SOIL MOISTURE TENSION AND FRUIT YIELD OF ITALIAN LEMON

Abstract

On the pressurized irrigation systems established on the citrus orchards in Tamaulipas, growers do not measure the soil water content for irrigation scheduling. Therefore, the objective of this research was to analyze the effect of different soil moisture tensions on fruit yield and size of the italian lemon (Citrus limon L). The field study was conducted from November 1999 to September 2001, in a seven year orchard of Italian lemon cv. Limonaria 8A located at Güemez, in Tamau lipas State, México. Treatments (T) were: initiate irrigation at 30 kPa (T1); 50 kPa (T2); 70 kPa (T3) of soil water tension measured at 0.3 m of soil depth respectively; and a control representing irrigation by the local producers, in which watering was based on visual symptoms of water stress (when the leaves began to wilt). The first harvest was in September 2000, and no statistical difference among treatments was observed in fruit yield, because the irrigation applied to the control resulted in a low soil water tension. However, fruit diameters of the 30 and 50 kPa treatments were larger (P ≤ 0.05) than the control, and the total irrigation depth applied was smaller than that applied to the other treatments, due to a more frequent watering of less irrigation depth. On the harvest made in the last week of August 2001, all treatments of soil moisture were higher (P ≤ 0.05) than the control. The highest fruit yield was registered in 30 kPa with 43.93 t ha^-1, while the yield of the control was 25.6 t ha^-1. Fruit size and content of soluble solids of the tension treatments were also higher(P ≤ 0.05) than the control. Again, total irrigation depth applied to the 30 kPa treatment was lower than the amounts applied to the other treatments, thus indicating a better water use efficiency by scheduling irrigation at 30 kPa of soil moisture tension.