Pepper N Uptake: Preliminary Field Study

One of the challenging aspects of growing pepper is the lack of empirical information on nutrient uptake.  To adequately manage the crop nutritional needs, growers rely on soil monitoring and crop and plant tissue analyses.  This is especially true for nitrogen (N).  However, as the regulatory environment gets tighter, there is an increasing need to better understand N uptake and partitioning in the plant The main objective of this first year trial was to investigate the nutrient uptake by pepper crops. Eight fields were included representing bell and jalapeno peppers, in the central coast of California.  The cooperating growers contributed their management practices and provided logistical support.  We selected and replicated plots in each field.  Plots consisted of five linear feet.  Based on row configuration, the sample population comprised either 5 or 10 plants.   Sampling consisted of collecting mature pepper pods, weighing and counting them, and  then categorizing as marketable or reject. At the last harvest, we also harvested the above-ground plant part.  Fruit and plant materials were separated, chopped, dried, and submitted for NPK analyses, to the University of California ANR laboratory.  In addition, we composite soil samples from each plots at the 0–8 and 10–16 inch-depths and submitted them for NPK analyses. Plot production ranged between 24–40 tons/acre for jalapenos and 34–56 tons/acre for bells.  Dry matter (DM) production was similar for both types of crops (2.6–2.7 tons/acre). Nitrogen content of above ground biomass varied between 224 and 240  pounds/acre for bells and jalapenos, respectively.  Bell pepper and jalapeno fruit also took up about 270 pounds/acre of K and around 30–33 pounds/acre of phosphorus.  In comparison with fertilizer applications, NP and K uptake was 72%, 48%,  and 100% of these applied nutrients. Additional work is planned to further validate the data presented here.