Understanding the Soil Rhizosphere System

Tom Miles

Understanding the Soil Rhizosphere System
Food & Fertilizer Technology Center, 2006-12-01

Sustainable Management of the Soil Rhizosphere System

Methods for the sustainable management of the soil rhizosphere system for efficient crop production and fertilizer use clearly fall into three distinct ways and methods: a) cultural management/practices; b) efficient nutrient application/fertilizer management; and c) use of organic fertilizers and bio-fertilizers.

Cultural management/practices. As presented during the workshop, one practice that can be used in sandy soil with coarse texture and low organic matter content, low water holding capacity and low cation exchange capacity, is sub-soiling treatment for better crop growth. Field experiments employing perennial forage crops with deeper root systems also demonstrated land productivity improvement.

Root distribution and cropping system of rice (Oryza sativa L.) play a significant role in sustainable rhizosphere management. Subsurface irrigation systems can be adopted to improve soil characteristics and rice root distribution, in relation to the physical properties of the soil and fertilization practices. Application of organic sources into paddy soil can also be beneficial in improving the root distribution in the subsoil layer and in magnifying the soil rhizosphere.

Efficient nutrient application/fertilizer management. Over application of chemical fertilizer can result in considerable decreases of micro-organism population and friendly insects, crop susceptibility to disease attack, acidification or alkalization of the soil or aggravation of soil physical properties, and pollution of water resources through leaching causing irreparable damage to the overall system.

Hence, designing sustainable management practices that focus on rhizosphere soil is more efficient and cost-effective for improving crop productivity with lesser agrochemical inputs. One of the more promising practices is the innovative Starter Solution Technology (SST), which reduces fertilizer application, increases vegetable yields, decreases fertilizer residues in the soil, and is simple to apply. Other practices for managing the fertility of rhizosphere soil include supplying nutrients through drip irrigation, applying organic fertilizers and biocharcoals to increase soil-buffering capacity, and localized amendment as strategies for problem soils. All of the proposed management practices can be easily adopted by Asian farmers.