<p>Oil palm (<i>Elaeis
guineensis</i> Jacq.) is the world’s leading source of vegetable oil and an
important driver of rural economic activity in Southeast Asia, West Africa, and
the equatorial region of Latin America. In the Llanos region of Colombia, palm
oil production is additionally an important vehicle for legal employment and
social stability in a region deeply affected by the country’s longstanding and
recently-concluded armed conflict. The economic viability of palm oil
production is thus of great interest to both those directly employed in the
industry and to the larger society around them, and yet oil palm remains a
relatively understudied cropping system.</p>
<p>Spending on
fertilizer is one of the largest costs in palm oil production, and plantations
face considerable pressure to apply fertilizer as efficiently as possible in
order to maintain the profitability of their operations. However, developing
strategies for optimizing fertilizer applications in oil palm can be
considerably challenging given the particular characteristics of palm oil
production systems. Oil palm has a typical life-cycle of 25 years, with
harvesting done manually approximately every fifteen days for the duration of
the palms productive life-cycle. The morphology of oil palm’s reproductive
system makes it possible for environmental changes to affect yield in irregular
ways, with the same soil or climate-related stressors having the potential to
affect yields either immediately or multiple years after the event. It can therefore be difficult for plantations
to link changes in yield patterns to individual management changes or
environmental factors. Additionally, since unlike all other major oilseeds oil
palms must be harvested manually, plantation managers do not have access to the
kind of detailed yield data made possible by mechanized harvesting equipment,
but must rely on much more irregular and coarser-resolution information to
examine yield variability within plantations. Understanding how the particular
soil conditions and fertilizer management history of an individual oil palm
plantation drive variability in yields requires employing innovative approaches
to maximize the insights to be learned from the available data. </p>
<p> For
this study, we worked with a 5,220 hectare oil palm plantation in the Colombian Llanos, in
the municipality of Villanueva, Casanare. Despite uniform fertilizer
applications and management practices, along with uniform climatic conditions
within the plantation, significant yield variability existed within the
plantation, with plantation managers initially unable to determine the
underlying causes. We proposed and evaluated a methodology for using
digital terrain and soil mapping for generating continuous soil data within an
oil palm production system, based on Functional Soil Mapping (FSM) methods
using the SRTM Global Digital Elevation model and geo-referenced soil sampling,
with the goal of identifying soil physical, chemical and hydrological
properties that could be directly linked to different yield responses to
fertilizer application at the field scale. Furthermore, the economic
implications for the plantation of infield variability in yield response to
fertilizer arising from variation in soil properties were examined. </p>
<p>The perennial
nature and particularities in reproductive morphology of oil palm, including an
approximately 8-10 year growth period before mature yields are reached, mean
that developing site-specific yield response curves to different nutrient
application levels in oil palm requires extensive time and resources. The PORIM
model, developed by the Malaysian Palm Oil Board (MPOB) across multiple decades
of extensive and continuous field testing, is one of the most commonly used
methods by which plantations can estimate yield response at different levels of
fertilizer application. Traditionally, the PORIM model is run by using
site-specific low-resolution vector-layer soil analysis to adjust various
parameters in multiple equation systems developed using statistical methods and
many decades worth of field tests by the MPOB. In this study, the PORIM model
is used as the basis for a methodology to employ a precision approach to
fertilizer management in oil palm using high-resolution raster-layer soil
property maps and a constrained-optimization model programmed in the General
Algebraic Modeling System (GAMS). </p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/8019524 |
| Date | 10 June 2019 |
| Creators | Alberto Martinez (6617777) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/Digital_Methods_for_Soil_Mapping_and_Fertilizer_Management_in_Oil_Palm/8019524 |
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