Comparison of soil quality and nutrient budgets between organic and conventional kiwifruit orchards
Introduction
There is an increasing worldwide requirement for agricultural and horticultural produce not only to meet high standards of quality but also to be produced using environmentally sound practices. To this end, principles of sustainability and resilience have an increasingly important part to play in the drafting of economically viable production protocols. The increasing interest in organic production systems is in response to notions that they are inherently more sustainable (Condron et al., 2000) although evidence for this is scarce. The market premiums that organic produce can earn over their conventional counterparts can ensure economic viability in the face of generally lower overall production (Pacini et al., 2003, Reganold et al., 1993, Springett et al., 1994).
The New Zealand Agriculture Research Group on Sustainability (ARGOS) is seeking to identify pathways to improve sustainability for New Zealand agriculture. To this end, ARGOS is studying and comparing the economic, social and environmental consequences of differing farming systems. An important first question for ARGOS is whether certified organic systems do, in fact, perform differently from their conventional counterparts. Kiwifruit orchards are a small scale, highly intense system which represents an important export industry for New Zealand. Kiwifruit orchards are a woody and complex ecological landscape supporting a highly intensive form of agriculture, which contrast greatly with the other types of broad-acre livestock farming systems that ARGOS is studying. A major part of any comparison of resilience between production systems includes soil quality and whether commercially intensive systems are more damaging to soil's fertility and biological function than an arguably more “natural” organic system.
In this study, three long-term (>10 years) kiwifruit (Actinidia spp.) systems are compared. These are (i) conventional production of the green-fleshed variety, ‘Hayward’, (ii) organic production of ‘Hayward’ and (iii) conventional production of the newer, golden-fleshed kiwifruit variety, ‘Hort 16A’. The comparison included simple input/output nutrient budgets, extractable soil nutrient levels, soil physical properties, size and activity of the soil microbial biomass and earthworm numbers.
Section snippets
Site selection
Thirty-six orchards were selected and evenly divided between three groups: (i) conventionally managed ‘Hayward’ (Actinidia deliciosa), (ii) organically managed ‘Hayward’, and (iii) conventionally managed ‘Hort 16A’ (Actinidia chinensis). Conventional management follows a crop protection programme called “KiwiGreen” prescribed by the export company ZESPRI International Ltd. which provides a single point of entry into markets. It is based on integrated management principles and has emphasis on
Site and soils characterization
The Te Puke region, where 10 of the clusters were based, has average annual air and soil temperatures and rainfall of 14.0 °C, 14.3 °C and 1720 mm, respectively, a little lower than that for the Keri Keri region cluster (15.2 °C, 15.2 °C and 1750 mm, respectively). The Motueka cluster, being considerably further south, has significantly lower average annual air and soil temperatures but also lower annual rainfall (12.5 °C, 11.5 °C and 1420 mm, respectively).
Approximately 90% of soil textures for the
Production, nutrient levels and budgets
Differences in production levels between conventional and organic Hayward kiwifruit systems in this study, and indeed industry-wide, can largely be attributed to the use of hydrogen cyanamide, a plant growth regulator permitted on conventional, but not organic, orchards that significantly improves bud break and flowering. Nutritional differences may also play a part as Organic fruit are generally smaller than Green and Gold fruit, typically by ∼5% (Zespri International, 2008). The Hort 16A
Conclusions
Simple input/output nutrient budgets at the orchards in this study showed that nutrient inputs greatly exceeded removals in the harvested crop for all measured nutrients (i.e. N, P, S, K and Mg) in all three systems. Even taking into account potential fixation/immobilization by soil components, nutrient inputs seem excessive and there is potential to reduce them, especially in conventional systems where inorganic inputs are the norm. The sources used in Organic systems, however, are more slowly
Acknowledgements
We wish to thank Dr. Jeff Reid, Andrea Pearson and Duncan Hedderley of the Institute of Crop and Food Research who were instrumental in the setting the original design of the ARGOS program and its statistical analysis (D. Hedderley). We are grateful to the growers who allowed us access to their land and Lesley Hunt of Lincoln University for advice on statistical analysis. The study was funded by the New Zealand Foundation for Research, Science and Technology (FRST) through the Agricultural
References (35)
- et al.
Methods for Chemical Analysis of Soils
(1987) - Benge, J., 2006. Annual ARGOS Sector Report—Kiwifruit. The Agriculture Research Group On Sustainability (ARGOS), A1...
- et al.
Pairwise comparison of the storage potential of kiwifruit from organic and conventional production systems
N. Z. J. Crop Hort. Sci.
(2000) - BioGro NZ Ltd., 2001. Bio-Gro New Zealand Organic Standards Module 3.1. Standards for Evaluation of Inputs. Website:...
- Boyd, L., 2005. Review of kiwifruit mineral nutrition. HortResearch Client Report No. 16838 for ZESPRI International...
- et al.
Seasonal accumulation of mineral nutrients by kiwifruit 2
Fruit. New Phytol.
(1988) - et al.
A comparison of soil and environmental quality under organic and conventional farming systems in New Zealand
N. Z. J. Agric. Res.
(2000) - et al.
Proc. of the N.Z. Grass. Ass.
(1997) Soils
- et al.
Estimated annual removal of macronutrients in fruit and prunings from a kiwifruit orchard
N. Z. J. Agric. Res.
(1983)
Soil management concepts and carbon sequestration in cropland soils
Soil Till. Res.
Earthworm species, population size and biomass under different cropping systems across the Canterbury Plains, New Zealand
Appl. Soil Ecol.
Bulk density and linear extensibility
A review of the effect of N fertilizer type on gaseous emissions
Adv. Agron.
New Zealand Soil Classification
Microbial activity—the fumigation extraction method
Microbial activity—the fumigation extraction method for microbial biomass nitrogen
Cited by (43)
Potential geographical distribution of Actinidia spp. and its predominant indices under climate change
2022, Ecological InformaticsCitation Excerpt :Another study showed that 14 °C temperatures profited kiwi fruit growth (Carey et al., 2009). The annual precipitation experienced by kiwi fruit in New Zealand is much greater than that in China (Carey et al., 2009; Salinger and Kenny, 1995). In recent years, expert evaluation, the analytic hierarchy process (AHP), fuzzy mathematics theory, and GIS technology have been successfully utilized in ecological suitability assessment (Kaur et al., 2020; Zabihi et al., 2020).
Both organic and integrated pest management of apple orchards maintain soil health as compared to a semi-natural reference system
2022, Journal of Environmental ManagementCitation Excerpt :For other soil health metrics, differences among organic and conventional fruit cultivation systems remain less clear and seem to be highly context dependent. Several studies report that organic practices are associated with improved levels of soil organic matter, lower soil bulk densities, higher availability of N and P and improved biological soil properties in general (Carey et al., 2009; Di Prima et al., 2018; Reganold et al., 2001; Sanchez et al., 2003). However, other studies have found no significant difference between organic and conventional fruit farms (Glover et al., 2000; Orpet et al., 2020).
Earthworm communities in conventional and organic fruit orchards under two different climates
2019, Applied Soil EcologyOptimising survey effort to monitor environmental variables: A case study using New Zealand kiwifruit orchards
2016, Journal of Environmental ManagementCitation Excerpt :Also, a further approach to potentially increasing power would be to conduct more intensive sampling within each orchard at each survey. For the purposes of our analyses we assumed that the sector adopts established sampling protocols for environmental monitoring on kiwifruit orchards, as employed for the collection of the pilot data (Carey et al., 2009; MacLeod et al., 2012b) and only considers varying survey frequency and size. We do not explicitly investigate the effects of varying ‘within orchard’ effort, since such methodological changes would vary among the environmental variables monitored, and thus difficult to compare.