Pakistan is an agriculture-based country and agriculture has a main role in the economy of the country. Soil is the key factor for the agricultural production and is a living entity, so it should be treated as a living. We must take care of those things which are necessary for soil health; soil organic matter (SOM) is one of them.
Soil organic matter is any material produced originally by living organisms (plant or animal) that is returned to the soil and goes through the decomposition process. It contain mainly three components i.e. small fresh plant residues (5-10 per cent), living soil organisms (10-40) and decomposed organic matter known as humus (40-60 per cent). It affects both the physical and chemical properties of soil. Physical properties of soil such as bulk density, porosity, texture and structure are improved with the increment of organic matter. Likewise, chemical properties of soil such as pH, electric conductivity (EC), cation exchange capacity (CEC), sodium absorption ratio (SAR), anion exchange capacity (AEC), exchangeable sodium ratio (ESR) and hydraulic conductivity are also effecting by the presence of organic matter.
Pakistani soils are very deficit of SOM. Most of the regions of Pakistan are scared with the SOM. The soil of upper districts of Punjab i.e. Sialkot, Gujranwala, Gujrat, etc. contain medium amount of SOM. In Sindh and Baluchistan soils are poor in organic matter. Reduction of organic matter in Pakistani soil is due to many reasons like environmental factors such as temperature, rainfall, and humidity are main reasons. The decomposition of organic matter is more in warm and humid climate. As Pakistan has warm humid climate so more the decomposition of organic matter and more it will attributed toward loss. Extensive tillage can also cause the reduction in organic matter by exposing more organic material to air causing more decomposition of organic material ends with loss of SOM.
Intensive cropping system is also reason for low SOM. Mostly exhaustive crops are sown in field which has more nutrient requirement, no return to soil.
Unfortunately Pakistani farmers cant pay attention to the farmyard manure (FMY), a big natural source of organic matter in soil; handling of FMY manure especially of animal dung is very poor. Annually 50 per cent of dung is lost due to improper handling and also due to its consumption as fresh cake. Most of our farmers depend only upon inorganic source of fertilizers, which enhances the productivity but lower down the soil consistency and soil health; also disturbing the nature which is very harmful for both human and animal health causing global warming. Due to above mention reasons SOM is low in Pakistani soils.
Different strategies may be adopted depending upon our climatic and soil condition with aims that to improve biomass production to build soil organic matter. First of all it must be clear that there is huge difference between soil organic materials and soil organic matter. Plant and animal residues which we incorporate in the soil are not organic matter rather they are organic material. Now we discuss different type of material which improves the SOM. FMY, Poultry manure, Crop residues, green manure, filter cake, slaughter house waste, biogas compost and silage are the material which enhances the organic matter in the soil. Among these FYM is most important and most common practice in Pakistan. Proper handling of farmyard manure will also increase the nutrient availability.
Crop rotation will also be use to enhance the productivity of soil in such a manner that after exhaustive crop there must be restorative crop for the maintenance of nutrient level in the soil. Addition of green manure (i.e. alfalfa, guara, berseam and sunhump, etc) crops in crop rotation also will be profitable in sense of increase biomass ultimately increase organic matter. Growing of cover crops is also beneficial in improving SOM and soil health. They maintain the soil temperature, add plant material, prevent erosion, provide habitat for beneficial insect and protect the soil microorganisms.
Reduced tillage practices will also favor activities of microbes. We should move toward minimum tillage, zero tillage and no tillage to save our soil, to improve health of our soil; with aims that mechanical disturbance of soil should be avoided as much as possible. Balanced fertilization encourages growth of crops; result in more production of biomass and also enhance the activity of microbes. In general greater productions of green manure or crop biomass greater will the microbial and beneficial microorganism population. Increase in microbial activity also enhances the production of SOM.
All these practices aimed increase soil organic matter in Pakistani soils; which increase the fertility status of soil. When our soil is healthy, contain more nutrients, it result in improved crop productivity.