Impact of Management Systems on Soil Properties and Their Relationships to Kiwifruit Quality

Abstract

Crop quality depends on several factors, among which soil properties play a great role. The use of organic products as sources of plant nutrients to improve crop quality has been established. The use of biological nutrient sources to improve crop quality as well as improve soil physical, chemical, and biological properties could be a viable alternative to organic and/or conventional farming. However, there is little information available on how soil properties and kiwifruit quality are affected by the use of a biological farming system. Therefore, research was conducted with the objective of comparing the response of conventional, organic, and biological management systems on soil properties and kiwifruit quality in respect to Actinidia deliciosa (Hayward) and A. chinensis (Hort16A). Greatest soil bulk density and lowest gas phase, maximum water-holding capacity, gravitational drainage, and hygroscopic moisture were observed in Hayward in both biological and conventional management systems. The variations in soil properties for total pH, nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), and aluminium (Al) were linked to management practices, and electrical conductivity (EC), organic matter (OM), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), and boron (B) were linked to cultural species. The Ca/Mg ratio of these orchards was more than 7:1, and the Mg/K ratio was less than 2:1, indicating application of dolomitic limestone is recommended over high-Ca liming materials. The greatest yield, total soluble solids, and ionic strength were obtained in Hort16A from conventional management. Greater P, Ca, Fe, Zn, and Cu levels were recorded in organic Hayward than in other management systems. However, greater total N, K, Mg, S, Na, Mn, and B contents were observed in conventional Hort16A than in organic, biological, or conventional Hayward. The results of this study indicated that all macronutrients flux in Hort16A better than in Hayward. On the other hand, flux of micronutrients in Hayward was greater than in Hort16A. The cost/benefit ratio is the most favorable, that is, lowest, for organic Hayward on volcanic soils in the Bay of Plenty.