This study was to evaluate the effect of organic amendments incorporation on soil properties and plant growth under two different soil salinity levels and various cultivated crops at Saemangeum reclaimed tidal land for three years from 2012 to 2014. The soil texture of the experimental site was sandy loam. Four different crops, sesbania (Sesbania grandiflora), sorghum-sudangrass hybrid (Sorghum bicolor-Sorghum sudanense), rice (Oryza sativa L.) and barley (Hordeum vulgare) were cultivated at low (< 1 dS m -1 ) and high (> 4 dS m -1 ) soil salinity levels. The soil salinity was significantly lowered at the rice cultivation site compared to continuous upland crops cultivation site in high soil salinity level. But the soil salinity was increased as cultivating sesbania coutinuously in low soil salinity level. The soil organic matter content was increased with the incorporation of straw at the continuous site of rice and barley, and the average of soil organic matter was increased by 0.9 g kg -1 per year which was effective in soil aggregate formation. The highest biomass yield plot was found in barley (high salinity level) and sesbania (low salinity level) cultivation site, respectively. Our research indicates that rice cultivation in paddy field with high salinity level was effective in lowering soil salinity and sesbania cultivation was useful to biomass production at upland with low salinity. In conclusion, soil salinity and organic matter content should be considered for multiple land use in newly reclaimed tidal land.

Italian ryegrass (Lolium multiflorum Lam.) was cultivated in a field experiment, on sandy loam soil of the Saemangeum reclaimed land, under different sowing rates and N fertilizer levels to estimate the optimum N fertilizer requirement and the most suitable sowing rate for seed production. The experiment was conducted in a split-plot design with four replications. The main-plots were four sowing rates of 10, 20, 30, and 40 kg ha -1 and sub-plots were five N fertilizer application rates of 0, 45, 90, 135, and 180 kg ha -1 . Harvest index decreased with increasing sowing and N fertilizer rate. The highest N use efficiency was obtained at 10 kg ha -1 sowing rate and 45 -90 kg ha -1 N fertilizer application rates. Maximum seed yield of Italian ryegrass based on the regression curve of N fertilizer application level was 102 kg ha -1 and was decreased with further N application. Economically, optimum rates of N application ranged from 70 to 101 kg ha -1 depending on the sowing rate. Results from this experiment, could therefore inform producers of the best combination of sowing and N fertilizer rates needed to increase profitability of Italian ryegrass seed production alongside preventing N loss. However, further research will be necessary to elucidate on increasing seed quality and stability of cultivation under various environmental conditions.

Although the forage production area of Italian ryegrass is expanding in Korea, most of the seeds are imported from abroad. This study was conducted to examine seed productivity of domestic varieties of Italian ryegrass under different soil salinity in reclaimed tideland. Compared to 0.1% of soil salinity, the emergence rate at 0.2 -0.3% salinity decreased by 7%. The number of ear and grain weight also decreased at the 0.2 -0.3% of salinity, eventually leading to 23% decreases in seed yield compared to the 0.1% salinity. There was no significant difference in yield components among cultivars, but Greenfarm showed slightly higher yield components than other cultivars. Therefore, when domestic cultivars are harvested in reclaimed land, it is expected to increase the self-sufficiency of domestic seeds and to replace imports of foreign seeds.

Loess processed material (LPM) was produced as a substitute for silicon, clay and minerals, and applied to tomato and cucumber cultivation. LPM was produced by using a NaOH addition ratio of 30%, a reaction temperature of 1,200 o C, a reaction time of 1 h, and an alumina ball diameter of 10 mm. Treatment with a 200-fold diluted LPM solution resulted in respective increase of 7.8% and 8.3% in the weight and quantity of the tomato fruit, and a 31.7% increase in the quantity of cucumber fruit produced, when compared to the control. On the other hand, commercial silicon fertilizer (CSF), with a price that is estimated to be four times that of LPM, did not significantly increase the yield of tomato or cucumber in terms of weight or quantity. Thus, it is suggested that LPM may be used as a potential complex silicon fertilizer.

No abstract