Comparative Insights for Investigation of Soil Fertility Degradation in a Piedmont Area which Cover the Anjamkhor Union of Baliadangi Upazila, Thakurgoan, Bangladesh

Abstract

A comparative study of plant nutrient changes between the years 1991 to 2012 in the northeastern piedmont soils of Anjamkhor Union, Thakurgoan district, Bangladesh was done to determine soil fertility degradation status. Plant nutrient status was compared based on soil analytical data from soil survey program of the Soil Resource Development Institute (SRDI), Ministry of Agriculture, Bangladesh. This comparative study results revealed that soil fertility status was higher during the period 1990's. Afterwards, soil fertility status has been changed with time causing fertility decline. Soil acidity, organic matter content and some plant nutrients have been reached beyond their critical levels. Soil organic matter has increased by 1% from the years 1991 to 2012 but present OM status is still low and inadequate (mean 1.62%). During this period, soil acidity has become strongly acidic beyond a critical level causing acidity intrusion (mean pH 4.82). Soil phosphorus has been increased sharply in a very higher level (mean value 78.76 µg/gm). While the status of calcium has been decreased sharply (mean 0.30 meq/100 gm, 69% decline) but potassium (mean 0.29 meq/100 gm) and magnesium (mean 0.64 meq/100 gm) has been found to be increased. Sulphar was also found to be decreased sharply by 72% between years 1991 to 2012. Micronutrients zinc (64% decline) and boron (82% decline) has been almost depleted reaching their critical level during the time period 1991 to 2012, and are causing crop productivity and yield decline. These study findings are not comparable to within or between field variability of nutrients rather compared on the basis of landscape scale. But it is evident that soil fertility is declining in the study area under northeastern Piedmont soil of Bangladesh.