Soil profile water content in pepper crop production as affected by different weed infestation

Experiments were conducted to evaluate the soil water status and pepper water use efficiency under irrigated and rainfed conditions as affected by different weed infestation in a semiarid environment. The experiment was carried out in 2008 and 2009 in Southern Italy. Two water regimes were imposed to compare water competitive effects under irrigated and rainfed conditions. Weeds were studied within a naturally occurring weed population in a pepper field, where a rainfed treatment was compared to a full irrigated one corresponding to the restoration of 100% of the maximum crop evapotranspiration. Leaf water potential, soil water content, water use efficiency, maximum Leaf Area Index, dry matter and pepper yield were measured. Results revealed that all parameters differed significantly due to irrigated and rainfed treatments. Weed infestation reduced the pepper yield and interaction between irrigation regime with weed interference was highly significant. In 2008 weed-free pepper yield of irrigated treatment was equal to 36.5 t ha -1, while it was 43.4 t ha-1 in 2009. Lower yield was obtained in rainfed weedy treatment in both years, 0.2 and 0.5 t ha-1, respectively. In semiarid environment, different weed population had a great impact on pepper growth and yield, both in rainfed and irrigated conditions. Results showed that a weed-free agrosystem, especially in a drought condition, is necessary to maximize production and water use efficiency.