Biomass and Rootstock Quality of Guava (Psidium guajava L.) Saline Water Irrigated under Nitrogen Fertilization

Evandro M Da Silva,Hans R Gheyi,Thiago A Pimenta,Jutahy J Elias,Reginaldo G Nobre,Leandro De P Souza,Joicy L Barbosa,Geovani S De Lima

doi:10.5539/jas.v9n11p162

Abstract

The increase in N concentration in the root zone of plants under saline conditions can inhibit the absorption of chloride and reduce the osmotic, toxic and nutritional effects caused by this ion. Thus, this study aimed to evaluate biomass and rootstock quality of guava. cv. Paluma irrigated with saline water under four N rates. The experiment was carried out in a greenhouse at the Center of Science and Agri-food Technology of the Federal University of Campina Grande (UFCG) at Pombal-PB, Brazil. The experimental design was randomized block with a 5 × 4 factorial arrangement. The treatments were levels of electrical conductivity of water - ECw (0.3. 1.1. 1.9. 2.7 and 3.5 dS m-1), with 70, 100, 130 and 160% of the N rate recommended for guava seedlings (541, 773, 1004.9 and 1236.8 mg N dm-3 of soil) and four replicates totaling 80 plots, each one with five plants. Salt stress caused by electrical conductivity of irrigation water of 1.4 dS m-1 onwards affected negatively the formation of phytomass of guava cv. Paluma rootstock, and this effect was mitigated on root dry matter and Dickson quality index by the increase in nitrogen rate up to 819.38 mg of N dm-3 of soil.

Highlights

The common guava (Psidium guajava L.) is a species over all the subtropical and tropical regions worldwide, due to its easy adaptation to different edaphoclimatic conditions
A randomized block design was used with a 5 × 4 factorial arrangement of treatments: 1) salinity of irrigation water, with five levels of electrical conductivity (ECw): 0.3, 1.1, 1.9, 2.7 and 3.5 dS m-1; 2) four N rates: 70, 100, 130 and 160% of the N rates recommended for production of guava seedlings (541, 773, 1004.9 and 1236.8 mg N dm-3), in four blocks (80 plots total), each one with five plants
There was quadratic response of stem fresh matter (StFM) and stem dry matter (StDM) with the increase in salinity of the irrigation water at 190 days after emergence (DAE) and the highest values (2.98 and 1.25 g), were obtained at the ECw levels of 1.4 dS m-1 and 1.3 dS m-1, respectively (Figure 1A). This behavior may be related to the adaptation of the rootstock to the saline stress because, according to Flowers (2004), plants adapt or acquire tolerance to salinity when they are able to adjust the osmotic potential of the cells with that in the soil, or even maintaining high contents of K, Ca and NO3 and low contents of Na and Cl inside the tissues, especially in the leaves (Dias & Blanco, 2010)

Summary

Introduction

The common guava (Psidium guajava L.) is a species over all the subtropical and tropical regions worldwide, due to its easy adaptation to different edaphoclimatic conditions. In the semiarid region of the Northeast, a large portion of the water used for irrigation comes from small and medium-sized reservoirs (superficial water) and wells (ground water), which have high salt content with an ECw between 1.97 and 2.98 dS m-1 (Medeiros et al, 2003). The use of this water for irrigating crops, including guava, may compromise formation of seedlings and productive capacity (Cavalcante et al, 2007). In studies using saline water in irrigation, salinity negatively affected the production of guava seedlings of cultivars ‘Paluma’, ‘Ogawa’, ‘Rica’, ‘Pentecoste’, ‘Surubim’ and ‘IPA-B38’, reducing growth and phytomass accumulation in plant parts (Ferreira et al, 2001; Cavalcante et al, 2005; Gurgel et al, 2007; Cavalcante et al, 2010)

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