The effects of pre-planting methods on yield and yield components of rice in Isfahan.

Manual transplanting is one of the most difficult operations, which currently has a very high contribution in labor costs of rice production. Mechanized transplanting of rice in Isfahan province is not widely practiced due to improper bed preparation equipment and method. In this study three bed preparation method including puddling with rotary tiller, puddling with a locally made rigidshank field cultivator and soil compaction using a heavy construction roller were compared for three local cultivars of Lengan rice (Sazandegi, Zayanderoud and Line No. 2) in two sites (Fozveh and Zarrin-shahr). The comparison were made using randomized complete block design with three replications where the bed preparation method was the main factor and the sub factor was different cultivars. In Fozveh site bed preparation method resulted in significant differences in grain yield, number of grains per panicle, plant height, number of tiller per hill, heading and complete maturity, water requirement and percentage of plant lodging (p0.05). Differences were also significant (p0.05) between cultivars in terms of number of panicles per square meter, number of grains per panicle, 1000-grain weight and number of tillers per hill. Interactions of method × cultivars influenced significantly (p0.05) on number of panicles per square meter, number of grains per panicle, number of tillers per hill, recovery percentage, heading and lodging. In Zarrin-shahr site the results showed significant differences (p0.05) between bed preparation methods in grain yield, number of grains per panicle, plant height, number of unfilled grains, number of tillers per hill, heading and complete maturity, water requirement and lodging. There were significant differences (p0.05) between cultivars in terms of number of panicles per square meter, number of grain per panicle, 1000-grain weight and number of unfilled grain. Also interactions of method × cultivars influenced significantly (p0.05) on grain yield, number of grain per panicle and plant height. In this site grain yield of Sazandegi was higher than the others. According to results of this study in both sites, in plots prepared by soil compaction water requirements, lodging, plant growth period were significantly lower than puddling methods. Time of seedlings establishment however, were longer than puddling methods. In addition, grain yield seems to be highly affected by soil texture. Therefore, soil compaction can be recommended especially in loamy soils as an alternative bed preparation management that can be gradually substituted to puddling the soil destructive conventional method of the Isfahan region.