307 12 Total Carbon and Labile Fractions Inventory and Mapping by Soil Orders under Long-Term No-Till Farming to Promote Precision Agriculture Daniel Ruiz Potma Gonçalves, João Carlos de Moraes Sá, Allison José Fornari, Flávia Juliana Ferreira Furlan, Lucimara Aparecida Ferreira, and Ademir de Oliveira Ferreira 12.1 INTRODUCTION Studies of the spatial distributions of carbon (C) and nitrogen (N) contents and stocks at a landscape scale have received increasing attention since the 1990s because of the development of Geographic Information System (GIS) software (Davidson and Lefebvre 1993; Levine et al. 1994; Poier and Richter 1992). The use of GIS software has led to signiicant advances in landscape-scale studies (Hartemink 2008; Lilburne et al. 2012) because GIS enables the grouping of a large number of vari- ables, the creation of different scenarios, and a panoramic view of the landscape. Research of landscape-scale variations in C inventories among soil orders has facilitated the creation of C stock maps (Batjes 1996; Bernoux et al. 2002; Sá et al. 2013a; Tornsquist et al. 2009) and has promoted substantial advances in the understanding of C dynamics. With the availabil- ity of C inventory data, it has become possible to predict the long-term accumulation of C using mathematical models (Easter et al. 2007; Tornquist et al. 2009). These predictions can be used as a baseline for identifying public policies to decrease the greenhouse effect, increase food safety, and diminish critical problems such as hunger (Cerri et al. 2007; Pan et al. 2010). Therefore, farm-scale CONTENTS 12.1 Introduction .......................................................................................................................... 307 12.2 Materials and Methods ......................................................................................................... 308 12.2.1 Location and Description of the Study Area ............................................................ 308 12.2.2 Soil Sampling and Sample Preparation .................................................................... 309 12.2.3 Determinations of Total C and Labile Fractions in the Soil..................................... 310 12.2.4 Statistical Analysis ................................................................................................... 312 12.3 Results and Discussion ......................................................................................................... 313 12.3.1 C Pools by Soil Order and Landscape Position ........................................................ 313 12.3.2 Effect of Crop Sequence ........................................................................................... 317 12.3.3 Maps of Total C and Labile C Fractions................................................................... 318 12.4 Conclusion ............................................................................................................................ 319 References ...................................................................................................................................... 319 K23532_C012.indd 307 3/26/2015 12:41:55 AM