Green Matter Research Articles

Crescimento de espécies do gênero Brachiaria, sob déficit hídrico, em casa de vegetação

Avaliaram-se as características morfogênicas, fisiológicas e produtivas de espécies de Brachiaria, durante e após período de estresse hídrico. Os tratamentos foram arranjados em um esquema fatorial 4 x 5 quatro espécies de Brachiaria (B. decumbens, B. brizantha, B. humidicola e B. mutica) e cinco níveis de potencial hídrico do solo (-0, 01, -0, 03, -0, 1, -0, 5 e -1, 5 MPa) em um delineamento experimental de blocos ao acaso, com três repetições. O experimento foi instalado em casa de vegetação, em colunas de PVC com 40 cm de altura e 30 cm de diâmetro. Os déficits hídricos foram impostos durante 23 dias e, após este período, um grupo de plantas foi mantido sob condições normais de disponibilidade de água no solo, durante, aproximadamente, uma semana, para se avaliar a capacidade de recuperação das plantas. A taxa de alongamento das lâminas foliares foi comprometida em B. brizantha e a taxa de senescência de lâminas foliares em B. mutica foi aumentada com o decréscimo do potencial hídrico no solo, denotando a maior sensibilidade destas duas espécies ao déficit hídrico. Observou-se controle estomático sobre as trocas gasosas em folhas de todas as espécies. O déficit hídrico reduziu a fotossíntese líquida em todas espécies, mais acentuadamente em B. mutica e B. humidicola. Todas as espécies recuperaram suas atividades fotossintéticas normais após o déficit hídrico, mas apenas a B. brizantha restabeleceu o status hídrico de seus tecidos foliares. O déficit hídrico afetou mais acentuadamente a área de lâminas foliares verdes em B. brizantha e B. decumbens, a produção de matéria verde seca de lâminas foliares em todas as espécies estudadas, e a produção de matéria verde seca de colmos em B. decumbens e B. mutica.

The essence of chromatography

Methods for rhenium extraction from plant materials were studied using model systems and the 186Re isotope. Conditions are described for the quantitative extraction of rhenium with acid and alkali solutions from plant ash and with ethanol and salt solutions from fresh green matter. Procedures for the analysis of real plant materials based on a combination of rhenium extraction with high-sensitive methods of its determination (catalytic, neutron activation, and solid-phase spectroscopy) were developed. Laboratory and field versions of the method are proposed. Analytical results for plant samples taken in different regions are presented.

Caracterización y obtención de funciones para producción de biomasa en cinco cultivares de frijol yorimón: ii método no destructivo

In this work, the production of biomass for five crops of cowpea was studied in the Carrizal Valley in La Paz, Baja California Sur (23Âo 20' 47'' North and 110Âo 16' 14'' East). The soil has a pH of 6.85, poor in organic matter, non-saline, low levels of calcium, nitrogen, and magnesium but a high level of phosphorus. The climate is dry with average temperature of 22°C. Five cowpea cultivars were used and established in the field under completed randomized block design with four replications. The data were analyzed by means of canonical discrimination, multivariate analysis, correlation, and simple and multiple linear regressions for the generation of green matter production (PMV) and dry matter production (PMS) functions. Analysis of variance were carried out and multiple comparison means (Tukey P=0.05) when the variables showed significant statistical differences among cultivars. In general, all variables showed significant differences (P<0.05) except the variables fresh weight (PFH) and dry weight of leaves (PSH). The cultivars 18 (IT90K-277-2) and 25 (Sesenteno) showed the higher values of PMV and PMS (105.33 and 90.66 and 44.90 and 35.80 g, respectively). The best function of PMV was to the cultivar 4 (Cuarenteno) with R2 of 0.69 and for PMS was the cultivar 23 (IT91K-118-20) with R2 of 0.71, being diameter of shoot (DT) and number of secondary branches (NRS) the variables with higher influence in the function of PMV, while number of leaves per plant (NHP) and NRS are the variables with higher influence in the function of PMS.

Productivity of Alfalfa, Rhodes Grass and Their Mixtures in Arid Conditions Under Sprinklers

The presently existing dominant perennial forages like Rhodes grass, alfalfa and their mixtures were investigated from January 1998 to August 1999 for their productivity as a part of ICARDA’s Arabian Peninsula Research Program (APRP) at Rumais in the Batinah Coast of the Sultanate of Oman. The results indicated that the Rhodes grass varieties produced significantly (P&lt; 0.01) higher green (230.50 - 306.10 t/ha-1) and dry matter yields (52.39 - 67.48 t/ha-1) during the period. followed by the mixture treatments (green matter: 223.51 - 241.76 tfha" and dry matter: 49.02 - 53.11 t/ha-1) and alfalfa cultivars (green matter: 182.05 - 184.04 t/ha-1 and dry matter: 40.83-44.67 t/ha-1). Among the Rhodes grass varieties, Callide had a very high significant yield potential (P&lt;0.05) in terms of both green and dry matter yields followed by Katambora and Topcut, a newly introduced variety. In alfalfa, both cultivars produced similar (P&gt; 0.05) green matter (182.05 - 184.04 film") and dry matter (40.83 44.67 t/ha-1) yields. Among the mixtures, both green and dry matter yields of l: 2 mixture of Alfalfa and Rhodes grass were significantly higher than the other two mixture proportions i.e. 1:1 and 2:1 (P&lt;0.05).

Impacto da aplicação de efluente maturado de fecularia de mandioca em solo e na cultura do sorgo

The aim of this experiment was to evaluate the behavior of sorghum culture submitted to portions of maturate effluent of cassava industry. Thus, this study was carried out at Centro Técnico de Irrigação (Technical Irrigation Center) of Universidade Estadual de Maringá (State University of Maringá), state of Paraná, Brazil. Maturate effluent samples were collected from a lagoon, whose depth was not up to 0.50 m. Lysimeters of 1.0 m3 volume and 2.0 m2 area were applied to a sorghum culture. The utilized experimental design was composed of blocks at random in three treatments and six replications. The treatments were consisted of an application of: 150, 450 and 900 m3 ha-1 portions per year of mature effluent. The mature effluent from cassava industry supplied the nutritional necessities, which were required by sorghum for its entire development and production of green matter (or dry matter). A positive reply in growth, considering the entire process, in which the maximum portion added to sorghum culture was 450 m3 há-1, was verified. Otherwise, the elements of variable senescent leaves showed a negative correlation compared to others. A fertilizing effect of effluent was verified and analyzed according to the growth of the sorghum culture in relation to the macronutrients by potassium increase

Influência das adubações nitrogenada e fosfatada sobre a produção e características da rebrota do capim Marandu (Brachiaria brizantha (Hochst) Stapf cv. Marandu)

The objective of this work was to evaluate the effect of nitrogen and phosphorus fertilization on the regrowth, tiller density, tiller weight, dry matter yield (DMY) and green leaf blade dry matter (LBDM), under levels of nitrogen (0; 200; 400; 600kg/ha of N) and phosphorus (0; 50; 100; 150; 200Kg/ha of P2O5) of Marandu grass (Brachiaria brizantha (Hochst) Stapf cv. Marandu), during the summer (SP) and winter periods (WP). The experimental design was randomized blocks using factorial design 4 x 5, with three replications. Nitrogen fertilization produced (p 0.05) by crescent levels of nitrogen and phosphorus fertilization in both periods. Results showed that nitrogen fertilization in pasture of Marandu grass increase DMY and LBDM, during the SP, and phosphorus fertilization did not affect the analyzed variables.

Efeito da aplicação de águas residuárias de suinocultura sobre a produção do milho para silagem

Este trabalho foi conduzido com o objetivo de se avaliar o efeito da aplicação de quatro lâminas de água e águas residuárias de suinocultura, bruta e peneirada, sobre os componentes de produção da cultura do milho (Zea mays L.) para silagem. Foram instalados 24 lisímetros de percolação, sendo que em 8 deles se aplicou água (A), em 8 água residuária bruta (ARB) e nos demais água residuária peneirada (ARP). As lâminas aplicadas correspondiam a 0,5, 1,0, 1,5 e 2,0 ET0. A colheita foi realizada 140 dias após o plantio, quando se avaliaram os componentes de produção: altura de plantas, peso, altura, produtividade e índice de espigas e produtividade de matéria verde. As produtividades médias de matéria verde nos tratamentos com ARB e ARP foram equivalente a 45 e 46 t ha-1, cerca de 51 e 52% superiores à testemunha, respectivamente. A aplicação das águas residuárias de suinocultura aumentou significativamente os valores de altura de plantas, índice de espigas, altura de espigas e peso de espigas. Em geral, o peneiramento das águas residuárias e as diferentes lâminas aplicadas não afetaram os parâmetros de produção do milho para silagem.

Biometrical analysis and selection of tetraploid progenies of Panicum maximum using mixed model methods

The objectives of this work were to estimate the genetic and phenotypic parameters and to predict the genetic and genotypic values of the selection candidates obtained from intraspecific crosses in Panicum maximum as well as the performance of the hybrid progeny of the existing and projected crosses. Seventy-nine intraspecific hybrids obtained from artificial crosses among five apomictic and three sexual autotetraploid individuals were evaluated in a clonal test with two replications and ten plants per plot. Green matter yield, total and leaf dry matter yields and leaf percentage were evaluated in five cuts per year during three years. Genetic parameters were estimated and breeding and genotypic values were predicted using the restricted maximum likelihood/best linear unbiased prediction procedure (REML/BLUP). The dominant genetic variance was estimated by adjusting the effect of full-sib families. Low magnitude individual narrow sense heritabilities (0.02-0.05), individual broad sense heritabilities (0.14-0.20) and repeatability measured on an individual basis (0.15-0.21) were obtained. Dominance effects for all evaluated characteristics indicated that breeding strategies that explore heterosis must be adopted. Less than 5% increase in the parameter repeatability was obtained for a three-year evaluation period and may be the criterion to determine the maximum number of years of evaluation to be adopted, without compromising gain per cycle of selection. The identification of hybrid candidates for future cultivars and of those that can be incorporated into the breeding program was based on the genotypic and breeding values, respectively. The prediction of the performance of the hybrid progeny, based on the breeding values of the progenitors, permitted the identification of the best crosses and indicated the best parents to use in crosses.

Studies on the Adaptation of Azolla mexicana in the Aegean and the Mediterranean Regions

abstractAzolla (Azolla anabaena) is an aquatic fern plant that can be used as a green manure and organic matter resource in many countries where irrigation water is not a problem. A. mexicana is one of the azolla species adapted to the environmental conditions of Izmir (Turkey). The objective of this research was to determine the adaptation and agronomic potential of azolla plants to the Mediterranean climate regions. The research was conducted at three locations (Izmir and Aydın located in the Aegean region and Antalya located in the Mediterranean region of Turkey) in 1999, 2000 and 2001. Fresh azolla was planted in April, May, June and October at the rate of 300 g m−2 at each application. The growing azolla plants were harvested 15 days after planting. The highest fresh yield (1481 g m−2) was obtained in April at Izmir. The total N, P, and K values were between 2.93-3.31 %, 0.43-0.54 % and 1.10-1.37 % at Izmir, Aydın, and Antalya, respectively. The shortest time to reach a two-fold increase was 3.53 days at Izmir based on the average of three years.

Utilização de técnicas multivariadas na avaliação da divergência genética entre clones de palma forrageira (Opuntia ficus-indica Mill.)

Avaliou-se, por meio de técnicas multivariadas, a divergência genética entre clones de palma forrageira (Opuntia ficus-indica Mill.), em um experimento instalado na Estação Experimental da Empresa Pernambucana de Pesquisa Agropecuária - IPA, Caruaru - PE. O delineamento foi em blocos casualizados, com três repetições. Os tratamentos foram 19 clones de palma do Banco de Germoplasma do IPA. Foram mensuradas: a) medidas em artículos, conforme a ordem: comprimento, largura, espessura, número e peso da matéria verde. b) medidas por planta: presença de espinho, número de artículos por ordem e total, altura total, infestação por cochonilha e peso da matéria verde. Realizaram-se análises de variância univariada (ANOVA) e multivariada (MANOVA), das variáveis canônicas (VC) e de agrupamento (AA). Na ANOVA, foi verificada diferença entre as médias de clones e por meio da MANOVA, diferença entre vetores de médias de clones. Com a aplicação da VC, foi possível reduzir a dimensionalidade original para duas dimensões, com explicação de 85,03% da variação total. Foi considerada, como característica passível de descarte, a porcentagem de infestação por cochonilha. Na AA discriminaram-se nove grupos. A característica porcentagem de infestação por cochonilha não deve ser incluída no estudo da diversidade genética nas condições estudadas. As características de maior discriminação foram espessuras dos artículos primário, secundário e terciário, número de artículo primário e pesos médios de matéria verde por artículos secundário e terciário. Em um programa de melhoramento de palma forrageira, devem-se considerar o grupo de clones e o desempenho do clone quanto às características de maior relevância agronômica e zootécnica.

Consórcio sorgo-soja. VII. Sistemas de corte no rendimento forrageiro das culturas consorciadas

Com o objetivo de testar sistemas de corte na cultura de soja [Glycine max (L.) Merrill] e sorgo (Sorghum bicolor L. Moench) em consórcio na entrelinha, visando à produção de forragem, foi realizado este experimento no campo experimental da Universidade Federal de Lavras (UFLA) - utilizando o solo classificado como Latossolo Roxo Distrófico de textura argilosa, fase cerrado. O delineamento experimental empregado foi o de blocos casualizados, com três repetições em esquema fatorial 5 x 2 x 2 + 2 + 2, constituído por 5 sistemas de corte, 2 cultivares de soja (CAC-1 e Conquista) e 2 híbridos de sorgo (AG 2002 e BR 601). No primeiro sistema, as plantas de sorgo e soja foram cortadas rente ao solo uma única vez no estádio farináceo do sorgo. No segundo, as plantas foram cortadas duas vezes, sendo o primeiro corte realizado a uma altura de 30 cm do colo da planta e o segundo após a rebrota, rente ao solo, ambos no estádio farináceo do sorgo. No terceiro sistema, os dois cortes foram realizados a uma altura de 30 cm do colo da planta, no estádio farináceo do sorgo. No quarto sistema, um corte foi realizado no estádio vegetativo da soja (V8-V12), a uma altura de 30 cm do colo da planta, e outro, após a rebrota no estádio R5, rente ao solo. No quinto sistema, o primeiro corte foi realizado no estádio vegetativo da soja (V8-V12), a uma altura de 30 cm do colo da planta, e o segundo, após a rebrota, no estádio farináceo do sorgo, rente ao solo. A utilização dos cortes obedecendo ao estádio farináceo do sorgo (sistema 3) proporcionou os maiores rendimentos de massa verde total, matéria seca total e proteína bruta total. Os sistemas 2 e 3 foram os mais eficientes para produção de matéria verde e matéria seca, quando analisaram-se as duas culturas juntas, e para o rendimento de proteína bruta, os melhores sistemas foram 1, 2 e 3. A associação do sorgo AG 2002 e CAC-1 apresentou os maiores rendimentos de massa verde total, matéria seca total e proteína bruta total.

Influence of fertilization rates on species composition, quality and yields of the meadow fodder

Four variants in four replications were studied on permanent meadow stand on Czech and Moravian highlands. The altitude a.s.l. is 485 m, original growth type was Dactylidetum, association Trifolio-Festucetum rubrae. Four variants: control (without fertilization), 40 kg P + 100 kg K/ha, 100 kg N/ha&amp;nbsp;(+ PK) and 200 N/ha&amp;nbsp;(+ PK) were evaluated. Botanical analyses of stands were done by the method of reduced projective dominance (D in %). The cut green matter was weighed up, mean samples for dry matter determination and chemical analyses were taken. Botanical composition of the meadow stand in 1991&amp;ndash;2000 was not stabile and was changing due to nourishment. The yields of dry matter ranged within 10 years in the control variant from 1.07&amp;ndash;3.42&amp;nbsp;t/ha&amp;nbsp;(in the plot fertilized by P&lt;sub&gt;40&lt;/sub&gt;K&lt;sub&gt;100&lt;/sub&gt;&amp;nbsp;2.09&amp;ndash;5.95 t/ha, in the plots with nitrogen (+ PK) 2.29&amp;ndash;6.52 t/ha, resp. 3.74&amp;ndash;7.61 t/ha). According to the t-test, the yields of dry mass in experimental variants are significant at 95% level.

Responses of Four Corn Hybrids to Plant Density

Corn is an important crop in northern Turkey, where it is used mainly as a source of energy for animal and food for human. Two-yr field experiments were conducted to evaluate the effects of plant density on the green herbage and dry matter yield (Experiment I); the grain yield and yield components (Experiment II) of hybrid corn. In both experiments, four hybrids, Sele, RX-770, RX-899, and RX-947 were grown at 51 282, 60 154, 76 923, and 102 564 plants/ha. Regression equations on the mean green herbage and grain yields of each hybrid estimated optimum plant density of each hybrid. There was a significant difference among hybrids with respect to green herbage and dry matter yield. Maximum green herbage and dry matter yields were obtained at RX-947. Plant density significantly affected green matter and dry matter yields. The highest green herbage and dry matter yields were obtained at 102 564 plants/ha. Hybrid x plant density interactions were not significant for both traits. Differences among hybrids for grain yield and yield components were significant, and RX-899 gave grain yield more than other hybrids. It was observed that plant density had a significant effect on grain yield and yield components. There also was a significant hybrid x plant density interaction for grain yield. The highest grain yield for Sele, RX-770, RX-947 were obtained at 76 923 plants/ha, for RX-899 was obtained at 60 154 plants/ha.

Efeito da mistura da planta de girassol (Helianthus annuus L.), durante a ensilagem do capim-elefante (Pennisetum purpureum Schum.) no valor nutritivo da silagem

O girassol foi misturado ao capim-elefante (Pennisetum purpureum Schum) na ensilagem. A colheita do capim-elefante foi realizada manualmente após 70 dias do corte de uniformização, à altura de 10 cm da superfície do solo. Para confecção da silagem, foram utilizados os híbridos de girassol M-742 e M-92007. As misturas capim-elefante e girassol foram feitas nas seguintes proporções de matéria verde: 100 e 0%, 75 e 25%; 50 e 50%; 25 e 75%; 0 e 100% de capim e girassol, respectivamente. As plantas foram picadas mecanicamente em partículas de 2,0 a 3,0 cm de tamanho, ensiladas por 30 dias, em silos de "PVC" de dez centímetros de diâmetro e quarenta centímetros de altura. Foram avaliadas as porcentagens de matéria seca (MS), proteína bruta (PB), extrato etéreo (EE), fibra em detergente neutro (FDN), digestibilidade in vitro da matéria seca (DIVMS) e valores de pH das silagens. O delineamento experimental empregado foi o inteiramente casualizado, com quatro repetições. Concluiu-se que as silagens de capim-elefante com mistura da planta de girassol apresentaram maiores porcentagens de MS, PB, EE e valores de pH, aumentos na DIVMS e menor porcentagem de FDN na matéria seca com o aumento dos níveis de substituição.

Características Morfogênicas e Acúmulo de Forragem do Capim-Tanzânia (Panicum maximum Jacq. cv. Tanzânia) em Dois Resíduos Forrageiros Pós-Pastejo

O experimento foi conduzido no Centro Nacional de Gado de Corte da Empresa Brasileira de Pesquisa Agropecuária (Embrapa Gado de Corte). Foram avaliadas as características morfogênicas de folhas e perfilhos, acúmulo de matéria seca verde e índices de crescimento do capim-tanzânia em dois resíduos forrageiros pós-pastejo (Resíduo alto -- RA 3,6 t de MS/ha e Resíduo baixo -- RB 2,3 t de MS/ha), até os 35 dias após o pastejo. O delineamento experimental foi em blocos casualizados completos com os tratamentos no esquema de parcelas subdivididas com três repetições. Para a dinâmica de perfilhamento houve diferença entre resíduos somente no aparecimento de novos perfilhos basilares. A taxa de aparecimento de novos perfilhos, tanto basilares quanto aéreos, decresceu linearmente com os dias de rebrotação após o pastejo. As taxas de alongamento e senescência de folhas não diferiram entre resíduos e tipos de perfilho. Em contrapartida, a duração de alongamento foliar foi menor no resíduo baixo e no perfilho novo, porém produzindo folhas com menor comprimento final. Houve interação entre resíduo e tipo de perfilho para a taxa de aparecimento de folhas, com maiores valores para o resíduo baixo no perfilho novo e remanescente. O acúmulo de matéria seca verde não diferiu entre resíduos, sendo, em média, 61,4 e 47,9 kg/ha.dia, nos resíduos baixo e alto, respectivamente. A taxa de crescimento relativo e o índice de área foliar não apresentaram diferenças entre resíduos forrageiros, porém apresentaram comportamento inverso em função dos dias após o pastejo.

Acumulação de Forragem e Material Morto em Pastagem Nativa sob Distintas Alternativas de Manejo em Relação às Queimadas

Foram estudados cinco sistemas de manejo da pastagem nativa, sob pastejo, do Estado do Rio Grande do Sul: com queima bienal há mais de 100 anos, sem queima há 32 anos com e sem roçada; e melhorado há 7 e 24 anos. O acúmulo de forragem e o material morto desprendido da planta foram coletados em gaiolas de exclusão ao pastejo. O delineamento experimental foi o completamente casualizado com três repetições. Os sistemas sem queima foram mais produtivos, e dentre estes a acumulação de forragem foi semelhante entre sem queima e sem roçada e os tratamentos melhorados com acúmulo anual superior a 9.000 kg/ha de matéria seca da forragem verde (MSFV). O material morto presente na superfície do solo foi maior no tratamento sem queima e sem roçada, menor no queimado e intermediário nos demais. Alternativas de manejo sem queima são mais produtivas e ecologicamente mais sustentáveis.

Effect of time of sowing, stage of harvest and plant population on fibre yield and quality of mesta (Hibiscus sabdariffa) under dryland condition

A field experiment was conducted at Regional Agricultural Research Station, Bijapur (Karnataka), in medium black soil during 1998 and 1999. The experiment comprised 24 treatments, consisting of 4 dates of sowing (first fortnight of July, second fortnight of July, first fortnight of August and second fortnight of August), 2 stages of har- vest (at 50% flowering and at maturity) and 3 plant populations (0.22, 0.33 and 0.66 million plantstha). The ex- periment was laid out in split-split plot design with 3 replications. Pooled results of 2 years showed that, fibre yield, green matter, green stalk, dry stalk yields and fibre recovery were significantly higher with early planting during first fortnight of July compared to later sowing dates of second fortnight of July, first fortnight of August and second fortnight of August. Fibre quality with respect to fineness increased, while strength decreased signifi- cantly with delay in sowing time from first fortnight of July to secod fortnight of August. Stage of harvesting did not cause significant differences in green stalk, dry stalk and fibre yields, while green matter yield was significantly higher when the corp was harvested at 50% flowering compared to maturity. Fibre fineness was greater at matu- rity compared to 50% flowering. Fibre strength did not vary significantly due to stage of harvesting. Fibre yield in- creased significantly with increase in plant population from 0.22 milliontha (484 kgtha) to 0.33 millionlha (559 (kglha) and with further increase in plant population to 0.66 milliontha (604 kgtha) no significant increase was noticed. Dry-stalk yield followed similar tend. However, green matter and green stalk yields increased signifi- cantly with successive increase in plant population from 0.22 to 0.66 milliontha.

Nutrient management for yield maximization of rice (Oryza sativa)- wheat (Triticum aestivum) cropping system

A field investigation was carried out during winter 1990- rainy season 1992 on loamy sand of average fertility status. The grain yield as well as the main crop pro- ductivity parameters significantly increased with maximum economic yield fertilizer level (MEYFL) of 180,30 and 30 kglha to rice (Oryza sativa L.) and 180,60 and 0 kg1 ha to wheat (Xticum aestivum L. emend. Fiori &amp; Paol.) (grown in sequence) over the recommended fertilizer level (RFL) of 120, 30 and 30 kglha to rice and 120, 60 and 30 kglha of N, P20, and K20 respectively. The MEYFL was significantly superior to RFL with yield advantages of 16.2%in rice (average grain yield 8.6 tonneslha) and 13.5% in wheat (average grain yield 5.8 tonneslha). Green-manuring with Sesbania aculeata Pers. (20-25 tonneslha green matter) saved 60 kdha equivalent of N in rice without any residual effect on wheat. The higher levels of P and K and growth regulators cycocel (1 gllitre at 45 days), followed by cytokinin (50 mgllitre at 80 days) in 500 litres waterlha did not show any significant influence on rice and wheat. The benefit :cost ratio with additional income over additional expenditure for the rice-wheat rotation at MEYFL was 2.35 with chemical fertilizer and 1.55 with green- manured series compared with 1.47 under RFL. Both crops showed higher uptake of N, P and K with MEYFL over RFL. The total uptake (kglha of N, P and K) was respectively 107, 18.8 and 94 in rice and 106, 18.3 and 97 in wheat at MEYFL; and 99, 16.5 and 88 in rice and 92, 15.8 and 97 in wheat at RFL. The rice and wheat straw component accounted only for 12 and 17% of N and 15 and 19% of P, though fraction of K retained was quite sizeable (92.1 and 82.1% respectively).

Competition between heather and grasses on Scottish moorlands: Interacting effects of nutrient enrichment and grazing regime

Abstract. Considerable losses and degradation of heathlands (in moorlands and lowlands) have been reported across Europe, with Calluna vulgaris (heather) being replaced by other species, often grasses. Increasing atmospheric nitrogen deposition and overgrazing have been suggested as the driving factors behind this change. This possibility was investigated in a study of the interacting effects of nutrient inputs and grazing on heather and three grass species (Nardus stricta, Deschampsia cespitosa and D. flexuosa) in the field, on a moorland in northeastern Scotland. In addition, the interacting effects of increasing nutrients and Calluna canopy height on N. stricta and D. cespitosa were studied using turves in an outdoor experimental area. In the field, fencing had a larger effect than fertilizer on the growth of all species, except for N. stricta, the species most unpalatable to herbivores. Fencing led to an increase in the height of the Calluna canopy, which may reduce light availability for the grasses. In the turf experiment, the height of the Calluna canopy affected the diameter of the grass tussocks and percentage of green matter (i.e. live leaf material), with plants under the more closed Calluna canopies being smaller.This study suggests that the slow‐growing, evergreen Calluna is a more effective competitor than the faster growing grasses when it has a tall, intact canopy, even at increased levels of nutrient supply. However, overgrazing promotes gap formation in the Calluna canopy, providing an opportunity for grasses to take advantage of increased nutrients. Thus the conservation of heather moorlands requires an understanding of the grazing level which allows Calluna to maintain sufficient canopy structure to outcompete grasses for light.

Physio-Morphological Characters of F1 Hybrids of Rice (Oryza sativa L.) in Japonica-Indica Crosses: II. Heterosis for leaf area and dry matter accumulation

SummaryA pot experiment was conducted to investigate the heterosis for morphological characters and to examine the relationship among some characters at active tillering, flowering and dough ripe stages of 12 Fj hybrids from crosses between japonica and indica rice. Heterosis for plant height, number of tillers, green leaf area and dry matter accumulation per plant was positive at all stages. The intensity of heterosis was higher at the active tillering stage for number of tillers, leaf area and dry matter accumulation per plant. A significant positive relationship was found between tiller number and leaf area per plant at active tillering and flowering stages. Significant positive relationships between leaf area and dry matter accumulation, and between tiller number and dry matter accumulation per plant were observed at all stages. A significant positive relationship was found between leaf area per plant at an early stage and dry matter accumulation per plant at a later stage, suggesting that early development of leaf area is an important factor for higher dry matter accumulation in 1 hybrids. Although heterosis for percent dead leaf blade was positive at the flowering stage due to early leaf senescence in some Fx hybrids, a larger leaf area was also found in Fx hybrids at this stage and leaves of Fx hybrids remained green longer compared to parent cultivars up to the dough ripe stage.