ch. 1. Soil ecology and agroecosystem studies : a dynamic and diverse world / David C. Coleman, Vadakattu V.S.R. Gupta, and John C. Moore -- ch. 2. Manipulation of beneficial microorganisms in crop rhizospheres / Richard P. Dick -- ch. 3. The influence of heterogeneity on soil microbial processes in agroecosystems : theory, evidence, and opportunities / Terry D. Loecke -- ch. 4. Soil food webs in agricultural ecosystems / John C. Moore and Peter C. de Ruiter -- ch. 5. Community composition of soil organisms under different wheatfarming systems / Klaus Birkhofer. [et al.] -- ch. 6. The biological basis for nitrogen management in agroecosystems / A. Stuart Grandy. [et al.] -- ch. 7. The contribution of arbuscular mycorrhizal fungi to the success or failure of agricultural practices / David D. Douds Jr. and Rita Seidel -- ch. 8. Effects of the cultivation of genetically modified Bt crops on nontarget soil organisms / Tanya E. Cheeke -- ch. 9. Maize legume relay intercrops in Malawi : meeting short- and long-term sustainability goals / Carol Shennan and Dorothy Sirrine -- ch. 10. Making soil biodiversity matter for agriculture : ecosystem services and challenges / Diana H. Wall.