SOIL CHEMICAL ATTRIBUTES AND CORN PRODUCTIVITY GROWN ON LEGUME STUBBLE IN AGROFORESTRY SYSTEMS

LEONARDO SANTOS COLLIER,JOSÉ NILTON VIEIRA NUNES,LUIZ FERNANDES CARDOSO CAMPOS,EVERTON MARTINS ARRUDA

doi:10.1590/1983-21252018v31n203rc

LEONARDO SANTOS COLLIER, JOSÉ NILTON VIEIRA NUNES + Show 2 more

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https://doi.org/10.1590/1983-21252018v31n203rc

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Abstract

ABSTRACT Leguminous species can improve nutrient cycling and chemical quality of Oxisols, resulting in higher productivity of intercropped crops. Thus, this research aimed to evaluate the decomposition rate and nutrient accumulation in legume stubble, as well as its contribution to soil chemical attributes, the growth of baru trees (Dipteryx alata Vogel), and yield of intercropped maize in an agroforestry system. The experiment was developed during the crop years of 2010-2011 and 2011-2012, in Goiás State, Brazil. The experimental design was a randomized block with five replicates. Leguminous species consisted of sunn hemp (Crotalaria juncea), jack bean (Canavalia ensiformis), pigeon pea (Cajanus cajan), Stylosanthes (Stylosanthes macrocephala - 20% and Stylosanthes capitata - 80%), and spontaneous vegetation (control treatment). The decomposition rates of legume and spontaneous vegetation residues remained unchanged in the agroforestry system. Sunn hemp, jack bean, and Stylosanthes plants are advantageous options for total accumulation of nutrients. However, sunn hemp grown as straw cover for next crop seasons increases the available phosphorus levels in the soil and productivity of maize cobs. With this coverage, maize productivity values were up to 24% higher than were those with maize growing on spontaneous vegetation, besides having no effect on the growth of baru trees.

Highlights

Baru (Dipteryx alata Vogel) is a forest native tree from Brazilian cerrado and produces chestnuts and wood, being a tree option for agroforestry systems
The high sunn hemp dry mass (DM) production in the first harvest was probably due to its pivotal root system, which penetrates deeper into the soil, increasing the soil volume explored for water and nutrients (TORRES et al, 2014)
The total DM production of both sunn hemp and stylosanthes were considered adequate for a conservationist system, based on crop rotation, showing straw amounts superior to 6.0 Mg ha-1 (ALVARENGA et al, 2001)

Summary

Introduction

Baru (Dipteryx alata Vogel) is a forest native tree from Brazilian cerrado and produces chestnuts and wood, being a tree option for agroforestry systems. Maize is a C4 plant with high grain yield and biomass requiring an intensive fertilization since it exports significant amounts of nutrients (PRADO, 2008) In addition to this demand, the association of maize with tree species in intercropping systems suggests a higher intake of nutrients from the soil, which increases the dependence of mineral fertilizers (ABREU et al, 2016). To reduce this dependence, it is important to use cover crops before the growing of annual crops to promote an efficient use of available nutrients (COLLIER et al, 2008; COLLIER et al, 2011; BARROS; GOMIDE; CARVALHO, 2013), improved soil protection (DAMOUR; GUÉRIN; DOREL, 2016), and benefits to soil chemical attributes (CANELLAS et al, 2004; PEREZ; SMYTH; ISRAEL, 2007). There is an increase in mineralization and availability of nutrients to the plants (TORRES; PEREIRA; FABIAN, 2008; PACHECO et al, 2017), mainly by biological fixation of nitrogen (BARROS; GOMIDE; CARVALHO, 2013), and release of cations and phosphate anions to soil solution (PAVINATO; ROSOLEM, 2008)

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