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Watermelon (Citrullus Lanatus) is one of the major irrigated vegetables in the Jordan Valley. Watermelon production has increased in the last few years with the introduction of trickle irrigation and plastic mulching, especially in the highlands. In this experiment it is intended to study the effects of different plastic mulching on crop water use and on yields of watermelon. Soil temperature data was also collected in an attempt to study its fluctuation and degree of change under different mulching. Also studied were the root density and distribution. Results indicate significant differences in water applied and in yields between treatments. Highest yield (average = 55.3 MT/HA) was obtained under transparent mulch and with average total water supply of 44.3 cm. Whereas under black mulch an average yield of 13.3 MT/HA was obtained although 40.1 cm total water was applied. Under no mulch, only 10.4 MT/HA was obtained with a highest total water supply of 51.2 cm. Root distribution and density did not show any significant differences. Soil temperature under mulched treatments were higher than those non‐mulched. Heat units determined showed no big difference between transparent and black mulched treatments.

Improving the soil environment for seedling emergence and plant growth is possible using a good tillage system. From March 1993 until June 1994, the effect of tillage system and plant residue incorporation practices on the bulk density and the soil strength of the surface layer of a vertisol (very fine, smectitic, thermic, chromic Haploxerert), on a less than 1 % slope, was investigated. The two tillage methods were moldboard (T1) and chisel (T2). The two plant residue incorporation dates were in August (R1) and in October (R2). Results indicated that R1 gave significantly higher bulk density than R2, while the different tillage treatments had no significant effect. Soil strength was significantly lower under T1 and R2 than under the other treatments.