Articles
Understanding nitrogen cycling in an irrigated deciduous permanent crop
Article number
1253_28
Pages
207 – 212
Language
English
Abstract
Recent advances in our understanding of nitrogen (N) cycling in deciduous permanent crops is the result of a decade of research in California on almond (Prunus dulcis). Planted on over 538,000 ha with N fertilizer rates averaging 300+ kg N ha‑1 year‑1 incremental increases in the N use efficiency (NUE) greatly reduces environmental impacts on air and water quality.
The purpose of this review is 1) to outline the different components of N cycling in deciduous permanent crops consisting of crop supply and demand and, soil N transformations and losses and; 2) to integrate grower and experiment based plant, soil, water and grower N research in California almond over the decade starting in 2008. Patterns of N uptake in almond are determined by whole-tree and spur level dynamics and growth and development of fruit, leaves and woody biomass.
Fertilization practices to maximize NUE require careful fertigation scheduling to match applications with plant demand.
Fertilizer injection toward the end of irrigation leads to fewer N losses below root zone while use of low concentration nitrate (NO3‑) fertilizers delivered in high frequency doses reduces nitrous oxide (N2O) production.
Overall, N2O emissions from almonds in California are lower compared to other global agricultural commodities.
Progress toward building soil organic matter is ongoing with adoption of organic matter amendments (OMA). Despite the concern for impacting short-term nutrient availability, efforts to build soil organic matter demonstrate a commitment to investing in long-term soil fertility.
Challenges in understanding N cycling in deciduous permanent crops still remain including year-to-year yield variability, the role of organic N inputs in building soil organic matter over longer periods, a lack of information connecting N fertilizer and irrigation practices, and barriers to adoption of N management practices.
The purpose of this review is 1) to outline the different components of N cycling in deciduous permanent crops consisting of crop supply and demand and, soil N transformations and losses and; 2) to integrate grower and experiment based plant, soil, water and grower N research in California almond over the decade starting in 2008. Patterns of N uptake in almond are determined by whole-tree and spur level dynamics and growth and development of fruit, leaves and woody biomass.
Fertilization practices to maximize NUE require careful fertigation scheduling to match applications with plant demand.
Fertilizer injection toward the end of irrigation leads to fewer N losses below root zone while use of low concentration nitrate (NO3‑) fertilizers delivered in high frequency doses reduces nitrous oxide (N2O) production.
Overall, N2O emissions from almonds in California are lower compared to other global agricultural commodities.
Progress toward building soil organic matter is ongoing with adoption of organic matter amendments (OMA). Despite the concern for impacting short-term nutrient availability, efforts to build soil organic matter demonstrate a commitment to investing in long-term soil fertility.
Challenges in understanding N cycling in deciduous permanent crops still remain including year-to-year yield variability, the role of organic N inputs in building soil organic matter over longer periods, a lack of information connecting N fertilizer and irrigation practices, and barriers to adoption of N management practices.
Authors
S.D.S. Khalsa, P.H. Brown
Keywords
nitrogen, N budgets, tree allocation, N losses, organic matter, almond, California
Online Articles (60)