Influência da precipitação no rendimento agrícola do feijão (Phaseolus vulgaris L.) e algodão herbáceo (Gossypium hirsutum L.) em Campina Grande-PB.

Abstract

This study was conducted to determine the relationship between the agricultural yield of crops, beans and upland cotton, and the rainfall during the period 1994 to 2009, in Campina Grande - PB. Was analyzed the driest and the wettest years, also the most productive years and less productive for crops during the period analyzed. Was also verified the frequency of days with rain during the rainfall series. The use of the planted area was analyzed calculating the index of area yield (I.A.Y), through the ratio of the area planted and harvested area. Was also verified the frequency of days with rains during the rainfall series. With data from agricultural production and rainfall was possible to develop linear regression equations, with rainfall as the independent variable. Was used for this the Student t test, to verify the level of significance of the correlation coefficients between the yield of crops chosen and the rainfall. Was analyzed the correlations between the amount produced and agricultural yield of upland cotton and beans with the annual rainfall, as well as the correlation between agricultural yield bean and cotton with the rainfall occurring during the rainy season, in this case from April to August, and rainfall occurred in the months from March to September. So as the correlations between the crop yield of beans and upland cotton with the rainfall that occurred during the early planting and harvest of these crops. During this period, the highest rainfall occurred in 2000, being the year of 1998 which had low rainfall. The most productive year for beans was the wettest of the series (2000) and the least productive was the driest year (1998). The upland cotton had the most productive year in 1995, and the least productive was the year of 1999. It is important to remember that in 2003, doesn't planted upland cotton in Campina Grande - PB. In the wettest year (2000) was also the year with higher frequency of days with rain, getting the year 1999 as the year of lower frequency of days with rain. The index of area yield for bean had a utilization of 100% in the period from 1994 to 1997, from 2002 to 2003 and from 2005 to 2009. For the upland cotton the index of area yield had a utilization of 100%, in all years except in 1999, which had a utilization of 87.5%. The bean crop yield showed significant correlations with rainfall occurring in the periods considered in this study in Campina Grande - PB. The yield of the upland cotton didn't show significant correlation with rainfall occurred in the periods considered in this study. There was a higher increase in prices of bean from 2003 and of upland cotton in 2004.