Estimation of fertilizer requirements of the country    

   Due to the importance of fertilizer inputs in increasing crop and orchard production on the one hand and preventing the excessive and unbalanced use of these fertilizers which increases production costs and environmental hazards, The Soil and Water Research Institute estimates annually the fertilizer requirements of country by province-product on the order of Deputies of Agronomic and Horticultural Affairs of the Ministry of Agriculture-Jahad.

Introduction

   Soil is substrate for the main producer and supplier of plant nutritional needs. The use of chemical, organic and biological fertilizers with respect to environmental and crop health, in order to maintain soil fertility and timely supply of plant nutritional needs in different stages of growth is essential, because of the limitation of arable land and the need to increase production per unit area. Therefore, to organize the management of timely preparation and distribution of fertilizer inputs in the range of climates and agricultural lands of the country and in terms of integrated management of soil fertility and plant nutrition to achieve sustainable soil fertility and crop production, calculation and estimation the fertilizer requirements of the country has a special priority and importance for different crops in each province.

The model used to estimate the fertilizer requirements of country

  There are several models for estimation the fertilizer requirements. One of the most accurate of these models is the Plant-based Model. Fertilizer estimation in the plant-based model requires having sufficient and accurate information about the rate of production of each crop, expected yield, the plant requirement for different nutrients according to the expected yield, climate and soil condition in terms of storage and nutrients supply.

   The required Principles for this estimation based on the forecast of crop area, expected yield of different crops in each province, dynamic bank of physical and chemical properties of soils that is collected from different parts of the country and includes more than forty thousand samples and is updated every two years, taking into account the different climates of the country, using the integrated soil fertility and plant nutrition recommendation guidelines and utilization of selected experts in field of soil fertility and plant nutrition in each of the products and with the priority approach of using domestically produced fertilizer inputs

Estimating Software Program for the country's fertilizer requirements

   The modeling software was used for estimation the fertilizer requirements in terms of four factors: crop area, expected yield, soil fertility (nutrients status) and fertilizer recommendation per hectare by crops and orchards in each province in accordance with the relevant climate after design in Microsoft Excel program.

   Attempts to model plant-based fertilizer estimates in Excel program began in 2004. The Estimating Software Program was upgraded while specifying the factors involved in the calculations and the variation range in each province with the participation of soil fertility experts and specialists across the country in 2006.

   In 2016, the latest information on integrated management of soil fertility and plant nutrition guidelines was entered into the Software Program.

   At present, this program is able to estimate the kinds of chemical fertilizers including macro, and micronutrients, organic fertilizers and stimulants and biofertilizers separately for each crop and orchard products by province in the shortest possible time and only by updating the input data.