Introduction

1. Loss of top soil due to erosion and landslide:

• Intensive cultivation of environmentally fragile lands, overgrazing, and deforestation have diminished vegetative cover on the hill slopes, thus reducing the water retention capacity and increasing run-off.
• That has led to the loss of top soil, soil nutrients of crop lands through erosion, and landslides affecting farmland, settlements and infrastructure in the hills.
• Changes in river behavior, leading to flooding, riverbank erosion and sedimentation in the terai, have caused the loss of farmland and irrigation infrastructure.

2. Depletion of organic matter:

• The organic matter content of Nepalese soils is very low.
• Low organic matter content of Nepalese soil is due to loss of organic matter through erosion, heavy use of chemical fertilizers in accessible areas, low application of organic manures in soil due to use cow dung as fuel, fodder plant as a fuel especially in terai region.
• These activities have led to organic matter depletion in soils which is a major soil fertility problem in Nepal.

3. Acidification:

• The pH of the average cultivated upland soil in Nepal is around 5.4, which does not limit the production of many agricultural crops (Land Resources Mapping Project, 1986).
• The decrease in acidity of the hill soils are due to leaching loss of calcium and magnesium cations through leaching, use of nitrogenous fertilizers, low organic matter addition in soil.

4. Unbalance and over/under use of chemical fertilizer:

• There are many instances where our farmer applies excessive/ low or imbalance use of chemical fertilizers. Improper timing and excess application of chemical fertilizers also causes wastage of resources as well as creates soil problems.

5. Unavailability of chemical fertilizers in time:

• Nepal does not produce any chemical fertilizer and is fully dependent on imports.
• The import of insufficient amount of fertilizer and untimely availability to the farmers are the major problem in nutrient management in Nepal.

6. Monocropping:

• The use of single crops (or species of crop) or no inclusion of legumes in the crop rotation is the major problem in maintain ace of soil fertility in Nepal. This has led to nutrient mining in soil.

7. Depletion of organic matter:

• The organic matter content of Nepalese soils is very low.
• Low organic matter content of Nepalese soil is due to loss of organic matter through erosion, heavy use of chemical fertilizers in accessible areas, low application of organic manures in soil due to use cow dung as fuel, fodder plant as a fuel especially in terai region.
• These activities have led to organic matter depletion in soils which is a major soil fertility problem in Nepal.

8. Emerging micronutrients problems in soils:

• Deficiency of micronutrients especially zinc, boron and molybdenum are increasing at different ecological belts at varying intensity (Karki et al., 2004).
• Zinc is a problem in the Terai belt on rice crop. Farmers are now applying zinc sulphate at a rate of 25 kg/ha without proper extension advice. In the hills where vegetables are being grown during off season and normal season, boron and molybdenum are deficient.
• There is lack of proper recommendation to farmers as well. The Agro-vets are supplying different kinds of products and their content and efficiency is not known in such circumstance farmers might have to bear financial loss.
• Some farmers apply these materials to every crop in succession; it may pose toxicity in the long run.