Agronomy and Crop Sciences Commons^™

Nitrogen Mineralization From Root Residues Of Subterranean Clover And Lucerne, T. P. Bolger, J. F. Angus, M. B. Peoples

IGC Proceedings (1977-2023)

To understand why crops grown in the first or second year after lucerne (Medicago sativa L.) yielded less than crops grown after subterranean clover (Trifolium subterraneum L.) despite greater nitrogen (N) fixation by the lucerne, we studied the N mineralization patterns of their root residues in soil incubation assays. Fine roots of both species produced more mineral N than the control soil with no root residues. In contrast, coarse roots mineralized less N than the control soil. These differences in N mineralization were not explained by the physical size and therefore surface area differences between fine and coarse …

Impact Of Urbanization Trends On Production Of Key Staple Crops, José F. Andrade, Kenneth G. Cassman, Juan I. Rattalino Edreira, Fahmuddin Agus, Abdullahi Bala, Nanyan Deng, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

Urbanization has appropriated millions of hectares of cropland, and this trend will persist as cities continue to expand. We estimate the impact of this conversion as the amount of land needed elsewhere to give the same yield potential as determined by differences in climate and soil properties. Robust spatial upscaling techniques, well-validated crop simulation models, and soil, climate, and cropping system databases are employed with a focus on populous countries with high rates of land conversion. We find that converted cropland is 30–40% more productive than new cropland, which means that projection of food production potential must account for expected …

Transgenic Maize Hybrid Crop Residues: Nutritive Value And Their Effects On Performance Of Grazing Beef Cows, S. K. Barnhart, J. R. Russell, M. J. Hersom, D. E. Farnham

IGC Proceedings (1977-2023)

Several maize (Zea mays) hybrids, including three transgenic hybrids containing Bacillus thuringiensis (Bt) enzymes (Bt-maize hybrids), were planted in a field study. Mature, midgestation, beef cows (Bos tarus) strip-grazed post-harvest residues as paddocks over 126 days. Body condition-scores and weights were monitored. Forage yield, weathering losses and forage composition were monitored on grazed and ungrazed areas. Forage selection and intake were estimated. Grain yields, dropped grain, initial crop residue concentrations of dry matter (DM), organic matter (OM) and in vitro digestible organic matter (IVDOM) yields were similar among hybrids. Hybrids varied in infestation of maize borers, …

Supplementation Of Temperate Pastures, D. H. Rearte, G. A. Pieroni

IGC Proceedings (1977-2023)

Generally in temperate regions, beef and milk were produced on extensive systems with forage from perennial pasture and natural grassland being the main component of animal diet. Supplementation on pasture was usually applied strategically to supply nutrients to grazing cattle only when forage availability was not enough to satisfy animal’s requirements. At present beef and dairy production systems have become more intensive and even when forage from pasture continue being the main component of the diet higher level of different type of supplement are fed to the animals. Intensive systems are characterized by a higher stocking rate capable of consuming …

Feeding Of Conserved Forage - Implications To Grassland Management And Production, C. W. Holmes, P. N. P. Matthews

IGC Proceedings (1977-2023)

This review will focus on the use of conserved forages in pastoral dairy farm systems; especially on their conservation as an aid to good grazing management during periods of rapid pasture growth, and on their consumption as an aid to good feeding management and grazing management during periods of slow pasture growth. Conservation of pasture, in order to move it from one time to another later time, always involves “costs”, either financial expenditure or physical losses (of dry matter/quality) or both, which must be evaluated in the whole system.

Most of the data is drawn from New Zealand and Australia, …

Protein Sources For Growing Beef Steers Fed With A Diet Based On Corn Silage, M. De León, E. Ustarroz, C. Boetto, J. M. Simondi, M. Bulaschevich

IGC Proceedings (1977-2023)

This study was conducted to determine the effect of different protein sources in growing beef cattle (25 Aberdeen Angus steers) fed with a corn silage based diet on daily live weight gain (DLWG), dry matter intake (DMI) and feed conversion (FC). Five treatments with different supplies of crude, degradable and metabolizable protein (MP) were used. The treatments were formulated with different protein sources to provide different rate and extents of protein degradation, as follow: a negative control (T0) without protein supplements and below animal requirements, urea (T1), soybean meal (T2), whole cotton seed (T3) and a positive control (T4), which …

High Moisture Sorghum Grain Silage: Effects Of Tannin Content And Urea Treatment On The Performance Of Dairy Cows, L. A. Romero, E. A. Comerón, O. A. Bruno, A. R. Castillo, M. C. Gaggiotti

IGC Proceedings (1977-2023)

Grain sorghum silage tannin content effect was evaluated on milk production and chemical composition of Argentinean Holstein bred cows, and it are described dry matter (DM) and crude protein (CP) in situ digestion parameters and effective degradability. The base diet was constituted by alfalfa pasture, maize silage, and a protein – mineral supplement, differing in three treatments based on high moisture grain silage characteristic: LTS= Low tannin grain sorghum, HTS= High tannin grain sorghum, and HTSu= High tannin sorghum plus the addition of urea. Grain sorghum silage tannin content affects milk production, without significant alteration of chemical composition. Beside the …

Changes Of Forages Fed To Dairy Cows In The Whole Year In Taiwan, F. H. Hsu, C. H. Lu

IGC Proceedings (1977-2023)

Objectives of this study were to determine the kinds and the percents of forages fed to dairy cows in the whole year. Data were taken weekly by the dairy farmers for one year, including kinds and weights of forages fed to dairy cows, the heads of milking cows, dry cows and heifers. Dairy farmer A used napiergrass (Pennisetum purpureum) green chop 68.2%, napiergrass silage 15.3%, pangolagrass (Digitaria decumbens) hay 3.2% and imported bermudagrass (Cynodon dactylon) hay 13.3% to feed cows. Dairy farmer B fed cows with napiergrass green chop 65.1%, pangolagrass 13.0% and imported …

Comparative Growth Performance Of West African Dwarf Goat Supplemented With Calliandra Calothyrsus, Leucaena Leucocephala, Or Cotton Seed Cake In West Cameroon, E. Tedonkeng Pamo, G. D. Assontia, C. Njehoya

IGC Proceedings (1977-2023)

A comparative growth performance study of African Dwarf Goats supplemented with Calliandra calothyrsus, Leucaena leucocephala or cotton seed cake was carried out on farm around Dschang and in the University Experimental Farm. Goats between 12 and 16 months of age were divided into 4 groups of 11 goats each with one group kept as a control. The supplemented animals received respectively 390 g of L. leucocephala, 380 g of C. calothyrsus (fresh matter) and 88.8 g of cotton seed cake each, corresponding to 6 g of nitrogen per animal per day. The animals were weighed every 21 days …

Voluntary Intake Of Tanzania Grass (Panicum Maximum) Under Rotational Grazing By Lactating Cows, M. L. P. Lima, T. T. Berchielli, J. R. Nogueira, A. K. D. Salman, Ana C. Ruggieri, Paulo Roberto Leme, L. J. M. Aroeira, J. P. G. Soares

IGC Proceedings (1977-2023)

The study was conducted at Nucleo de Pesquisas Zootecnicas Nordeste of the Instituto de Zootecnia, Ribeirão Preto, SP, in a rotational grazing area of Tanzania grass (Panicum maximum), to estimate the dry matter intake by lactanting cows. The estimation of dry matter intake was calculated from the feces production estimated using extrusa Chromium-mordent and the in vitro digestibility of diet. The three treatments were crossbreed cows fed 3 kg.day^-1 of concentrate, crossbred cows without concentrate suplementation and pure Gir cows also without concentrate supplementation. The milk production was 11.98, 6.53 and 5.46 kg per cow per day, …

The Effect Of Browse Species When Fed As A Supplement To Low Quality Native Grass Hay On Animal Performance, A. Elgersma, J. F. Oerlemans, D. B. Coates

IGC Proceedings (1977-2023)

A pen trial was conducted to measure the impact of some browse species when fed as a supplement on the nitrogen (N) and dry matter intake of cattle receiving low quality native grass hay. There were 8 treatments consisting of a nil-supplement control treatment, a urea supplement control, a green oaten hay control and 5 treatment groups based on browse supplements (Albizia lebbeck, Carissa spp. and Bursaria spp.). Treatment effect on increased native pasture intake was related to the amount of supplementary nitrogen (N), such that there was a significant linear relationship between dry matter intake of native …

Effects Of Different Levels Of Energy Supplementation On Growth Of Grazing Holstein Heifers, L. P. Novaes, C. E. Polan

IGC Proceedings (1977-2023)

Growth of Holstein heifers was studied for 1987 grazing season to evaluate pasture-drylot systems for raising dairy replacements. Orchardgrass (Dactylis glomerata L), tall fescue (Festuca arundinacea Schreb), bluegrass (Poa pratensis L) and white (Trifolium repens L) and red clover (Trifolium pratense, L) were the principal components of the grass-legume mixture in six paddocks of 1.5 ha each. Carrying capacity was estimated at six animals/ha (3.1 animal units) and excess forage was harvested as hay to control forage growth and quality. Grazing days were 140 days. None or 2.0 kg/d …

Intake And Growth Of Steers Offered Different Allowances Of Autumn Grass And Concentrates, Edward G. O’Riordan, P. French, Padraig O’Kiely, A. P. Moloney

IGC Proceedings (1977-2023)

The aim of this experiment was to quantify the relationship between autumn grass supply and concentrate supplementation level on grass intake and animal performance. One hundred and ten continental steers (567kg) were assigned to ten treatments in a three grass allowances: (6, 12 and 18kg dry matter (DM) per head daily) by three concentrate levels: (0, 2.5 and 5kg/head/daily) factorial design with a positive control group offered concentrates ad-libitum. Grass allowance was offered daily and concentrates were fed individually. The experiment began on August 22 and all animals were slaughtered after a mean experimental period of 95 days. Grass …

Fatty Acid Composition And Eating Quality Of Muscle From Steers Offered Grazed Grass, Grass Silage Or Concentrate-Based Diets, A. P. Moloney, P. French

IGC Proceedings (1977-2023)

The effects of grazed grass, grass silage or concentrates on the eating quality and fatty acid composition of intra-muscular fat of steers fed to achieve similar carcass growth rates were investigated. Fifty steers were assigned to one of five dietary treatments. The experimental rations offered daily for 85 days pre-slaughter were (a) grass silage plus 4 kg concentrate, (b) 8 kg concentrate plus 1 kg hay, (c) 6 kg grazed grass dry matter (DM) plus 5 kg concentrate, (d) 12 kg grazed grass DM plus 2.5 kg concentrate or (e) 22 kg grazed grass DM. Decreasing the proportion of concentrate …

Supplementation Of Lactating Cows Grazing Stargrass (Cynodon Nlenfuensis Var. Nlenfuensis) With Conjugated Linoleic Acid: Effects On Persistency And Estimated Net Energy Balance, S. R. Medeiros, D. E. Oliveira, L. J. M. Aroeira, M. Mcguire, D. P. D. Lanna

IGC Proceedings (1977-2023)

Thirty crossbread cows grazed stargrass (Cynodon nlenfuensis var. nlenfuensis) receiving 4kg/d of a supplement formulated to provide 115% of metabolizable protein requirements from the 4^th to the 11^th week of lactation. The cows received either 150g/head/day of Megalac (Control) or 150g/head/day of a Ca-protected conjugated linoleic acid (CLA, Church & Dwight). Residual effects of treatment were evaluated in weeks 12^th and 13^th. Milk production increased in CLA treated cows (P< 0.05). CLA decreased milk fat content (P< 0.0001) and yield (P< 0.01). Protected CLA increased protein content (P< 0.01) and yield (P< 0.01). The CLA residual effect on milk fat ends within one week after withdrawal but the benefits on milk yield and total solids production continued, due to the increased persistency. The estimated energy balance and intake were not greatly affected by treatment, as treated cows had higher milk volume and had higher protein productions.

Use Of Supplements For Maintenance Of Nelore Bullocks In Brachiaria Decumbens, During The Dry Season In Acre, Brazilian Amazon, J. C. Carneiro, Judson F. Valentim, L. A. R. Valle

IGC Proceedings (1977-2023)

This study had the objective of evaluating animal performance and net economic returns of Nelore bullocks receiving: 1) mineral mixture (MM), 2) mineral mixture + urea (MMU), and 3) multiple supplement (MS), during the dry season of 1999 in Acre, Brazilian Amazon. The animals were maintained in pastures of Brachiaria decumbens, and liveweight gains, forage availability and chemical composition were assessed during the experimental period. Liveweight gains of 0.58, 0.65 and 0.60 kg/day, respectively, for MM, MMU and MS, were not different (P> 0.05). The use of MMU provided additional net economic return of 10.8% in comparison with the …

Roots And Potatoes As Supplements To An Alfalfa – Grass Diet To Dairy Cows, T. Eriksson, P. Ciszuk, E. Burstedt

IGC Proceedings (1977-2023)

Fourteen multiparous dairy cows were used in 3 x 3 change-over experiment designed to study effects of replacing barley by roots and potatoes in diets based on leguminous forage on feed intake, milk production and utilisation of feed nitrogen. The cows received a mixture of alfalfa (Medicago L.) and grass silage ad libitum and an isoenergetic quantity of a supplement based on either barley and potatoes (Ba/P), fodder beets (Beta vulgaris L.) and potatoes (Be/P) or barley (Ba). The grass in grass silage was dominated by timothy (Phleum pratense L.). Total DM intake as well as yield …

Agronomic Evaluation Of Forage Grasses Under Mature Rubber Plantation, N. L. Costa, Valdinei T. Paulino, A. C. M. Igreja, C. R. Townsend, J. A. Magalhães, R. G. De A Pereira, T. S. Paulino

IGC Proceedings (1977-2023)

The agronomic performance of seven forage grasses, under a mature rubber plantation, was assessed in a cutting trial carried out at Porto Velho, Rondônia. During the rainy season, the higher dry matter yields were obtained with B. brizantha, P. atratum BRA-9610 and B. humidicola. During the dry season, the grasses more productive were B. brizantha and P. atratum BRA-9610. In both seasons, magnesium and potassium contents did not vary among grasses. During the rainy season, the higher nitrogen and phosphorus contents were obtained with P. regnelli BRA-0159 and, P. guenoarum BRA-3824 and B. humidicola, respectively, while P. atratum …

Constraints And Opportunities For Development Of Grasslands In Urban Areas Of The Niayes Zone In Senegal, S. T. Fall, I. Cissé

IGC Proceedings (1977-2023)

A survey was carried out in urban areas of the Niayes zone in Senegal to explore grasslands development in agropastoral systems around towns. Rapid rural appraisal and farms multiple visits were done to describe the forage cropping system, identify constraints and opportunities of developing grasslands in urban areas. In Niayes urban areas, forage production system is being developed based on the cropping of several grass and tree species. Only a minority of farmers is involved in that activity. Level of grass production is rather low. Weak development of grasslands is observed. Main reasons are: farmer poor willingness to crop for …

Semiarid Grassland And Winter Cereals For Lamb Production In Northeast Patagonia, Argentina, D. P. Miñón, G. G. Durañona, J. C. García Vinent, H. D. Giorgetti, G. D. Rodríguez

IGC Proceedings (1977-2023)

In northeastern Patagonia where grain crops often led to harvest failure, low yields and a high drought risk, a lamb production system was established. On a 10 years old agriculture wheat cropping was interrupted in 1996, allowing re-vegetation through exclusion of grazing. Natural grassland recovered, prevailing the species Stipa tenuis, Piptochaetium napostaense, Stipa ambigua. Part of the plot was sown to wheat grass (Thinopyrum ponticum). In 1999, to improve sheep feeding, oat (Avena sativa) and barley (Hordeum vulgare) were sown for grazing during winter-spring season. In this system Corriedale sheep, Texel x australian …

Nutritive Quality Of Tropical Grasses Sown Under A Pine Plantation, D. Gutmanis, Antonio João Lourenço, V. B. G. Alcantara, Maria T. Colozza

IGC Proceedings (1977-2023)

A trial was conducted in Brazil to evaluate the nutritive quality of 6 tropical grasses: tanzania (Panicum maximum cv. Tanzania), green-panic (P. maximum var. Trichoglume), aruana (P. maximum cv. Aruana), brizanta (Brachiaria brizantha), humidicola (B. humidicola) and tifton-85 (Cynodon dactylon cv. Tifton 85), planted under two different densities of pines (Pinus elliottis): 200 and 400 stems/ha, as well as in full sunlight. The results showed a significant increase in protein content and a significant decrease in NDF and cellulose contents as tree density increased. Comparing the values obtained under shading conditions …

Production And Mineral Composition Of Tropical Grasses Sown Under A Pine Plantation, D. Gutmanis, V. B. G. Alcantara, Maria T. Colozza, Antonio João Lourenço

IGC Proceedings (1977-2023)

A trial was conducted in Brazil to evaluate the performance of 6 tropical grasses: tanzania (Panicum maximum cv. Tanzania), green-panic (P. maximum var. Trichoglume), aruana (P. maximum cv. Aruana), brizanta (Brachiaria brizantha), humidicola (B. humidicola) and tifton-85 (Cynodon dactylon cv. Tifton 85), planted under two different densities of pines (Pinus elliottis): 200 and 400 stems/ha, as well as in the full sunlight. The results showed that the dry matter yield decreased as shading increased. The grasses tanzania and brizanta were the most tolerant to shading. Although N concentration increased with …

Dry Matter Production And Nutritive Value Of Alfalfa (Medicago Sativa L.) And Orchardgrass (Dactylis Glomerata L.) Under Different Light Regimes, A. C. Varella, P. L. Peri, R. J. Lucas, D. J. Moot, D. L. Mcneil

IGC Proceedings (1977-2023)

Spring and summer alfalfa dry matter and nitrogen production rates were greater than orchardgrass in open pasture and under three shade levels. Ten years old Pinus radiata allowed 60% light transmissivity. The addition of artificial shade resulted in 45% and 25% transmissivity. Orchardgrass pastures were nitrogen deficient and water stressed. In contrast, alfalfa was not stressed and it was more light responsive than orchardgrass. Differences in nutritive value were relatively small between species and between light regimes. Sheep liveweight gain on alfalfa was greater than on orchardgrass. Orchardgrass demonstrated shade tolerance, but alfalfa was more productive even at 25% transmissivity. …

Different Methods Of Artificial Shade For Agro-Silvipastoral Research, A. C. Varella, D. J. Moot, R. J. Lucas, D. L. Mcneil, P. L. Peri, K. M. Pollock

IGC Proceedings (1977-2023)

Artificial shading sources are used to simulate silvipastoral light environments and study the effect of shade on pasture. Different sources of shade may not imitate normal forest light environment. An experiment was conducted to examine the light environment and effect on pasture yield components of two artificial shading materials. Alfalfa (Medicago sativa L.) pasture was submitted to three light regimes: full sunlight (100% transmissivity); black shade cloth (40%) and wooden slats (45%).

The pattern of light exposure for plants differed under slats and shade cloth, but light intensity and quality were similar. Alfalfa dry matter (DM) yield and leaf …

Competition For Light In A Leucaena Leucocephala / Chloris Gayana Silvopastoral System, N. F. G. Rethman, J. P. Lindeque

IGC Proceedings (1977-2023)

The spatial variation in the vigour of Leucaena (Leucaena leucocephala cv. Cunningham) trees growing together with Rhodesgrass (Chloris gayana cv. Katambora) in an alley cropping system made it possible to assess the competitive effect for light. The height and especially lateral development of trees had a strong influence on light interception by the canopy, with radiation in the intercrop area being 49% lower where the trees were more vigorous. There was a corresponding (43%) decrease in grass production. These findings indicate that future studies should also include aspects such as espacement of trees, pruning of trees in the …

Optimizing Yield And Quality Of Orchardgrass Pasture In Temperate Silvipastoral Systems, P. L. Peri, R. J. Lucas, D. J. Moot, A. C. Varella, D. L. Mcneil

IGC Proceedings (1977-2023)

The objective of this study was to provide grazing management recommendations for a silvipastoral system by determining the effects of shade and nitrogen (N) on the pattern of dry matter accumulation and nutritive value of orchardgrass (Dactylis glomerata) in a subhumid temperate environment. Orchardgrass in open pasture (100% transmittance) and under 10 year old Pinus radiata tree shade (60% transmittance) at 200 stems/ha was used as the main plot and nitrogen (0 and 300 kg N/ha as synthetic urine) was the subplot factor. Dry matter (DM) production of orchardgrass in the first 60-day spring rotation was similar in …

Herbage Characteristics As Affected By The Canopies Of Dominant Trees In A Savanna Of Southern Mozambique, James P. Muir, A. Alage, Inacio C. Maposse

IGC Proceedings (1977-2023)

This study surveyed the species composition, forage yield and forage nitrogen concentration of the herbaceous layer 50, 100 and 200% of the canopy radius from the trunks of many-stemmed false thorn, knob thorn, scented thorn and marula trees in a southern Mozambican savanna. Tree species did not affect herbaceous DM yield or species diversity. Neither direction nor distance from the tree trunk affected DM or specific diversity. Crude protein percentages were 15% higher for legumes and 9% higher for grasses at 50% canopy than at 200% canopy. Grasses under the marulas, the only non-legume tree in the study, had 18% …

Selecting New Brachiaria For Brazilian Pastures, Cacilda B. Do Valle, Valéria P. B. Euclides, Manuel C. M. Macedo, José R. Valério, S. Calixto

IGC Proceedings (1977-2023)

Brazilian beef production relies heavily on cultivated pastures, of which about 80% are planted mainly to two Brachiaria cultivars. The narrowness of diversity associated with reproduction by apomixis of most plants in this genus prompted an intense search for new cultivars amongst recently collected and introduced ecotypes from Africa. This paper reports results for a three-year evaluation of 21 pre-selected ecotypes in two typical Cerrado ecosystems. Plots, replicated four times, were seeded in rows and cut every 6 weeks during the rainy season followed by a cut in the middle and one at the end of the dry season. Significant …

Diversity And Composition Of Plant Species In The Geita Gold Mining Catchment Area, Tanzania, Mariam G. Mgendi, Mkabwa Lawrence Manoko, William J.S. Mwegoha

Journal of Humanities and Social Sciences

A study on the diversity of plant species is of vital importance for the conservation of natural ecosystems that are increasingly being threatened by various anthropogenic activities. Greater diversity makes ecosystems healthier and resilient to stress, thus providing its services on which humans depend. This study aimed to assess the health of the ecosystem around the Geita Gold Mine (GGM) based on the diversity and composition of plant species. Two transects with a total of 14 sampling sites were established where the number of plant species were systematically recorded using nested quadrats. The diversity of species was determined using species …

Supplmentary Feeding And Management Strategies To Overcome Drought Situations On Three High Producing New Zealand Seasonal Dairy Farms, S. H. Benson, P. N. P. Matthews

IGC Proceedings (1977-2023)

This paper investigates the outcomes of the management strategies to overcome dry summer conditions on three New Zealand seasonal supply dairy farms where the summer management philosophy is towards production rather than survival aimed at giving the farmer control rather than accepting the unreliable production outcomes often achieved. Actual data collected from the case farms as part of a large on-farm monitoring programme was used to model the dry 1998/99 season. This was compared with simulated models for an average season to estimate milksolids responses (g milksolids (MS)/kg DM) and net returns (cents/kg DM) to the additional feeds used. In …