A. May

BASIL PLANTS GROWTH AND ESSENTIAL OIL YIELD IN A PRODUCTION SYSTEM WITH SUCCESSIVE CUTS ( 1 )

This work studied the growth of basil plants and the effect of successive cuts on the total yield and quality of the essential oil, throughout the crop cycle. Steady increases were observed in the dry weight of the aerial part and in the essential oil yield, during the cultivation cycle. Intensive cultivation and successive cuts could improve the agronomical and industrial yield in each harvest.

Estimating 20-year land-use change and derived CO2 emissions associated with crops, pasture and forestry in Brazil and each of its 27 states

Abstract Land‐use change (LUC) in Brazil has important implications on global climate change, ecosystem services and biodiversity, and agricultural expansion plays a critical role in this process. Concerns over these issues have led to the need for estimating the magnitude and impacts associated with that, which are increasingly reported in the environmental assessment of products. Currently, there is an extensive debate on which methods are more appropriate for estimating LUC and related emissions and regionalized estimates are lacking for Brazil, which is a world leader in agricultural production (e.g. food, fibres and bioenergy). We developed a method for estimating scenarios of past 20‐year LUC and derived CO2 emission rates associated with 64 crops, pasture and forestry in Brazil as whole and in each of its 27 states, based on time‐series statistics and in accordance with most used carbon‐footprinting standards. The scenarios adopted provide a range between minimum and maximum rates of CO2 emissions from LUC according to different possibilities of land‐use transitions, which can have large impacts in the results. Specificities of Brazil, like multiple cropping and highly heterogeneous carbon stocks, are also addressed. The highest CO2 emission rates are observed in the Amazon biome states and crops with the highest rates are those that have undergone expansion in this region. Some states and crops showing large agricultural areas have low emissions associated, especially in southern and eastern Brazil. Native carbon stocks and time of agricultural expansion are the most decisive factors to the patterns of emissions. Some implications on LUC estimation methods and standards and on agri‐environmental policies are discussed.

Interferência de plantas daninhas na cultura do sorgo sacarino

This work aimed to carry out a phytosociological study and to determine the critical period of weed interference on sweet sorghum crop. The experimental design adopted was randomized blocks with three replications. Treatments consisted by increasing periods of control or coexistence of weeds in different phenological stages of crop growth: 0-3 (V3), 0-5 (V5), 0-7 (V7), 0-9 (V9), 0-11(V11) fully expanded leaves and 0-R5 (harvest). The weed community was evaluated based on number the number of individuals and their correspondent dry mass accumulation, for each weed population in different periods of coexistence. Sweet sorghum was harvested at 101 days after emergence, when was measured plant height, culm diameter, total soluble solids (°Brix) in function of coexistence periods between crop and weeds, besides the yield of culms. Commelina benghalensis e Panicum maximum were the two species of higher relative importance at the crop harvested. The lack of weed control, during the crop cycle, caused an increase in total soluble solids (°Brix) and reduction of, respectively, 9 and 25% in plant height and culms diameter when compared with the hoed control during all cycle. Accepting losses of 5% in culm yield, was observed that the critical period of weed interference corresponded to the period of time between the phenological growth stage V3 to V11.

Influência do espaçamento e da população de plantas de sorgo sacarino em diferentes épocas semeadura

The research aimed to evaluate the effect of row spacing and plant population on the production of sweet sorghum in sowing season and off-season crop. The experiments were conducted at Embrapa Maize and Sorghum, Sete Lagoas (MG) in an Oxisol in the 2011/2012 season. For two seasons of sowing, the plots were composed of five row spacings (50;60;70 and 80cm and double line 100x50cm), and sub-plots for four plant populations of sweet sorghum (80.000, 100.000, 120.000 and 140.000 plants ha-1). The experimental design was randomized blocks with three replications. It was used the variety of sweet sorghum BRS506. The experiment in the sowing season was implemented in November/2011 and the off-season in March/2012. The sowing season period resulted in higher fresh weight of total biomass, juice mass and Brix of sweet sorghum, regardless of plant arrangement. The row spacing of 50cm resulted in higher total biomass and juice mass ha-1, regardless of the period sowing. The double spacing resulted in values similar to the row spacing of 80cm for the main production variables, regardless of the period sowing. The plant population did not influence the yield of fresh mass of stems and juice mass, regardless of the period sowing.

Bacterial Structure of Agricultural Soils with High and Low Yields

The purpose of this study was to evaluate the structure of bacterial communities at two agricultural fields in Brazil (Parana (PR) and Bahia (BA) states) with a history of high and low productivity of soybean. 16S rRNA gene amplicons revealed that plots with low yield of grains showed greater bacterial richness than plots with high yield. The phylum Acidobacteria was more abundant in soil samples from PR site. The rhizosphere of plants presented a similar bacterial community for both high and low yield plots. Soil samples from BA showed differences in the diversity between the plots with high and low productivity. The use of 16S rRNA amplicon sequencing allowed the assessment of differences between plots with different soybean yields. This might be useful in the future to harness plant microbiomes for increased crop productivity.