Sustainability of Organic Fertilization of Macadamia with Macadamia Husk–Manure Compost

Abstract

<jats:p>A fertilization experiment, started in 1989, evaluated the merits of macadamia husk-manure compost as fertilizer for the production of macadamia. Three fertilization treatments were compared at four sites over 4 years on the MacFarms of Hawaii Honomalino orchard. The treatments were conventional fertilization, a combination of solid and liquid mineral fertilizers annually adjusted by the orchard manager based on leaf and soil analysis; compost only as 5 tons of a macadamia husk-cattle manure compost applied annually between July and October; and compost plus supplemental mineral fertilizers deemed needed by the orchard manager based on leaf and soil analysis. In-shell nut and kernel yield and quality was not significantly different between treatments. Change in leaf nutrient values appears minimum except for slightly lower N at two sites for the compost treatment. Higher Mg was noted for the compost but not the compost plus treatments at the irrigated sites. The effect of compost on the soil nutrient levels was more distinct and may have a delayed and longer term effect. Total exchange capacity of the soil increased, as did soil pH, Ca, Mg, K, and Na. Organic matter increased only at the site with least soil. Extractable soil Fe decreased, this maybe related to the change in pH, but had no consistent effect on leaf Fe. Compost fertilization was not considered sustainable as the cost of compost and its application exceeded conventional fertilization.</jats:p>

Nutrient dynamics from surface‐applied organic matter amendments on no‐till orchard soil

“…Heavily cultivated landscapes with coarse‐textured soils in mild climates are at the highest risk for soil carbon (C) deficits (Angers et al, 2011). In many irrigated orchard crops, OMA sources have been shown to increase soil C storage (Bittenbender et al, 1998; Canali et al, 2004; Neilsen et al, 2014; Sanchez et al, 2003). Many different OMA sources are also capable of increasing soil extractable P (Neilsen et al, 2014; Preusch & Tworkoski, 2003) and K (Baldi et al, 2010; Bittenbender et al, 1998; Gülser et al, 2015) as well as improving cation exchange capacity (Cayuela et al, 2004; Arvanitoyannis & Kassaveti, 2007; Amiri & Fallahi, 2009; Miller et al, 2013; Villa et al, 2021) without increasing the risk of soil pollution from heavy metals (Baldi et al, 2021).…”

Grower Analysis of Organic Matter Amendments in California Orchards

“…Outreach efforts promoting OMA practices that demonstrate benefits while addressing solutions like composting offer a means to address the food safety barrier (Lubell et al, 2011). Greater concern by nonusers for cost and logistics may result from lack of practical experience or poor understanding the value of OMA, leading to exclusion from orchards (Bittenbender et al, 1998; Canali et al, 2004). In contrast, users showed greater concern for nutrient availability, perhaps due to a lack of validated strategies for orchards.…”

“…Organic matter amendments offer multiple benefits by providing a source of essential nutrients and a partial substitute for chemical fertilizer (Bittenbender et al, 1998; Mordoğan et al, 2013; Preusch and Tworkoski, 2003; Roosta and Mohammadi, 2013) while maintaining or improving yields (Amiri and Fallahi, 2009; Baldi et al, 2010; Forge et al, 2013; Sanchez et al, 2003) and improving soil health (Briones et al, 2011; Mathews et al, 2002; van Overbeek et al, 2010). Soils commonly used for orchard production can be at greater risk for carbon loss (Angers et al, 2011).…”

“…Soils commonly used for orchard production can be at greater risk for carbon loss (Angers et al, 2011). In orchard crops, an increase in soil carbon has been observed when applying OMA (Bittenbender et al, 1998; Canali et al, 2004; Neilsen et al, 2014) as well as increased infiltration and water holding capacity by reducing soil bulk density and compaction (Cayuela et al, 2004; Mujdeci, 2011; Peck et al, 2011; Walsh et al, 1996). These materials can also control weeds and nematodes and suppress disease during replant (Braun et al, 2010; Brown and Tworkoski, 2004; Sanchez et al, 2003; Stirling et al, 1995).…”

“…Composting is the most effective treatment to eliminate pathogens; however, the process increases cost and alters biological and chemical properties of the material (Adler and Sikora, 2003; Albiach et al, 2000; Miller et al, 2013). Cost and logistics associated with OMA transport and application also create a barrier to adoption (Bittenbender et al, 1998). Nutrient availability is an additional concern because supply of nutrients from OMA can be variable and the application of OMA can render other applied nutrients unavailable (Chalk et al, 2013; Fortuna et al, 2003; Sørensen, 2004).…”