Effects of nitrogen, main-crop cutting height and planting time of berseem clover on yield and grain quality of ratoon rice and berseem intercropping

To study the effect of nitrogen application, cutting height of main crop and berseem clover intercropping time on quantitative and qualitative traits of ratoon and berseem, a split split plot experiment based on a randomized complete block design with three replications was performed during 2009-2010 and 2010-2011 cropping season. Three levels of N (0, 35 and 70 kg.ha-1), two planting times of berseem clover (simultaneous planting with main crop harvest and 40 days after harvest) and two cutting heights (10 and 40 cm) were considered as main, sub- and sub-sub- factors, respectively. Analysis of variance showed that the highest ratoon yield, days to 50% heading and harvest index were achieved to applying of 70 kg.ha-1 N and 10 cm cutting height, whereas the maximum of biological yield in both two years was obtained from 40 cm cutting height. The increasing of N fertilizer increased qualitative traits of ratoon grain including gelatinization temperature (GT) and protein content (PC), but amylose content (AC) and gel consistency (GC) were not significantly affected by the N content. The highest forage fresh and dry yield in both harvesting times of berseem clover were obtained by 35 kg.ha-1 N and 10 cm cutting height. The grain yield and qualitative traits of ratoon were not significantly influenced by planting time of berseem clover. The highest forage fresh and dry yield and fiber content was observed in first planting time of berseem clover. Results from this experiment showed that planting of berseem clover simultaneous with rice harvest specially with 10 cm cutting height and applying of N fertilizer as starter can be suitable to produce higher quality of ratoon grain and berseem clover forage in the studied region.