The recent heavy rainfall and flooding events in NSW may cause some immediate damage to trees, but may also have significant long term impacts on citrus orchards, particularly those planted on heavy soils or those with impeded drainage.
Soil aeration is considered the third most important factor affecting soil fertility (after water and nutrient availability). The main reasons for poor soil aeration are slow drainage, excessive precipitation or irrigation, or a sealing soil cover. Shallow groundwater impedes drainage by reducing the downwardly hydraulic gradient, which consequently increases the water content of the soil in the root zone, thus limiting soil aeration. In this study, we examined the effects of different parameters (e.g., soil texture, depth of groundwater table) on the severity of oxygen deficiency in the root zone of a mature Valencia orange (Citrus sinensis) grove planted above shallow groundwater. In addition, we examined the effect of the O2 stress level on tree growth, yield, and fruit quality. We also evaluated the effects of air injection and of irrigation intensity on tree growth, yield, fruit quality, and O2 concentration in the soil’s air, and looked into the (technical and economic) feasibility of air injection into the soil.
Current market trends of higher income group consumers include a desire for information related to the products they buy, such as its origin, safety, and social responsibility of the producer. Organically grown fruits seem to be favoured over conventionally produced fruit. Organic production requirements affect all practices related to fruit production including type of fertilisers used, pest and disease control as well as post-harvest chemicals used.