COVER FEATURE
Soil Properties Mapping System for Fertiliser Management
By Ezrin Mohd Husin Aimrun Wayayok Hasfalina Che Man
SMART Farming Technology Research Center Faculty of Engineering , Universiti Putra Malaysia
COVER FEATURE
The macronutrients , nitrogen ( N ), phosphorus ( P ), and potassium ( K ) are pivotal constituents in agriculture , forming the foundation of nearly all fertilisers . Assessing the presence of NPK fertilisers in agricultural fields is indispensable for optimising fertiliser application rates in accordance with crop requirements .
Traditionally , soil nutrient measurements relied solely on chemical analyses conducted in laboratory settings . However , implementing a precision fertilisation regimen necessitates intricate and resource-intensive laboratory assessments , rendering the sampling and evaluation of soil samples across vast expanses of farmland physically impractical and financially burdensome [ 1 ]. Consequently , fertiliser application has historically been tailored on a hectare scale or larger . Although fertiliser is typically broadcasted uniformly throughout a field , it is well-established that soil fertility exhibits significant spatial variability . Notably , elevated concentrations of fertiliser in soil correspond to heightened nutrient uptake by plants [ 2 ]. Prior investigations underscore the imperative of discerning fertiliser content to facilitate precise application at optimal locations and during critical growth stages , thereby advancing best management practices [ 3 ]. Consequently , the development of expeditious soil nutrient measurement tools such as on-the-go devices is imperative for effective crop field management .
Numerous researchers have documented the development and elucidation of on-the-go soil measurement devices and soil sampling methodologies [ 4 ], [ 5 ], [ 6 ], [ 7 ], [ 8 ], [ 9 ], [ 10 ]. Notably , the advent of technologies such as the soil electrical conductivity sensor ( ECa sensor ) has garnered attention for its reliability in characterising field conditions and nitrogen content [ 10 ]. Designed for real-time measurement of soil properties , the sensor is a pragmatic tool for mapping diverse soil attributes due to its capacity for rapid measurement at predefined locations .
The apparent Electrical Conductivity ( ECa ) of soil is influenced by various soil characteristics including soil water content , clay content , salinity , temperature , organic compounds , and metallic elements [ 11 ]. While certain soil factors affecting ECa remain relatively stable over time ( e . g ., clay content ), others may exhibit pronounced seasonal variations . Furthermore , investigations employing ECa sensors have explored their utility in establishing co-relations between rice yield and soil ECa , revealing a close association between ECa values and rice productivity [ 12 ].
The utilisation of apparent soil electrical conductivity sensors holds promise in delineating management zones characterised by varying
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