Impact of Nitrate and Ammonium Ratios on Flowering and Asexual Reproduction in the Everbearing Strawberry Cultivar Fragaria × ananassa Albion

Ever-bearing (EB) strawberries are long-day cultivars that show perpetual flowering behavior. Compared to June-bearing short-day cultivars, EB cultivars can initiate flowers with less dependency on light and temperature levels. This leads to a more consistent flowering and fruiting pattern, making EB cultivars favorable for areas with long growing seasons. However, this flowering pattern also brings significant challenges to open-field strawberry nurseries. Consistent flower development in EB cultivars frequently leads to increased labor cost for manual flower removal on nursery ground. The alteration of flowering behavior via fertilizer regimes could be a cost-effective tool for strawberry nurseries. However, while it is known that the source of nitrogen (N) impacts strawberry flowering, its effect on strawberry propagation rates needs further investigation. The objective of this study was to investigate the impact of nitrate (NO3−) to ammonium (NH4+) ratio on flower and daughter plant production in the EB strawberry cultivar ‘Albion’ (Fragaria × ananassa c.v. ‘Albion’). Strawberry plants were grown in a completely randomized design under greenhouse conditions (26.6 °C, 16 h photoperiod). Four treatments of NO3−:NH4+ were implemented: (1) 100%:0%; (2) 80%:20%; (3) 60%:40%; (4) 50%:50%. Strawberry plants fertilized with a 60%:40% NO3−:NH4+ ratio produced 17–31% fewer inflorescences than those fertilized with 100%:0% (8.8 ± 1.19) and 80%:20% (10.3 ± 1.85) ratios. The production of daughter plants remained similar in all four treatments. Our results show that increased ratios of ammonium in combination with decreased ratios of nitrate reduce flowering of EB strawberry cultivars, while propagation rates remain consistent. These results could potentially lead to the development of fertilizer regimes for strawberry nurseries to reduce flower production in EB cultivars.

Evaluation of Agronomic Performance of Maize (Zea mays L.) under a Fertilization Gradient in Transylvanian Plain

In the last few years, Romania has become a top maize producer. Export potential is sustained by ensuring high-quantity and -quality maize. Success of maize crop is highly dependent on inputs. In this context, insight into the potential of different fertilizers to maximize crop performance could shed light on best practices to enhance yields and other traits of interest. The aim of this study was to assess the agronomic performance of maize under a fertilization gradient. Six fertilizer regimes were tested on three maize hybrids between 2018 and 2020, in conditions from the Transylvanian Plain. Results showed that fertilization had a significant influence on yield, thousand kernels weight, grain quality (starch and protein content) and crop health. The experimental year also played a significant role in the expression of productivity potential of maize genotypes. Different fertilizer regimes could be used for targeting desired outcomes, but top performance across all or multiple agronomic components remains a challenge and should receive further attention for optimization.

The Influence of Three Years of Supplemental Nitrogen on Above- and Belowground Biomass Partitioning in a Decade-Old Miscanthus × giganteus in the Lower Silesian Voivodeship (Poland)

Because of the different opinions regarding nitrogen (N) requirements for Miscanthus × giganteus biomass production, we conducted an experiment with a set dose of nitrogen. The objective of this study was to examine the effects of nitrogen fertilization on the biomass yield, water content, and morphological features of rhizomes and aboveground plant parts in various terms during a growing season over the course of three years (2014–2016) in Lower Silesia (Wroclaw, Poland). The nitrogen fertilization (dose 60 kg/ha and control) significantly affected the number of shoots (p = 0.0018), the water concentration of rhizomes (p = 0.0004) and stems (p = 0.0218), the dry matter yield of leaves (p = 0.0000), and the nitrogen uptake (p = 0.0000). Nitrogen fertilization significantly affected the nitrogen uptake in all plant parts (p = 0.0000). Although low levels of nitrogen appeared to be important in maintaining the maximum growth potentials of mature Miscanthus × giganteus, the small reductions in the above- and belowground biomass production are unlikely to outweigh the environmental costs of applying nitrogen. More studies should use the protocols for the above- and belowground yield determination described in this paper in order to create site- and year-specific fertilizer regimes that are optimized for quality and yield for autumn (green) and spring (delayed) harvests.

A meta-analysis of the effect of organic and mineral fertilizers on soil microbial diversity

ABSTRACTThe Green Revolution of agriculture was in part driven by application of synthetic mineral fertilizers, largely supplanting organic manure as a source of the major nutrients nitrogen, phosphorous and potassium (NPK). Though enhancing crop production and global food security, fertilizers have contributed to soil acidification, eutrophication of water bodies, and greenhouse gas emissions. Organic agriculture, employing manures or composts, has been proposed as a way of mitigating these undesirable effects. Of particular interest is the effect of fertilizer regime on soil microbes, which are key to nutrient cycling, plant health and soil structure. Meta-analyses of experimental studies indicate that mineral fertilizer increases soil microbial biomass over unfertilized controls, and that organic fertilizers increase microbial biomass and activity over mineral fertilizers. However, the effect of fertilizers on soil microbial diversity remains poorly understood. Since biological diversity is an important determinant of ecosystem function and a fundamental metric in community ecology, the effects of fertilizer regimes on soil microbial diversity are of theoretical and applied interest. Here, we conduct a meta-analysis of 31 studies reporting microbial diversity metrics in mineral fertilized (NPK), organically fertilized (ORG) and unfertilized control (CON) soils. Of these studies, 26 reported taxonomic diversity derived from sequencing, gradient gel electrophoresis, RFLP, or dilution plate assay. Functional diversity, derived from Biolog Ecoplate™ measures of carbon substrate metabolism, was reported in 8 studies, with 3 studies reporting both diversity metrics. We found that functional diversity was on average 2.6 % greater in NPK compared with CON, 6.8 % greater in ORG vs CON and 3.6 % greater in ORG vs NPK. Prokaryote taxonomic diversity was not significantly different between NPK and CON, 4.2 % greater in ORG vs CON and 4.6 % greater in ORG vs. NPK. Fungal taxonomic diversity was not significantly different between NPK or ORG vs CON, but 5.4 % lower between ORG and NPK. There was very high residual heterogeneity in all meta-analyses of soil diversity, suggesting that a large amount of further research with detailed analysis of soil properties is required to fully understand the influence of fertilizer regimes on microbial diversity and ecosystem function.

Influence of different types of fertilizers application on the lettuce (Lactuca sativa L.) growth and quality

The experiment was conducted during the period from March to the end of April 2019 to observe the effect of different fertilizer regimes on the growth, quality and yield of lettuce under field conditions. The experiment was consisting of four treatments as well as a control without fertilizer T1, compost T2, compost tea T3 and chemical fertilizer T4, in each treatment 50 replicates were planted. The measurements included wet and dry weight for shoot and root, plant length, and chlorophyll percentage. The study revealed that lettuce's best growth values were obtained with the use of eco-friendly organic fertilizer accompanied by more than control one and chemical fertilizer. The average maximum length of plants after 60 days were recorded in T2 (42.3 cm) > T3 (37.3 cm), T4 (35.9 cm) and > T1 (23.8 cm). The results indicated that compost treated plant (T2 and tea compost T3) had highest chlorophyll content, i.e. 42.3 and 40.6%, respectively, as compared to chemical fertilizers T4 (37.3%) and the lowest chlorophyll content was in control T1 (30.9%). The values for wet shoot and root after 60 days were: 1575.2, 81.5 gm T2 > 1367.6, 64.9 gm T3 > 1251.1, 53.4 gm T4 and 612.1, 43.7 gm T1, respectively. The values for dry shoot and root after 60 days were: 131.5, 8.2 gm, T2 > 112.7, 6.4 gm, T3 > 101.9, 5.3 gm T4 and > 51, 4.1 gm T1, respectively.