Three winter wheat cultivars were grown under low-N and high-N fertilization rates over two growing seasons. In spite of smaller 1000-grain weight, the high-N fertilization produced higher grain yields as well as grain N and trace element concentrations in both growing seasons. Trace element increments with high-N rate averaged 14.0% for Fe, 9.2% for Zn, 19.7% for Mn, 13.2% for Cu, 15.1% for Ni, and 23.0% for Cd. Only Na concentration was unaffected by N fertilization, whereas Pb and Cr were below detection limits. Absolutely small, but significant differences existed among tested cultivars for all trace elements and these cultivar effects were uniform on both N fertilization rates. However, cultivars differed in their rankings for trace element concentrations across two growing seasons and these specific responses appeared to be closely related to grain N.

In order to achieve a high-quality product, sweet corn should be harvested at the optimal stage of maturity. The taste of sweet corn depends largely on the kernel moisture (KM) and total sugars (TS) content while its health properties are attributed to the content of total phenols (TPH) and antioxidant activity (AO). This study aimed to estimate quality in sugary (su1) sweet corn hybrids based on the maximum content of kernel chemical compounds and the content change during maturation. During two growing seasons, five harvests by year were made at 2-day intervals from 17 to 25 days after pollination (DAP). KM decreased among hybrids from 6.6% to 14% over an eight-day period, or 0.8% to 1.8% per day. TS content was the highest at 17 DAP (16.5–28.7 mg/g DW) and decreased during maturation from 27% to 67%. Hybrids differed significantly in TPH at 17 DAP (204.4–357.1 mg GAE/100 g DW). TPH change during maturation ranged from the no significant differences up to a 29.3% decrease. DPPH- radical scavenging activity ranged among genotypes from 52.5% to 74.9% inhibition at 17 DAP and significantly increased during maturation. A well-defined hybrid-specific harvest window is necessary to maintain kernel quality in su1 sweet corn.

Previous research indicated the potential use of struvite (STR) as an alternative source of phosphorus (P) in crop production. A greenhouse experiment was conducted to evaluate the effect of STR and triple superphosphate (TSP) on the growth and chemical composition of butterhead lettuce grown on peat substrate over a three-month period (May–July). Both alternative (STR) and conventional (TSP) fertilizers were applied at three rates: (1) recommended rate based on the elemental content of substrate and crop nutritional need; (2) reduced rate (50% lower than recommended); and (3) increased rate (50% higher than recommended). Unfertilized (control) plants were also grown in the pot experiment. As expected, fertilizer application tended to increase the content of heavy metals in the substrate. Thus, an increase in Zn, Pb, and Cu content in peat substrate was found following STR amendments. However, compared with unfertilized plants, the applied rates of the STR and TSP fertilizers did not increase the content of Cd and Cu in the plant leaf, while Hg content was below the detection limit. In addition, Zn content in the plant leaf significantly decreased following STR and TSP applications. In comparison to unfertilized plants, both alternative and conventional fertilizers increased the content of P and nitrate nitrogen (N-NO₃⁻) in the plant leaf while their effect on Mg content was negligible. The increased rate of STR was the best fertilizer treatment because it produced the largest number of leaves, which were also characterized by the highest P content. Our findings showed that STR was an effective source of P in butterhead lettuce cultivation without adverse effects on heavy metal accumulation.

Winter wheat ( Triticum aestivum L.) cultivars may differ in grain quality responses to nitrogen (N) and fungicide applications, the two most important management inputs in the temperate climates of Europe. Limited information is available on N and fungicide effects on wheat quality in Croatia, where the wheat crop is widely grown under low N inputs without fungicide application. Field experiments were conducted during three years to evaluate the effects of fungicide (tebuconazol applied around heading) and two N fertilization rates on the grain quality of six widely grown winter wheat cultivars. Most cultivars failed to achieve the minimum breadmaking standards at a low N rate because of low protein content (103 g kg ⁻¹ ), Zeleny sedimentation (22.2 cm ³ ) and wet gluten (201 g kg ⁻¹ ). High N fertilization significantly increased these quality traits in all cultivars (an average of 21% for grain protein, 58% for Zeleny sedimentation and 40% for wet gluten). However, some cultivars with low genetic potential for accumulating grain protein failed to reach the breadmaking quality even at a high N rate when the N availability in the soil was limited by drought. Significant cultivar × N interactions existed for all grain quality traits, but were mainly associated with differences in the magnitude of the responses and less with the ranks. Five cultivars consistently showed increased falling number as the N rate rose, but these cultivar-specific responses to N fertilization were of much lesser magnitude than those across years. Fungicide application showed no effect on grain protein. Zeleny sedimentation, wet gluten or gluten index in all six cultivars tested, whereas one cultivar consistently showed decreased falling number after fungicide use. Only the hectolitre weights increased following fungicide application, especially for disease-susceptible cultivars at the high N rate. Thus, high N fertilization resulted in cultivar-dependent increases in protein content, Zeleny sedimentation, wet gluten and falling number, whereas fungicide application had no effect on grain quality except improved hectolitre weights.