Increased Dry Matter Production Research Articles

An assessment of herbage mass, ryegrass cultivar and red clover inclusion on sward productivity, quality and morphology under a cutting protocol

AbstractThe use of ‘cut-and-carry’ (the mechanical harvesting and feeding of fresh grass) has increased in some temperate regions in recent years and evidence suggests that sward management practices in this system differ to conventional grazing. In order to investigate this further, a 2 × 3 × 2 factorial experiment was used to examine the effect of low (1489 kg dry matter (DM)/ha; LHM) and high (2142 kg DM/ha; HHM) pre-cutting herbage mass; three ryegrass cultivars, diploid perennial ryegrass (Lolium perenne; DIP), tetraploid perennial ryegrass (TET) and a hybrid ryegrass (Lolium multiflorum × L. perenne; HY); and the inclusion of red clover (Trifolium pratense) on sward herbage production, nutritive value and ryegrass morphology. Plots were harvested according to herbage mass from March to November in 2018 and 2019. Annual DM production was 1489 kg DM/ha higher in HHM than in LHM swards. Pre-cutting herbage mass had no effect on organic matter digestibility (OMD) in early season for DIP and TET swards or in late season for all cultivars. There was an interaction between ryegrass cultivar and clover inclusion in annual yield whereby red clover increased DM production in all cultivars however, its effect was largest in HY swards. Red clover inclusion increased DM production but reduced OMD in early and mid-seasons. Overall, TET swards were lowest in neutral detergent fibre and highest in OMD compared to HY and DIP. Pre-cutting herbage mass, ryegrass cultivar and red clover inclusion require careful consideration when establishing and managing pastures in cut-and-carry systems.

Reducing Eragrostis lehmanniana populations by preparing seedbeds with unconventional tillage implements and seeding in a semiarid grassland

AbstractThe invasion of Lehmann lovegrass (Eragrostis lehmanniana Nees) in rangelands of Chihuahua, Mexico, has resulted in a need for revegetation to recover lost forage productivity. Thus, new knowledge on generating alternatives to improve these invaded grasslands is of great importance. This study evaluated seedbeds prepared with unconventional tillage implements and seeded with a grass mixture to reduce the plant density of E. lehmanniana while increasing the productivity of an invaded semiarid grassland of Chihuahua. The unconventional tillage implements were: a Rangeland Harrow, which was used to prepare the Striped Harrowing and Full Harrowing seedbeds; Rangeland Rehabilitator, which was used to prepare the Deep-Stingray Subsoiler seedbed; and a Tandem-type Aerator Roller, which was used to prepare the Double-Digging Aeration seedbed. An area without tillage was left as a control. The seed mixture was composed of blue grama [Bouteloua gracilis (Willd. ex Kunth) Lag. ex Griffiths var. Hachita] (25%); sideoats grama [Bouteloua curtipendula (Michx.) Torr. ‘6107 Kansas’] (25%); green sprangletop [Leptochloa dubia (Kunth) Nees var. Van Horn] (5%); weeping lovegrass [Eragrostis curvula (Schrad.) Nees var. Ermelo] (40%), and Columbus grass [Sorghum almum Parodi] (5%). The experiment was conducted across 4 yr, and the evaluation started at the second year. Plant density and dry matter (DM) production were evaluated per species. In the control plot, the plant density of E. lehmanniana increased approximately 180% from the 2nd to the 4th year (18 to 50 plants m−2). The use of unconventional tillage implements for seedbed preparation and the inclusion of E. curvula in the seed mixture decreased E. lehmanniana density in more than 50% of plots and increased DM production in around 100% of plots. Considering the whole experimental period, in all the prepared seedbed treatments, E. curvula had the highest establishment and DM production of all the seeded species. The native species B. gracilis, B. curtipendula, and L. dubia had poor establishment in all the prepared seedbeds.

The effects of urine and urine-separated plant nutrient sources on growth and dry matter production of perennial ryegrass (Lolium perenne. L)

The use of urine, and urine-derived products can supplement chemical fertilisers. There is little information on the use of urine products in agriculture particularly in South Africa. A laboratory incubation experiment was conducted to determine effects of urine-derived sources on nitrogen (N) release in soil. A 5 × 2 factorial in a completely randomised design was used with two soils, differing in clay and carbon contents, and five nitrogen (N) sources; unamended control, urine, struvite effluent, stuvite + struvite effluent, nitrified urine concentrate. A follow up tunnel pot trial was conducted to determine effects of the urine-derived N sources on dry matter production of perennial ryegrass. The experiment was conducted with the Cartref soil as a 6 × 2 factorial in a completely randomised design, with the same N sources as in the incubation experiment, applied either once-off or split, replicated three times. In the Cartref soil (lower clay and C), ammonium- N declined from 1000 to about 3 mg/kg from day one to day 70, while nitrate- N increased significantly from 0.3 mg/kg to about 400 mg/kg during the same period. Conversely, ammonium-N declined from 100 mg/kg to 8.5 mg/kg in the Inanda soil (higher clay and C), while nitrate- N did not significantly increase. Split application of urine derived N sources resulted in higher cumulative dry matter (873–993 kg/ha) than once-off application (602–727 kg/ha). When split applied only struvite effluent resulted in higher drymatter than struvite effluent + struvite, while once-off application resulted in higher drymatter in the NUC (725 kg/ha) and urine (707 kg/ha) than struvite effluent (602 kg/ha) and struvite effluent + struvite (663 kg/ha). The study indicate that urine derived nitrogen sources, particularly nitrified urine concentrate, can release nitrogen in soil and increase drymatter production of perennial ryegrass, particularly with split application.

Genetic gains in NSW wheat cultivars from 1901 to 2014 as revealed from synchronous flowering during the optimum period

Quantifying historic increases in water-limited potential yield (PYw) achieved through breeding provides insight into associated changes in physiology and can assist with future cultivar improvement. We compared PYw of bread wheat cultivars popular in southern New South Wales released between 1901 and 2014. In both 2015 and 2016, cultivars were sown at multiple sowing dates to allow comparisons to be made at a consistent optimal flowering date (early October), and thus control for the large differences in life cycle duration. Seasonal conditions were close to average in 2015 and extremely favorable in 2016. In both, grain yield increased across the historic period studied at 26 kg/ha per annum, regardless of whether a common sowing date or flowering date was used. Yield gain was not linear, and there was a period of rapid yield increase during the middle of the 20th century, that culminated with the release of semi-dwarf cultivars. Yield gain was relatively slower from the 1980s until the present day, possibly due to selection for grain quality traits (grain size) at the expense of grain number. Historic yield increases were not associated with earlier flowering, but with an interplay between greater grain number/m2 and greater grain weight which was the result of increased partitioning of assimilates to spikes, and greater number of grains per unit spike weight (fruiting efficiency). Greater partitioning to the spike in modern cultivars was associated with reduced dry matter (DM) production prior to flowering. Modern cultivars have a less stable flowering time across sowing dates, and shorter life cycle, but improved partitioning in modern cultivars appeared decoupled from shorter developmental phases prior to flowering. The performance of the novel vernalisation sensitive cultivar Longsword showed that future yield gain may be achieved through the combination of early sowing and slow development, increased DM production and superior partitioning to grain.

PENINGKATAN PRODUKSI DAN KECERNAAN BAHAN KERING Centrosema pubescens DAN Pueraria phaseoloides OLEH PEMUPUKAN BATUAN FOSFAT DAN INOKULASI MVA

Centrosem a pubescens (centro) and Pueraria phaseoloides (puero) are important forage legumes as protein and mineral sources for ruminant livestock in the tropics. However, most of the land that used for forage production is characterized by a low phosphorus content. As the high cost of superphosphate is a major limiting factor, a combination of rock phosphate (RP) fertilization and vesicular-arbuscular mycorrhizae (VAM) fungi inoculation maybe a promising technique. A field experiment was conducted in Bogor during 7 months, on a latosolic soil (low pH and low available Bray II extractable P) to evaluate the effects of RP fertilization and VAM inoculation and their interaction on dry matter (DM) production and in vitro dry matter digestibility. A completely randomized block design with 3 replicates was used . The main experiment consisted therein the combination of three factors as follows 1) legume species (centro, puero), 2) VAM inoculation (with, and without VAM inoculation), and 3) rock phosphate fertilization (0, 44, 87, 131, and 175 kg P ha-1). The period of defoliation was used as sub factor (defoliation I, II, and III). Results showed that DM production and DM digestibility of puero was significantly higher (P 0.05) with or without VAM inoculation. When inoculated, rock phosphate fertilization increased DM production of legume. Success of VAM inoculation in the field affected by effectiveness of indigenous- VAM fungi or depending upon VAM inoculum potential.

Does post‐grazing sward height influence sward characteristics, seasonal herbage dry‐matter production and herbage quality?

AbstractExtending the grazing season through the production and utilization of high‐quality forage is a key objective in grassland‐based dairy production systems. Grazing swards to a low post‐grazing sward height (PGSH) is a strategy for improving grass utilization. A grazing experiment conducted in Ireland investigated immediate and subsequent effects of PGSH on sward production, utilization and structural characteristics. Swards were grazed to 2·7 cm (severe; S1) or 3·5 cm (moderate; M1) from 10 February to 18 April 2010 (Period 1; P1). From 19 April, each P1 paddock was halved and grazed to either 3·8 cm (S2) or 4·8 cm (M2), until 30 October (Period 2; P2). The first grazing rotation was +7 d on S1 swards compared with M1 swards (45 d), due to greater herbage utilization (+0·22). Herbage production during P1 was not affected by PGSH but a severe PGSH during this period reduced subsequent herbage production: 13·9 (S1) vs. 15·5 t dry matter (DM) ha−1 (M1) by the end of the study. Leaf proportion was increased (+0·10) on S2 swards compared with M2 swards, but M2 swards produced 1·2 t DM ha−1 more herbage during P2. Despite the relatively lower level of sward utilization obtained from moderate grazing in P1 (3·5 cm) and P2 (4·5–5·0 cm), such levels of PGSH increased DM production while maintaining sward quality, compared with severe grazing (2·7 cm in P1 and 3·5–4·0 cm in P2).

경북에서 도입 콤먼베치 및 자생종의 생육특성과 수량

본 시험은 2010년부터 2012년까지 경북 성주에서 2모작 작부체계에 알맞은 다수성이며 조숙성인 콤먼베치의 품종을 선발 할 목적으로 헤어리베치 Cold green, 콤먼베치 Maxivesa, Wild common, Rasina, Morava 및 Blanchefleur의 생육특성, 건물수량 및 사초품질을 평가하였다. 시험설계는 품종을 처리로한 6처리 3반복의 난괴법으로 배치하였다. 파종은 2010년 10월 11일과 2011년 10월 3일에 하였으며 수확은 2011년 5월 4일과 2012년 5월 10일에 실시하였다. 가을의 초형은 Wild common은 부복형이었으며 다른 품종들은 반직립형이었다. 유식물의 활력은 다른 품종들에 비해 Wild common이 다소 낮았다. 내한성은 Cold green과 Wild common이 우수했으나 다른 콤먼베치 품종들은 낮았다. 개화기는 Cold green이 4월 22일로 가장 빨랐으며 Wild common은 4월 26일 Rasina와 Blanchefleur가 4월 28일이었으며 Maxivesa가 5월 17일이었다. 1년차 시험에서 건물수량은 Cold green은 다른 5품종보다 수량이 높았으며 (p<0.05), Wild common은 나머지 4품종보다 많았으며 (p<0.05), Maxivesa와 Blanchefleur는 Rasina와 Morava보다 높았다 (p<0.05). 2년차 시험에서도 건물수량은 Cold green은 다른 5품종 보다 높았으며 (p<0.05), Wild common은 다른 4품종보다 높았다 (p<0.05). 일반적으로 베치의 CP 함량은 높았고 섬유소함량은 낮았다. 가을 파종 콤먼베치의 품종은 개화기가 빠르며 내한성이 강한 Wild common이 좋을 것으로 생각된다. This experiment was conducted to evaluate agronomic characteristics, forage quality, and dry matter (DM) yield of hairy vetch 'Cold green', common vetch 'Maxivesa', 'Wild common', 'Rasina', 'Morava', and 'Blanchefleur', at Seongju in Kyeongbuk from 2010 to 2012. The experiment was arranged in randomized complete block design with three replications. Vetchs were seeded on the 10th of Oct. 2010 and on the 3rd of Oct. 2011. Vetch plants were harvested on the 4th of May 2011 and on the 10th of May in 2012. 'Cold green' and 'Wild common' exhibited greater cold tolerance than other cultivars. Fifty percent-flowering of 'Cold green' occurred on the 22nd of Apr., whereas that of 'Wild common' occurred on the 26th of Apr. and those of 'Rasina' and 'Blanchefleur' occurred on 28th of Apr. and that of 'Maxivesa' occurred on 17th of May. The DM yield of 'Cold green' was higher (p<0.05) than all other cultivars, whereas the DM yield of 'Wild common' was higher (p<0.05) than those of the remaining 4 cultivars. According to the results obtained from this study, it is suggested 'Wild common' vetch is be recommendable for cultivation where increased DM production is sought.

PENINGKATAN PRODUKSI DAN KECERNAAN BAHAN KERING ALFALFA DENGAN PEMUPUKAN FOSFAT

Alfalfa (Medicago sativa L.) as one of legume forage crops for ruminant livestock is very sensitive to the phosphorus deficiency. Phosphorus fertilizers have been used widely to overcome those problem. However, the high cost of superphosphate (SP) is now focusing attention on cheaper rock phosphate (RP) fertilizer. A field experiment was conducted on a latosolic soil (low pH, and low available Bray II extractable P). The objective of the research is to evaluate the effect of phosphorus fertilizer from difference sources on dry matter production, and in vitro dry matter digestibility of alfalfa. Completely randomized block design with 7 treatments in 3 replicates was used in this field experiment. The treatments were T0 (control), T1 (SP, 100 kg P2O5/ha), T2 (SP, 200 kg P2O5/ha), T3 (SP, 300 kg P2O5/ha), T4 (RP, 100 kg P2O5/ha), T5 (RP, 200 kg P2O5/ha), T6 (RP, 300 kg P2O5/ha). Size of each plot was 2 m x 2 m, and fertilized with P fertilizer (SP, RP) according to the assigned treatment. All plot received basal fertilizer of urea (50 kg N/ha), KCl (100 kg K2O/ha) and poultry manure (2 ton/ha). Medicago sativa was defoliated on 12 weeks after planting and analyzed for dry matter (DM) production and in vitro DM digestibility. Result showed that DM production significantly influenced by the treatments. Superphosphate fertilization resulted DM production significantly higher compared to control and RP, except on RP 300 kg P2O5/ha was non-significant difference. In vitro dry matter digestibility (IVDMD) of alfalfa was not affected by the treatment. There was non-significant difference in IVDMD between the treatments. Therefore, RP (300 kg P2O5/ha) could replace SP to increased DM production and not affected for IVDMD of Medicago sativa in acid latosolic soil.

Possible utilization of high-salinity waters and application of low amounts of water for production of the halophyte Kochia scoparia as alternative fodder in saline agroecosystems

Production of halophytes using saline waters and soils and feeding them to livestock is one of the most sustainable methods of conservation in desert ecosystems, in addition to accomplishing food production for the people living in these areas. Therefore, to study the possibility of irrigating Kochia ( Kochia scoparia L. Schrad) with minimum quantities of highly saline water for use as a fodder crop in arid environments stretching across saline waters, two experiments were carried out in the Research Farm of the Ferdowsi University of Mashhad, Iran. In the salinity experiments, two populations of Kochia, including the Sabzevar and Indian genotypes, were irrigated with ground water having electrical conductivity (EC) of 5, 15, and 20 dS m −1 . In the irrigation-treatment experiments, two local populations of Kochia, including Sabzevar and Borujerd, were subjected to four irrigation regimes as follows: complete irrigation (100%), 80%, 60%, and 40% of the water requirements using a saline ground water with EC = 5 dS m −1 . Because, the Indian genotype is preferred as an ornamental plant , it is not suitable for increased dry-matter production under high-salinity irrigation water compared to the local genotype (Sabzevar), which is suitable for forage. The Sabzevar genotype produced a large amount of dry matter (7530 kg ha −1 ), even when irrigated with 20 dS m −1 saline water. The best time for harvesting Kochia for fresh feeding is at the end of flowering (88 days after sowing or DAS), when the biomass is relatively high (6500 kg ha −1 ) and the leaf-to-shoot ratio, as a quality index, is approximately 50%. The highest green-area index was observed at 15 dS m −1 and decreased at high levels of salinity. Photosynthesis and transpiration rate did not decline significantly with increasing external salinity four weeks after salinization , but increased in both genotypes at 15 dS m −1 , indicating that the salinity-tolerance threshold of Kochia for both photosynthesis and transpiration reduction is above this salinity level. The Indian genotype also showed a very low seed yield (210 kg ha −1 ) at low levels of salinity, whereas Sabzevar produced 1120 kg ha −1 seed under the same conditions. Different irrigation regimes had a significant effect on the biomass and seed production of Kochia. The highest forage yield was obtained from complete irrigation, with 11.1 Mg ha −1 dry material. Sabzevar local population represented a better performance in terms of all characteristics, except accumulation of inflorescence dry matter, and no significant effects were recorded. In conclusion, Kochia's high foliage production capacity in the presence of salinity and limited irrigation make this plant suitable for use as an alternative forage crop in harsh environmental conditions. There is a wide range of intraspecific variation in K. scoparia, but more investigation is needed to introduce it as a cash crop.

Effectiveness of Recovered Magnesium Phosphates as Fertilizers in Neutral and Slightly Alkaline Soils

Magnesium phosphates such as struvite (MgNH4PO4 · 6H2O) can be recovered from municipal, industrial, and agricultural wastewaters. However, limited information is available on the beneficial reuse of these recovered products; research has focused on low pH soils. This study determined whether recovered struvite and dittmarite (MgNH4PO4 · H2O) were effective P fertilizers in neutral to slightly alkaline soils. In addition to commercially available triple superphosphate (TSP) and certified organic rock phosphate (RP), recovered struvite, dittmarite, and a heterogeneous recovered phosphate were evaluated in a laboratory dissolution study and as fertilizers for spring wheat (Triticum aestivum L.) in a greenhouse study. Struvite and dittmarite were much more soluble than RP, but less soluble than TSP. Laboratory dissolution kinetics were fast, with most materials nearing equilibrium within 7 to 14 d. At a soil pH of 6.5, both dittmarite and struvite increased the average plant P concentration over the control. Struvite and dittmarite performance was similar to TSP. There were no significant differences in plant dry matter (DM) production or total P uptake at pH 6.5. In the limed soil (pH 7.6), many treatments had plant P concentrations significantly lower than the control, but most fertilizers increased DM production over the control; all fertilizers generally performed similarly to one another. These findings support previous work showing recovered Mg phosphates to be effective in acidic soils, and provide evidence that they are also effective in slightly alkaline soils. Recovered Mg phosphates could become a useful alternative for P fertilization in arid and semiarid environments.

Metal uptake by tall fescue (Festuca arundinacea) as affected by poultry litter application

AbstractPoultry litter is commonly applied to pastures as an organic fertilizer. However, poultry litter also typically contains numerous heavy metals that may accumulate in soil and can pose an environmental threat when it is applied to pastures. The objective was to ascertain uptake characteristics of heavy metals by tall fescue (Festuca arundinacea Schreb.) from soil with a history of poultry litter additions as affected by subsequent applications of poultry litter. Poultry litter was applied to small plots at rates of 0, 2·2 and 4·5 t dry litter ha−1. In the 7·5 months following application of litter, cumulative dry‐matter (DM) production of herbage was higher (P &lt; 0·05) in the plots that received poultry litter compared with the control plots where no litter was applied. However, concentrations of Al, Cu, Fe, Mg, Mn, Se and Zn in herbage were unaffected by the rate of application of poultry litter. All metal tissue concentrations, except for Fe, were affected by sampling date. While tall fescue responds to poultry litter with increased DM production, it does not appear to accumulate excessive quantities of micronutrients associated with the application of poultry litter.

Effect of irrigation schedule, residue incorporation and nutrient management on system productivity and profitability of soybean (Glycine max)wheat (Triticum aestivum) cropping system in Vertisols of Rajasthan

A 3-year field experiment was carried out at Kota, Rajasthan during 201516 to 201718, to study the effect of irrigation schedule, residue incorporation and nutrient management on system productivity and profitability of soy- bean [Glycine max (L.) Merr.]wheat (Triticum aestivum L.) cropping system in Vertisols of Rajasthan. The treat- ments consisted of 24 combinations of 2 irrigation schedules in soybean, viz. 1 irrigation at flowering stage and 2 irrigations at flowering and other pod-development stages -in main plots; 4 wheat residue-management practices, viz. sowing of soybean after wheat-residue burning, wheat-residue incorporation without irrigation, residue incor- poration with irrigation and application of urea @ 25 kg/ha and residue incorporation with irrigation and application of urea @ 25 kg/ha + cellulolytic microbes @ 2.0 kg/ha in subplots; and 3 nutrient-management practices, viz. 75% recommended dose of fertilizers (RDF), 100% RDF (20 kg N, 40 kg P O , 40 kg K O/ha) and 125% RDF in sub- 2 5 2 subplots. The experiment was laid out in a split split-plot design with 3 replications. Wheat crop was sown every year with the adoption of recommended package of practices. Pooled data of 3 years revealed that 2 irrigations at flowering and other at pod development stages-in soybean crop significantly increased dry-matter production, unit- area efficiency, branches/plant, pods/plant, seeds/pod, seed index, seed and straw yields and net returns of soy- bean, grain yield of wheat, soybean-equivalent yield (SEY), profitability, production- and economic-efficiency of system, available N, P and K status of soil after harvesting of wheat and soybean as compared to 1 irrigation at flowering stage. However, available K status of soil after harvesting of soybean was found non-significant in rela- tion to irrigation. Wheat-residue incorporation with irrigation and application of urea @ 25 kg/ha + cellulolytic mi- crobes @ 2.0 kg/ha resulted in the highest growth and yield attributes, seed and straw yields and net returns of soybean, water-use efficiency (WUE), water productivity (WP), soybean-equivalent yield (4.51 t/ha), system profit- ability ( 96,520/ha), production (12.35 kg/ha/day) and economic (264 /ha/day) efficiency of system, organic car- bon, bulk density of soil after harvesting of soybean and N, P and K status of soil after harvesting of both soybean as well as wheat over wheat-residue burning. Application of 125% RDF resulted in the maximum growth and yield attributes, seed (1.51 t/ha) and straw (2.17 t/ha) yield, net returns ( 25,700), benefit: cost ratio (1.09) of soybean and SEY (4.44 t/ha), system profitability ( 95,740/ha), production (12.15 kg/ha/day) and economic efficiency (262 /ha/day), bulk density (1.42 Mg/m3), N (282, 288 kg/ha) P O (24.6,25.9 kg/ha) and K O (293, 299 kg/ha) of 2 5 2 soil after harvesting of wheat and soybean respectively.

Nutrient omission effects on yield, water productivity and profitability of maize (Zea mays)

A 2-year field experiment was conducted during the rainy seasons (JulyOctober) of 2012 and 2013 on a non- calcareous alkaline sandy clay loam soil, to (i) assess the effect of omitted nutrients on growth, yield, water pro- ductivity (WP) and profitability of maize (Zea mays L.) crop, and (ii) develop guidelines for the use of soil test crop response (STCR) approach and omission plots, in site-specific nutrient management (SSNM) for targeted and sustained yield of maize in the maize (Zea mays L.)wheat [Triticum aestivum (L.) emend. Fiori &amp; Paol.] cropping system. The experiment comprised 15 treatments, involving application of N (-PKZn), NP (-KZn), NPK (-Zn) and NPZn (-K) to both maize and wheat crops, to maize and to wheat crop only, absolute control (no nutrient applied), recommended rate of nutrients (120, 60, 40, 5.5 kg/ha N, P, K, Zn) and STCR-based application of nutrients (200, 100, 55, 4 kg/ha N, P, K, Zn). The experiment was set in a randomized complete-block design with 3 replications, in fixed plots. Growth and yield attributes were significantly influenced by nutrient-omission treatments and their values were higher when nutrients were applied according to STCR approach. The STCR-based nutrient applica- tion increased dry-matter production and grain yield by 5.9 and 5.7%, respectively over balanced fertilization (rec- ommended doses of NPKZn). Omission of P and K resulted in 9 and 9.7% reduction, respectively, in grain yield of maize. The yield reduction caused by Zn omission was about 3% only. On an average, STCR-based fertilization enhanced water productivity (WP) by over 6.2% compared to balanced fertilization with recommended doses of nutrients. Omission of K in both maize and wheat crops reduced WP by 9.3% compared to recommended doses of NPKZn-applied plot. The highest gross profit of 70,425/ha was also realized from STCR-based nutrient appli- cation.

Fungos micorrízicos nativos e Glomus clarun no rendimento de trevo vesiculoso cultivado em condições naturais e modificadas pela calagem e aplicação de fósforo

Em experimento desenvolvido na casa de vegetação na UFSM-RS, avaliou-se o efeito da introdução de fungos micorrizicos arbusculares (fMA) Glomus clarum e nativos no rendimento de massa seca (MS) e absorção de P pelo trevo vesiculoso (Trifolium spp.) e verificou-se a compatibilidade entre a espécie introduzida e os fMA nativos ocorrentes no solo estudado. Os tratamentos/oram constituídos defatorial 4x2x2 com quatro níveis de fMA: G. clarum, fungos nativos, mistura de ambas as populações e controle sem inoculação de fMA: com dois valores de pH: 4,4 e 5,4 e com dois níveis de fósforo disponível (Mehlich l): 6 e ISmg/kg de solo. A introdução de G. clarum isoladamente ou em conjunto com fMA nativos, na condição de pH 4,4, e em baixa disponibilidade de P, aumentou o rendimento de MS e absorção de P. Em disponibilidade intermediária de P (l5mg/kg de solo) e pH 5,4 não ocorreu diferença entre os tratamentos inoculados com fMA, mas destes ocorreu diferença para o tratamento sem inoculação, evidenciando a dependência do trevo pela micorrizaçâo. Tratamentos inoculados com G. clarum apresentaram maiores rendimentos de MS, absorção de P, colonização micorrizica e esporulação, mostrando que a introdução dessa espécie pode ser viável quando espécies nativas não são eficientes para a cultura ou tornam-se ineficientes quando a fertilidade do solo é modificada por aplicação de P e/ou calagem.

Effect of Daylength on the Nitrogen Status of Timothy (Phleum pratenseL.)

Abstract In two experiments timothy plants (Phleum pratense L., cultivars ‘Bodin’ and ‘Grindstad’, well established and vernalized in the first experiment and 7 weeks old in the second) were given daylength treatments with 12 h of photosynthetically active radiation (PAR) and day-lengthening light of low irradiance for from 2 to 13 weeks. Significant daylength effects on dry-matter, total nitrogen, nitrate and soluble protein content in the leaves of plants were demonstrated after only two weeks of treatment. The nitrogen and protein content decreased with increasing daylength, irrespective of the developmental stage of the plants. The dry-matter content increased with daylength when long days had induced generative development and decreased when all treatments at the same harvest were vegetative. The total nitrogen and protein per plant did not decrease from short to long days. The lower nitrogen and protein content in long days can therefore be regarded as a dilution caused by the increased dry-matter production found in these treatments. The observed effects of daylength on the ratio of assimilated nitrogen to assimilated carbon might be direct or indirect, since long days induce both enhanced dry-matter production and generative development in Bodin and Grindstad.

Effects of perennial forage-legume living mulches on no-till winter wheat and rye

No-till winter cereals sown in narrow rows may compete successfully with perennial forage-legume living mulches that can fix nitrogen (N), conserve soil, increase dry-matter production, and suppress weeds. The effects of small-grain species, mulch species, and top-dress N on grain and mulch yield and the grain N concentration of winter cereals direct-drilled into legume living mulches were examined in a two-year field study in New York, U.S.A., on soils of the Lima and Kendaia series: fine-loamy, mixed, mesic Glossoboric and Aeric Hapludalfs. Wheat ( Triticum aestivum L.) or rye ( Secale cereale L.) were grown in monoculture or drilled into summer-established plots of alfalfa ( Medicago sativa L.), birdsfoot trefoil ( Lotus corniculatus L.), crownvetch ( Coronilla varia L.), ladino clover ( Trifolium repens L. forma lodigense Hort ex. Gams), red clover ( T. pratense L.), or white clover ( T. repens L.). Spring top-dress N was applied at 0 or 56 kg N ha −1. Cereals were reseeded for a second season. Mulches generally interfered more and yielded more with wheat than with rye. Birdsfoot trefoil, crownvetch, and white clover had little effect on grain-yield the first year; birdsfoot trefoil and crownvetch interfered strongly with cereals the second year. Red clover did not affect rye grain-yield in the absence of top-dress N, but did tend to reduce wheat yield. Top-dress N increased cereal grain-yield and decreased mulch yield. In general, legume mulches did not appear to enhance cereal N nutrition the first year; red and white clovers appeared to contribute N to rye the second year. Second-year grain-yields were generally lower than first-year yields, due to increased interference from living mulches and broadleaf weeds. All living mulches except crownvetch suppressed weeds the second year. The results indicate that some species of perennial forage legumes may be suitable for use as living mulches for direct-drilled small grains, especially tall early winter cereals.

Agronomic studies on soybean (Glycine max (L.) Merrill) in the dry season of the tropics. III. Effect of artificial photoperiod extension on phenology, growth and seed yield

Soybean cultivars developed for the tropical wet season performed poorly when grown in the dry season in north-west Australia. The proposition that breeding for later flowering time might enhance yields was tested by using artificial photoperiod extension (14 h day-1 for 28 days post-emergence) to delay flowering of field plots of agronomically improved genotypes. Canopy development and interception of photosynthetically active radiation (PAR), dry matter (DM) accumulation, seed yield and seed composition were examined, and compared with that from plants grown under natural photoperiods. Photoperiod extension delayed flowering an average 24 days, and maturity by an average 14.5 days, the effect being greater in the earlier-flowering genotypes. Differences among genotypes and photoperiod treatments in above-ground DM at the beginning and end of flowering were almost entirely due to the consequences of differences in phenology for cumulative PAR interception. DM at maturity was a simple linear function of crop duration (r2 = 0.95**), while seed yield exhibited an optimum-type response with DM ( R2 = 0.79**). The net consequence was that photoperiod extension increased DM production by an average 2.23 t ha-1 and seed yield by an average 0.65 t ha-1. The analyses suggested that a crop duration of c. 143-146 days would be needed to maximize seed yield under the agronomic conditions of the study, whereas the longest duration among the agronomically improved genotypes under natural photoperiod conditions was 136 days. It was concluded that breeding to constrain precocious flowering under short day conditions would be a viable strategy to improve the yield potential of soybean in the dry season.

Alfalfa response to lime, phosphorus, potassium, magnesium, and molybdenum on acid ultisols

Alfalfa (Medicago sativa L.) is a high protein forage, cultivated widely in young, fertile soils. There is considerable potential for alfalfa production in areas with acidic, highly weathered soils, but few field studies on fertility requirements under these conditions have been published. Two field trials were conducted on ultisols to study the effects of lime, P, K, Mg and Mo on alfalfa growth and tissue composition. A trial with three rates of calcitic lime (0, 2400, and 3800 kg ha−1) and P (0, 25, and 50 kg ha−1) and two rates each of K (20 and 200 kg ha−1 the first year, 250 and 500 kg ha−1 in subsequent years), Mg (36 and 106 kg ha−1) and Mo (0 and 0.25 kg ha−1) was conducted on an Appling coarse sandy loam (Typic Hapludult). Another factorial experiment with three levels each of lime (0, 2000, and 4,000 kg ha−1), P (0, 100, and 200 kg ha−1), and K (0, 150, 300 kg ha−1) was conducted on a Davidson sandy clay loam (Rhodic Paleudult). Application of lime or P resulted in increased dry matter (DM) production at both locations. Liming also raised plant tissue N concentration. Addition of Mo had no effect on DM production or on foliar composition. Addition of K depressed soil Mg, plant tissue Mg, and plant Mg uptake at both locations. On the Davidson soil DM increased when K was applied, but on the Appling soil K increased DM production only where Mg was also added. Addition of Mg decreased K uptake and depressed DM production unless K was also added. The observed antagonism between K and Mg is of importance for alfalfa production in highly weathered soils. Successful alfalfa production in these soils is unlikely unless attention is paid to the balance between these two nutrients. Raising soil pH increased foliar N concentration affecting forage quality as well as DM production.

Lime and major nutrient fertilizers required to establish a perennial ryegrass/white clover pasture on a non‐calcareous gley in the Scottish uplands

AbstractA field experiment with mixed swards of perennial ryegrass and while clover carded out in 1982–83 using small cut plots is described. With perennial ryegrass, lime slightly decreased annual dry matter (DM) production in 1982 (the sowing year) but increased it in 1983 (the first harvest year) by about 1 t ha‐1. Applications of N and P produced small increases in DM in 1982 and greater increases in 1983. In the latter season annual DM production varied from an average of 3·5 to about 10 t ha‐1 with 0 or 480 kg N ha‐1 applied in three equal‐sized dressings throughout the growing season. Application of 40 kg P ha‐1 in 1982 increased DM production by about 2·5 t ha‐1 in 1983 but higher rates had little effect. Fifteen mg extractable P kg‐1 soil seemed sufficient to support levels of production normally expected from ryegrass pastures in upland Scotland, Applications of K did not affect DM production. N increased tiller weight and sward height of ryegrass; lime and P tended to increase tiller weight but this effect was not statistically significant. Leaf appearance and tiller number were not affected by treatments.The white clover content of the pasture was decreased 10‐fold by application of N and increased by lime and P (1·45 and 1·46‐fold. respectively). The DM response to P was most apparent in limed soil and was also affected by the siting of the plots in the experimental area. Effects of lime and P on growth of white clover were to increase the number of stolon growing points and root nodule numbers per unit area.The results emphasize the importance of lime and P fertilizer for establishment and growth of pasture in this soil and the differences between white clover and ryegrass in their responses to these.

Influence of soil pH and fertilization on the dry matter production, chemical composition and digestibility of perennial grasses: I.Anthephora pubescensnees1

Reports the results of a study conducted to investigate the influence of soil pH and fertilization on the dry matter production, chemical composition and organic matter digestibility of Anthephora pubescens evaluated in pots; The influence of soil pH and fertilization (N, P and Zn) on the dry matter (DM) production, chemical composition (crude protein, P, K, Ca, Mg and Zn content) and organic matter (OM) digestibility of Anthephora pubescens Nees was evaluated in pots. The highest DM production was obtained in the neutral soil medium (pH 6,5 in H 2 O) and alkaline (pH 7,5 in H 2 O) soil mediums adversely affected DM yield, crude protein (CP), Zn content and OM digestibility of A. pubescens . Fertilization invariably increased DM production. Keywords: anthephora pubescens ; botany; chemical composition; crude protein; digestibility; dm yield; dry matter production; fertilization; Grasses; k; organic matter; perennial grass; Perennial grasses; ph; phytomass; soil culture; Soil pH; yield; zn Journal of the Grassland Society of Southern Africa.