Gualter Guenther Costa da Silva

Nutritional diagnosis for eucalypt by DRIS, M-DRIS, and CND

The evaluation of the nutritional status in eucalypt (Eucalyptus grandis W. Hill ex Maid.) forests through vegetal tissue analyses what reflects water and nutrient flows in the system, and represents a complementary tool to soil analysis can be helpful to raise and maintain the forest productivity at high levels. This study compared the use of the Diagnosis and Recommendation Integrated System (DRIS), Modified-DRIS (M-DRIS), and Compositional Nutrient Diagnosis (CND) diagnose methods in eucalypt stands in Central-Eastern Minas Gerais State, Brazil. Data of productivity and of N, P, K, Ca, and Mg leaf contents in 993 Eucalyptus grandis stands aging between 72 and 153 months, planted on six sites in 3 ´ 2 m spacing, were used. The nutritional status was diagnosed by the DRIS, M-DRIS, and CND methods, and validated by the chi-square (c2) test applied to the nutrients diagnosed as primary limiting by deficiency. These three methods were compared to each other based on the diagnosis concordance frequency (DCF) derived from the fertilization response potential (FRP) by the criteria considering each nutrient separately; from all (5) to none (0); and only the primary limiting nutrients by either deficiency or excess. The diagnosis concordance level among the methods was procedure-dependent, and varied according to the nutrient concentration in trees.

BIOMASS AND ENERGY PRODUCTION AT SHORT ROTATION Eucalyptus CLONAL PLANTATIONS DEPLOYED IN RIO GRANDE DO NORTE

1 Received on 08.08.2014 accepted for publication on 30.11.2016. 2 Universidade Federal do Rio Grande do Norte, Unidade Acadêmica Especializada em Ciências Agraria, Macaíba, RN, Brasil . E-mail: <marabio_rn@hotmail.com>,<meire_caico@yahoo.com.br>,<gualtergcs@yahoo.com.br>,<sarahcostaa@yahoo.com.br> and <aspimenta@ufrnet.br>. Universidade Federal de São João Del-Rei, Departamento de Ciências Agrárias, Sete Lagoas, MG, Brasil . E-mail: <castrorvo@ymail.com> and <mendesafn@hotmail.com> 4 Universidade Federal de Viçosa, Departamento de Engenharia Florestal, Viçosa, MG, Brasil . E-mail: <cassiacarneiro@ufv.br>.

CARVÃO VEGETAL COMO CONDICIONADOR DE SOLO NA SUCESSÃO ARROZ E FEIJÃO-CAUPI ADUBADOS COM NITROGÊNIO

The effects of biochar and nitrogen application on yields of upland rice and cowpea and on soil fertility were determined in a greenhouse in Macaíba, RN, Brazil. The trial consisted of the succession of two crops in a completely randomized design and a factorial scheme, with four replicates. Initially, four doses of biochar and four doses of nitrogen were tested for cultivation of rice. Subsequently, four doses of biochar and two doses of nitrogen were tested in half of the pots maintained for planting cowpea. Soil was sampled after rice harvest for half of the pots and at end of the trial for the remaining pots. We evaluated the following parameters: mass of hundred grains of rice, dry shoot mass, panicle number, number of filled spikelets and of empty spikelets, and grain production. Determinations for cowpea were: pod number per pot, grain number per pod, and grain production per pot. Measured soil parameters were: pH, contents of organic carbon, P, K, Ca, Mg, Na, cation exchange capacity, and exchangeable sodium percentage. Biochar addition did not influence yield components of upland rice and cowpea, but resulted in increased soil N retention, which influenced rice dry shoot mass, spikelets sterility, panicle number, and grain mass. Biochar also promoted increased soil pH, potassium content, and exchangeable sodium percentage and decreased calcium and magnesium concentrations.