Land Degradation & Conservation

Land is the most valuable asset blessed by nature and is prime resource for survival of mankind. Demand for land is ever increasing for agriculture, forestry, housing, industrial growth and communications.  Human and animal population is rising but per capita productive land base is declining. Over exploitation, improper and unscientific management of this natural resource is leading to its severer degradation. This resource is degraded due to soil erosion, salinity/alkalinity, water logging, depleting under ground water, deforestation, removal of natural vegetation, frequent use of heavy machinery, overgrazing, improper crop rotation and poor irrigation practices. Natural disasters, including droughts and floods also contribute in the process of land degradation.

Land degradation may be physical, chemical and biological in nature. Each of these types has different processes responsible for decline in land quality and productivity. Physical degradation results in deterioration in the physical properties of soils. It includes compaction and hard setting of soils due to dispersion of soil aggregates. Reduction in organic matter results in poor aggregation and lower water holding capacity in the soil. Chemical degradation is due to nutrient depletion, excessive leaching, build up of some toxic elements and elemental imbalance. Reduction in organic matter, decline in biomass, decrease in microbial activities and diversity of soil fauna are ramifications of biological land degradation. 

In India out of the total geographical area of 329 million hectares, over 150 million-hectares area is suffering from different kinds of degradation such as erosion, salinity and alkalinity and water logging. Wind and water erosion alone contribute 83% of total degraded area (Source: Punjab State Land Use Board). Similarly Intensive agriculture is posing a serious problem for sustainable agriculture production in the Punjab. Over exploitation of soil and water resources has led to the problem of soil degradation and declining water table in the large areas of Punjab. Punjab has 0.25 hectare of  per capita availability of land. Out of total land area of 5036000 hectare, 228840 hectare (4.54% of Total area) is suffering from different kinds soil problems (Source: Punjab State Land Use Board). The detail of area under different categories of degraded soils in Punjab are given in the pie chart below: -

                                                       Source: Punjab State Land Use Board.

When land is degraded, wildlife, plants and people suffer. Degradation of land has serious consequences for food security. Many small-scale farmers in areas of degraded land can only watch in dismay as their soil grows less each year to feed their families. The state of Punjab is one of the most advanced agrarian states in India. Nearly 84% of total geographical area of the state is cultivated and any further increase in the area may only be possible by reclaiming various categories of degraded lands which have been rendered as wastelands. The major area in Punjab barring Siwalik hills forms part of Indo-Gangetic alluvial plain. Low lying pockets in the alluvial plain of Punjab are having the problem of water logging, soils salinity and/or alkalinity etc.  

Thus, conservation of land resources needs to be taken on priority to support the livelihood of rural people and remain self sufficient in food requirement of the country.  It is not easy to restore the productivity of the degraded soils, as steps to restore productivity are as complex as the process of soil degradation. Extremely degraded soils are difficult to be restored but these can be rehabilitated through alternative land uses. Light to moderate process can be checked and production potential of soils can be restored through scientific land management practices.

Some of the ways to restore productivity of degraded soil are given below:-

Alternative land Use
Introduction of forestry species or fruit species in place of raising of traditional field crops or intercropping tress with field crops have proved to be helpful in restoring productivity of soils and increasing profit of farmers. Eco friendly systems based on the use of nitrogen fixing tress such as leucaena leucocephala (subabul) has potential to bring about favourable changes in soil properties by promoting soil conservation.  Perennial plants have capacity to grow under unfavorable conditions. Fast growing tree species like Eucalyptus  are used effectively for bio drainage in waterlogged soils. Prosopis Juliflora, Terminalia arjuna(arjan) and Albizzia lebbek (Siris), Acacia nilotica (Kikar/Babul) and Eucalyptus tereticornis (safeda) have proved more useful in management of alkali soils. These tress have the capacity to reduce soil pH and salt content by increasing organic matter, nitrogen, phosphorus and potassium content.

Agroforestry System
Tree Species have ameliorative  capacity for land restoration. The plantation adds sufficient residues to soil, reduce run off and soil loss besides providing economic returns to the farmers. Multipurpose tree species can be introduced into agro forestry systems to regenerate soil health without any appreciable investments. Ameliorative capacity of trees can be utilized by mixed cropping of tress with crops: the common system is called agrofoerstry. For details, please click here

Intercropping System
Introduction of legumes through crop rotation, intercropping, mixed cropping or some other forms add leaf litter to soil for fertility and organic matter build up. Nitrogen content is also improved by biological nitrogen fixation. Growing of cluster bean in single growing period provides   around 8.00 and 8.67 q/ ha of residue through leaves and stalks, respectively containing 1.46% and 0.96% of nitrogen.

Recycling of crop residue
Degraded soils are inherently poor in fertility and crop production, therefore invariable respond to fertilizer application. Efficiency of inorganic fertilizers is often low and results in uneconomic return to the users. Upto fifty percent substitution of fertilizers nitrogen requirement by farmyard manure results almost similar yield as obtained with complete fertilizing. Application of FYM not only increased  N-use efficiency of urea but also improved the fertility status of soils. Crop residue cab be efficient source of nutrient substitution for FYM and compost. These residue can be left on the soil as mulch or can be incorporated the soil as `Green manure` for supplying nutrients and soil environment. For details about Green Manuring, please click here

It has been observed from hydrological studies that some model watersheds with suitable site specific soil and water conservation measures not only protected the land from degradation in watershed but also enhance the productivity. Keeping this in view a watershed area of 550 ha in southeastern part of Punjab in district patiala was selected for wasteland development under IWDP scheme funded by ministry of Rural development , Government of India.  

Source: Summarized from Punjab State Land Use Board, Newsletter Vol. 1 Nov, 2003