Effects Of Organic Manures And Urea On Soil Properties, Nutrient Uptake And Yield Of Amaranthus Cruentus In A Rainforest Ultisol In Nigeria

ABSTRACT

The withdrawal of fertilizer subsidy by the Federal Government in 1996 made mineral fertilizers scarce, expensive and beyond the reach of many farmers. Although mineral fertilizers ensure quick availability of nutrients to crops, its continuous application aggravates soil acidity, nutrient imbalance, and loss of organic matter, leading to reduced nutrient uptake (Ojeniyi and Adeniyan, 1999). Arable soils of the tropics get degraded quickly in physical, chemical and biological qualities as a result of continuous cropping. Continuous cropping with persistent use of inorganic fertilizers increased soil acidity and physical degradation while crop yield may fall. Currently, farmers and scientists are showing renewed interest in proper and effective use of organic manure to get rid of wastes and to maintain soil fertility. Organic manure application improves the nutrient status 6f soils, increases the level of organic matter in the soil nd gives high residual effects on soil fertility. The role played by organic manure in soil fertility maintenance notwithstanding, the increasing awareness by consumers in western and tropical countries on illnesses such as diabetics, hypertension, cancer and obesity associated with consumption of food produced with chemical fertilizers, has shifted their focus to safe eating habits by consuming food crops produced with organic fertilizers (MoyinJesu, 2007). The acceptance of a crop can be influenced by the type and source of nutrients used in its production (Hodges, 1982). Generally, in developed countries, a kilogram of vegetable produced using organic fertilizer attracts higher prices than the same quantity produced using inorganic fertilizers because it is believed that the former is devoid of synthetic chemicals