Effect of Jellyfish fertilizer on Seedling Growth and Soil Properties (第43回大会特集)
The excessive increase of jellyfish swarms could threaten the fishers and the marine food chain. The aim of research was to evaluate the potential benefit of the jellyfish as a fertilizer for different trees. The greenhouse experiment was conducted at Kutan, Chuncheon, South Korea using two tree species. Jellyfish was applied to soil before planting at different application rates (1.6, 2.7, 5.5, and 11.1 g/kg). Generally, the addition of jellyfish fertilizer increased soil moisture contents. It is concluded that low application rate of jellyfish fertilizer increased soil moisture and nutrient contents, consequently, enhancing the seedling growth.
Effects of organic manure and chemical fertilizer on soil fertility and productivity of plant and ratoon crops of sugarcane
A study was undertaken to evaluate the effects of integrated use of some organic manures and chemical fertilizers on soil fertility and productivity in plant and the subsequent ratoon crops of sugarcane. The manures included press mud, farmyard manure (FYM) and green manure (Crotalaria juncea) and the fertilizers were urea, TSP, MOP, gypsum and zinc sulphate. Application of organic manure in combination with chemical fertilizer increased absorption of N, P and K in cane leaf tissues both in the plant and ratoon crop as compared with chemical fertilizer alone. This led to higher cane and sugar yield of both crops. The maximum cane yield of 108.4 t ha − 1 and sugar yield of 9.47 t ha − 1 for the plant crop, and 96.8 t ha − 1 cane and 9.18 t ha − 1 sugar yields for the second crop (ratoon) were recorded where FYM at 15 t ha − 1 accompanied with chemical fertilizer (N178P53K54S26Zn2.6 kg ha − 1) were applied. The organic carbon, total N, and available P, K & S contents of soils increased slightly due to incorporation of organic manure. It appeared that 25% reduction of fertilizer application is possible if FYM or press mud at 15 t ha − 1 is used in plant and ratoon crops of sugarcane.
Mechanisms of sodium uptake by roots of higher plants
The negative impact of soil salinity on agricultural yields is significant. For agricultural plants, sensitivity to salinity is commonly (but not exclusively) due to the abundance of Na+ in the soil as excess Na+ is toxic to plants. We consider reducing Na+ uptake to be the key, as well as the most efficient approach, to control Na+ accumulation in crop plants and hence to improve their salt resistance. Understanding the mechanism of Na+ uptake by the roots of higher plants is crucial for manipulating salt resistance. Hence, the aim of this review is to highlight and discuss recent advances in our understanding of the mechanisms of Na+ uptake by plant roots at both physiological and molecular levels. We conclude that continued efforts to investigate the mechanisms of root Na+ uptake in higher plants are necessary, especially that of low-affinity Na+ uptake, as it is the means by which sodium enters into plants growing in saline soils.