02582naa a2200373 a 450000100080000000500110000800800410001902400330006010000210009324501340011426000090024852014790025765000170173665000230175365000120177665000200178865000260180865000230183465000150185765000250187265000140189765300260191165300190193765300260195665300260198270000190200870000220202770000170204970000150206670000260208170000190210770000260212677300560215220880422018-05-07       2016    bl uuuu     u00u1 u    #d7 a10.2134/agronj2015.05652DOI1 aPONTES, L. da S.  aInteractive effects of trees and nitrogen supply on the agronomic characteristics of warm-climate grasses.h[electronic resource]  c2016  aPlant adaptations to cope with shade may vary according to the degree of shade tolerance and nutrient availability for each species. Studies of diff erent understory species and their responses to combined shade and N eff ects are important to identify ways to optimize the quantity and quality of forage production. Our objective was to measure the dry matter yield (DMY) and nutritive value of six C4 grasses grown in two systems (full sunlight [FS] vs. a naturally shaded system composed of Eucalyptus dunnii Maiden trees) with two N levels (0 vs. 300 kg N ha?1yr?1) using the same target sward conditions (i.e., 50% depletion of the canopy height set by 95% light interception). Over 3 yr, the decreases in DMY under shade compared with FS ranged from 7% [Urochloa brizantha (Hochst. ex A. Rich) R.D. Webster] to 56% (Cynodon spp.) in fertilized treatments and between 11% (Paspalum notatum Fluegge) to 46% (Cynodon spp.) in treatments without N. Th e N eff ect was more important to the nutritive value of the forage than the shade eff ect, particularly for crude protein (CP, +46 g kg?1 with N supply), acid detergent fi ber (ADF, ?46 g kg?1) and leaf proportion (+11.2%). However, most of the species displayed higher leaf digestibility under shade due to decreases in ADF. Even with intense shading (light approximately 48% of unshaded), the digestible DMY and CP yield under trees were, on average, 70 and 71% of the 6.8 and 1.4 t ha?1 recorded in FS, respectively.  aAgroforestry  aDactylis glomerata  aGrasses  aShade tolerance  aSilvopastoral systems  aUrochloa brizantha  aBrachiaria  aBrachiaria Brizantha  aGramínea  aDry matter production  aLight gradient  aSistema agroflorestal  aTolerância à sombra1 aGIOSTRI, A. F.1 aBALDISSERA, T. C.1 aBARRO, R. S.1 aSTAFIN, G.1 aPORFIRIO-DA-SILVA, V.1 aMOLETTA, J. L.1 aCARVALHO, P. C. de F.  tAgronomy Journalgv. 108, n. 4, p. 1531-1541, 2016.