Integrated soil nutrient management envisaging supply of all the essential plant nutrients in balanced proportions using manures, fertilisers and biofertilisers would not be sufficient today for improving and sustaining soil fertility and health.
Can be effective
It is important for farmers to remember that integrated practices could prove to be effective only if the soil texture is loamy or at least clayey loam or sandy loam besides being nonsaline with the soil reaction in the neutral range of pH 6.5 to 7.5 or at least between 6.0 and 8.0 and the organic matter status not lower than 2 per cent.
Even if all the essential plant nutrients are supplied in sufficient amounts and desirable proportions, the bioavailability of these nutrients in balanced proportions for absorption by the crops depends upon the physical, chemical and biological properties of the soil.
So, the overall soil environment must be taken care of, to ensure better performance of the crops.
Most of our arable soils are not loamy in texture, being either sandy or clayey. Excessive drainage accompanied by the loss of nutrients through leaching and low water-holding and nutrient-holding capacities are the major problems of sandy soils limiting plant growth.
Poor drainage accompanied by anaerobic conditions and hard pan formation in the subsoil zone are the major problems of heavy clayey soils.
They must be improved towards loamy texture through soil breeding technology, salinity must be reduced in some soils to alleviate the physiological drought and to ease the absorption of water and nutrients by the plant roots.
Optimal level
Soil acidity and alkalinity must be reclaimed and the pH must be maintained in the range of 6.5 to 7.5 so that the availability of nutrients will be optimal.
Scope for extending the area for agriculture is limited due to diversion of more lands every year for non-agricultural purposes. However, our country has a number of hybrids and good growing varieties of all crops readily available at all ICAR institutes.
So, the only possible scope to maximize crop production with the available varieties is hybrids of crops, efficient water management and plant protection measures.
(K. Kumaraswamy, former Professor of soil science & Agrl. Chemistry, TNAU Coimbatore,email: email: kkkswamy9@yahoo.co.in, mobile: 94436 52332)
