Organic N Fertilizers and Irrigation Influence Organic Broccoli Production in Two Regions of California

Abstract

Abstract Nitrogen and water management are essential factors for achieving adequate crop growth and development in organic production systems. A three-year field study examined effects of different forms of organic N fertilizers applied at side-dress and with different irrigation application rates on leaf, stem, and floret yields, volumetric soil water content (P v), and crop water use efficiency (WUE) in organically-grown broccoli (Brassica oleracea L.) in two regions of California; Santa Cruz (UCSC farm) and Five Points (Harris farm). At preplant, ‘compost only’ treatment (CO) was applied at 140 kg·ha−1 of N with an additional 112 kg·ha−1 of N applied as side-dress in one of the following forms: (1) fish powder (FP); (2) Phytamin [bloodmeal and feathermeal mix (BF)]; (3) BF mixed with NaNO3 (SN), or (4) seabird guano (SG). Leaf, stem, and floret yields collected from the UCSC farm had a greater response to additional N from side-dressing treatments irrespective of the form than plants at the Harris farm...