Organic management of Brachiaria brizantha cv. Marandu pasture mixed with Stylosanthes spp. in the Cerrado.

2016

Beyond conservation agriculture.

ABSTRACT: Global support for Conservation Agriculture (CA) as a pathway to Sustainable Intensification is strong. CA revolves around three principles: no-till (or minimal soil disturbance), soil cover, and crop rotation. The benefits arising from the ease of crop management, energy/cost/time savings, and soil and water conservation led to widespread adoption of CA, particularly on large farms in the Americas and Australia, where farmers harness the tools of modern science: highly-sophisticated machines, potent agrochemicals, and biotechnology. Over the past 10 years CA has been promoted among smallholder farmers in the (sub-) tropics, often with disappointing results. Growing evidence challenges the claims that CA increases crop yields and builds-up soil carbon although increased stability of crop yields in dry climates is evident. Our analyses suggest pragmatic adoption on larger mechanized farms, and limited uptake of CA by smallholder farmers in developing countries. We propose a rigorous, context-sensitive approach based on Systems Agronomy to analyze and explore sustainable intensification options, including the potential of CA. There is an urgent need to move beyond dogma and prescriptive approaches to provide soil and crop management options for farmers to enable the Sustainable Intensification of agriculture.

Agronomic efficiency of Bradyrhizobium in peanut under different environments in Brazilian Northeast.

Several legumes have natural ability to associate with nitrogen - fixing bacteria known as rhizobia. The efficiency of this association depends on the plant and bacterial genotype and the edaphoclimatic conditions. Peanut is a tropical legume able to associate with a wide range of rhizobia and the selection of efficient bacteria is important to increase the nitrogen fixation in this crop. In order to investigate the agronomic efficiency of two Bradyrhizobiumstrains, two peanut genotypes were used in field trails carried out in three environments located at Brazilian Northeast. The genotypes (BR1 and L7 Bege) were submitted to rhizobial inoculation (SEMIA 6144 or ESA 123, both Bradyrhizobium strains, and chemical nitrogen fertilization in randomized block design experiments. The following traits were analyzed: flowering (F), main axis height (MAH), number of nodules/plant (NN), number of pods/plant (NP) and weight of pods (WP). Differential responses were found in all to treatments to NN, NP and WP, in the three environments studied. Overall, ESA 123 showed good agronomic performance inducing higher pod production. The results supportthe evaluation of the Bradyrhizobium in further experiments aiming at its recommendation to commercial inoculants in Brazilian Northeast region.

Forage peanut (Arachis spp.) genetic evaluation and selection.

Forage peanut improvement for use in grass?legume mixtures is expected to have a great impact on the sustainability of Brazilian livestock production. Eighteen cloned Arachis spp. ecotypes were evaluated under clipping in a Brazilian Cerrado region and results analysed using a mixed model methodology. The objective was to estimate genetic and phenotypic parameters and to select the best ecotypes based on selection index applied on their predicted genotypic value. The traits of total dry-matter (DM) and leaf DM yield presented moderate (0_30 < h2g < 0_50) to high (>0_50) broad-sense heritability, in contrast to the low genetic variability in nutritional quality-associated traits. Ecotypes of Arachis spp. contained average crude protein concentrations of 224 g kg _1 DM in leaves and 138 g kg _1 DM in stems, supporting the potential role of these species to overcome the low protein content in Cerrado pastures. The correlations between yield traits and traits associated with low nutritional value in leaves were consistently significant and positive. Genetic correlations among all the yield traits evaluated during the rainy or dry seasons were significant and positive. The ecotypes were ranked based on selection index. The next step is to validate long-term selection of grass?Arachis in combination with pastures under competition and adjusted grazing in the Cerrado region.

Endemic Mimosa species from Mexico prefer alphaproteobacterial rhizobial symbionts.

2016

Production and Nutritive Value of Indigofera zollingeriana and Leucaena leucocephala in Peatland

Abstract. This study was aimed to determine and compare the dry matter yield and nutrient content of Indigofera and Leucaena grown in peatland. This experiment was conducted in peatland type soil (type sapric) in Pekanbaru city, DM yield and nutrient contents data were analyzed by 2x3 factorial design with 3 replication. Two treatments compared were Indigofera zollingeriana (Indigofera) and Leucaena leucocephala (Leucaena). Indigofera was proven significantly higher than Leucaena in all harvest regarding dry matter (DM) of leaf and stem of 29.9% and 25%, respectively, crude protein (CP) of 23.1% and 17.6%, respectively. While neutral detergent fibre (NDF) and acid detergent fibre (ADF) content of Indigofera leaf (35.9% and 25.1%, respectively) was significantly lower than those of Leucaena leaf (40.9% and 29.3%, respectively). It was concluded that the production and nutritive value of Indigofera zollingeriana was superior to Leucaena leucocephala in peatland (type sapric). Key words: Legume tree, Sapric, nutrient content, In vitro digestibiliy              Abstrak.  Penelitian ini bertujuan menentukan dan membandingkan bahan kering dan kandungan nutrisi Indigofera dan Leucaena yang tumbuh di lahan gambut. Percobaan ini dilakukan di lahan gambut di Pekanbaru menggunakan pola faktorial 2x3 dengan ulangan 3 kali. Dua perlakuan yang dibandingkan adalah Indigofera zollingeriana (Indigofera) dan Leucaena leucocephala (Leucaena). Indigofera terbukti secara nyata lebih tinggi daripada Leucana di semua periode panen, berkaitan dengan kandungan BK (bahan kering) daun dan batang berturut-turut 29,9% dan 25%, dan protein kasar (PK) 23,1% dan 17,6%. sedangkan neutral detergent fibre (NDF) dan acid detergent fibre (ADF) daun indigofera berturut-turut 35,9% dan 25,1%, lebih rendah secara nyata daripada daun Leucaena, yaitu 40,9% dan 29,3%. Disimpulkan bahwa produksi dan nilai nutrisi Indigofera zollingeriana lebih tinggi dari Leucaena leucocephala di lahan gambut (jenis saprik) Kata kunci: Pohon legume, Saprik, Kandungan Nutrisi, Kecernaan in vitro