Born and raised in Cuba, Dr. Pedro Sanchez studies how soils in tropical regions can be managed and improved to increase food production in these parts of the world while also conserving the environment. Dr. Sanchez has worked in Latin America, Southeast Asia and Africa both as research with universities and international projects. His work has influenced research in agronomy, ecology, and changed the way technology is used to increase food production.
Industry Expertise (2)
Areas of Expertise (5)
Pesticide and Waste Management
Latin American Studies
Agricultural productivity must improve in sub-Saharan AfricaScience
Thomas S Jayne, Pedro A Sanchez
2021 In the first two decades of the 21st century, sub-Saharan Africa (SSA) has changed rapidly for the better in many ways, counter to many outdated narratives. Many of these improvements—including those in gross domestic product (GDP) per capita, poverty rates, health, life expectancy, education, and agriculture—have been mutually reinforcing (1, 2). SSA achieved the highest rate of growth in agricultural production value (crops and livestock) of any region in the world since 2000, expanding by 4.3% per year in real [inflation-adjusted US dollars (USD)] between 2000 and 2018, roughly double that of the prior three decades. The world average over the same period was 2.7% per year (1). Agricultural value added per worker in real 2010 USD rose from $846 in 2000 to $1563 in 2019, a 3.2% annual rate of growth. But to assert that Africa is rapidly developing does not mean that all livelihood indicators are improving, though most are in most countries (1, 3). SSA faces many major challenges. We focus below on one such challenge, which we see as a precondition for sustaining livelihood improvements in the region: transitioning from area expansion to productivity growth as the source of Africa's agricultural development.
Special Session Symposium--Grand Soil Challenges Across LatitudesSSSA International Soils Meeting
William L Pan, Pedro A Sanchez
2019 Tackling this meeting's theme, this symposium will provide a global view of the major challenges soils face at boreal, humid temperate, arid temperate and tropical latitudes. The grand challenges identified by the Soil Science Society of America are summarized in one sentence: “Optimizing soil ecosystem services for greater food and energy security, water quality, and adaptation to and mitigation of climate change”.Each speaker will discuss these challenges as they pertain to major latitudinal regions of the world.
Phosphorus: The Wicked Nutrient in Soil ManagementSSSA International Soils Meeting
Pedro A Sanchez
2019 Phosphorus management in soils remains a wicked problem (one that is resistant to resolution) because of many complex characteristics. The P cycle involves both organic and inorganic stocks, unlike the N cycle, which has only organic stocks, and the K cycle, where all the stocks are inorganic. In addition to straightforward P deficiencies, soils with variable charge, abundant in the tropics, often show strong sorption (fixation) by iron and aluminum oxides, which still are not well understood, and present additional management complexities. Although considered a macronutrient to plants, P contents are one order of magnitude lower than N or K uptake values, and similar to S. Although soil tests for available P -some over a century old- work reasonably well as a tool for fertilizer recommendations, the extractants are artifacts, and all that infrared spectroscopy can determine is Total P in a soil sample, which is seldom if ever related to plant growth. Long-term experiments in both variable and permanent charge soils show that 40-60% of the applied P fertilizer remains in the topsoil, representing a huge pool of P already in the soil, but we do not know how to use it. Our challenge is to figure out how to use this immense resource!
Overarching Concepts of Soil Organic Management in the TropicsASA, CSSA and SSSA International Annual
Pedro A Sanchez
2017 The term “organic matter” is misleading and should be replaced with Organic Inputs and Soil Organic Matter. SOM contents in tropical soils are similar to soils of the temperate region, and just as variable. SOM can be divided in 2 pools that provide different ecosystem services. The Active pool, with a turnover time of about 1.5 years, is responsible for providing nutrients to plants in the short term. It is now possible to classify organic inputs in terms of their quality, i.e., speed of nutrient release according to their lignin and N contents. To overcome the widespread nutrient depletion in smallholder farmers field of Africa it is necessary to begin with mineral fertilizer inputs until the soils are capable of producing sufficient organic inputs. But many such soils are not responsive to fertilizers in spite of obvious nutrient deficiency symptoms. In such cases, incorporating high quality organic inputs will provide a needed shot of C and decrease topsoil compaction to start the replenishment process. The Slow and Passive pools differ from the Active pool in that their fractions are stabilized by various forms of physical or chemical protection, due to interactions with mineral particles that form micro-aggregates inaccessible to many microorganisms. These pools are where carbon sequestration takes place. The main determinants of formation and stabilization of aggregates are texture and clay mineralogy. Sandy topsoils are unlikely to be relevant for carbon sequestration. The tropics have a huge carbon sequestration potential particularly with tree-based systems. This is because many soils in the tropics have lost much of its topsoil organic carbon; trees grow fast in the tropics, and there is lots of deep soil carbon that is probably unsaturated.
Soil Fertility Views from the TropicsASA, CSSA and SSSA International Annual
Pedro A Sanchez
2017 Soil nutrient depletion is widely acknowledged to be the number 1 biophysical constraint to increasing yields in sub-Saharan Africa. Spurred by the ongoing African Green Revolution, cereal crop yields are beginning to increase. Tropical Africa presents a different setting (mainly smallholder family farms of < 5 hectares with not enough nutrients) in comparison with large commercial farms, many with too many nutrients. Research results include that mineral fertilizers must go first while the much needed organic fertilizers have to wait until soil fertility is restored; on site soil testing to guide the different blends are needed. P is limiting in only specific regions, while K, S, Fe and Zn deficiencies are very variable. Aluminum toxicity is rare in most of tropical Africa. The issue of non-responsive soils need to be fully understood. Organic inputs are now effectively classified in terms of their quality, and together are part of an integrated soil fertility management strategy. New metrics for high P fixing soils are proposed. There is a need to find out how to utilize the 50% of the P applied that remains in the topsoil worldwide.