A Study of the Effects of Various Press Wheels of Rangeland Sowing Machines on Salnfoin Germination and Growth Rate

Considering the importance of the country's rangelands in providing pasture for feeding domestic
animals as well as in protecting the soil, it is necessary to find concrete measures on the basis of
scientific findings and practical experience. Such measures can help the executive branch as well as
the users in better and more efficient use of these resources. It is equally important to utilize suitable
machines 'for mechanizing reclamation of impoverished rangelands. This will increase speed, accuracy
and efficiency as well as save time and cost.
For this purpose, proper selection of implement is essential. Among the machines used for pasture
reclamation are planters. Their proper utilization, particulary use of suitable press wheels is very
important due 'to the significant effects that compaction of the soil around the seed has on soil moisture
preservation as well as seed germination and growth. In this research, conducted as a split plot
experiment based on. a completely randomized block design in three replications, the effect of five
types of press wheels and two initial soil moisture contents(9.1% and 19.3%) on selected plant and soil parameters was studied. Soil texture was heavy clay-loam with some ,lime. Soil parameters under
study included moisture content and bulk density, measured at the following time stages after planting:
one week and two months, at 0-15 cm and 15-30 cm depths. Plant Parameters included: l)percent
germination of sainfoin 2) percent emergence, and 3)plant dry matter. Using analysis of variance and
Duncan's 'multiple range test for comparison of the means, it was determined that at both levels of
initial moisture content, using a press wheel on the .planter .is essential Furthermore, rubber wheels
were found to be superior to the metal ones. The lugged press ,wheel (type P3) performed better than
all the others. The regular rubber wheel (type P4 with out lugs) ranks next, having a significant
difference With P3 the moist, but not in the dry treatments. Therefore, due to lower production costs,
the regular rubber ,press wheel is recommended in dry soil conditions . Considering the parameters
measured in this study, press wheels PI (boat type), P2 (metallic with a groove), and P, (metallic
without groove) didn't exhibit suitable results.