Fermentation dynamics and bacterial diversity of mixed lucerne and sweet corn stalk silage ensiled at six ratios

The fermentation dynamics and bacterial diversity of mixed lucerne (LU) and sweet corn stalk (SS) silage ensiled at six ratios were evaluated. LU and SS, harvested at 187 and 222 g/kg dry matter, respectively, were chopped to a length of about 1 cm and mixed in the fresh weight proportions of 10:0, 8:2 (Mix 1), 6:4 (Mix 2), 4:6 (Mix 3), 2:8 (Mix 4) and 0:10. Silos of each ratio were prepared in triplicate and stored at ambient conditions for 5, 10, 15, 30 and 65 days. The fermentation profile of silage during storage was determined at each point, and the bacterial diversity of silage stored for 65 days was analysed by high‐throughput sequencing. The silages with more SS inclusion in the forage mixtures were higher in lactic acid and lower in butyric acid and ammonia N, regardless of storage time. After 65 days of storage, Lactobacillus (relative abundance, 91.36%–95.86%) dominated the bacterial community in Mix 3, Mix 4 and SS silages, whereas the community composition in LU, Mix 1 and Mix 2 silages was complex, mainly consisting of Lactobacillus (45.48%–61.01%), Enterobacter (11.09%–19.57%) and Weissella (10.44%–14.13%). Inclusion of SS significantly enhanced the fermentation characteristics, and remarkably improved the bacterial community structure, reflected by increasing the relative abundance of Lactobacillus and reducing the relative abundance of Enterobacter and Pantoea. The fermentation quality was better when LU was ensiled in a mixture with ≥ 40% SS.     

The effect of molasses‐based pre‐fermented juice on the fermentation quality of first‐cut lucerne silage

The aim of this study was to evaluate the possible effect of pre‐fermented juice (PFJ) on the fermentation quality and nutritive value of first‐cut lucerne (Medicago sativa L.) silage. The PFJs were prepared using barley (B), wheat (W) and grass herbages (G). Both fresh (PFJ‐B, PFJ‐W and PFJ‐G) and frozen (PFJ‐B_F, PFJ‐W_F and PFJ‐G_F) PFJs were examined. Frozen PFJs were prepared by freezing fresh PFJs at ?22°C with 20% glycerol (v/v). Treatments of lucerne silage included (1) control; (2) silage treated with PFJ‐B; (3) silage treated with PFJ‐W; (4) silage treated with PFJ‐G; (5) silage treated with PFJ‐B_F; (6) silage treated with PFJ‐W_F; and (7) silage treated with PFJ‐G_F. All the treatments consisted of five replicate silos, and they were prepared in 1·0‐L glass jar silos. Results showed that silages treated with fresh and frozen PFJs, regardless of plant material, had better fermentation quality than the control silage in terms of lower pH, butyric acid (BA) and ammonia nitrogen (NH₃‐N) concentrations, as well as higher lactic acid (LA) concentration (P < 0·05) and in vitro organic matter digestibility (IVOMD), metabolizable energy (ME) content, and gas production values (P < 0·05). Results indicated that PFJ treatments enhanced the nutritive value, fermentation quality and IVOMD, ME content and gas production values of first‐cut lucerne silages.     

Efficacy of different temperate pasture species to reduce nitrogen leaching from cattle urine applied in different seasons: A soil lysimeter study

A soil lysimeter field study assessed the efficacy of different pasture species to reduce nitrogen (N) leaching loss from cow urine deposited in different seasons. A single application of cow urine (¹⁵N‐labelled; equivalent to 622 kg N ha^?1) was applied in three different seasons (summer, autumn or winter) to three pasture species monocultures (perennial ryegrass, plantain or lucerne) on a free‐draining volcanic soil and monitored over 362 days. Leachate analyses revealed consistently large leaching losses of inorganic‐N from lucerne (>200 kg N ha^?1) across different urine application times due to the relatively low plant growth rates during winter (<15 kg DM ha^?1 day^?1) that led to low total recovery of urine‐N by lucerne plants (<20% of the applied urine‐¹⁵N). Conversely, plant uptake of the urine‐N was higher by plantain (ranging from 30% to 45% of that applied) driven by moderately higher winter plant growth rates (30 to 60 kg DM ha^?1 day^?1). Plantain exhibited large seasonal variation in its efficacy to reduce urine‐N leaching relative to ryegrass (ranging from 15% to 50% reduction for summer or winter urine applications, respectively) with an overall reduction of 39% in the total amount of inorganic‐N leached across the three seasons (53 vs. 87 kg N ha^?1 leached relative to ryegrass). This study has demonstrated the potential benefit of using plantain to reduce N leaching losses from urine deposited in the summer to winter grazing period. However, further research is required to quantify the effects of plantain on annual N leaching losses from grazed pastoral systems.     

杀菌剂拌种对紫花苜蓿,苏丹草不同活力种批出苗的影响

在４０％土壤饱和持水量和最适萌发温度下，研究了甲基托布津、甲霜灵、杀毒矾和福美双等杀菌剂拌种对紫花苜蓿和苏丹草出苗的影响；进而探讨了不同活力的供试种种批对杀毒矾拌种的反应。４种参试杀菌剂以杀毒矾效果最好，与对照比，其可使紫花苜蓿和苏丹草的存苗率分别提高１４１．９％和３７．７％（Ｐ＜０．０５），使紫花苜蓿死苗率降低８０．８％（Ｐ＜０．０５）。其他３种杀菌剂亦可显著（Ｐ＜０．０５）提高紫花苜蓿种子的存苗率和降低死苗率，提高存苗率的效果依次为甲霜灵（１０９．７％）、甲基托布津（８３．９％）和福美双（４８．４％），但对苏丹草种子作用不显著。杀毒矾处理对中活力和高活力紫花苜蓿种子较低活力种子更为明显、有效，与对照比，中活力和高活力种批的存苗率分别提高了１１１．５％和１００．０％，而低活力种批仅提高了３１．０％。但杀毒矾对苏丹草不同活力种批的作用效果不显著。     

Forage quality of genetically diverse alfalfa germplasms at four phenological growth stages

Summary Forage quality of various alfalfa (Medicago sativa L.) cultivars has been determined under different environmental conditions, and numerous trials with alfalfa have documented an inverse relationship between forage quality and maturity. Little information is available, however, regarding the comparative forage quality of the germplasm sources from which most USA cultivars were developed. We compared forage quality of these germplasm sources at four phenological stages under disease- and insect-free conditions in a greenhouse. Germplasm sources (cultivars) tested were: Indian (Sirsa #9), African (African), Peruvian (Hairy Peruvian), Flemish (DuPuits), Turkistan (Lahontan), Chilean (Kansas Common), M. varia (Grimm), and Ladak (Ladak). Four harvests were taken and forage was separated into four phenological stages: vegetative, early bud (1–3 buds-per-stem), late bud (>3 buds-per-stem), and bloom. The germplasm source X phenological stage interaction was significant for crude protein (CP) and in vitro digestible dry matter (IVDDM) concentrations. M. varia showed the least decline in IVDDM and CP with increasing maturity. M. varia had higher IVDDM than did African and Indian at late bud and bloom stages. Indian and Flemish had higher CP than did Turkistan and Peruvian at late bud and bloom stages. Alfalfa germplasm sources differ in forage quality when comparisions are made within similar stages of phenological development.Joint contribution of the Dept. of Agronomy and USDA-ARS, Kansas Agricultural Experiment Station, Manhattan, KS 66506, USA. Contribution no. 90-475-J.     

Field resistance of perennial glandular-haired Medicago strains and alfalfa cultivars to the alfalfa weevil

Summary Field plots planted in 1986 to four, perennial, glandular-haired Medicago strains and four alfalfa cultivars were evaluated for alfalfa weevil, [Hypera postica (Gyllenhal)], abundance and feeding damage as well as plant height from 23 April through 21 may 1987 and from 25 April through 26 May 1988. The plots were located near Mead, Nebraska and both sweep and stem sampling methods were utilized. In 1987, M. glandulosa had the fewest larvae present in sweep samples on 1, 9, and 15 May, although on the last date it did not differ significantly from three other entries. The glandular-haired M. glandulosa also was among those entries having the fewest number of larvae present in stem samples on 9 May, 1987. Significant differences in the number of damaged stem tips were observed on 9 and 21 May, 1987, when M. glandulosa was among those entries having the least amount of damage. The other three glandular-haired strains had larval infestations and damage similar to those for the cultivars. Weevil abundance and damage were generally low in 1988. Medicago glandulosa was shortest of the glandular-haired strains, which were shorter than the cultivars.     

The effects of kinetin on callus characters in alfalfa (Medicago sativa L.)

Summary Three callus initiation media, B2-k, B2, and 7951, were used to study the effects of kinetin on callus initiation, morphology, histology, and regenerability in alfalfa (Medicago sativa L.). The presence of kinetin in callus initiation media retarded callus initiation, but enhanced division and differentiation of callus cells. Calluses induced on kinetin-containing media (B2 and 7951) had many compact cell aggregations, which were considered meristematic regions that might differentiate to plantlets on a regeneration medium. Visually, these calluses were compact and had many nodular structures. In contrast, most calluses induced on a kinetin-free medium were composed of large, individual cells and had friable structures without nodules. After transfer to a hormone-free medium, calluses induced on kinetin-containing media regenerated more frequently than those induced on a kinetin-free medium, but cytokinin (kinetin) autotrophism also occurred. Autotrophism was sexually transmissable and especially affected by the female parent.     

Species of Shootflies Reared from Sorghum in Andra Pradesh,India

Abstract

A total of 13 species of shootflies from two genera, Atherigona and Acritochaeta, were reared over a four-year period from a range of sorghum (Sorghum bicolor) cultivars showing typical ‘dead heart’ symptoms. Atherigona soccata Rond. was the dominant species (<99% of the flies reared), while the second most common species was Acritochaeta orientalis Schin. An interesting record was Atherigona eriochloae Mall. reared from tillers of ratooned sorghum. Three species as yet undescribed were recorded. More females than males were reared in the course of the study — the sex ratio was 1:1.27. It was concluded that only A. soccata is likely to be important when considering control of damage to sorghum by resistance breeding or the use of insecticides.     

Production, survival and nutritive value of the perennial legumes Dorycnium hirsutum and D. rectum subjected to different cutting heights

Dorycnium hirsutum and D. rectum are perennial legumes which may have potential for use as pastures for the control of groundwater recharge in southern Australia. Little is known about the quality of the forage of Dorycnium species for grazing livestock or how these species respond to cutting. The effect of cutting height on plant survival, production of dry matter (DM), the proportion of leaf, edible stem (approximately <5 mm diameter) and woody stem in the DM and the nutritive value of the edible components was investigated. Biomass above five cutting‐height treatments (uncut, ground level, 5–8 cm, 10–15 cm and 15–30 cm above ground level) was removed at 8‐week intervals from plots of D. hirsutum and D. rectum from September 2002 to July 2003. In both species, plants subjected to lower cutting height treatments produced less DM above the height of the cut than those cut at higher heights. DM production declined over time in all treatments. Plants cut to ground level failed to regrow after the second harvest in D. hirsutum and the fourth harvest in D. rectum. Thus, these Dorycnium species were susceptible to high severity defoliations at 8‐week intervals. Negligible inedible woody stem was present in regrowth of both species after 8 weeks but D. hirsutum regrowth had a higher proportion of leaf (0·72) than D. rectum (0·56). Plants left uncut accumulated a large proportion of inedible woody stem in the DM (0·69 in both species) by July 2003, particularly at the base of the plant. Edible DM from regrowth of D. hirsutum and D. rectum had crude protein (CP) concentrations of 120 and 150 g kg^?1 DM; dry matter digestibility (DMD) values of 0·45 and 0·58; organic matter digestibility (OMD) values of 0·50 and 0·64; neutral‐detergent fibre (NDF) concentrations of 370 and 290 g kg^?1 DM; and acid‐detergent fibre (ADF) concentrations of 260 and 210 g kg^?1 DM, respectively. Medicago sativa, grown under similar conditions, had higher digestibility values (0·63 DMD and 0·66 OMD) and similar CP concentrations to D. rectum (140 g kg^?1 DM), but higher concentrations of NDF and ADF (410 and 290 g kg^?1 DM). Leaf material from both Dorycnium species had a higher nutritive value than edible stems, with DMD and OMD values of leaf of D. rectum being 0·68 and 0·74 respectively. Uncut plants had a much lower nutritive value of edible DM than the regrowth from cut treatments; older material was also of a lower nutritive value. The relatively low nutritive value of even the young regrowth of Dorycnium species suggests that forage quality is a major limitation to its use. Forage of Dorycnium species could be used during periods when other sources of forage are in short supply but infrequent grazing it is likely to produce forage of a low nutritive value.