After being accused as the cause of deforestation, the palm oil was then attacked with a negative perception that its cultivation causes wasteful water consumption. It is vilified as not friendly to environment because it is considered threatening the water availability and potential to turn the oil palm plantation areas into desert.
The issue of wasteful water use had become one of the themes of black campaigns, which are aimed to hinder the development of palm oil industry at domestic and international markets.
To prove whether it is a hoax or true story, it is necessary to review a number of researches on the water need of the oil palm trees and other plants. The water need can be seen through the level of evapotranspiration which reflects the water volume absorbed by plants and discharged through evaporation and transpiration. Besides the level of evapotranspiration, the water excessive use can be also proven through its water footprint.
Water efficient plant
Coster (1938) used the indicator of evapotranspiration level to determine the water consumption level in plants.
Based on the research, the level of evapotranspiration in oil palm plantations shows that the water need of oil palm trees is only 1.104 mm per year.
Meanwhile, the water need of bamboo and lamtoro (Leucaena leucocephala) reaches 3,000 mm per year, which shows that these two trees need plenty of water. It is followed by acacia (acacia mangium) at 2,400 mm per year, sengon (Albizia chinensis) at 2,300 mm per year, and pine (‘Pinus roxburghii) and rubber tree (Hevea brasiliensis) at around 1,300 mm per year.
The pine, acacia and sengon trees have been popularly known as forest plants under the programs of reforestation and industrial forests. They are relatively very wasteful of water use. But the oil palm trees, which had been accused as excessive in using water, are apparently much more water efficient as compared to the forest plants. Even the oil palm trees are more water efficient than the rubber trees which are considered as water efficient.
Seen through the rainfalls used by oil palm trees, Pasaribu et a.l, (2012) found that the percentage of rainfalls used by the oil palm trees is only 40 percent of the total annual rainfalls. The percentage is lower than mahogany tree (Swietenia macrophylla) at 58 percent and pine tree at 65 percent.
Makonnen & Hoekstra (2010) conducted a research on the water needs of agricultural commodities by using the concept of “water footprint”. The concept can be defined as the total fresh water volume used by the agricultural commodities to produce one product. As a whole, the agricultural commodity with the largest percentage of global water footprint during the period of 1996- 2005 is wheat (15 percent), rice (13 percent) and corn (10 percent). Meanwhile, the contribution of oil palm to the global water footprint was only 2 percent.
The concept of Water Footprint in the research of Makonnen & Hoekstra (2010) also used three definitions of water sources, namely: (a) Blue Water, which refers to the surface water and ground water consumed (evaporation); (b) Green Water, which refers to the rainwater consumed; and (c) Grey Water, which refers to the water needed to assimilate pollutants based on the quality standard of existing water as the Grey Water is also used as an indicator of the polluted water volume.
The largest global water footprint in agricultural commodities is found in cloves at 61.205 m3/ton, which consists of green water (98 percent) and grey water (2 percent). The water footprint in oil palm trees is only 1,097 m3/ton, which consists of green water (96 percent) and grey water (4 percent).
Meanwhile, the water footprint of other vegetable oils, such as rapeseed at 2.270 m3/ton (75 percent green water, 10 percent blue water and 15 percent grey water) and soybean at 2.144 m3/ton (95 percent green water, 3 percent blue water and 2 percent grey water).
Based on the fact, the water need of oil palm trees is lower and it has been proven that it is very efficient in water use. The research also shows that the water need of oil palm trees is mostly fulfilled through green water or rainwater. The fact has also denied the accusation that the oil palm trees threaten the supply of groundwater.
Most efficient source of bioenergy
Countries across the globe have been developing the renewable energy as the alternative to the fossil fuels to mitigate the impact of climate change. The agricultural commodities are the big potential sources of bioenergy which is eco-friendly. Considering the focus of this research on the water need of plants, the research conducted by Gerbens-Leenes et al., (2009) shows the relations of the two, namely the water need of oil plants as the source of bioenergy.
Apparently, seen from the source of bioenergy production, the oil plant that is the highest in terms water use is rapeseed, followed by coconut, cassava, corn, soybean and sunflower. To produce every GJ of bioenergy, the rapeseed needs 184 m3 of water, while coconut, which is mainly produced in Indonesia, Philippines, and India, needs averagely 126 m3 of water.
Cassava (source of bioethanol) averagely needs 118 m3 of water, soybean that is mainly produced by the USA needs averagely 100 m3 of water. The research has also proven that the oil palm is very efficient (after sugarcane) in using water for every Giga Joule (GJ) of bioenergy production.
One of the renewable energy sources, which is produced by a number of countries, is biodiesel. Data of Oil World shows that the main feedstock for the global production of biodiesel is palm oil (33 percent), followed by soybean (19 percent) and rapeseed (19 percent) (PASPI, 2019).
The research of Makonnen & Hoekstra (2010) has also shown the fact on the water need of various agricultural commodities as the feedstock to produce biodiesel.
The research reveals that water need of coconut as feedstock for production of 1 liter of biodiesel is 157.617 liter, and the water need of sunflower, soybean and rapeseed is respectively 15.841 liter, 11.397 liter, and 6.429 liter.
Meanwhile, the water need of oil palm to produce 1 liter of biodiesel is only 5.166 liter. This has proven that besides able to produce eco-friendly energy, the water need of oil palm is also much lower than other oil plants.
In addition to the fact, oil palm with its fibrous and massive root system forms natural bio-pores that can absorb water and maintain its water holding capacity through infiltration of rainwater into the earth. That way the oil palm trees can reduce run-off and store water inside the earth.
The accusation that oil palm is water-hungry is part of the black campaigns, which are widely launched to hinder the development of palm oil industry at domestic and international markets. Based on the researches, the level of evapotranspiration has shown that the water need of oil palm trees is only 1,104 mm per year, which is lower than that of bamboo, lamtoro, acacia, sengon, pine, and rubber trees. The percentage of rainfalls used by oil palm is also lower than that of mahagony and pine trees.
Based on the global water footprint during the period of 1996-2005, the percentage of water consumption needed by oil palm trees globally is only at 2 percent or 1,097 m3/ton, while the cereal plants (such as wheat, rice, corn) and soybean have the percentage of water footprint at the range of 5-15 percent. If seen from the fulfillment of water need in oil palm trees, most of it derived from green water or rainwater. The fact reveals that the oil palm trees are water efficient and do not exploit groundwater or surface water.
The oil palm is also proven as ecofriendly and water efficient source of bioenergy as compared to other oil plants as feedstock for production of renewable energy. For such purpose, it only needs 75 m3 of water for production of every Giga Joule (GJ) of bioenergy. To produce 1 liter of biodiesel, the water need of oil palm is only at 5.166 liter or lower than the water need of coconut, rapeseed, and soybean.
Coster, C. 1938. Superficial Run-off and Erosion on Java. Tecnona. 31 : 613-728.
Gerbens-Leenes, Hoekstra P. Van der Meer, T. 2009: The Water Footprint of Energy from Biomass: a Quantitative Assessment and Consequences of an Increasing Share of Bioenergy Supply. Ecological Economics 68 (4): 1052- 1060.
Gleick PH. 2000. The Changing Water Paradigm: A look at Twenty First Century Water Resources Development. Water International. 25 (1): 127-138.
Hoekstra AY, Chapagain AK. 2007. Water Footprint of Nation: Water User by People as a Function of Their Consumption Pattern. Water Resources Management. 21 (1): 35-48.
Mekonnen M. M and A.Y. Hoekstra. 2010. The Green, Blue And Grey Water Footprint Of Crops And Derived Crop Products. UNESCO-IHE Institute for Water Education
Pasaribu, H., A. Mulyadi dan S. Tarumun. 2012. Water Balance in oil palm plantations in PPKS Sub Unit Kalianta Kabun Riau. Ejournal.unri.ac.id/960-1908-1- SM.pdf.
PASPI. 2019. Palm oil contribution in Global Biodiesel Industry. Monitor. 5(31): 1603-1610
Source: palmoilina.asia | gapki.id