ABSTRACT Cow dung serves as a nutrient source in pastures mainly through decomposition by microorganisms, whose abundance and composition can influence nutrient concentrations and microbial biomass in the underlying soil during this process. The primary objective of this study was to clarify the microbial dynamics within both dung and the underlying soil during dung decomposition and to examine the effects of corn silage (CS) supplementation on these processes. Two types of dung, one from dairy cows fed pasture forage only (PO) and the other from cows fed pasture supplemented with CS, were deposited on the pasture. Changes in the disappearance of chemical components, microbial biomass, and community composition were monitored over 70 days in the dung and underlying soil (0–5‐cm depth). Microbial properties were assessed using phospholipid fatty acids (PLFAs). By Day 70, the remaining masses of dung organic matter ( p < 0.1) and neutral detergent fiber ( p < 0.05) were lower in the CS than in the PO treatment. Microbial biomass within the dung increased over time in both treatments ( p < 0.01). By Day 70, the CS dung was higher in the biomass of gram‐negative bacteria ( p < 0.05), fungi ( p < 0.01), and arbuscular mycorrhizal fungi ( p < 0.05) than the PO dung. Differences in dung chemical properties also influenced the soil nutrient dynamics beneath the dung patches. The soil nitrate‐nitrogen content was higher in the PO treatment ( p < 0.05), whereas the available phosphate content was higher in the CS treatment ( p < 0.01). Overall, differences in the chemical properties of cow dung affected the microbial biomass within the dung, thereby altering the decomposition rate of dung in grazed pastures. Differences in the chemical properties of cow dung affected the soil nutrient content beneath the dung but had no influence on soil microbial biomass.
ABSTRACT The diversity of silage corn types has increased in the Huang–Huai–Hai region, including dual‐purpose, general‐purpose, and silage‐specific types. We investigated the yield and quality in response to different silage corn (dual‐type: Jiyu3421; general‐type: Jiyu 757, and silage‐specific type: Jingke 516) at different planting densities (D1, 6.75 × 10 4 ; D2, 7.50 × 10 4 ; D3, 8.25 × 10 4 ; D4, 9.00 × 10 4 ; and D5, 9.75 × 10 4 plants/ha) and nitrogen topdressing levels (non, N0; 60 kg/ha, N60; and 120 kg/ha, N120) over 2 years. Results showed that nitrogen topdressing significantly increased both total fresh matter yield and ear fresh weight yield of silage corn, with the maximum total fresh matter yield rising by up to 16.3%. Both total fresh matter and ear fresh weight yield showed a quadratic relationship with planting density, and those in N60 were more sensitive to planting density than in N0 or N120. Jiyu3421 and Jingke516 were suitable for medium density, whereas Jiyu757 had better yield at low density. Regarding quality, starch content was highest in N60D3, followed by N120D1 and N0D5. The highest crude protein content occurred in N120D3, followed by N60D5 and N0D1. Jingke516 exhibits superior quality compared with other cultivars under high topdressing nitrogen. Further analysis revealed that nitrogen use efficiency in N120 was greater than that in N60 and showed a positive correlation with planting density. Conversely, nitrogen absorption efficiency decreased significantly under N120, exhibiting a strong negative correlation with planting density. Overall, our findings demonstrate that nitrogen‐density combinations have different effects on yield and quality regulation, and nitrogen‐density adaptability among varieties varies significantly. Under 120 kg/ha base nitrogen fertilizer, all the silage corn types enhanced nitrogen absorption and utilization when the nitrogen topdressing and planting density combinations of 60 kg/ha–8.25 × 10 4 plants/ha, 60 kg/ha–6.75 × 10 4 plants/ha, and 120 kg/ha–8.25 × 10 4 plants/ha, respectively. These combinations synergistically improved both yield and quality in silage corn.
The goal of cultivating silage is to obtain a high yield of dry matter. However, high-density planting leads to high yields but low quality. The goal of this study was to solve this problem by comparing the effects of planting pattern (conventional row: CR, twin row: TR, and narrow row: NR) on the yield and quality of silage maize and their synergistic coupling relationship under different planting densities from 2023 to 2024. This study showed that the planting pattern is a key regulatory variable that improves yield. Under TR, the yields of total and ear dry matter of both cultivars were significantly higher than those of CR and NR. Changes in the yield of dry matter with planting density followed significant quadratic regression curves in all the planting patterns, and there was a larger absolute value of the quadratic coefficient (a) of TR. An increase in planting density resulted in an optimal planting density (b) for the high-starch cultivar that clustered within the range of 7.2 & times; 104 to 8.4 & times; 104 plants/ha, which was higher than the range of the ordinary cultivar. There were significant differences in the degree of correlation between the cultivars. Jiyu 757 had a higher potential maximum yield (c) and starch content than Zhengdan 958, but there was a more prominent negative correlation between yield and crude protein. Conversely, Zhengdan 958 had a superior synergy between yield and quality. Therefore, the high-starch cultivars are more likely to achieve a synergistic effect of high yields, high starch, and crude protein contents within a wider range of optimal planting densities than the ordinary cultivars, but they are less stable than the ordinary cultivars. In addressing the specific cultivation requirements of different cultivars, the TR was more effective at harmonizing yield and quality compared with the CR and NR.
Epichlo & euml; uncinata (Eu), which has a symbiotic relationship with meadow fescue in nature, can be cultured and artificially inoculated, raising expectations for its expanded use in the breeding of other grass species. However, its introduction into non-native host species may increase the risk of unstable symbiosis. In this study, we aimed to compare the stability of Eu and E. occultans (Eo), a species naturally associated with Italian ryegrass (IR; Lolium multiflorum Lam.), in IR seeds. Endophyte viability tests under seed storage with accelerated aging conditions using genetically similar IR seeds revealed a significantly lower stability of the Eu Eto8 strain than that of the Eo strain. This suggests that the risk of reduced endophyte infection rates in the Eu-IR symbiotic system depends on the seed storage conditions. Factors other than endophyte density or localization may have contributed to the differences in viability between the Epichlo & euml; strains in the IR seeds.
Selecting high-quality forage cultivars is essential for stabilizing regional forage supply and enhancing feed conversion efficiency. To identify suitable varieties for the Hulunbuir region, this study evaluated five sorghum-sudangrass hybrids (designated SS1-SS5). The evaluation was conducted by comprehensively analyzing their agronomic traits, silage quality and bacterial community diversity. Forage materials were harvested at the late milk stage. After being chopped and vacuum-sealed, the samples were subjected to 60-day fermentation. Among the tested hybrids, SS4 exhibited superior comprehensive performance. It achieved the highest (P < .05) fresh forage yield (8.48 t/hm(2)) and the largest (P < .05) stem diameter (22.00 mm). In terms of silage fermentation quality, SS4 also outperformed its counterparts. It was characterized by the highest (P < .05) lactic acid concentration (26.30 g/kg DM), which was markedly higher (P < .05) than the range of 14.20-19.50 g/kg DM observed in other hybrids. Concurrently, SS4 had the lower (P < .05) pH value (3.67 vs. 3.73-3.95). It also showed lower neutral detergent fiber content (540 g/kg DM vs. 603-640 g/kg DM) and acid detergent fiber content (317 g/kg DM vs. 388-430 g/kg DM). Microbiological analysis showed that ensiling shifted bacterial dominance from Proteobacteria to Firmicutes. Specifically, SS4 selectively enriched Lactobacillus (58.2%) and Nitrospira (2.5%). The Kyoto Encyclopedia of Genes and Genomes (KEGG) functional prediction further indicated that this bacterial community succession substantially upregulated carbohydrate and energy metabolism pathways. Furthermore, SS4 presented a robust fibrolytic potential, as evidenced by the enhanced (P < .05) expression of cellulase (EC 3.2.1.4) and endo-1,4-beta-xylanase (EC 3.2.1.8). In conclusion, SS4 is the optimal candidate for promotion as the primary forage variety in the Hulunbuir region.
