Fertilizer Management: Future Works and Research

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The future work in oil palm agronomy has been well discussed by Soh et al . (2006), Kee and Goh (2006), Goh (2005), Chew and Goh (2003), Kee et al . (2003) and Chew et al . (1997) just to name a few from AAR only amongst the many from other organisations in the oil palm industry over the years. It is neither our duty nor the place here to summarize these papers but to complement them.

The principles and philosophy of nutrient budget have served us well as evidenced by the high productivity of oil palm despite being largely grown on weathered, degraded soils in the tropics. Currently, the oil palm has probably the best nutrient use efficiency per tonne of vegetable oil. While the K budget can account for the optimal K rates in fertilizer response experiments, the N budget cannot explain over 30% of the N balance (Table 1) in the same set of experiments. This will require the more difficult research work on nutrient cycling and dynamics, which should yield results for further improvement of fertilizer use efficiency of oil palm. This work should include other minor nutrients and elements known to affect crop performances.

Table 1: Nutrient balance computations for commercial areas. Source: Chew et al . (1994b)

The roles of biotic factors on palm nutrition are expected to become more prominent as we breed for truer inbred hybrids with more uniform (identical) genetic make-up on a commercial scale. Similarly, the greater use of clones and re-clones will necessitate the study of their specific or differential nutrient requirements. For example, in Clone 1, there was hardly any response to K fertilizer inputs after years of experimentation compared with Clone 2 and DxP materials (Figure 16). Similar results have been reported by Jacquemard et al . (2002) and Donough et al . (1996). Another black box in oil palm nutrition is the roles of soil microbes and biodiversity. This needs urgent studies if we are to exploit this largely unknown soil resource.

Figure 1: Differential FFB yield responses of oil palms propagated by tissue culture (clonal) and seeds (DxP) to K fertilizer in Kumansi Family soil in Sabah, Malaysia. Average yields between 2003 and 2008 were shown in the graph. Source: AAR (Unpublished)

The lack of study on physiological plant nutrition in the oil palm industry is still glaring. This deficiency must be addressed quickly to understand the various phenomena seen in the fields such as pre-mature frond desiccation, relationship between pest and diseases and palm nutrition, the root system and its mechanism for nutrient uptake, and the roles of plant nutrition in climate change amongst others; and develop new direction for studying plant nutrition and better, practical fertilizer use technology.

In the seventies and early eighties, there was much co-operation among the research organisations in Malaysia for joint research on common problems and meta-analysis of experimental data. For example, the combined analysis of fertilizer response trials from the industry by Dr. Foster and co-workers has resulted in a fertilizer recommendation system for oil palm and a set of indicators of palm health (Goh, 2005). However, newer agronomic data are now available and these experiments are conducted with later generation of planting materials and current recommended management practices on more diverse soil types and environments, which are probably more relevant to the industry today. Thus, it appears logical to conduct another meta-analysis of these newer data.

The palm oil mills should be regarded as large stores or reservoirs of nutrients/fertilizers and carbon/organic matter. The current methods to utilize these resources are still tedious, laborious, cumbersome and limited to specific areas. Furthermore, the expensive soluble nutrients such as K are probably not fully recovered. Theoretically, if all the nutrients can be recovered, the oil palm industry needs very little fertilizers because our main produce, palm oil, does not contain much nutrients. While we are not suggesting turning the palm oil mill into fertilizer factory, scrutinizing for new technology to recover these nutrients and carbon and making them user friendly e.g. granulation or liquid fertilizers are urgently needed. In fact, a growing number of agronomists worldwide has the opinion that producing higher yields requires not only advanced genetics but good agronomic management which includes good plant nutrition utilizing both organic and inorganic nutrient sources (Roberts, 2009). Apart from the above impact, it will have huge implications on carbon credit, carbon balance, energy balance, sustainability and a host of other initiatives related to global palm oil trade.

Research Work

Research work on precision agriculture in oil palm has commenced in the 1990s and its potential applications have been demonstrated (Goh et al. , 2000). For example, the generation and combination of yield maps of plots with and without nitrogen application in a classical fertilizer response trial (about 25 ha) using geostatistical methods showed strong spatial yield responses to nitrogen (Figure 2). They ranged from good FFB yield response of more than 50 kg/palm/yr or 6.6 t/ha/yr in the central portion of the field to poor or negative yield responses in the eastern and western parts. This information can be transformed into management zone for site-specific management (Anuar et al ., 2008). Further work is needed to exploit this technology for improved effectiveness and efficiency of inputs leading to better productivity and profitability.

Figure 2: Spatial FFB yield response of oil palms on Kumansi Family soil to N fertilizers

Source: Goh et al . (2000)

The oil palm environments comprise numerous elements or growing conditions where their interplays have a strong impact on the yield response to fertilizer inputs. For example, Kee and Chew (1993) demonstrated that the N rate may be reduced by half under irrigated compared with non-irrigated oil palm in an area with monsoonal climate (Figure 4). This was attributed to better nutrient uptake under adequate soil water throughout the year ensuring optimal palm nutritional status at most times with consequent fuller expression of FFB yields. Similarly, FELDA Agricultural Services Sdn Bhd. (FASSB) clearly showed that the FFB yields of oil palm under irrigated condition in a dry region were consistently higher (35% or 45 t/ha over five years) than non-irrigated condition given the same fertilizer regime (Figure 3). These results indicate that we may need a series of multi-factorial trials to decipher and understand the role of each growing condition on fertilizer response and to provide the recommended set to the planters to implement for best results. In fact, it is of utmost importance that the agronomists identify these conditions and design farming system that optimises the fertilizer use efficiency.

Figure 3: Effect of irrigation on N response of oil palm in a wet monsoonal climate in Malaysia

Source: Kee and Chew (1993)

Figure 4: Effect of fertilizer (N1P1K1) on oil palm yields in a dry region under irrigated and non-irrigated (FASSB, unpublished)

Technology, techniques and equipment are now available and there are hardly any reasons why these studies cannot be undertaken successfully. What is needed is creativity and ingenuity to solve our problems. As published by The Sunday Star, the local newspaper on 5 th April 2009, “Science triumphs common sense when it really matters”. Thus, the future of effective fertilizers, fertilizer use efficiency and fertilizer management, and the consequent productivity of oil palm reside in continuous generation of new applicable sciences, adaption of new technologies and designing new methods to implement them correctly and efficiently, and reducing the uncertainties related to fertilizer management.

Reference:

GOH, K.J., G, P.H.C. AND LEE, C.T.: Fertilizer Management and Productivity of Oil Palm in Malaysia

The full list of references quoted in this article is available from the above paper.