02274naa a2200217 a 450000100080000000500110000800800410001902400350006010000150009524501160011026000090022652016240023565000160185965000110187565300220188670000180190870000180192670000230194470000160196777300730198320667312022-05-20       2016    bl uuuu     u00u1 u    #d7 a10.1007/s10705-016-9783-02DOI1 aJOSLIN, A.  aImproved fallowbgrowth and nitrogen accumulation of five native tree species in Brazil.h[electronic resource]  c2016  aSmall-holding farmers of the Brazilian Amazon often use a rotation of secondary forest, slash-and-burn land-clearing and fallow phase regeneration for agriculture. In recent decades reduction of the fallow phase from ~20 to ~5 years has limited nutrient accumulation by fallow vegetation to sustain future crop growth. Slash-and-mulch and improved fallow schemes, including use of native nitrogen-fixing species, have been investigated to address the issue. In the current study in eastern Amazonia of Brazil, a 7-year old forest site was slash-and-mulched and four treatments applied; no fertilizer and no N-fixer as the control; no fertilizer with N-fixer; P + K fertilizer with no N-fixer; P + K fertilizer with N-fixer. Manioc was planted in all plots at establishment. After manioc harvest and 4 years of fallow, a total of 6 years after planting, use of P + K fertilizer increased tree growth of four of five planted species. In the presence of the N-fixer I. edulis, trends of increased growth and survival among these four tree species were observed. After 6 years, fertilization with P + K significantly increased tree volume and biomass. The N-fixer lowered survival of other species yet increased estimated N uptake of planted trees. Use of P + K fertilizer without N-fixer might allow for commercial harvest of S. amazonicum at the end of one 7-year crop-fallow cycle without jeopardizing agroecosystem N stocks. Use of P + K fertilizer in the presence of I. edulis can increase planted-tree N-content but increases in competition may limit commercial harvest yet may better sustain future food crop growth.  aNitrogênio  aPousio  aEspécie arbórea1 aMARKEWITZ, D.1 aMORRIS, L. A.1 aOLIVEIRA, F. de A.1 aKATO, O. R.  tNutrient Cycling in Agroecosystemsgv. 106, n. 1, p 1-15, Sep. 2016.