Organic Nitrogen : Mineralization

Contains brief overview of terms:

[caption id="" align="aligncenter" width="358"] Nitrogen Cycle (Source: Commons)[/caption]

Soil Fertility and Plant Nutrition

Essential Plant Nutrients and their Functions

The essential elements required for the plants for the continuation of their life cycle are the plant nutrients. The plant nutrients are defined in terms of its involvement in metabolic activities of the plants growth and development whose absence cannot be replenished by the other element. Broadly, 16 different elements play important role in the plants growth. Nitrogen (N), Phosphorous (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Sulfur (S) required in large amount by plants are called macronutrients. The other elements required comparatively in lesser amount are called micronutrients, which include Boron (B), Chlorine (Cl), Copper (Cu), Manganese (Mn), Molybdenum (Mo), and Zinc (Zn). Other elements such as Sodium, Silicon and Selenium are explained as beneficial elements due to their specific functions in the plants.

When the nutrient is deficient, the plant shows the deficient symptoms. The deficient nutrient can be toxic and may show the toxic symptom. Toxic symptoms are generally after luxury consumption in the plants.

Earthworms of Nepal: A Brief Information

Earthworms
Earthworms are the commonly found, tube-shaped, red-coloured worms belonging to Phylum Annelida (Latin: little rings) with about 150 segments. The segmentations of earthworms are presented with the setae which is responsible for locomotion. The digestive system of earthworm consists of mouth, esophagus with glands, gizzard for grinding and intestine for absorption. The circulatory system of earthworm is closed with mainly three vessels aortic arches, dorsal blood vessels, and ventral blood vessels. The respiration of earthworm is through skin; kept moist through mucous. Earthworms are hermaphrodite in nature, but requires mate to exchange their sperm. The earthworms can be epigenic (living in surface), endogenic (below 10-30 cm of soil), or anecic (living in permanent vertical burrows).(Earthworms - Penn Arts & Sciences)

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Photo Source: Commons

Soil Types of Nepal

Introduction

The topography of Nepal ranges from 60 to 8848 metre, which is generally classified into 'Terai' (plain land), 'Hilly', and the 'Himalayan' region. The difference in altitude has resulted in differences in climate, vegetation, and variety soil type as well. Furthermore, the formation and constituent of any soil is dependent on the parent materials.

The first soil survey in Nepal dates back to 1965 in Khajura Forest Area (Nepalgunj-Surkhet road) which continued annually up to 1995. The initial report of soil classification in Nepal was generated under Land Resource Mapping Project (LRMP, 1986) which was funded by Canadian International Development Agency (CIDA). It relied on the United States Department Of Agricultural System. The classification represented 14 soil groups and 4 soil orders; Entisols, Inceptisols, Mollisols, Alfisols (other orders: Spodosols, Histosols, Utisols, Aridisols in lesser occurrence).

However, the difficulties and unavailability of uniform methods in classification of soil are the probable reasons for the hindrance of detailed classification of soil in Nepal. Soil Science Division, Nepal Agricultural Research Council (NARC) has been able to conduct soil survey of Terai (20 districts, till 2015) and Hill districts (35 districts, till 2015) of Nepal. It has helped in the development of general inferential guide of soil of those districts.

Deficiency Symptoms in Leaves

Deficiency symptoms seen in old leaves: N, P, K, Mg, Mo

• with dead spots (K. Mo)


• no dead spots (N, P, Mg)

Soil : Glossary

Includes Soil Science Related Vocabulary: