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Land-Potential and Soil Texture

The knowledge engine of LandPKS supports land use planning, land restoration, future agricultural scenarios, climate change adaption, and conservation programs. However, a critical first step in using our integrated suite of smartphone applications includes the evaluation of soil and vegetation properties. As soil serves as the media for growth for all kinds of plants, identification of soil properties is vital for land managers, policy makers, and researchers in order for them to assess land potential.

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Soil texture is considered one of the soil’s most important properties, influencing nearly all soil processes and functions. Soil texture is defined by the relative fractions of sand, silt, and clay-sized particles in a soil sample. Soil is often divided into 12 soil texture classes, allowing for communication of soil type amongst land resource specialists. Each particle type has benefits to plant growth, yet sometimes can be unfavorable when only one soil class (all sand, for example) makes up the majority of the soil sample. For example, clay holds water well and is usually fertile. However, clays swell when they get wet (limiting the water available to plant roots), and harden when dry (becoming difficult to manage). Deep sands drain easily and do not hold water effectively. Silt-sized grains retain water and nutrients, but can easily become water-logged and prevent movement of water, air, and roots throughout the soil profile. While most soil types can be managed, often Loam is considered the most desirable for plant growth because Loam contains equal parts of sand, silt, and clay. Different particle sizes allow for air, water, and roots to easily move through the soil, with Loam having enough sand to drain well, yet also enough clay and silt to hold onto water and nutrients.

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The LandInfo module of LandPKS walks users through estimation of texture by probing and working the soil. Users are asked to take a sample and test it for grittiness (sand), smoothness (silt), and stickiness (clay). Currently, the LandInfo module streamlines steps from a soil texture-by-feel flow chart which tests the relative fraction of sand, silt, and clay. However, through feedback from our trainings we have learned that often the user questions accuracy of their own texture-by-feel estimates. Our next steps to help address this issue include: (1) evaluating the accuracy of these texture-by-feel estimates, and (2) improving our decision support tools to allow users additional manipulative tests shown to differentiate between texture classes. Look for the results of these steps in the near future!

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LandPKS for Soil Identification: Using Soil Texture and Color

Soil is one of the most important factors that control crop yields and land potentials. There are many possible soils with different properties within a given location. How to correctly identify soils and the subsequent soil properties is critically important for farmers, natural resource managers, policy makers, and scientists to make decisions and predictions regarding land suitability, productivity, profitability, and sustainability.

In our effort to help make soil identification in the field easier, LandPKS has two team members, Zhaosheng Fan and Samira Pakravan, who are working on improving our current LandInfo module, as well as developing a completely new module, SoilColor. Fan and Samira are currently focused on, 1) developing algorithms that can be used to identify correct soils with spatial location (latitude and longitude) and other easily-measured field observations input by LandPKS users (e.g., soil texture by depth), and 2) developing a SoilColor module that can be used to measure soil color in the field with a smartphone camera. Soil color is one of the most important attributes of the soil which provides useful information about many other significant soil properties, such as soil organic carbon content. The SoilColor module will use smartphone camera images of soil samples to measure the soil color. Once complete, LandPKS users will be able to identify soil color without the use of expensive soil color books.

Soil color app photos

Further, the two efforts mentioned above are tied together – the measured soil color with the SoilColor module can, in turn, be used by the soil-identification algorithms to further improve the accuracy of the identified soils. Once the correct soils are identified, the corresponding soil properties will be used to drive crop models to simulate crop yields, erosion, and crop-failure risks. Please do look for the release of SoilColor in the near future!

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Zhaosheng Fan – Postdoctoral Researcher
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Samira Pakravan – Soil Color Developer

The Role of LandPKS in Land Use Planning

In Tanzania, the Land Potential Knowledge System (LandPKS; landpotential.org) has been working with the National Land Use Planning Commission as well as USAID’s Land Tenure Assistance (LTA) Project to assist in effective land use planning and land tenure efforts.  LandPKS is a mobile app that helps users identify their soil, and the potential productivity and long term agricultural sustainability of that soil.  By identifying areas with sustainable agricultural potential, land use planners can integrate biophysical assessments into their participatory land use planning process.  The LTA project is helping to revise village-level land use plans. Once land use planning is complete, LTA is using a mobile technology called MAST (Mobile Application to Secure Tenure) to assist village members attain a CCRO (Certificate of Customary Right of Occupancy) for their farms and properties. By integrating LandPKS soil information into their land-use plans, LTA and other land use planners can make better decisions about which areas within a village are suitable for agriculture, and which are not. Focusing agricultural growth on soils suitable for sustainable agriculture not only increases farmer revenues and productivity, but saves other village land for other, less intensive uses such as grazing areas or forest reserves.

At the national-level, Dr. Stephen Nindi, Director General of the National Land Use Planning Commission, is working with the LandPKS team to implement LandPKS tools in the future for the national land use planning process. Tanzania currently uses a 6-step process for participatory land use management, involving community members and stakeholders at every step. On the biophysical side of land use planning process, Tanzania draws from the seven land capabilities classes. Categorizing the land into these seven classes helps planners to determine which livelihood activities are sustainable in which areas. For example, land capability class one refers to land that is suitable for all land uses with normal land management practices, such as flat, well drained and fertile land. LandPKS could play a key role in helping land use planners classify land into these seven classes based on soil texture, soil water holding capacity, potential erosion risk, and potential productivity. While soil texture is not the only important soil characteristic, it can be a critical predictor of a lands potential and its degradation risk. Implementing LandPKS in the land use planning process will simply, and cheaply, help the National Land Use Planning Commission include more biophysical data into their land use planning process.

Therefore, LandPKS has a role not only in improving sustainable land management for farmers and pastoralists, but also on a larger scale through the land use planning process. Matching appropriate land uses to their proper soil types can increase productivity and decrease land degradation, important goals for long-term environmental sustainability. For more information, please write to contact@landpotential.org

Nyamihuu, Tanzania – Comparing 3 LandPKS Plots

LandPKS Modeling for Agricultural Sustainability: Meet our Modelers

We are lucky at LandPKS to have a wonderful team of people who work on various aspects of LandPKS.  Behind the scenes, we have two dedicated modelers who are working to take LandPKS input and model future agricultural scenarios to help LandPKS users make more sustainable land management decisions.  While these types of outputs are not currently available on LandPKS, we hope that in the near future such modeled future scenarios will be delivered to LandPKS users on their phones.

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Dr. Won Seok Jang is a hydrologist and modeler for LandPKS based at the University of Colorado Boulder, in the Sustainability Innovation Lab at Colorado (SILC).  Won Seok’s primary roles include developing a modeling framework and assessing the effect of soil degradation on crop productivity and local/regional/global scale hydrological modeling for climate change impact assessment.  He currently uses EPIC (Environmental Policy Integrated Climate) model to estimate potential crop yield and soil erosion and is developing an EPIC parallel computing framework for global modeling with big data.  The goal of his research is to explore and measure the impact of climate change on food production worldwide, to develop multi-objective optimization of crop yield and minimization of soil erosion initially in Eastern Africa with a plan to expand to the United States and other global locations in the future.

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Dr. Tegenu Engda is a postdoctoral researcher, also located at the University of Colorado Boulder, in SILC. His primary role is to understand Soil-Plant-Water interactions under different environmental conditions. He mainly uses the EPIC model to investigate factors affecting crop yield trends including hydrologic processes, erosion and management practices in the case of East Africa. Currently, he is working on sensitivity analysis of EPIC input soil properties to better understand yield estimates across soil types.  Tegenu is also working on EPIC model calibration and nutrient dynamics exploration, as well as incorporation of local knowledge to improve EPIC yield calculations.

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A Creative Collaboration for Developing LandPKS Trainings

Last week, Amy Quandt (LandPKS Global Coordinator) and Michaela Buenemann (Associate Professor of Geography, New Mexico State University) traveled to Nairobi, Kenya to help develop a comprehensive one-day LandPKS training.  Amy and Michaela worked in partnership with the Regional Centre for Mapping of Resources for Development (RCMRD), a LandPKS collaborator.  RCMRD is located in Nairobi, Kenya and works as a leading regional center for GIS and remote sensing technologies and trainings.  Lillian Ndungu at RCMRD has been a part of the LandPKS team and a major proponent of LandPKS in Kenya.  Antony Ndubi from RCMRD also joined the training development team.

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The training development team spent Monday through Wednesday (September 4th-6th) developing a comprehensive one-day LandPKS training. The training is meant to be a general overview of LandPKS, explain how to use the apps, and help users understand how to analyze and interpret the information that they receive from LandPKS. Importantly, the training also focuses on the potential uses and applications of LandPKS for rangelands, agriculture, and biodiversity conservation. The training materials include a step-by-step outline of the course for the instructor, presentations, hand-outs, activities, worksheets, and assessments. Anyone can pick up the training materials and teach this one-day training. In order to test out the training materials, on Thursday (Sept 7th) the training development team conducted a training of the trainers or ToT. For the ToT, the training development team worked with instructors at RCMRD’s training college and did a ‘dry run’ of the one-day training (see photos). The instructors enjoyed learning about the LandPKS tools and also provided feedback on the training materials.

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RCMRD plans to integrate this training into their own curriculum and courses, while the LandPKS team will also utilize from these training materials to conduct trainings with various partners and LandPKS users in the future. If you have questions or are interested in these training materials please e-mail contact@landpotential.org.

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LandPKS in Ethiopia

Since 2015, the US Forest Service has been using the Land Potential Knowledge System (LandPKS) to collect monitoring data in Ethiopia to develop a baseline for rangeland condition, and to evaluate the efficacy of rangeland management treatments in an adaptive management approach. As part of the USAID Pastoral Resilient Improved Market Expansion (PRIME) project, US Forest Service (USFS) ecologists Tom DeMeo and Sabine Mellman-Brown have been working with CARE Ethiopia Rangeland Specialists Gudina and Beressa Edessa to track local vegetation changes over time, and to record grazing effects and soil erosion trends. USFS has been conducted monitoring work primarily in the Borana, Guji and Afar regions of Ethiopia, using both the LandPKS LandInfo and LandCover applications for electronic data collection and online cloud storage. To date this work has resulted in 149 monitoring plots.

Guest Post Authored By: Allison Holt – Forest Service

Local perceptions of land potential

How do local perceptions of land potential compare with soil types and textures measured with LandPKS?

That is what we set out to figure out in the rural village of Lyamgungwe, Tanzania. We asked the village government officials and elders to identify two locations within their village: one with a soil that is highly productive and does well growing maize, and one with a soil that is not very productive and where farmers have a hard time growing maize. The results were quite dramatic and the local perceptions were supported by LandPKS. The locally perceived productive soil was a Sandy Clay Loam until about 20cm depth where it turns into a Sandy Clay, and then a Silty Clay after 50cm. The locally perceived unproductive soil was a Clay for the first 20cm, then a Sandy Clay Loam, and a Loamy Sand after 50cm.

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LandPKS results showed that the first soil can hold a lot more water (X vs Y cm in the top 70cm). Future LandPKS interpretations would also indicate that the first soil also has a higher potential infiltration, so it should be able to capture more water before it runs off. This type of information can be used to decide which land to – and not to – cultivate, which can help with land use planning for both agriculture and conservation.

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The Importance of Village Agricultural Officers in LandPKS adoption in Tanzania

Village Agricultural Officers provide a critical service to smallholder farmers in rural Tanzania. They serve as the major source of agricultural information for farmers, and connect farmers to larger projects and organizations.

This week, the LandPKS team had the pleasure to spend a few days with the Agricultural Officer for Malagosi Village in Iringa Region, Tanzania. The Agricultural Officer is young, motivated, and cares about providing quality information to the farmers of Malagosi. After only a morning of training on how to use LandPKS, she was able to not only go through the LandInfo App on her own, but also helped train a few active youth in Malagosi on how to use LandPKS. She stated that she “could put the LandPKS results for each sub-village up on in village office, and if a farmer wants more information they can ask me to conduct LandPKS on their farm.”

The LandPKS team hopes that Village Agriculture Officers throughout Tanzania can play a role in increasing the adoption of LandPKS and thereby helping farmers make more sustainable agricultural choices based on their soils.

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