Nitrogen Fertilization on Pearl Millet and Guinea Grass: Phytomass Decomposition,Cellulose, Lignin,and Nutrients Release

ABSTRACT

Nitrogen (N) anticipation in cover crops, besides increasing the accumulation of dry weight and nutrients, may favor the subsequent crop by increasing the availability of N. However, N can alter the decomposition of phytomass, which could reduce the beneficial effects of cover crops. The objective of this study was to evaluate the decomposition rate and nutrients release from Pennisetum glaucum and Panicum maximum syn. Urochloa maxima as a function of N fertilization. A randomized blocks design with four replicates, constituted by four treatments (pearl millet with N, pearl millet without N, guinea grass with N and guinea grass without and six sampling times (0, 14, 34, 41, 51 and 68 days after management (DAM)). The pearl millet produces more shoot dry weight than guinea grass, and the N fertilization increases the amount of dry weight for both species, but does not alter the decomposition rate. Pearl millet accumulates and releases to the soil large amounts of nutrients followed by guinea grass, regardless of N fertilization. N fertilization increases the amount of N accumulated and accelerates the release of N into the soil. The maximum release rates occur in the period of 0–14 DAM, more intensely with the N fertilization for the N.     

皇竹草与玉米秸秆青贮料饲喂肉牛的对比试验

利用皇竹草和抽穗期玉米秸秆青贮料作为能繁母牛、育肥牛的主要青粗饲料开展对比试验。通过120 d饲喂对比试验,饲喂2种不同饲料的能繁母牛受胎率分别为70.37%和76.92%,说明皇竹草和抽穗期玉米秸秆青贮料饲养能繁母牛对其受胎率无明显影响（P〉0.05）;育肥牛的日增重分别为1294 g/d和1320 g/d,表明利用皇竹草和抽穗期玉米秸秆青贮料育肥肉牛,其生长速度无明显差异（P〉0.05）。由于皇竹草在低海拔喀斯特山区易于种植,生长期长,产量高,易于加工和青贮,是低海拔喀斯特山区解决肉牛产业发展中青粗饲料来源的有效途径,适宜大面积推广应用。     

Ustilago kamerunensis on Napier grass in Kenya

Napier or elephant grass, Pennisetum purpureum Schum., is the major source of fodder for stall-fed dairy cattle in Kenya. In the early 1990s, a new disease, caused by Utilago kamerunensis P. & H. Sydow was reported on the grass. Since there was a lack of information on the general pest and disease status of Napier grass in Kenya, a survey was carried out. The survey confirmed that U. kamerunensis was the major pest and disease threat to Napier grass production in the country, having spread to four districts and occurring in 27% of farm plots sampled. The existence of disease hotspots suggests that the main means of spread is through transport of infected planting material, and that the severity of the disease in Kenya compared with other countries results from an increase in the cultivation of Napier grass over the past decade.     

A simple tentative model of the losses caused by the Senegalese grasshopper,Oedaleus senegalensis (Krauss 1877) to millet in the Sahel

Oedaleus senegalensis is a serious pest of millet in the Sahel, but the correlation to crop loss remains largely unknown. Therefore, the correlation between densities of O. senegalensis, defoliation level and millet yields was investigated in Niger in 2008, and a simple model to foresee the yield based on these parameters was developed. The yield was significantly correlated to both the density of O. senegalensis and the defoliation level on 17 September. The best model to foresee millet yield involved grasshopper density and cumulated rainfall and may be regarded a tentative method in O. senegalensis control.     

A model for predicting livemass gain from stocking rate and annual rainfall

Abstract

The relationship between livemass gain and stocking rate was established for young beef animals grazing kikuyu and Coastcross II pastures in each of five grazing seasons. The annual rainfall within these seasons ranged from 506 mm to 990 mm. Relationships between pasture production variables and annual rainfall are described and these are used to construct a model for predicting livemass gain/ha/season for different stocking rates and levels of annual rainfall.     

Evaluation of the Forage Potentials of Pearl Millet in a Semi-arid Tropical Environment

The pastures and rangelands of the semi-arid region of Nigeria wherein is the bulk of the livestock in the country, provide sufficient nutrients for livestock for no more than three to five months of the year. There is therefore need to have high yielding and good quality forages to ensure adequate all-year-round forage supply for the livestock. The objective of this study was to evaluate the forage potentials of pearl millet ( Pennistetum americanum [L.] K. Schum.) which is well adapted to the region. Twenty cultivars were evaluated for their growth, forage yield and mineral content potentials.
The cultivars were significantly different in the number of leaves per plant, plant height, dry matter yield and potassium content in each cutting. Differences in crude protein and crude fibre contents were significant only between cuttings. Variations in crude protein and crude fibre contents ranged from 14.1 to 20.3 % and from 28 to 30.8 %, respectively. Cultivars had a progressive dimunition in growth, yield and mineral content potentials after the first or second cutting. Pearl millet therefore seems less suited to forage production in the semi-arid region of Nigeria since no cultivar showed the potentials for adequate supply of all-year-round forage.     

Comparative efficacy of strobilurin fungicides against downy mildew disease of pearl millet

Three commercial formulations of strobilurins, viz., azoxystrobin, kresoxim-methyl, and trifloxystrobin were evaluated for their efficacy against pearl millet downy mildew disease caused by Sclerospora graminicola. In vitro studies revealed inhibition of S. graminicola sporulation, zoospore release, and zoospore motility at 0.1-2 μg ml⁻¹ of all the three fungicides. The fungicides were evaluated for phytotoxic effects on seed quality parameters and for their effectiveness against downy mildew disease by treating pearl millet by: (1) seed dressing, (2) seed dressing followed by foliar spray, and (3) also by foliar spray alone. The highest non-phytotoxic concentrations of 5, 10, and 10 μg ml⁻¹ for azoxystrobin, trifloxystrobin, and kresoxim-methyl, respectively, were selected for further studies. Under greenhouse conditions, these fungicides showed varying degrees of protection against downy mildew disease. Among the three fungicides, azoxystrobin proved to be the best by offering disease protection of 66%. Further, seed treatment along with foliar application of these fungicides to diseased plants showed enhanced protection against the disease to 93, 82, and 62% in treatments of azoxystrobin, kresoxim-methyl and trifloxystrobin respectively. Foliar spray alone provided significant increase in disease protection levels of 91, 79, and 59% in treatments of azoxystrobin, kresoxim-methyl, and trifloxystrobin, respectively. Disease curative activity of azoxystrobin was higher compared to trifloxystrobin and kresoxim-methyl. Tested fungicides showed weaker translaminar activity, as the disease inhibition was marginal when applied on adaxial leaf surface. Partial systemic activity of azoxystrobin was evident by root uptake, while trifloxystrobin and kresoxim-methyl showed lack of systemic action in pearl millet. A trend in protection against downy mildew disease similar to greenhouse results was evident in the field trials. Grain yield was significantly increased in all strobilurin fungicide treatments over control and maximum increase in yield of 1673 kg ha⁻¹ was observed in combination treatments of seed treatment and foliar spray with azoxystrobin.     

Evaluation of smothering effect of four legume covers on Pennisetum polystachion ssp. setosum (Swartz) Brunken

The smothering effect of four legume covers, Canavalia ensiformis , Lablab purpureus, Mucuna pruriens and Calopogonium caeruleum , on Pennisetum polystachion ssp. setosum , a troublesome weed in rubber plantations in southern Thailand, was evaluated. Growing legume covers with Pennisetum , M. pruriens , C. ensiformis and L. purpureus caused strong suppression of Pennisetum in this order. Pennisetum grew little under 10% relative light intensity (RLI), but almost normally under 40% RLI. The three legume species generally attained lower RLI than C. caeruleum . The high shading ability of these three species was thought to contribute to the suppression of Pennisetum growth.     

"猪-沼-草"生态养猪工程技术研究

论述了生态猪采用的技术方法和生产全过程。该技术以保障消费者身体健康、生产无公害绿色食品为宗旨,采用生态学理论指导生态猪生产,运用优质高产牧草作为主要青饲料,结合中草药进行防疫灭病,使用沼液灌溉牧草,改变了传统养殖技术对环境的污染,“猪-沼-草”工程模式创造了良好的经济效益和社会效益,为生态治理和可循环经济开辟了一条新途径。     

桂牧一号杂交象草留种越冬方法的研究

在对桂牧一号杂交象草繁殖特性了解的基础上,采用种茎半掩埋法越冬和覆盖种蔸留地越冬两种方法使其安全越冬,其中覆盖种蔸留地越冬的方法又采用种蔸覆盖牛粪、覆盖薄膜、覆盖火土灰、覆盖稻草、覆盖黄土等5种不同的处理方式.结果表明:种茎半掩埋法越冬种茎的越冬率为75%,每667 m2年产量为18 589.2kg,;种蔸留地越冬中覆盖牛粪、覆盖薄膜、覆盖火土灰、覆盖稻草和覆盖黄土的越冬率分别为:80%、100%、80%、70%、75%,比对照区分别高出30%、50%、30%、20%、25%,产量分别为:19 451.2 kg、19018.5 kg、18 9364 kg、18 106.6 kg、17 982.9 kg,比对照区分别高出19.9%、17.2%、16.7%、11.6%、10.9%.另外对每个处理作出了评价.