption capacity of the soil. Nutrient (phosphate and ammonium) adsorption potential will be measured using adsorption isotherms. Nutrient adsorption maximum can be determined from modeling the Langmuir isotherm equation. The adsorption intensity factor represents the solid-solution partitioning affinity of the adsorbate. It is calculated by multiplying the adsorption coefficients and the adsorption capacity.Amended soils incubated in the field for various times will be tested to determine the overall microbial activity and relative abundances of microbes. Overall microbial activity of the biochar amended soils will be evaluated using samples in CO2 evolution jar tests to measure microbial respiration rates and Phospholipids Fatty Acids (PFLA) assays to measure species diversity. Chemical analysis will be conducted using the University of Idaho's Analytical Sciences Laboratory. In situ microbial respiration can also be measured with the LI-6400 soil chamber.High Resolution Advanced Computer ModelingSoil moisture retention and nutrient transport will be modeled using HYDRUS® 3D software to determine the optimum biochar application rate. HYDRUS® is a widely used software for modeling vadose zone water flow and solute transport that takes into account the effects of infiltration, soil moisture storage, evaporation, plant water uptake, precipitation, runoff, and water accumulation at the ground surface. HYDRUS can handle up to 10 million nodes, enabling large-scale modeling. We will incorporte snow melt into the model to assess effect on groundwter recharge rate from use of biochar.Experimental Setup for Model ValidationUniversity of Idaho's two local research farms to conduct experiments to validate the impact of water and nutrient transport for the following variables.Surface orientation (3 treatments, North, Top, and South facing slope)Biochar type (3 treatments, No biochar (Control), RSD biochar and WS biochar)Fertilizer rate (2 levels, No fertilizer and at recommended rate)Soil physical characteristics such as texture, particle distribution, pH, bulk density will be measured. The experiment will be carried out at one or both experimental sites depending on plot availability:A partially randomized, full factorial experimental design will be implemented for surface orientation (3 factors), biochar type (3 factors including control with no biochar) and fertilizer application rate (2 factors). The application will be replicated two times, making it a total of 36 plots. Each test bed will be 10ftx25with longer side aligned with hill slope along N-S direction. The plots will be separated at least by 20 ft in lateral (E-W) direction and 50 ft along lateral (N-S) direction to prevent cross linkage of moisture flow. The total test bed area will occupy 0.2 acre of land.The treatments combinations are shown in Table below .BiocharFertilizerNo BiocharNoneNo BiocharFullWheat Straw BiocharNoneWheat Straw BiocharFullRedwood BiocharNoneRedwood BiocharFullSite Preparation and Instrumentationsoil moisture at two depths at the at the center and corners of the plot will be measured and read frequently throughout the year. Our preliminary research has shown that a generic capacitance-based moisture probe's performance is on par with high-end sensors with the use of high bit depth analog-to-digital converter with built-in low-pass filter and a programmable gain such as ADS1115 from Texas Instruments. The ADS1115 will interface with a microcontroller with I2C communication protocol. The microcontroller will read and save the moisture data once every hour and transmit the data using LORA FRM95 radio (lowpowerlab.com/shop/product/143) to base station on demand. Other than waking up once every hour to record data and transmitting the system will be put to a deep sleep mode to save battery. The battery is expected to last several years with this infrequent reading.Calibrated capacitance-based moisture data loggers, ADS1115, microcontroller, and transceivers will be enclosed on a 3D printed box with hard wax filled seal and installed at two depths of 1 ft and 3 ft to capture vertical and horizontal moisture distribution.?Data CollectionOn the surface, we will use snow sampling tubes to measure spatially distributed SWE across the experimental test beds caused by drifting. We will also deploy a sonic snow depth sensor at the Kambitsch Farm to identify when and what depth of new snowfall events occur for comparison with the manual COOP snow observations at the Parker Farm.We will adapt the satellite remote sensing snow model developed by Co-PI Qualls to track snow covered area for use with finer spatial resolution Landsat data. This can identify the spatial pattern of snow drift accumulation and the interannually recurring depletion pattern followed as the drifts melt. This remote sensing model will be incorporated into the software tool to identify drift regions on user's farm for use in generating the biochar application map.