Building resilience: future directions in mineral nutrition of woody perennial crops

The concept of system resilience has gained prominence in describing adaptation to a multitude of stresses associated with climate change. Resilience and resistance are terms borrowed from ecology describing how multi-organism systems respond to change, but our ability to describe agricultural production systems in this way is still quite limited. Agricultural systems need to respond to the abiotic stresses associated with seasonal weather extremes (e.g., heat, drought), long term shifts in regional crop suitability and the biotic stresses associated with enhanced pressure from new and existing pests. Access to land and water may become limited and the need for intensified food production increase which traditionally has increased inputs of plant nutrients. However, the reduction of agriculture’s environmental footprint in order to maintain market access, may force different strategies to cope with change. Improved understanding of nutrient dynamics and management under stress and in practices introduced to cope with stress such as protected cultivation, deficit irrigation and amendments to improve soil C, soil health and soil biodiversity will be required. Precision management of nutrient and water inputs attempts to match temporal variability in the demand for plant nutrients and water and spatial variability imposed by soil and landscape. Temporal variation in inputs can be managed though fertigation, irrigation scheduling and foliar nutrient applications. Our understanding of spatial variability may be aided by crop and soil sensing techniques, but remediation is challenging in perennial systems. New sensor technology could determine fruit nutrient content and fruit maturity and be used to manage nutrient management, fruit harvest and storage quality. Other potential solutions include building resistance to stress through genetic enhancement of plant materials, particularly rootstocks. Emphasising traits such as Ca accumulation in apple scions may reduce the need for remedial measures. However, there may be trade-offs among beneficial practices. For example, fertigation and irrigation scheduling (temporal precision) which reduce leaching, may have negative effects on greenhouse gas emissions and may be compromised by asynchrony of plant nutrient supply/demand when organic amendments (soil health and biodiversity) are used. The methodology to examine these trade-offs may include system life cycle analysis and/or environmental goods and services assessment.