Assessment of Relationship between Soil Organic Matter and Macronutrients,
Western Nepal

Dinesh Khadka
Page No. 4-12

Soil organic matter is an important soil chemical parameter influencing soil sustainability.
Revealing this factor, the study was conducted to determine relationship between soil organic
matter and total nitrogen, available phosphorus, extractable potassium, calcium and magnesium,
and available sulphur. The total 172 soil samples were collected from the three sites of western
region at 0-20 cm depth. The collected samples were analyzed by standard method in Soil Science
Division, Khumaltar. To compute the relationship between soil organic matter and the
macronutrients, simple linear correlation and regression were preformed. The result revealed soil
organic matter was significantly and positively correlated with primary nutrients namely; total N
(r=.73).), available P2O5 (r=.57) and extractable K2O (r=.35). While, there was significant
and negative correlation between with secondary nutrients as extractable Ca (r=.29), Mg
(r=.33) and available S (r=.19). In addition, with the increase on organic matter by one unit,
total N, available P2O5 and extractable K2O increases by 0.038, 31.19 and 5.92 units, respectively
and vice-versa. Whereas, extractable Ca, Mg and available S decreases by 87.75, 13.39 and 0.37
units, respectively and vice-versa. Therefore, maintenance of optimal soil organic matter is essential
to make macronutrients concentration balanced in western Nepal.
Key words: Correlation, Macronutrients, Regression, Soil organic matter.