دراسة تأثير الكثافة و دورية القطع و ارتفاعه في مؤشرات النمو و الإنتاجية لأشجار اللوسينا Leucaena leucocephala Lam.

الملخص EN

This study was conducted in the campus of Mosul university, Iraq to study the effect of planting spaces, cutting intervals and cutting heights upon the continuous range forage production from the forage leucaena stand of the second year growth.

The stand was planted since 2005 in six planting densities, on 1st April of 2006, the seedling was cut at two different height (25 and 50 cm) and from 1st May- 2006 cutting period operation have been started: six cutting operations during the growing season of cutting each months, three cutting operation for treatment of one cutting each two month, two cuttings operation for treatment of one cutting each three month and finally one cutting operation for treatment of one cutting each six months period.

The diameter of the seedlings was measured at height of 10 cm above the ground at the beginning and the end of the study to find out the diameter growth.

The quantitative and qualitative characteristic which has been studied for forage leucaena were: Dry matter production, Diameter growth, shoots growth heights, Branches number, Eaten part ratio, crude protein ratio, ash ratio, ratio of ether extracts, crude fibers ratio, dissolved carbohydrate ratio, phosphorous ratio, calcium ratio and potassium ratio).

The experimental design was done according to split plot in the space and time using factorial RCBD and the means compared using Duncan test.

The results showed that the first season surpassed over second seasons in most of the characteristics that have been studied.

planting space (0.5X0.5 m) recorded the highest dry matter production and it reached (8.72 t/ha), highest ratio of Eaten Part ratio (70.02%), highest ratio of crude protein (10.65%) and lowest ratio of crude fiber (32.54%).

The cutting interval for six months gave the highest dry matter yield (10.5 t/ha) and highest shoots growth height (220.21cm).

while the cutting period for one month gave less dry matter yield (3.88 T/ha).

The cutting height (50 cm) gave higher yield of dry matter (7.21 t/ha).

With respect to the interaction between seasons and planting space, the first season with 0.5X0.5m planting space gave highest yield of dry matter (12.04 t/ ha) and highest ratio of crude protein (11.48%) and lowest ratio of crude fibers (28.99%).

The first season with the cutting of six months period gave highest yield of dry matter (14.59 t/ha) and lowest ratio of crude protein (7.48%).

With respect to the interaction between planting spacing, cutting heights and seasons, the plant space (0.5X0.5 m) with cutting period of six months at the first season gave the highest yield of dry matter (24.18 t/ha) and also planting space at 0.25X0.75 m with cutting period of one month during first season gave the highest crude protein ratio which reached (15.12%) and lowest ratio of fibers (23.16%).

Plant spacing of 0.5X0.5 with cutting highest 50 cm during the first season gave the highest yield of dry matter (13.27 T/ha) and with highest ratio of crude protein (13.52%) and lowest ratio of fiber (28.21%).