Properirrigation systems essential for maximum soybean production and becomes even more important withideal land preparation system. A field study was conducted at the research farm of Rice Mechanization Center (RMC), Meet El-Deeba, Kafr El-Sheikh Governorate, Egypt during the summer seasons 2015 and 2016.The aim of the present research was to study the effect of sprinkler irrigation and land preparation systems on Soybean productivity.The sprinkler irrigation system was studiedatthree different distances between sprinklers;D1= 9m (50% diameter of throw ), D2= 10.8m (60% diameter of throw) and D3=14.5m (80% diameter of throw ) and three different values of applied water;60,80 and 100% from crop evapotranspiration (ETc).The land preparation systems were: LP1(Chiseling twice + leveling),LP2 (Chiseling one pass + rotary two passes + leveling) and LP3 (Moldboard one pass + rotary one pass + leveling).
The experimental results revealed that:
· LP3 treatment gave the least soil bulk density for three layers comparing with other land preparation systems. Also, it gave the average of lowest infiltration rate value (2 mm/h) that obtained after 110 min of infiltration time.
· The highest value of soil penetration resistance was 13.02 kg/cm2 which obtained at LP2treatment while the lowest value was 11.83 kg/cm2at LP3 treatment.
· Increasing distances between sprinklers from 9 to 14.5 m tended to decrease Christiansen uniformity coefficient (Cu) by 11.14% and distribution uniformity (Du) by 21.97%.
· The highest soybean yield value was 1650 kg/fed.that obtained at 100% ETc, D1 and LP3 treatment, while the lowest soybean yield value was 683 kg/fed. that obtained at 60% ETc, D3 and LP2 treatment. Soybean yield value was 1295 kg/fed.for traditional furrow irrigation (control treatment).
· Highest value of soil dehydrogenase was 20.4 mg g-1dry soil/96 h obtained at 100% ETc, D1 and LP2 treatment, while the lowest value was 6.28 mg g-1dry soil/96 h that obtained at 60% ETc, D3 and LP1 treatment.
The highest value of irrigation water use efficiency (IWUE)was 0.53 kg/m3obtained at 60% ETc, D1 and LP3 while the lowest value was 0.31 kg/m3obtained at 60% ETc,D3 and LP2.