Sulfur (S) deficiency is becoming increasingly prevalent, posing a serious threat to crop yield and quality. The incorporation of S fertilizers into macronutrient fertilizers such as ammonium phosphate represents a straightforward and economically efficient approach to alleviating S deficiency, strengthening S supply, and improving crop yield. However, limited research has been conducted to assess the effect of monoammonium phosphate (MAP) and diammonium phosphate (DAP) with different S additions on agronomic outcomes. In this study, ammonium sulfate and elemental S with S set at 3%, 6%, 9%, and 12% (ensuring a 1:1 ratio of SO₄−S to elemental S) were granulated with MAP and DAP, respectively. Maize was used as the test crop to evaluate its yield, nutrient uptake, and apparent sulfur recovery. The results showed that S-fortified MAP treatment increased crop yield and S uptake by an average of 9.3% and 10.6%, respectively. A significant difference in crop yield and S uptake was observed when the S addition in MAP exceeded 9% S. Nevertheless, no statistical difference was found among the DAP-based treatments in calcareous soil. There was a strong relationship between S applied in fertilizers and S uptake by crops for MAP-based treatments. However, the apparent sulfur recovery drastically dropped from 44.2% to 7.19% with the increased addition level of S for MAP-based fertilizers. The results of this study indicate that the addition of S to MAP could be a simple, low-cost, and effective approach with great potential to promote S fertilizer application, minimize soil S deficiency, and improve crop yield in calcareous soil.

Polyphosphate, which can improve crop yield and phosphorus use efficiency in calcareous soils, has gained increasing global attention. However, the effects of polyphosphate properties (pH and polymerization degree) on agronomic effects are still unclear. In this study, the nutrient solubility, nutrient release, nutrient uptake, and maize growth in calcareous soil of alkaline diammonium phosphate (DAP), acidic ammonium polyphosphate (APP) with a polymerization degree of 1.8, and alkaline potassium tripolyphosphate (KTPP) with a higher polymerization degree of 2.8 were evaluated. The results showed that KTPP at pH 8.0 could significantly increase the solubility of Ca²⁺ by 24.3 times and 3.1 times than those by DAP and APP, respectively, and significantly increase the solubility of Mg²⁺ by 172.8 times and 1.6 times than those by DAP and APP, respectively. The nutrient release experiment indicated 100% P was released after 15 d for the three P fertilizers, and the cumulative released amounts of soluble Ca and Mg with KTPP were about 2.9 and 3.2 times higher than those of DAP, respectively. The result of the pot experiment demonstrated that KTPP significantly enhanced shoot biomass by 24.1% compared with that by DAP. The P, Ca, and Mg uptake of maize shoots with KTPP significantly improved by 49.7%, 20.9%, and 20.9%, respectively, compared to that of DAP. However, no significant differences in yield or nutrient uptake between the KTPP and APP treatments were observed. This study demonstrated that polyphosphate with a higher polymerization degree had a better effect on increasing the solubility of cations, crop yield, and nutrient uptake, and polyphosphate application provides a synergistic interaction between P and Ca in calcareous soil, which may promote the application of polyphosphate fertilizers to expand to large-scale agriculture.

GATA proteins are transcription factors of zinc finger proteins, which play an important role in plant growth development and abiotic stress. However, there have been no identification or systematic studies of the GATA gene family in eggplant. In this study, 28 SmGATA genes were identified in the genome database of eggplant, which could be divided into four subgroups. Plant development, hormones, and stress-related cis-acting elements were identified in promoter regions of the SmGATA gene family. RT-qPCR indicated that 4 SmGATA genes displayed upregulated expressions during fruit developmental stage, whereas 2 SmGATA genes were down-regulated expression patterns. It was also demonstrated that SmGATA genes may be involved in light signals to regulate fruit anthocyanin biosynthesis. Furthermore, the expression patterns of SmGATA genes under ABA, GA and MeJA treatments showed that the SmGATAs were involved in the process of fruit ripening. Notably, SmGATA4 and SmGATA23 were highly correlated with the expression of anthocyanin biosynthesis genes, light-responsive genes, and genes that function in multiple hormone signaling pathways and the proteins they encoded were localized in the nucleus. All these results showed GATA genes likely play a major role in regulating fruit anthocyanin biosynthesis by integrating the light, ABA, GA and MeJA signaling pathways and provided references for further research on fruit quality in eggplant.