Brazilian Soil Fertility Survey
Brazil lacks modern data for soil fertility surveys which can help the government, industry and crop consultants in their efforts to ameriolate soil chemical properties for adequate plant nutrition. IPNI Brazil has been involved in guiding the proccess for obtaining such surveys. The project was delineated in three phases. Phase 1 was a simple soil fertility survey from soil test results presently at IPNI Brazil database. Phase 2 is under development and will consist in a survey with laboratories running the ion exchange resin methodology and will concentrate in the State of Sao Paulo. Phase 3 will include the most important laboratories in the country. This project will be reported every 5 years.
IPNI-2010-BRA-61
25 Mar 2014
2013 Annual Interpretive Summary
Soil fertility surveys of specific countries or regions are important tools to ascertain soil chemical properties for adequate crop nutrition. Due to a paucity of such information in Brazil, the IPNI program is currently developing comprehensive soil fertility information. The plan is to complete this endeavor in three phases. This summary presents results of Phase 1, which are also stored in the IPNI Brazil database as Brazilian Soil Fertility Survey based on soil samples.
For this phase, a total of 5,556 soil samples were collected, but only 3,365 samples were used to interpret and classify different levels of nutrient sufficiency. For plant available P, three types of interpretation were necessary (exchange resin (P-Res); Mehlich 1 + clay content (P-Meh); or remaining P in solution (P-Rem)), and all three types predicted plant response to P in the great majority of the samples (86, 63 and 38% for P-Res, P-Meh and P-Rem, respectively). Simulation of collected data, considering that only the soybean crop was grown in all areas, showed a requirement of about 1.5 to 2.0 million tons (M t) of P2O5 for Brazil. For K, the survey showed that 44% of the soil samples had K concentrations that are very low or low in terms of K bioavailability. A positive growth response to K is predicted in 78% of the samples. Simulations showed that about 2.2 M t of K2O would be necessary to overcome this limitation considering the recommendations from EMBRAPA (Brazilian Agronomic Research Agency) and with soybean cropped in all areas. Among secondary nutrients, the survey showed that 76% of the soils would give a S response, while among the micronutrients considered (Zn, Cu, Mn, and B), the survey indicated low levels of their bioavailability in the great majority of samples. Interestingly, 98% of the analyzed soil samples showed a clear trend to some kind of response to B. Phase 2 will deal with results of soil samples utilizing the ion exchange resin methodology. Phase 3 will expand include the highest possible number of soil samples from laboratories around the country. This project has been reactivated in order to complete phase 3 by using data from the Midwest region of Brazil.