Long-Term Impact of Phosphorous Fertilization on Yield and Alternate Bearing in Intensive Irrigated Olive Cultivation.

Amnon Haberman,Nerya Shtern,Ran Erel,Isaac Zipori,Alon Ben-Gal,Uri Yermiyahu,Arnon Dag

doi:10.3390/plants10091821

Abstract

Phosphorus (P) availability significantly impacts olive tree reproductive development and consequential fruit production. However, the importance of P fertilization in olive cultivation is not clear, and P application is usually recommended only after P deficiency is identified. In order to determine the long-term impacts of continuous P fertilization in intensive irrigated olive cultivation, the growth and production of trees in an intensive orchard with or without P fertilization were evaluated over six consecutive seasons. Withholding of P resulted in significant reduction in soil P quantity and availability. Under lower P availability, long-term fruit production was significantly impaired due to reduced flowering and fruit set. In addition, trees under conditions of low P were characterized by higher alternate bearing fluctuations. Olive tree vegetative growth was hardly affected by P fertilizer level. The impairment of tree productivity was evident in spite of the fact that leaf P content in the treatment without P fertilization did not decrease below commonly reported and accepted thresholds for P deficiency. This implies that the leaf P content sufficiency threshold for intensive olive orchards should be reconsidered. The results demonstrate the negative impact of insufficient P fertilization and signify the need for routine P fertilization in intensive olive cultivation.

Highlights

Phosphorus (P) is an essential plant macronutrient, participating in an array of plant functions [1,2]
In order to determine the long-term impacts of continuous P fertilization in intensive irrigated olive cultivation, we evaluated the growth and production of trees growing in an intensive orchard with or without P fertilization over six consecutive seasons
The rapid depletion of extractable P in the upper soil in the current experiment demonstrates that P availability can decrease significantly without fertilization, which is the common practice in many olive orchards [19]

Summary

Introduction

Phosphorus (P) is an essential plant macronutrient, participating in an array of plant functions [1,2]. Plants generally absorb orthophosphate through their roots from the soil solution. Most soils are rich in P, which can exist in both inorganic and organic form [3]. A small fraction of the soil inorganic P is available for plant uptake, and P release rates from soil minerals are generally too slow to meet the crop demand [3]. Most soil organic P is found in stable organic structures, making it hardly available for plant uptake [5]. Plants can accelerate organic P mineralization by releasing acidic phosphatases from roots and by affecting the rhizosphere chemical conditions, resulting in a higher release of inorganic P to the soil solution, where it becomes available for plant uptake [4,6]

Methods

Results

Discussion

Conclusion