THE BACK bone of the most developing countries is considered as Agriculture. It contributes about 60-80 percent of GDP of a country. It is the basic source of foreign exchange for a country. Agriculture is not only the source of food for human beings but also a fodder source for animals. Most of the population in the whole world lives on diet based on one or more of the staple foods like, rice, wheat, maize, millet and sorghum etc. Wheat, rice and maize contributes about two-third of population. Therefore, the quality and quantity of these crops is basic concentration point for the farmers, scientists etc to feed the people of their countries.
The wheat is considered as a staple food of Pakistan. In Pakistan, the wheat yield is decreasing since 2002 due to different factors like lack of irrigation water, use of waste water which contain different heavy metals such as cadmium, lead, and mercury etc, which is toxic to plant growth and development. Cadmium reached in water and soil due to the natural activities like volcanic eruptions, different mining operations, smoking and different type of smelting operations.
Cadmium is a major environmental pollutant and it is considered as poison for plants and it is also harmful for human health when exceed from a certain level. If cadmium exceed from 200mg per kg in human body , then it have negative impact on kidney functioning, it causes the skeletal disorder and it also cause the problem in respiration process. While in plants, it causes the problem of intake nutrients and water through roots. It affects the plant organs and stops the mobilization of nutrients in soil and during grain filling, it causes the hormone imbalance, hence ultimately plant growth stopped and with the passage of time plant died.
Cadmium have inhibitory effects on plant growth like it suppress the germination of seed , it decrease the leaf area ratio, it causes the respiration problem in plant and specially photosynthesis rate decrease, hence yield also decreased. Hence, cadmium is considered the major problem of yield loss.
Silicon have positive effects towards the growth and development of a crop as it stops the accumulation of toxic substances specially cadmium accumulation is prohibited by silicon and ultimately it promotes hormones during grain filling and yield increases. It also makes plant resistant against diseases which is caused by bacteria, fungi etc. It provides the enzymatic balance which helps in the metabolism processes.
Plants mostly uptake the silicon mostly in the form of mono-silicic solutions. This form is very less mobile in plant and its concentration ranges from 0.1- 0.6mmol per liter in soil solution. Plants continuously uptake the silicon for their optimum growth and development at different growth stages.
Silicon is considered as the basic element for the plant growth and it can be applied in any form but mostly liquid form is preferred. Silicon can control the cadmium accumulation in crop plants. When it is applied in the soil, it increases the soil pH. As the pH of soil increased, the number of negative ions also increased in the soil which bound the cadmium. The cadmium becomes bound and no free for plant uptake. Silicon application also strengthen the roots of plant and roots becomes resistant against the uptake of Cd.
Cadmium is the toxic element which causes the decrease in the yield of crops especially in wheat plant. By using silicon as a fertilizer helps in the bounding of Cd and helps in the better production of a crop.