Use of Mefluidide to Alter Growth and Nutritive Value of Pearl Millet

Abstract

Pearl millet (Pennisetum americanum L. Leeke) has an inherent rapid growth rate that often presents management problems to achieve optimum utilization by livestock throughout the growing season. Both the rapid spring–summer growth rate and photoperiodism that diminishes growth in late summer—early fall creates the need to use both grazing and mechanical defoliation to have efficient use of forage production. The objectives of this 2‐year field study were to evaluate the effects of a growth regulator, mefluidide (N‐[2, 4‐dimethyl‐5‐([(trifluoromethyl) sulfonyl] amino) phenyl] acetamide), on growth characteristics and nutritive parameters of “Millex 24” pearl millet. Mefluidide was broadcast applied at different rates to determine the effect on dry matter (DM) yield and nutritive value of leaves and stems of pearl millet. Mefluidide reduced DM biomass at each weekly harvest, and at three weeks post‐treatment DM was reduced 3‐fold in Year 1 and 2‐fold in Year 2. Percent leaf, however, was nearly doubled by mefluidide application. Crude protein (CP) of leaves was not affected by mefluidide, however, CP of treated stems was significantly higher (P < 0.05) than untreated pearl millet. Fiber components were lowered (P < 0.05) in treated leaves and stems compared to untreated pearl millet. The 2‐year study showed that mefluidide enhanced nutritive value of pearl millet, but at the expense of DM.     

Variation in primitive landraces of common bean (<Emphasis Type="Italic">Phaseolus vulgaris</Emphasis> L.) from Argentina

The phenotypic variation found in four common bean (Phaseolus vulgaris L.) complex primitive landraces, among a group of accessions collected in Northwestern Argentina in several missions is described, with particular attention to the wide diversity found in some small areas. It is presented a hypothesis about the maintenance of such diversity in bean mixtures or complex primitive landraces that grow close to their wild relative. Wide diversity regarding to seed type and plant characteristics was displayed by the landraces MCM-SV (composed of 11 lines), MCM-292 (14 lines), MCM-298 (5 lines) and VAV-3716 (14 lines). Food uses of dry seed and fresh pod seemed to be more relevant than the aesthetic use although all of them were presumably considered by humans for centuries resulting in the current phenotypes of these complex primitive landraces. Additionally, some weedy types (intermediate between wild and domesticated types) were detected in the landracesMCM-292 and MCM-298. The four complex landraces described consisted of highly diverse mixtures and they could play a role in breeding to enlarge the genetic basis of domesticated bean varieties belonging to the Andean gene pool.     

Sources of nitrogen and yield advantages for monocropping and mixed cropping with cowpeas (Vigna unguiculata L.) and upland rice (Oryza sativa L.)

Summary Sources of N used by cropped and intercropped cowpeas and rice were determined by the ¹⁵N isotope-dilution technique. The biological efficiency of intercropping cowpeas and rice was assessed by calculating the land equivalent ratio of dry matter yield, total N, and uptake of N. A reduced N uptake by both cowpeas and rice during mixed cropping was attributed to mutual competition, with both crops competing effectively for the scarce environmental resources. The lack of a significant difference in the uptake of fertilizer and soil N by mixed-crop rice and cowpeas is an indication that the soil N was sufficient and that the mixed cropping did not create any imbalance in soil and fertilizer N uptake. The land equivalent ratio ranged between 120% and 180% for shoot dry matter and total N, showing that biological efficiency was increased by intercropping cowpeas with rice. The proportion of N derived from the atmosphere by mono- and intercropped cowpeas was not significantly different, showing that the potential of cowpeas to fix N₂ was independent of the cropping system, since the rice did not stimulate the cowpeas to fix more N₂.     

Growth response of field-grown Siratro (Macroptilium atropurpureum Urb.) and Aeschynomene american L. to inoculation with selected vesicular-arbuscular mycorrhizal fungi

Summary The effect of inoculation with a selected isolate of Glomus etunicatum Becker and Gerdemann and one of G. intraradices Schenck and Smith on the growth and nutrient content of Macroptilium atropurpureum Urb. cv. Siratro and Aeschynomene americana L., at applied P levels of 10, 30, 60, and 120 kg ha^-1, was studied under field conditions. At all P levels and for all harvests, the shoot dry mass of Siratro and A. americana were greater for the plants inoculated with the vesicular-arbuscular mycorrhizal (VAM) fungi than the control plants. Differences between the VAM fungus-inoculated and the control plants were most marked between 30 and 90 kg ha^-1 of applied P and diminished at 120 kg ha^-1. At the first harvest of Siratro, the plants inoculated with G. etunicatum had a greater shoot dry mass than those inoculated with G. intraradices, for all levels of applied P. However, for subsequent harvest of Siratro and for the one harvest of A. americana the response of shoot dry mass to the two VAM fungi was equivocal. Fungal inoculation gave at least a 30% saving in the amount of P fertilizer required (40 kg ha^-1) for the maximum yield. The plants inoculated with VAM fungi had a greater tissue concentration and total content of P and N than the control plants at low and intermediate levels of applied P. The percentage of root colonized by VAM fungi for the inoculated plants of the two legumes increased linearly with P additions up to 60 kg ha^-1. The conclusion is that under amended (limed and fertilized) soil conditions, inoculation with selected VAM fungi can improve the establishement and growth of forage legumes in fields that contain ineffective populations of native VAM fungi.     

Acid soil tolerance of soybean (Glycine Max L. Merr.) germplasm from the USSR

Nineteen soybean genotypes (ten from the former USSR, two from Brazil and seven from USA) were tested for aluminum (Al) tolerance by growing them for 21 days in greenhouse pots of acid, Al‐toxic, unlimed Tatum (Typic Hapludult) subsoil at pH 4.0 and in limed subsoil at pH 5.1. Aluminum tolerance ranking depended upon the plant traits used in the screening process. Based on absolute dry shoot weights at pH 4.0, Giessener, Brunatna, and St.‐59 (USSR), and Biloxi (USA) were most tolerant; least tolerant entries included Yantarnaya and Smena (USSR), and Davis (USA). Based on relative shoot dry weights (pH 4.0/pH 5.1 %), Giessener, Brunatna, and St.‐59 (USSR) were among the most tolerant, Bossier, Biloxi, Essex, and Perry were intermediate, and Salute 216 (USSR), Chief (USA), and Santa Rosa and IAC‐9 (Brazil) were more sensitive to the acid soil. Based on absolute root dry weights, Giessener, and St.‐59 (USSR), and Biloxi (USA) were among the most tolerant and Smena, Yantarnaya and Salute 216 (USSR), and Chief (USA) were most sensitive. Based on relative root dry weights (pH 4.0/ pH 5.1 %), Giessener was most tolerant and Smena and Salute 216 least tolerant.

Preliminary evidence indicated that soybean entries screened for Al tolerance on acid Tatum soil also differed in tolerance to naturally occurring levels of ambient ozone in greenhouses at Beltsville. The Russian entries VNIIS‐2, Giessener, and Brunatna appeared more sensitive than USA entries Perry, Biloxi, Davis, and Bossier (USA), and Santa Rosa (Brazil). Aluminum tolerance and ozone tolerance appeared to coincide in the Perry genotype. Studies on Al‐ozone‐soybean genotype relationships are being continued at Beltsville.     

Adoption potential of fruit-tree-based agroforestry on small farms in the subtropical highlands

Worldwide, fruit-tree-based agroforestry systems have been only modestly studied, although they are common on smallholder farms. Such systems based on apple (Malus spp.), peach (Prunus spp.), and pear (Pyrus spp.) are common in northwest Guatemala as low intensity homegardens and are known to increase total farm productivity in communities where farm size is a limiting factor. This study investigated the potential for adoption of fruit-tree-based agroforestry by resource-limited farmers using ethnographic investigation and linear programming simulations of farm activities at the household level. Two communities with differing demographics, infrastructure, and access to regional markets were selected based on the presence of extensive fruit-tree-based agroforestry. The influences of family size, land holdings, and tree and crop yields on the optimal adoption levels of fruit trees were evaluated through a comparative study of the varying social and physical infrastructure present in the two communities. Fruit-tree-based agroforestry was potentially more attractive to relatively prosperous families or those with larger land holdings. Improvements in fruit-tree productivity and interspecies competition were of greater importance where family land holdings were smaller. The inability of families to produce sufficient food to meet annual needs, poor fruit quality, and lack of market infrastructure were identified as constraints that limit adoption. The complementarity of production with the dominant maize (Zea mays) crop, home consumption of fruit, and the potential to generate additional cash on limited land holdings were identified as factors promoting adoption of fruit-tree-based agroforestry.     

Knot attributes and occlusion of naturally pruned branches of Fagus sylvatica

The aim of this study was to develop models on occluded branch characteristics for Fagus sylvatica (beech) based on 41 sample trees. A total of 717 beech branches were sampled; this information was then used to predict (1) the time for a complete occlusion, (2) the total radius of the occluded branch inside the trunk, (3) the branch insertion angle at the year of its death and during branch development, and (4) the dead branch portion of the occluded branch (loose knot). Generalized hierarchical mixed models with nonlinear forms were used in this analysis. The models explained between 6.3 and 52.2% of the total variance (including random effects 23.8–77.1%). The diameter of the occluded branch and the stem radial increment played dominant roles as predictors. Larger branches showed a significantly longer occlusion time, a larger occluded branch radius, a steeper insertion angle, and a higher loose knot portion. Simulations showed a biologically reasonable overall behavior of the models. The residual variation was tolerable for integrating the models into a growth simulation system.     

湟源地区草场封育对牧草结构及产草量影响的研究

对寺寨牧场1997－2000年3年牧草结构及产草量进行了测定分析,结果表明,天然草场通过围栏封育比未封育草场牧草种类,高度,盖度,明显增加,产草量提高68．4％。     

Growth Analysis, Herbage and Seed Yield of Certain Forage Legume Species Under Rainfed Conditions

The need to increase forage production for the growing livestock population in the Mediterranean region necessitates the evaluation of various promising forage species with respect to maximum herbage yield, optimum time for harvest and seed yield. Seven forage legumes, woolly pod vetch ( Vicia villosa subsp. dasycarpa accession 683), narbon vetch (V. narbonensis accession 67), common vetch ( V. sativa selections 2541, 2037, 2020), common chickling ( Lathyrus sativus selection 439) and ochrus chickling ( L. ochrus selection 104) were compared over two years with contrasting rainfall. In both years the entries were sown in November and their primary growths sampled periodically during growth. For each sample, phenology, total dry matter, leaf area index (LAI) and, at maturity, total dry matter, seed yield and harvest index, were recorded.
In both seasons, narbon vetch attained the highest dry matter and seed yields, and there was very limited variability in the maximum dry matter yield of the other entries. In general, the maximum dry matter occurred at 20–50 % podding in woolly pod vetch, 100 % podding in common vetch selection 2541 (local), narbon vetch and common chickling and at maturity in common vetch selection 2037, selection 2020 and ochrus chickling.
Throughout the vegetative to early flowering stages, woolly pod vetch had the highest dry matter yield and LAI. Possible uses of each species as animal feed are discussed.