DROUGHT AND HIGH TEMPERATURES IN BRAZILIAN COFFEE PLANTATIONS: A CASE STUDY AND ITS NATIONAL RANGE Alemar Braga Rena
Brazil , March/2014
I) PREAMBLE Given the current severe climatic anomaly (January / February / March 2014), which occurs in almost all the regions of Arabic coffee cultivation in Brazil, it is necessary to clarify their impact upon the next harvest that begins in mid-April, but also to clarify its effects on the crop 2015/16 . In the academic environment, this erratic 2014 summer is already considered as being the largest climate anomaly in the Brazilian coffee production , only surpassed by the “Black Frost� in 1975 . It is also worth mentioning that December 2013, countless Brazilian producers of Arabic coffee underwent a lack of investments in their plantations , due to low coffee prices which were far below the production costs (Figure below). Thus, many dicouraged coffee-growers went through accentuated abandonment, drastic pruning, or even eradication of their coffee growing areas.
II) INTRODUCTION: This study was conducted in a coffee estate area of 30 ha located at 750 m altitude in Viçosa, in the Zona da Mata of Minas Gerais, Brazil. The January/February (1968 – 2008) average temperature was about 22° C and the average rainfall was about 350 mm in this micro region. In the first two months of 2014, it rained only 47 mm and the average temperature was 4° C above the historical average, with frequent daytime average of 34° C. However, the trees of all plots analyzed were with excellent leafiness and the leaf mineral nutrition content was completely within the technical range indicated for coffee on 01/15/2014, except for foliar N (3,5%), which was slightly above the traditional level (3.2%). By 02/28/2014, just a few st nd plants had shown visible temporary wilting. However, in only on days, March 1 and 2 , 2014, it rained about 140 mm.
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The fruit damage determinations were performed on March 17 and 18 , 2014. Five samples of 50 fruits each, apparently in late grain filling stage, were taken randomly from the third upper middle of the trees in each plot, seeking to prevent the ends of the planting lines and drilled fruits. In over 90% of the abnormal fruits, the defects in the beans were from medium to mild, according to the scale proposed by Furlan/Parreiras/Rena on the Rede Social do Café (http://www.redepeabirus.com.br/redes/form/post?topico_id = 50871) of Peabirus portal on 03/18/2014 (see figure below). Fruits called "black heart" had not reached 0.1% and, in general, only one seed per fruit was affected, in this study.
The focus area was divided into 7 plots taking into account sun exposure, the age of the trees, the planting density, the fruit load and pruning. The technique of water immersion did not apply to this work, since a minimum fraction of the fruits floated, and in the submerged layer of fruits was the most significant fraction of defects. This indicates that, even defective, the deposition of starch in the seeds was enough to make them denser than water. Obviously, when these fruits ripen, their volume, therefore , will increase, its density will decrease, and they will come together in the float washer. As the floaters are not peeled, obviously it will lose a great deal of the CD (Cereja Descascada or Washed Coffee ) coffee beans, of higher quality (soft drink, note 82, in this micro climate), in this fraction. Thus, verification of the defects was performed only on the cross-section of the fruit and its visual analysis.
III) RESULTS The results are shown below. No statistical analysis was performed, but the variation of the repetitions suggests that values should be taken as X%+/-10%.
A. Plots Soalheiros (highest exposure to the sun ): 1. 2. 3. 4.
Catuaí 44, 9 years old, 6000 plants/ha, expected yield of 65 bags/ha. Catuaí 44, 9 years old, 6000 plants/ha, expected yield of 40 bags/ha. Catuaí 86, 33 years old, 3200 plant/ha, expected yield of 50 bags/ha. Catuaí 86, 26 years old, 3400 plants/ha, expected yield of 55 bags/ha.
Fruit with defects= 30%. Fruit with defects= 26%. Fruit with defects= 24%. Fruit with defects= 30%.
5.
Catuaí 44, 26 years old, 3400 plants/ha, first production after neck/skeleton pruning (18 months), expected yield of 50 bags/ha. Fruit with defects= 14%.
B. Plot Noruega (lower exposure to the sun): 6. 7.
Catuaí 44, 9 years old, 6000 plants/ha, first production after neck/skeleton pruning (18 months), expected yield of 60 bags/ha. Fruit with defects= 19%. Catuaí 44, 24 years old, 6000 plants/ha, first production after neck/skeleton pruning (18 months), expected yield of 75 bags/ha. Fruit with defects= 10%.
C. Plants taken randomly, fully exposed to the sun, with leaves dull and slightly yellowed, but with little “scalding”, located at the ends of the planting lines.
Fruit with very strong defects = 69%.
D. Overall average of fruit defects in the experimental area, excluding the value of the item C:
Approximately 22% +/- 2.2%.
IV) BRIEF DISCUSSION The data points out that at the studied coffee estate, the damages had not been to the same extent as observed in other coffee producing regions of Brazil. The damage is noticeable, but not representative of what is going on with the national coffee production. The reasons are difficult to be diagnosed, but it is likely to be related to a milder microclimate, soil more fertile and richer in organic matter, or perhaps, to some specific detail in the management of the plantation. But one should not forget that the property is at 750 meters above sea level and the latitude farther north than in the south of Minas Gerais, which should have aggravated the situation. Crop losses in 2014 at this estate are mainly due to the small bean size (low sieve), estimated at 15% and misshapen seeds at 10% (considering only the mass, not the quality), totaling 25 %. At this altitude, the drink is absolutely dependent on the stripping of cherry fruit. The low production of CD coffee, probably 20% less, therefore, represents another major source of losses, as the fruit with the lowest defect inevitably will come together to floater fruits during washing. In the most affected regions of Brazilian estate coffee plantations, however, with losses above 25%, and that apparently represent the majority. The culprit of the whole process was the lack of water in the soil (almost absent of rainfall), the excessive solar radiation, especially infrared (temperature) and ultraviolet radiations, the very high water vapor pressure deficit in the atmosphere, and soil and crop management. The reservoir of soil water was quickly used up due to the strong evapotranspiration demand that was not replenished accordingly. Both the powerful electromagnetic radiation and the strong water stress broke all the natural defense mechanisms of the coffee tree, which is not a species evolutionarily adapted to an environment so aggressive, furthermore, it is a C3 plant from high altitude and moist understory environment in tropical forests. As a result, there was almost a complete breakdown of the photosynthetic system, the only source of energy for the plant, exactly at the peak of water and carbohydrates demand, i.e., when the period of great expansion and grain formation was at its maximum. It was a festival of photo-inhibition, photo-degradation, imbalance in the hormonal system, disruption of water, organic, and mineral solute (xylem and phloem) transport systems, visible dehydration, burning of leaf tissues and younger branches, and, what we usually resist accepting, since it is not visual, death of the root system, one of the “brain lobes” of the plant. Moreover, the mechanical action of the water, i.e., its ability to generate swelling in the cells trough turgor pressure, leading to growth, either of branches, leaves, or fruits, ceased completely. Hence, in the full season of most active growth of the coffee tree, it simply did not happen. Consequently, the fruits have not expanded enough, resulting in unforeseeable losses in 2014; new productive nodes had not formed in adequate numbers, all of which, besides the
general weakening of the plant, mainly the root system, will dramatically affect the future crop of 2015/2016. Therefore, the coffee harvest in 2015 is already somewhat compromised. In addition, if the blossoms are good in September 2014 and the fruit set is reasonable, any adverse environmental jolt may be interpreted by the coffee tree, which is just out of the “Intensive Care Room�, as a major earthquake, damaging even further the 2015 crop, and sending warning signals for the 2016 biological cycle.
V) CONCLUSIONS Considering all of the above, with research and visits to various dry lands of coffee plantations in the main producing regions of Arabic coffee in Brazil, I can say that for the 2014 harvest: A. In the best coffee plantations, with rainfall above average, at higher altitudes, so being cooler, fertile and rich in organic matter soils, there will be a loss of approximately 15% of production due to: Incidence of malformed beans and void fruits Smaller beans Lower yield of green-beans and Lower final coffee quality B. In plantations where the rainfall was a bit lower, but with fertile clay soils, rich in organic matter, a loss of 20% to 30% may occur, depending on the following variables: Plant age (five years or more) Pending fruit loads Smaller beans Higher incidence of less dense beans and malformed and void fruits
C.
In plantations in sandy and low organic matter soils, at lower altitudes, and with low rainfall, there will be losses of 30% to 50%, depending on: Increased exposure to sunlight Higher water vapor pressure deficit in the air Higher evapotranspiration Greater root stress and damage Lower usage of water and mineral nutrients Lower photosynthetic rates Smaller beans Higher incidence of less dense beans and malformed and void fruits
D. In young plantations with four years or less, due to the smaller root system, depending on rainfall and soil organic matter content, losses can exceed 50%, because: Increased exposure to sunlight Higher water vapor pressure deficit in the air Higher evapotranspiration Greater root stress and damage Lower usage of water and mineral nutrients Lower photosynthetic rates Smaller beans Higher incidence of less dense beans and malformed and void fruits
E.
A well-irrigated and healthy estate of arabica coffee was also visited in the region of Pirapora (northern Minas Gerais), at 500m altitude. Within the reach of three center pivots, covering an area of over 200 ha containing fields of various ages, high density planting and yield of over 70 bags / ha, the defects in fruits ranged from medium to large, producing more than 3 L / plant of void fruit on the ground. Total losses easily exceed 30%. This demonstrates that the lack of water is not the only cause of significant losses. The excess of radiation, high temperature and water vapor pressure deficit in the atmosphere are also highly harmful.
Water: Photosynthesis requires a constant supply of water.
The water reaches the leaves through the roots and stems.
For those who want to deepen about photosynthesis of coffee culture, I recommend the scholarly work below: Seasonal vegetative growth of the coffee and its relation with photoperiod, fruiting, stomatal resistance and photosynthesis. http://www.scielo.br/pdf/pab/v41n3/29107.pdf FREQUENCY OF VEGETATIVE GROWTH IN Coffea arabica L.: RELATIONS WITH PHOTOSYNTHESIS IN FIELD CONDITIONS. http://www.sbicafe.ufv.br/bitstream/handle/10820/115/155537_Art018f.pdf?sequence=1
For the reasons presented here, the harvest of 2015 might be dramatically more affected than it was in 2014. First, due to the erroneous climatic behavior, very common at the present times resulting in insufficient water in the soil, huge exposure to sunlight, excessive heat, and high water vapor pressure deficit of the air. Second, vegetative growth in the 2013/2014 cycle was too slow to permit a wealthy reproductive growth to produce a good crop in 2015. Third, and finally, white an absence of abundant rain in the next 120 days, which are necessary to replenish the whole hydric deficit of the soil, and keeping the climatic “status quo”, the “brain of the coffee tree”, its roots and rootlets, might suffer irreversible damages, even affecting the 2016 harvest.
Fundação Procafé : Folha Técnica 223 http://fundacaoprocafe.com.br/sites/default/files/publicacoes/pdf/folhas/Folha%20223%20-%20Efeitos%20da%20seca%20para%202015.PDF
Fundação Procafé : illustration of levels of water storage in the soil water balance
ALEMAR BRAGA RENA, 72 is an expert in physiology and plant nutrition and grower in the Zone Mata-Minas Gerais since 1980. He is Agronomist by UFV - Universidade Federal de Viรงosa, M.Sc. in Plant Physiology by National University of La Plata, Argentina, and PhD in Biology from the University of Illinois, USA. Retired Professor of UFV - Universidade Federal de Viรงosa. Published numerous technical and scientific papers and book chapters in Brazil and abroad, including the book "Culture of coffee: Factors affecting productivity" in 1986. "Acknowledgment: The author acknowledges the important contributions of Marco Antonio Jacob, especially in graphics and publishing."