Effect of Agricultural Management on Kiwifruit Nutritional Plant Status, Fruit Quality and Yield

Kiwifruit (Actinidia deliciosa) is intensively cultivated in Spain, mainly under conventional agricultural management (CONV). However, integrated (INT) and organic (ORG) systems have been recently introduced in order to decrease the negative environmental impacts associated with CONV practices. Here, we investigated the effects of three management systems (CONV, INT and ORG) on the nutrient allocation in kiwifruit orchards by measuring the content of potassium (K), calcium (Ca), magnesium (Mg) and boron (B) in soils, leaves and fruits to assess the overall soil and plant nutritional status, fruit quality and yield. Soil, leaves and fruit samples were collected monthly. Results showed that the greatest effective cation exchange capacity (ECEC) and the lowest Ca: Mg ratio were found in the soils from the CONV management. In contrast, the highest K: Mg ratio was found in the INT soils. Both ratios can be related to Ca2+ and Mg2+ absorption problems by kiwifruit plants. Foliar macronutrient disorders were not detected; however, deficient B concentrations were measured in those plants growing under INT and CONV systems, which were likely to decrease fruit yields. ORG kiwifruits showed higher Ca2+, K+, P and B concentrations than those under INT and CONV practices and had better quality (higher Ca: P index). Finally, more marketable fruits were produced under ORG managements. Our results illustrate that a well-balanced soil nutritional status is essential for reducing plant nutritional deficiencies and promoting fruit quality and yield. The low-external input ORG systems provided these suitable conditions and a better nutritive value of the kiwifruits produced.