Challenges and Opportunities in Fertilizer Placement in No-Till Farming Systems

Abstract

No-till (NT) farming systems are now widespread and are part of Conservation Agriculture. The adoption of any new system brings consequences, and NT means changes in fertilizer practices to realise the potential of improved soil conditions. Less soil mixing results in the vertical stratification of immobile nutrients and banded, deep placement of fertilizers away from the seeding rows is a common approach to address stratification. Lateral stratification will require adjustments to soil sampling strategies and soil test interpretations. Nitrogen dynamics also alter where crop residues are retained, requiring a review of the source, rate, time, and placement of fertilizers Wider seeding rows and higher fertilizer rates present an increased risk of fertilizer damage in the seed row. Banding nutrients away from the seed row with improved machinery design and selecting fertilizers with low damage potential are options to manage the risk of damage. A significant challenge to NT is to manage soil acidity, given the relatively low mobility of lime. Consideration of interventions with strategic tillage have been proposed to address lime incorporation as well as alleviate nutrient stratification, although the guidelines for the application of these strategies are still developing.