Effect of nitrogen and magnesium sulfate application on sugar beet yield and quality

Adequate nutrition of sugar beet with magnesium (Mg) and sulfur (S) has been assumed to be the key to increase fertiliser nitrogen (N) efficiency. This hypothesis was validated on two soils differing in textural class, i.e., sandy and loamy. The experiment consisted of three factors: (1) in-soil application of Kieserite (0, 24 kg Mg/ha); (2) foliar application of Epsom salt (0.2 kg Mg/ha); (3) N rates (0, 40, 80, 120, 160 and 200 kg N/ha). The following parameters were evaluated: (i) yield of storage roots (TY); (ii) qualitative features of storage roots, and (iii) yield of white sugar (WSY). Both yield characteristics, regardless on soil, were affected to a greater extent by in-soil than foliar MgS application. The highest increments of TY and WSY were obtained in 2016, a year with fewer favourable weather conditions and in soil with a wider Ca : Mg ratio. The greatest effect of Kieserite on TY and WSY was observed under low rates of applied N (up to 80 kg/ha). It can be concluded that the right nutrition of sugar beet with MgS in the early stages of sugar beet growth is the prerequisite of an effective N management on soils rich in mineral N.

Sulfate enhances drought tolerance in foxtail millet seedlings by promoting ABA biosynthesis and inducing stomatal closure

Background and aims Sulfate, the main source of sulfur in natural soil, is critical for plant growth and development, as well as plant responses to environmental stress, including drought. However, our understanding of the detailed mechanisms of sulfate-modulated drought tolerance in crop plants is far from complete. In the present study, by using foxtail millet (Setaria italica L.), an emerging model crop, we investigated the possible mechanisms involved in sulfate-induced crop tolerance to drought stress. Methods A combination of biochemical and molecular approaches, as well as stomatal apertures analyses were applied to determine the effect of sulfate application on sulfur assimilation, ABA biosynthesis, and stomatal movement. Results Upon drought exposure, sulfate (4 mM) pretreatment significantly alleviated the decrease in relative water content in foxtail millet leaves. Exogenous sulfate increased endogenous sulfate content and markedly enhanced the enzyme activity of sulfite reductase (SiR) and O-acetylserine(thiol)lyase (OASTL), as well as levels of their transcripts, leading to an increase in cysteine (Cys) production in drought-stressed leaves. Furthermore, in comparison with drought stress alone, sulfate application significantly upregulated the transcriptional expression of SiABA3 and SiAAO3, which contributed to the increased ABA levels in the leaves of drought-stressed foxtail millet seedlings. Moreover, the addition of sulfate decreased stomatal aperture, thus resulting in reduced leaf water loss in foxtail millet exposed to drought. Conclusion Our data suggest that sulfate application was able to promote drought tolerance of foxtail millet plants, at least partially by increasing ABA biosynthesis and triggering stomatal closure.

Effect of Ammonium Sulfate Application Levels on the Growth and Yield of IR-28 Rice

The study was conducted in JICA Tsukuba experimental rice field RE-2 from April 2018 to September 2018, to determine the effect of different levels of nitrogen fertilizer (Ammonium sulfate) application, on the growth and the yield of IR-28 rice. Four levels of nitrogen fertilizer were applied; 0kg.ha-1 (N0), 40kg.ha-1(N40), 60kg.ha-1(N60) and 80kg.ha-1(N80). For each of the four levels, part of the fertilizer was applied as basal dressing prior to transplanting, and the rest was applied as top-dressing at the panicle initiation stage. The experimental design was a Randomized Complete Block Design (RCBD) with four treatments and three replications. The plant length, the tiller number and the leaf colour were measured for growth data. The number of panicles per m2, the number of spikelets per panicle, the spikelet fertility rate, the 1000 grains weight, and the calculated yield were determined for yield components assessment. The plant length and the tiller number were significantly higher in N80 and N60 compared to N40 and N0, and N80 showed the highest values. There was no significant difference among the four nitrogen levels in terms of the number of panicles per m2 and the number of spikelets per panicle. The spikelet fertility rate and the 1000 grains weight were significantly higher in N80, N60 and N40 compared to N0, and no significant difference was observed among the three. Calculated yield values were higher in N80 (5.74 tons.ha-1) and N60 (5.38 tons.ha-1) compared to N40(4.88 tons.ha-1) and N0 (4.36 tons.ha-1), but there were no significant differences among the four treatments (5% Level of HSD). These results suggest that a high yield of rice can be achieved through the application of high amounts of nitrogen fertilizers. N60 nitrogen level can be recommended for optimum yield of IR-28. Although N80 showed higher yield and yield components, N60 is the best and the most economical nitrogen level required for optimum yield of IR-28.