Soil enzymatic activity under coffee cultivation with different water regimes associated to liming and intercropped brachiaria

ABSTRACT: This research evaluated the effects of coffee cultivation with two different water regimes associated or not with liming and the presence/absence of brachiaria as intercrop on the activities of the soil enzymes β-glucosidase, arylsulfatase and acid phosphatase. The study was carried out at the experimental farm of Embrapa Cerrados, using the cultivar IAC 144 (Coffea arabica L.), under a clayey dystrophic Cerrado Oxisol. Two water regimes (WR) were considered, WR1 with irrigation shifts throughout the year and WR3 with controlled water stress, for about 70 days, in the dry season. In each water regime, effects of lime application (with/without) and the presence/absence of brachiaria cultivated between the lines of coffee plants were evaluated. The activities of the enzymes β-glucosidase, arylsulfatase and acid phosphatase were evaluated during the rainy and dry seasons. Liming and intercropped brachiaria positively affected the activities of the three enzymes assessed in this study at varying degrees, depending on season and/or the WR. Our findings evidenced that intercropped brachiaria in coffee rows was the factor that most positively impacted soil enzymes activities.

Doenças associadas à Xylella fastidiosa no Brasil

Based on genomic information, the Xylella fastidiosa bacterium is classified into three main subspecies: fastidiosa, multiplex and pauca. These different subspecies are naturally transmitted through vector insects, known as sharpshooters, which feed on the sap of xylem vessels of plants, where the bacteria colonize. Mainly due to the obstruction in the transport of water and mineral salts in these conducting vessels, the X. fastidiosa bacterium causes serious diseases in different cultures of economic interest. In Brazil, this phytopathogen was detected for the first time in plum trees, a crop in which the multiplex subspecies is responsible for the disease known as plum leaf scald. Subsequently, the pauca subspecie was associated with citrus variegated chlorosis in sweet orange orchards in São Paulo State. In the same state, the pauca subspecie was also found in coffee plants causing atrophy of the coffee tree branches, a disease whose damage has not been quantified yet. Recently, the pauca subspecie has also been found in olive trees, causing the olive quick decline syndrome, reported in the southeast region, especially in the Serra da Mantiqueira region. In this review, specific aspects of these diseases were focused, as well as measures that can be adopted as management.

Does Shade Impact Coffee Yield, Tree Trunk, and Soil Moisture on Coffea canephora Plantations in Mondulkiri, Cambodia?

Shade is a natural condition for coffee plants; however, unshaded plantations currently predominate in Asia. The benefits of shading increase as the environment becomes less favorable for coffee cultivation, e.g., because of climate change. It is necessary to determine the effects of shade on the yield of Coffea canephora and on the soil water availability. Therefore, three coffee plantations (of 3, 6, and 9 ha) in the province of Mondulkiri, Cambodia, were selected to evaluate the effect of shade on Coffea canephora yields, coffee bush trunk changes, and soil moisture. Our study shows that shade-grown coffee delivers the same yields as coffee that is grown without shading in terms of coffee bean weight or size (comparing average values and bean variability), the total weight of coffee fruits per coffee shrub and the total weight of 100 fruits (fresh and dry). Additionally, fruit ripeness was not influenced by shade in terms of variability nor in terms of a possible delay in ripening. There was no difference in the coffee stem diameter changes between shaded and sunny sites, although the soil moisture was shown to be higher throughout the shaded sites.

Nitrous Oxide Emission Fluxes in Coffee Plantations during Fertilization: A Case Study in Costa Rica

The main source of N2O emissions is agriculture, and coffee monocultures have become an important part of these emissions. The demand for coffee has increased in the last five decades. Thus, its production in agricultural fields and the excess of fertilizers have increased. This study quantified N2O emissions from different dose applications and types of nitrogen fertilizer in a region of major coffee production in Costa Rica. A specific methodology to measure N2O fluxes from coffee plants was developed using Fourier-transform infrared spectroscopy (FTIR). Measurements were performed in a botanical garden in Germany and plots in Costa Rica, analyzing the behavior of a fertilizer in two varieties of coffee (Catuai and Geisha), and in a field experiment, testing two types of fertilizers (chemical (F1) and physical mixture (F2)) and compost (SA). As a result, the additions of synthetic fertilizer increased the N2O fluxes. F2 showed higher emissions than F1 by up to 90% in the field experiment, and an increase in general emissions occurred after a rain event in the coffee plantation. The weak levels of N2O emissions were caused by a rainfall deficit, maintaining low water content in the soil. Robust research is suggested for the inventories.

Enhanced Drought Tolerance of Arabica Coffee (Coffea arabica L.) by Grafting Method

The objective of this study was to evaluate grafting method to improve the drought tolerance of Coffea arabica. Using C. arabica species as scions, and C. robusta as rootstock, the grafted plant was compared with the non-grafted plant (C. arabica) under water deficit condition. The result shown that growth parameters such as plant height, leaf length, and leaf width of the grafted coffee plants were higher than those of the non-grafted. The leaf area, fresh and dry weight of plants were highly reduced in non-grafted coffee plants. The leaf chlorophyll content (SPAD) and chlorophyll fluorescence (Fv/Fm) values of the grafted and non-grafted coffee plants decreased significantly with increasing duration under water deficit condition. The SPAD and Fv/Fm values of the two coffee types were also increased significantly with increasing duration after re-watering. Compared to the non-grafted plants, higher values of SPAD, Fv/Fm and relative water content in the leaf were observed in the grafted coffee plants. Moreover, lower values of relative ion leakage were observed in the grafted coffee plants after three days of water withholding and one month after re-watering. On the other hand, the grafted coffee plants showed enhanced drought tolerance by reducing the percentages of wilting plant under water deficit condition, and increasing the recovery percentages after re-watering.

COMPARATIVE ANALYSIS OF ADVANTAGES OF COFFEE FARMING WITH DIFFERENT CULTIVATION SYSTEMS AND PLANTING DISTANCES

Coffee plants in general are one of the plantation commodities that are suitable for smallholder plantations because they can produce fruit throughout the year. Coffee production can be used as a source of daily or weekly income for the community. The problem in the upstream subsystem is that the productivity of Indonesian coffee plants is still below its normal potential and tends to decrease. One of the reasons for this low productivity is the cultivation system, starting from maintenance, pruning and fertilizing, as well as plant spacing. The difference in treatment in the coffee cultivation system will also affect the profits that will be obtained by farmers. This study aims to analyze the differences in the profits of coffee farming with a spacing of 2.5 x 2.5 m with a spacing of 1.5 x 1.5 m and different cultivation systems. This research uses descriptive quantitative method using profit analysis and profit difference test. The results showed that the spacing of 1.5 x 1.5 m is more profitable than the spacing of 2.5 x 2.5 m. This happened because the population per hectare at a spacing of 1.5 x 1.5 m was 4,444 plants accompanied by very intensive care, while at a spacing of 2.5 x 2.5 m the population was only 1,600 plants. The follow-up to the results of this research will be submitted to the Sinta-2 journal by preparing articles according to the format given to the journal in question. This happened because the population per hectare at a spacing of 1.5 x 1.5 m was 4,444 plants accompanied by very intensive care, while at a spacing of 2.5 x 2.5 m the population was only 1,600 plants. The follow-up to the results of this research will be submitted to the Sinta-2 journal by preparing articles in accordance with the format given to the journal in question. This happened because the population per hectare at a spacing of 1.5 x 1.5 m was 4,444 plants accompanied by very intensive care, while at a spacing of 2.5 x 2.5 m the population was only 1,600 plants. The follow-up to the results of this research will be submitted to the Sinta-2 journal by preparing articles in accordance with the format given to the journal in question.

Screening coffee genotypes for Cercospora coffeicola resistance in Brazil

Several efforts have been made by many researchers worldwide to develop coffee plants resistant to different Cercospora species; however, studies concerning C. coffeicola , specifically, are still incipient. In the present study, a blend of strains from this pathogen was inoculated into 18 Brazilian commercial cultivars, a coffee clone of Arabica, as well as into 41 accessions from the Germplasm Collection of Minas Gerais, to evaluate the genetic resistance ability within the population and select superior genotypes for the breeding program. After predicting genotypic values of the evaluated material, the most efficient way to select genotypes based on the data of severity to brown eye spot (BES) was also examined. Moreover, the action of defense mechanisms against C. coffeicola attacks was investigated by assessing the levels of total soluble phenolic compounds and soluble lignin in contrasting genotypes regarding disease susceptibility. Based on the results, the accession MG 1207 Sumatra demonstrated an intrinsic genetic capacity to maintain low levels of severity to brown eye spot. This genotype can thus substantially contribute to the development of new cultivars, which may lead to reduced use of pesticides. This study also evidenced that four evaluations of severity is enough to reach accuracy and efficiency for the severity of BES, thus providing expressive genetic gains. Finally, it is suggested that the levels of lignin and phenolic compounds are not associated with the resistance of coffee genotypes to brown eye spot.