Soil fertility mapping project by Dr. Al-Mario Casimir

The soil fertility and mapping project is one of many areas of technical cooperation between

the Government of the Commonwealth of Dominica and the Kingdom of Morocco.

 

The project is being implemented through the Ministry of Agriculture and Fisheries with technical assistance

from the Moroccan Agency for International Cooperation (AMCI) and the National Institute for

Agronomic Research (INRA). The project was signed and came into effect on the 12th February

2015, with an agreed duration of four (4) years built on eight (8) work-packages 

 

The global objectives of the project are timely as agricultural practices carried out in the

Commonwealth of Dominica are based on low to medium input farming systems but with an

ever increasing demand for phosphorus (P) nutrition in particular as is the case in many tropical

developing countries where phosphorus deficiency is severe. During the execution of this

project, it is expected that farmers and extension agents will be better able to address the

challenges associated with soil fertility, including the use and management of fertilizers for

sustainable crop production.  However, with the long-term trend of minimal P use and the

seemingly glut of applied P fertilizers when compared to P removal in harvested produce; it is of

no surprise that there has been a gradual depletion of P in most Dominican agricultural soils.

The specific objectives of the project are very attractive and encouraging as it highlights the

importance of soil fertility management. 

In addition, the project alludes to

the re-classification of soil types based on international norms such as the world reference base

2

(FAO, 1988, 1998; SSS, 2003; FAO, 2006) 

A concerted effort has been made with regards to reviewing and

analyzing existing soil studies conducted locally. Information looking at geological, land use

and soil data sets have been assembled and synthesized with the overall project objective of

updating, upgrading and completing existing soil and land use maps (see 6.0 Geophysical

description of the Dominican environment and general characterization of soil types).

Work-package 2 captioned as soil fertility assessment and mapping points to the need to

explore the determinants of soil fertility management practices. The activity attempts to obtain a

measure of soil fertility parameters in relation to crop nutrition and fertilization of dominant

cropping systems, in addition to designing a GIS tool for soil fertility information, and preparing

soil fertility maps for major and micro-elements. The activity highlights the need for soil

sampling based on a grid system using global positioning system from surface soil, assumed to

be a 0-20 cm soil horizon, but should ideally include a 20-40 cm soil horizon and possibly a 40-

60 cm soil horizon which undoubtedly will reflect the financial cost of soil sampling and

analytical testing. Furthermore, the activity points to a detailed scale, assumed to be (1:50,000)

however as was reported by Lang et al., (1970) a soil map of Dominica which could show the

boundaries of every soil type would need to be at a scale of about 1:5000 and would take a great

deal of time to produce, variables which might be outside the immediate scope of this project.

According to Lang and co-workers, “the existing reconnaissance map made in 1961 is not

intended to give more than a fairly complete catalogue of the soils represented and their

approximate location”. Thus it has long been suggested that detailed soil mapping required for

land use planning be initiated at the ministerial and preferably at the divisional level.

 However,

the exercise should ideally address proper fertilizer management to include application and

placement methods (broadcasting versus band application versus sub-soil application), timing of

application, types of P fertilizers (e.g Triple Super Phosphate, Di-Ammonium Phosphate, Rock

Phosphate) and their sequence of application in combination with other soil amendments (e.g

low molecular weight organic acids, agricultural lime, compost and organic amendments, etc).

To this extent the relative agronomic effectiveness (RAE) to include residual effects and cost has

to be given attention with respect to mineralogy, chemical reactivity, rate of application and soil

factors which may be site specific requiring alternating management strategies. 

Work-package 4 captioned as the development of soil fertility information and expert system

for Dominica islands (GIS-Ferti-Car) calls for the development of an application “expert system”

that would provide opportunities for visualization, query and assistance in crop fertilization.

This element is highly desirous as all maps and data compiled in work package 1, 2 and 3 will be

included in the GIS platform.

Work-package 5 (training and human capacity building) and work-package 6 (technical

capacity building) identifies the need for intensive training programmes in various domains

pertaining to GIS and information-communication. Justifiably the project identifies the expertise

and capability of INRA providing additional training to gradually build competence. Due

consideration has to be given to the designation of a portfolio of communications specialist

within the overall project management team. Given the multi-tier structure of the target audience

the dissemination of information will need to be designed, developed and disseminated

accordingly.

The project expected outputs and outcomes primarily pivot on the development of a freely

accessible web-based soil information and expert system. Indeed the improvement in human and

technical capacities for knowledge expansion and performance development also advantageous.

Rightfully, the project has

identified that in order to plan but moreover to execute the activities, it is necessary to have indepth understanding of the production systems, soil types and soil classification. More

importantly it is necessary to understand the level of competence with regards to instrumentation

and scientific facilities, technical skills and human capacities; and the level of information

technology.

In conclusion, the soil fertility and mapping exercise represents a very important and timely

exercise for the Commonwealth of Dominica. This exercise examines the influence of soil

properties in order to obtain an improved comprehension of soil fertility limitations with the goal

of developing nutrient management and farm developmental strategies geared towards increased

crop production and overall farm productivity. In this regard special attention must be paid to

low cost input systems. This is particularly relevant given the agrarian base of the economy

characterized by low native soil status coupled with low application rates of mineral fertilizers

owed to the low purchasing power on the international market as is evident in the long term

trends of increase prices for nitrogenous and phosphate fertilizers. Hence this project needs to

critically understand how native nutrient stocks as well as applied fertilizer can potentially

become more plant available thus reducing fertilizer applications to a required minimum.

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