Review on nutrient management, cycles, flows and balances in different farming systems

Soil fertility management is continuously modified and adapted as conditions change in time and integrated plant nutrient management is a holistic approach to optimizing plant nutrient supply for the objective of adequately nourish the crop as efficiently as possible, while minimizing potentially adverse impacts to the environment Existence of life depends on continuous cycling of nutrients from the nutrient pool (in the abiotic component of environment) to the living beings and then back to the nutrient pool. These complex series of invisible, delicately balanced, and interrelated biochemical reactions fuel life on earth. Nutrients cycles have been substantially altered by human activities mainly agriculture with large positive and negative consequences for a range of ecosystem services and for human well-being and The presence of animals into the agricultural production system can modify the rates and flows of nutrient dynamics between the compartments of the system and Integrated crop-livestock systems can positively change the biophysical and socio-economic dynamics of farming systems, reestablishing sustainable rural development and promoting higher overall farm profitability. Soil nutrient balances reflect the net change in soil fertility and indicate trends in time, but do not necessarily determine the current state of soil fertility yet; soil nutrient balances can differ considerably between different crops, farming systems and agro-ecological zones.