The Nepali Himalaya constitutes a threatened ecosystem and cultivation of marginal lands; livestock grazing and loss of depletion of biomass cover effect its dynamism. Nepal’s ecological sensitiveness, fragility and other disturbances further aggravate the scale and dimensions of land degradation. The consequences of such disturbances have been severe.

Desertification is basically a land degradation process. It expands from small patches and progresses to huge areas exhibiting desert like environment. It is caused by unsustainable human use of land resources such as overgrazing, over-cultivation, poor irrigation and deforestation. In general, desertification is associated with a sequence of interactive processes resulting in the loss of vegetation cover. Land productivity is taken as an indicator of the measure of the degree of desertification.

Desertification problem is mainly associated with deforestation. Forest is declining both in quality and quantity due to increasing human population. Deforestation in the extremely fragile hill slopes has led to degeneration of the watershed with the loss of surface cover, upsetting the hydrological cycle, drying up of perennial flows, increasing flash floods and sedimentation, loss of water supply and farm production.

There has been continuous migration of people from the hills and mountains to the Terai. The forest areas have been encroached on in search of more cultivable land for resettlement purposes. Overgrazing of the livestock has resulted in desert-like environment through the expansion of bare soil surface. As the topsoil becomes eroded the associated organic matter and plant nutrients are being lost, and as a result, soil fertility and land productivity decline. The results from various experiments carried out for measuring soil loss have shown that tremendous amount of fertile topsoil is eroded from the hill slopes each year.

Acidification carried out by pesticides and the continuous application of compost of pine needles in mountainous areas, alkalinity, siltation, and flooding are also major causes of increasing land degradation in Nepal.

Due to lack of long period as well as inconsistent climatic/agro meteorological data set, it is difficult to correlate and bring about the conclusion of the impact of climatic uncertainties on the desertification process. But, it is seen that crop yield is decreasing generally throughout hilly and mountainous regions especially in the western and far western region of Nepal.

A result of all the land degradation factors has slowly led to desertification in Nepal. A research indicates the loss of vegetation cover accelerates erosion and soil nutrients leading

to the loss of agricultural production. About one-third of the total area in Nepal exhibits the characteristics of cold desert and about 10,000 sq km of the total area is estimated to be progressing towards desertification.

Nepal has to prepare and implement a National Action Programme to combat desertification. Desertification is a long-term and long-lasting phenomenon. While the initiative to combat desertification has been in a positive direction, there is certainly a long way to go to arrest the trend completely, as the efforts should be stepped up.