Removal of Salts by Atriplex Nummularia Depending on Soil Moisture

Removal of salts by Atriplex nummularia depending on soil moisture

Edivan Rodrigues de Souza A, Maria Betânia Galvão dos Santos Freire B, Heitor Henrique Félix Duarte C and Fernando José Freire B

AUniversidade Federal Rural de Pernambuco, Rua Dom Manoel de Medeiros, Recife, Pernambuco, Brasil. CEP. 52171-900. student on a scholarship - CNPq/CTHidro, E-mail [email protected] BUniversidade Federal Rural de Pernambuco, Rua Dom Manoel de Medeiros, Recife, Pernambuco, Brasil. CEP. 52171-900, E-mails [email protected], [email protected] CUniversidade Federal Rural de Pernambuco, Rua Dom Manoel de Medeiros, Recife, Pernambuco, Brasil. CEP. 52171-900. student on a scholarship - PIBIC/CNPq, E-mail [email protected]

Abstract The degradation of soils by the salinity and sodicity has been an important subject in the handling and use of soils, and its reclamation contributes with the improvement of the productivity and sustainability of the environments. Studying the phytoremediation of salt- affected soils with Atriplex nummularia , this study aims to determine the extraction of salts by plants grown in saline-sodic soil under conditions of water stress. The experiment was conducted in a greenhouse for 134 days cultivating Atriplex nummularia in pots containing 20 kg of saline-sodic soil at four moisture levels (35, 55, 75 and 95% of field capacity) , designed on blocks with eight replications, collecting plant and dividing it into leaf, stem and roots to determine the extraction of salts. The values of extraction of sodium by leaves + stem were 251.63, 277.84, 394,92 and 440,36 kg/ha 134 days -1 to 35, 55, 75 and 95% of FC respectively. Removal of Ca, Mg, Na, K and Cl by leaf + stem were 644.25, 757.81, 1058.55 and 1182.00 kg/ha at 35; 55; 75 and 95% of field capacity, making it an alternative for the phytoremediation of salt-affected soils in the semi-arid region of Brazil.

Key Words Phytoextraction, salt-affected soils , halophytes, field capacity.

Introduction Salinity and the sodicity are among the main causes of degradation of the soil in semi-arid environments, because they damage soil properties, plant development and the society, which culminates in serious social and environmental impacts. Recovery of these soils contributes to the improvement of productivity and sustainability of the ecosystems. Reclamation practices and efficient handling should be adopted, since these soils are a valuable resource for agriculture and cannot be neglected (Qadir et al. 2007). The use of halophyte vegetation is based on phytoextraction, that is a phytoremediation technique that uses species of plants that absorb and accumulate the sodium in the shoot, which can be removed and used for other purposes. Qadir et al. (2007) claim that the phytoextraction is an efficient strategy of recovery of saline-sodic soils, with performance comparable to the use of alleviation chemical. One of the factors that should influence the extraction of salts by plants is soil moisture, by increasing the vegetative growth and, consequently, the absorption of salts. This work determined the extraction of elements by Atriplex nummularia grown on saline-sodic soil under conditions of water stress (35, 55, 75 and 95% of field capacity ).

Methods The experiment was carried out in a greenhouse. We used sodic-saline soil collected from 0-30 cm depth, dried in air, homogenized and passed through a sieve of 4 mm before filling the pots. For physical and chemical characterization a -2mm subsample had 229 g/kg of coarse sand, 363 g/kg of fine sand, 327 g/kg of silt and 81 g/kg of clay, with soil bulk density of 1,40 kg/dm 3 ; soil pH(1:2,5) = 8,66; pH of the saturation extract = 7,45; electrical conductivity (EC) of the saturation extract = 42,56 dS/m; Exchangeable Na + = 3,31 cmol c/kg; cation exchange capacity = 4,69 cmol c/kg; exchangeable sodium percentage = 71,20%. Polyethylene pots were used with capacity of 20 kg of dry soil. Seedlings of Atriplex nummularia were used of 120 days age. The soil had a field capacity of 0.152 g/g. Pots were maintained at four moisture levels (35, 55, 75 and 95% FC). The treatments were disposed in randomized blocks with eight replications. The water used in the irrigation had EC of 0.75 dS/m. 134 days after the seedlings (DAS) the plants were collected and divided in leaf, stem and root, that were oven dried at 65 ºC for 48 h. The dried matter was ground subjected to nitricperchloric digestion to determine sodium, potassium, calcium, magnesium, zinc and copper. Chloride was determined by extraction in water and titration with silver nitrate (Malavolta et al. 1989). The results were analyzed through variance analysis and Tukey test (P < 0.05) using the Software SAEG 9.1 (UFV 2007).

© 2010 19 th World Congress of Soil Science, Soil Solutions for a Changing World 121 1 – 6 August 2010, Brisbane, Australia. Published on DVD. Results The dry matter of the leaves increased as a function of the soil moisture, with increment of 81% for the treatment with 95% of FC in relation to 35% FC, however, a decrease occued in the production of dry mass of stem and root for the soil at 95% FC, in relation to the treatment a 75% of FC (Figure 1).

30 Leaf

) 25 Stem -1 20 Root 15 10

Dry matter (g pl 5 0 30 50 70 90 110 FC (%)

Figure 1. Dry matter production of parts of Atriplex nummularia as a function of soil water content.

The production of dry matter of stem + leaves were 3978.93; 5228.35, 7639.82 and 6925.11 kg/ha for 35, 55, 75 and 95% of FC, respectively. This biomass can be used as forage (Masters et al. 2007). The element content varied among the parts of the plant, with prevalence of chloride and sodium in the leaf, stem and root, followed by potassium and then calcium and magnesium (Table 1).

Table 1. Leaf, stem and root chemical composition of Atriplex nummularia grown in saline sodic soil Element Leaf Stem Root Ca (g/kg) 5,24 1,55 3,40 Mg (g/kg) 6,13 1,13 2,50 Na (g/kg) 124,73 13,01 15,29 K (g/kg) 19,33 10,50 7,09 Cl (g/kg) 149,45 26,52 19,96 Cu (mg/kg ) 1,03 0,35 7,84 Zn (mg/kg ) 40,81 3,74 15,42

The leaf was the organ with the larger concentrations, especially for chloride and sodium, indicating the potentiality of use of the species in the phytoextraction of NaCl in soil-affected salts. The contents of Cu and Zn in the leaves were 1.03 and 40.81 mg/kg of dry matter respectively (Table 1). Norman et al. (2008) found values of Cu and Zn to leaves and small stems (< 3 mm) of Atriplex nummularia corresponding to 4.1 and 40 mg/kg of dry matter. Underwood and Suttle (1999) suggested that a diet for lambs should contain > 4 mg Cu/kg DM at highest rates of absorption and as much as 17 mg Cu kg DM -1 at lowest absorbability (Table 1).

The highest content of sodium and chlorine were removed by the leaves (Figure 2). The treatments 75 and 95% of FC removed more Na than for 35 and 55% FC. The contents of K were similar for the three fractions of the plant and there were not significant differences among the treatments, except for the stem. The same behavior of the sodium was observed for chlorine in the three analyzed fractions, with the largest content in the leaf, reaching 2.92 g/plant for the 95% FC treatment. The ratio of Na:K differed significantly among the treatments, that had larger values in relation to the stem and the root. The sodium removed by the stem + leaves were 251.63, 277.84, 394.92 and 440.36 kg/ha for 35, 55, 75 and 95% of FC. Leal et al. (2008), evaluating phytoremediation with Atriplex in the same soil type, cultivated in a greenhouse, found values similar of sodium content in the leaves to 130 DAS. In addition, Ravindram et al. (2007), evaluate the reclamation of a saline soil in India, verified that the halophyte species Saueda and Sesuvium portulacastrum removed 504 to 474 kg/ha of sodium chloride in four months, respectively. Considering removal of total Ca, Mg, Na, K and Cl by leaf + stem were found 644.25, 757.81, 1058.55 and 1182.00 kg/ha for 35; 55; 75 and 95% FC.

2,50 -1 ) 1,94 A )

-1 2,00 2,00 -1 2,00 1,37 B 1,50 1,50 1,24 B 1,00 1,50 1,00 0,50 0,20 A 0,22 A 0,32 A 0,24 A 1,00 0,50 Na stem (g pl 0,00 0,34 A

Na root (g pl (g root Na 0,50 0,28 A 0,19 A 0,28 A Na leaf (g pl 30 50 70 90 110 0,00 0,00 30 50 70 90 110 30 50 70 90 110

0,30 0,25 A 0,27 A 0,25 A 0,30 0,27 A 0,30 ) 0,24 A ) -1 0,25 0,25 ) 0,25 -1

0,20 AB -1 0,20 0,18 B 0,20 0,16 B 0,20 0,16 A 0,15 0,15 0,15 0,13 A 0,10 0,11 A 0,10 A 0,10 0,10

K leaf (g pl 0,05 K root (g pl 0,00 K stem (g pl 0,05 0,05 0,00 0,00 30 50 70 90 110 30 50 70 90 110 30 50 70 90 110

0,30 0,30 0,30 ) ) ) -1

0,25 -1

-1 0,25 0,25 0,20 0,20 0,20 0,15 0,15 0,15 0,0879 A 0,0864 A 0,0514 B 0,0632 B 0,10 0,10 0,045 B 0,081 A 0,069 AB 0,10 0,0182 C 0,0295 BC 0,0420 A 0,0417 AB 0,044 B

Ca stem (g pl 0,05

Ca leaf (g pl 0,05 0,05 Ca root ( g pl 0,00 0,00 0,00 30 50 70 90 110 30 50 70 90 110 30 50 70 90 110 0,30 0,30 ) 0,30 ) ) -1 -1 0,25 0,25 -1 0,25 0,20 0,20 0,20 0,15 0,15 0,0725 A 0,0993 B 0,0978 B 0,15 0,10 0,0632 A 0,10 0,10 0,035 B 0,071 A 0,0144 B 0,0215 AB 0,0285 A 0,05 0,05 0,0283 A 0,034 B 0,058 A Mg Mg stem(g pl Mg leaf (g pl 0,00 Mg root (g pl 0,05 0,00 0,00 30 50 70 90 110 30 50 70 90 110 30 50 70 90 110

) 3,00 2,92 A 3,00 3,00 -1 2,33 B ) 2,50 2,50 -1 2,50 2,00 1,34 C 1,64 C 2,00 2,00 1,50 1,50 1,50 1,00 1,00 0,67 A 0,64 A 1,00 0,55 A 0,50 0,36 B 0,47 AB 0,26 B 0,31 B 0,37 A Cl root (g pl Cl leaf (g pl 0,00 0,50 0,50 Cl Cl stem (g pl-1) 0,00 0,00 30 50 70 90 110 30 50 70 90 110 30 50 70 90 110 FC (%) FC (%) FC (%) Figure 2. Sodium, potassium, calcium, magnesium and chlorine content in leaf, stem and root of Atriplex nummularia grown at salt-affect soil in Pernambuco (Brazil). Medium follow by same letter are no different by Tukey’s test at 5% probability.

Conclusion The production of dry matter by the leaf, stem and root was sensitive to soil moisture; The values of extraction of sodium by leaf + stem were 251.63, 277.84, 394,92 and 440,36 kg/ha 134 days -1 to 35, 55, 75 and 95% of FC respectively. Considering the removal of total Ca, Mg, Na, K and Cl by leaf + stem were found 644.25, 757.81, 1058.55 and 1182.00 kg/ha for 35; 55; 75 and 95% of field capacity.

References Leal IG, Accioly AMA, Nascimento CWA, Freire MBGS, Montenegro AAA, Ferreira FL (2008) Fitorremediação de solo salino sódico por Atriplex nummularia e gesso de jazida. Revista Brasileira de Ciência do Solo 32 , 1065-1072. Malavolta E, Vitti G, Oliveira AS (1989) ‘Avaliação do estado nutricional das plantas: princípios e aplicações’. (Piracicaba: POTAFOS). Masters D, Benes S, Norman H (2007) Biosaline agriculture for forage and livestock production. Agricultual Ecosystem Environmental 119, 234–248. Norman HC, Masters DG, Wilmot MG, Rintoul AJ (2008) Effect of supplementation with grain, hay or straw on the performance of Weaner Merino sheep grazing old man (A triplex nummularia ) or river (A triplex Amnicola ) saltbush. Grass and forage science 63, 179-192. Qadir M, Oster JD, Schubert S, Noble AD, Sahrawat KL (2007) Phytoremediation of sodic and saline-sodic soils. Advances in Agronomy 96, 197-247. Ravindram KC, Venkatesan K, Balakrishnan NV, Chellappan KP, Balasubramanian T (2007) Restoration of saline land by halophytes for Indian soils. Soil Biology & Biochemistry 39, 2661-2664. Underwood EJ, Suttle NF (1999) ‘The mineral nutrition of livestock, 3rd ed’. (CAB International: New York). Universidade Federal de Viçosa–UFV (2007) SAEG 9.1: Sistema de Análises Estatísticas. Viçosa, MG: Fundação Arthur Bernardes (CD-ROM) © 2010 19 th World Congress of Soil Science, Soil Solutions for a Changing World 123 1 – 6 August 2010, Brisbane, Australia. Published on DVD.