Desenvolvimento e produção do coqueiro sob diferentes salinidades de água de irrigação.

Abstract

The work was developed in the experimental field of Jiqui of the Company of Agricultural Research of Rio Grande of the Norte (EMPARN), located in the municipal district of Parnamirim-RN, tends as objective to study development and production of the coconut tree (Coconut nucifera L,), in initial phase, seeking use the saline waters in the irrigation for the Northeast area of Brazil. The treatments consisted of four levels of electric conductivity of the irrigation water - CEa (0,1, 5,0, 10,0 and 15,0 dS m"1) tested in the irrigation of the dwarf coconut tree (to cultivate midget-green of Jiqui) and in the evolution of the salinity of the soil. The adopted experimental design was it of blocks completely randomized with 4 treatments and 5 repetitions, contends 4 plants for repetition, in a total of 80 experimental plants in production beginning. The waters were prepared in boxes of water of 3.000 L with water (CE=0,1 dS m-1) coming of the pond of Jiqui using the salt NaCl. They were appraised the variable n° of leaves and emitted inflorescence, flower/inflorescence n°, n° of picked fruits, quality of the fruits (weigh, volume, °Brix, CE, pH and chemical composition of the coconut water) and salinity of the soil. The levels N3 and N4 of salinity of the irrigation water reduced the n° of leaves significantly for plant and the interval among emission to foliate it was increased with the increment of the irrigation salinity. The saline level of the irrigation water increased the interval of inflorescencia emission among the last three emissions (7th, 8th and 9th), with the larger medium interval for the T4. The saline treatments (T2, T3 and T4) they produced larger no. of flowers. The reduction provoked by the salinity in the production went due to reduction in the size and in the weight of the fruits and not to the reduction in its number, the productions obtained for all the salinity levels, went superiors to those of the cultivation of the coconut tree in sequeiro conditions, considering the four year-old age. With the increment of the salinity there were significant increase of °Brix, pH and CE of the coconut water. CI was the predominant component in the coconut water. The increase of the salinity of the irrigation water originated an increase in the electric conductivity of the saturation extract, with values varying from 0,37 to 5,39 dSm-1, for waters of 0,1 and 15,0 dS m"1, respectively.