Growth response of Hydrangea macrophylla and Ilex crenata cultivars to low-phosphorus controlled-release fertilizers

Abstract

In containerized nursery-crop production, conventional phosphorus (P) fertilization amounts are reported to be in excess of plant needs which has resulted in poor P use efficiency (PUE) and subsequent P leaching from containers. Phosphorus leaching can be reduced and PUE improved without affecting plant growth by reducing P fertilization. The objective of this study was to identify the lowest controlled-release fertilizer (CRF)-P content and subsequent pour-through-extracted substrate pore-water P (PWP) concentration that produces maximal shoot growth of two common container-grown nursery crop species, Hydrangea macrophylla 'PIIHM-II' (hydrangea) and Ilex crenata 'Helleri' (holly), in a pine bark substrate. Hydrangea and holly liners were potted into 3.8-L containers containing a pine bark substrate and grown simultaneously in two different Virginia ecoregions, Middle Atlantic Coastal Plain (MACP) and Ridge and Valley (RV). Plants were fertilized with one of five CRF formulations, each containing equal nitrogen (N) and potassium (K) and 0.4%, 0.9%, 1.3%, 1.7% or 2.6% (control) P to supply containers with 0.1, 0.2, 0.3, 0.4 or 0.6 g P, respectively. In both ecoregions, hydrangea shoot dry weight (SDW) and growth index [i.e., (widest width + perpendicular width + height) ÷ 3, GI] values were maximal in plants fertilized with 0.3 to 0.4 g P or the control. The lowest CRF-P rate needed for maximal SDW and GI of holly was 0.2 g P at the RV site and 0.4 g P at the MACP site. Mean PWP concentrations that corresponded with highest SDW were as low as 0.8 and 1.2 mg L −1 for hydrangea and holly, respectively. Results from this research suggest hydrangea requires approximately half the P rate supplied by recommended rates of conventional CRFs. Since the growth response of holly to CRF-P rate at the MACP site was inconsistent with results observed at the RV site and findings in scientific literature, further research is needed to determine the minimum required CRF-P rate for this taxon.

Controlled‐release urea improved rice yields by providing nitrogen in synchrony with the nitrogen requirements of plants

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Decreasing Phosphorus Fertility to Reduce Sweetpotato Root Growth During Container-grown Transplant Production

“…and Ilex crenata (Thunb.) (Shreckhise et al 2019) and has led to questions regarding P fertility practices for many container-grown plants. In the final two weeks of the 6-week production cycle, symptoms associated with the plant becoming root-bound (Latimer 1991) resulted in an overall decline in transplant leaf color from 35.0 to 27.2 SPAD units accompanied with an average 48% decrease in shoot biomass.…”

Production Analysis, Minimum Cost, and Profit in Sentra Production of Rice and Corn Farming in Padang Pariaman

“…Increasing the accuracy of seeding is not possible without the knowledge of work principles (Kosti, Radomirovi, Savin, & Crnojevi, 2018). Excess nurseries on the amount of planting will reduce the efficiency of these seeds (Shreckhise, Owen, & Niemiera, 2019). In addition to the number and distance of seed quality, it should also be considered so that it has a good impact on agriculture (Sadowski & Baer-nawrocka, 2017).…”