Parametrização do método de irrigação por sulcos no vale do Açu-RN.

Abstract

The main purpose of this present work was the improvement of a research study about furrow irrigation method i n Vale do Açu-RN, with the objective to achieve basic data to efficient lanagement of the irrigation. Fieldworks were developed on average texture latosols i n Production and Experimentation Physical Base, of -the Empresa de Pesquisa Agropecuária do Rio Grande do Norte- EMPARN, i n Ipanguaçú-RN. Fieldtests were conduted i n 100 m lenght furrows with average of 0,29 percent. Advance's equations were established based on f l o w o f 1,52 l/s obtáined by formula qmax= S , where and equal to 0,613 and - 0,733, respctively. For this flow, furrows showed a moderated erosion. Besides, they were realized for flows of 1,45 and 1,70 l / s . For the first flow, furrows didh't show any erosion along of themselves, whereas for the second it was well evident. Advance's equations and acumulated water intake, determined with a flow of 1,45 l / s , were L= 10,62 T0,86 D= 4,78 T°'5 7(mm), o respectively. The moestening strip reached by lateral water intake with the action of a furrow. obtáined an average width of 76 cm, after 70 minutes of irrigation . The method"s survery was done odedying the metodology suggested by Bernado (1982) , for 50, 75, 100 and 125 m furrows lenght; valnes of R- varying from 1 up t o 4 and flow reduction from 1,45 to 1,0 l/s ' and 0,75 l / s, respctively. The results analysis showed that the r e a l nomerosive maximun flow f o r a slope of 0,29 percent was 1,45 l / s ; the most efficient flow reduction•was from 1,45 to 1,0 l / s to whatever value of R; furrows of 100 and 125 m lenght were recommended with a médium watêr application efficiency of 75%.