Ground Cover Crops Research Articles

Ability to Supply Macro-nutrients as Affected by Time and Height of Mowing of Ground Cover Crops on a Pesticide-free Pear Orchard

Ability to Supply Macro-nutrients as Affected by Time and Height of Mowing of Ground Cover Crops on a Pesticide-free Pear Orchard

Effect of vegetal ground cover crops on wine anthocyanin content

Wine colour is a quality index that can provide information about conservation state, age or the presence of defects. Anthocyanin compounds are colour-related molecules and their concentration is affected by several factors such as grape variety, berry maturity degree or cultural practices. The aim of this work was to determine the anthocyanin composition of Mencía wines and how this is affected by the establishment of different cover crops (native vegetation, ryegrass and subterranean clover) respect to soil tillage treatment. This study was carried out during two consecutive seasons in the same vineyard. The use of cover crops significantly affected wine anthocyanin content; even though, their basic attributes were not altered by the treatments. In 2013, the wines from the ryegrass treatment had a significantly greater total anthocyanins concentration and, in 2014, the wines under the native cover had the highest concentration of these compounds. In both years, wines coming from the treatment under subterranean clover had a lower concentration of total anthocyanins when compared with those from the rest of the treatments. Cover crops increased wine anthocyanin concentrations when compared to the tilled treatment. However, the type of cover crop causing the highest increases differed from year to year.

Análise econômica da produção de feijão em função de doses de nitrogênio e coberturas vegetais

O nitrogênio é o nutriente aplicado em maior quantidade à cultura do feijão, o mais limitante ao crescimento e desenvolvimento das plantas e o que mais onera o custo de produção. Uma boa opção para o produtor diminuir custos, com a utilização de fertilizantes nitrogenados, é a utilização de plantas de cobertura do solo, também conhecidas como adubos verdes. Assim, este trabalho objetivou avaliar os custos de produção e índices de lucratividade de diferentes tratamentos envolvendo coberturas vegetais e doses de nitrogênio em cobertura, na cultura do feijoeiro irrigado, em sistema plantio direto, nas safras de inverno de 2010 e 2011. O trabalho foi realizado em área experimental localizada no município de Selvíria (MS), em Latossolo Vermelho distrófico típico. Os tratamentos constituíram-se de seis coberturas vegetais (Crotalaria juncea, milheto, guandú, Crotalaria juncea + milheto, guandú + milheto e pousio) e quatro doses de N (0 kg ha-1, 30 kg ha-1, 60 kg ha-1 e 90 kg ha-1). Foram estimados o custo operacional total, receita bruta, lucro operacional, índice de lucratividade, produtividade de equilíbrio e o preço de equilíbrio. Concluiu-se que o uso da Crotalaria juncea, como cobertura vegetal do solo, proporcionou os maiores valores de custo operacional total e lucro operacional e os melhores índices de lucratividade, e que o incremento nas doses de nitrogênio aumentou o custo operacional total, com tendência de aumento na produtividade e, consequentemente, no preço de equilíbrio.

NITROGEN LIMITATION OF RHIZOMA PEANUT GROWTH

Rhizoma peanut (Arachis glabrata) is a forage and groundcover crop of increasing importance in the southeastern United States, but little is known of its nitrogen (N) requirement for optimal production, or if this requirement is being met through symbiotic nitrogen fixation. Nitrogen fertilization greenhouse experiments were performed with Florigraze and Ecoturf genotypes and response measured by shoot production, nodulation, nitrogenase activity, shoot N concentrations, and N accumulation. Rhizome N concentrations with and without N fertilization were also evaluated in the field. From the two greenhouse studies, we found a saturating response to N fertilization between 11 and 23 kg N ha-1 during the 11-week evaluation period. In both the greenhouse, and to a lesser extent, the field experiment, N accumulation was found to increase with increased N fertilization, which indicates that N2-fixation may not provide the necessary N for optimal shoot production.

Characterization of culturable bacterial endophytes of switchgrass (Panicum virgatum L.) and their capacity to influence plant growth

AbstractSwitchgrass (Panicum virgatum L.) is a perennial warm season grass that is native to the plains of North America and is widely grown as a forage, bioenergy or groundcover crop. Despite its importance, a bottleneck in switchgrass production is poor seedling vigor, which as a perennial crop represents an important time for management. Herein, data identify a suite of culturable bacterial microflora extracted from switchgrass, and show their capability to influence host plant growth and development. A total of 307 bacterial isolates were cultured and isolated from surface sterilized switchgrass biomass and sequence identified into 76 strains (subspecies classification), 36 species and 5 phyla. Approximately 58% of bacterial strains, when reintroduced into surface‐sterilized switchgrass seeds, were documented to increase lamina length (cm from base to tip after 60 days growth) relative to uninoculated controls. Ecologically, Phylum Firmicutes was the most abundant bacterial classification and encompassed 75% of all isolates. Although the culturable bacterial community studies herein represent an unknown and assumedly minor proportion of the total microbiome, by focusing on culturable bacteria, we delineate functional feedback between the presence of isolated bacteria and switchgrass seedling growth.

Desenvolvimento de plantas de cobertura e produtividade da soja conforme atributos físicos em solo compactado

Com a intensa utilização de tecnologias voltadas à mecanização das operações agrícolas, a compactação do solo é um fator que tem limitado a produtividade. Para atenuar este problema, o uso de plantas de cobertura do solo é frequentemente recomendado. Com o objetivo de avaliar o efeito da compactação nas propriedades físicas do solo, no desenvolvimento de plantas de cobertura e na produtividade da soja, conduziu-se um experimento no delineamento em blocos casualizados no esquema fatorial 2 x 5, sendo duas espécies de plantas de cobertura (aveia preta - Avena strigosa e nabo forrageiro - Raphanus sativus) e cinco níveis de compactação (0, 2, 4, 6 e 8 passadas de trator com 5,0 Mg na superfície do solo), com quatro repetições. Intensidades de tráfego superiores a 2 passadas de trator alteram a densidade do solo, a porosidade total e a resistência mecânica à penetração, na camada de 0-0,10 m, e reduzem, de forma linear, a altura e a produção de matéria seca da parte aérea das plantas de cobertura. O cultivo da aveia preta ou nabo forrageiro antecedendo a soja, associado ao uso de sulcadores na operação de semeadura da soja minimiza os efeitos da compactação do solo, possibilitando obter-se produtividades superiores a 3,5 t ha-1.

Can Leguminous Cover Crops Partially Replace Nitrogen Fertilization in Mississippi Delta Cotton Production?

Petroleum prices impact cotton nitrogen (N) fertilization cost. A field study was conducted from 2005 to 2007 to assess the interactions of cover crop (none, Austrian winter pea (Pisum sativumspp.arvense) or hairy vetch (Vicia villosaRoth)) and N fertilization (0, 67 or 134 kg N/ha applied at planting) on N availability and cotton yield under reduced-tillage management. Nitrogen content in desiccated residues averaged 49, 220, and 183 kg N/ha, in no cover crop, Austrian winter pea, and hairy vetch, respectively. Seventy percent of N in the above ground cover crop was derived from biological N fixation. In 2005, cover crops decreased cotton yield, while fertilizer N had no effect. In 2006, cover crops did not affect yield, but yield was positively correlated with N rate. In 2007, in no N plots, cotton yields were 65% higher in cover crops than in no cover crop. However, yield from N fertilized cover crop plots were similar to N fertilized no cover plots. These results indicate that leguminous cover crops can provide over 150 kg N/ha, but this N may not be as effective as fertilizer N for lack of synchronization between cotton N requirements and N release from residues.

Seeding Rate and Planting Arrangement Effects on Growth and Weed Suppression of a Legume‐Oat Cover Crop for Organic Vegetable Systems

Winter cover crops can add soil organic matter, improve nutrient cycling, and suppress weeds in organic vegetable systems. A 2‐yr study was conducted on organic farms in Salinas and Hollister, CA, to evaluate the effect of seeding rate (SR) and planting arrangement on cover crop density, ground cover, and cover crop and weed dry matter (DM) with a mixed cover crop. The mix contained legumes (35% Vicia faba L., bell bean; 15% Vicia dasycarpa Ten., woolypod vetch; 15% Vicia benghalensis L., purple vetch; and 25% Pisum sativum L., pea) and 10% oat (Avena sativa L.) by seed weight. Three SRs (112, 224, and 336 kg ha−1) and two planting arrangements (one‐way versus grid pattern) were evaluated. Planting arrangement had no effect on the variables measured. When weeds were abundant, weed DM declined linearly with increasing SR from approximately 300 kg ha−1 at the low SR to <100 kg ha−1 at the high SR. Increasing SR increased oat and legume DM early in the season, but did not affect final cover crop DM that ranged from 7 to 12 Mg ha−1. Year affected final cover crop DM production at both sites. The legume DM portion of the total cover crop declined through the season but varied between sites and year, probably due to soil and climatic differences. Higher SRs may be cost effective because weed control is expensive and cover crop seed is a relatively small component of cover cropping costs in this region.

Radiation balance of coffee hedgerows

The radiation balance of hedgerows is an important variable in studies of mass and energy exchanges between parcial ground cover crops and the atmosphere. This paper describes a device with eight net radiometers encompassing the plants of a hedgerow. The radiometers were moved along a length of hedgerow, in a continuous and reversible movement. The canopy net radiation in this length (Rnc) was found by integration of the measurements over the notional cylinder formed. The device showed good performance and provided reliable measurements of Rnc of coffee hedgerows, showing itselfto be an useful technique of measurement in field conditions. Good correlations between Rnc and global solar radiation, turfgrass and coffee crop net radiation were found in 15-min, daytime and 24-hr periods, allowing the possibility of estimating Rnc from these simple measurements. Beer’s law was also used to have an independent estimation of Rnc. A good agreement was found between values of Rnc estimated by this law of attenuation and those integrated by the device in periods of 15 min, with overestimation of 10%, whereas for values integrated over daytime periods the agreement was not satisfactory.

Study on Competition Characteristics of a Land Cover Crop Arachis pintoito Growth of Cocoa

The existence of ground cover crop, such as Arachis pintoiin cocoa farm may enhance physical, chemistry and biological fertility of soil. Nevertheless, the presence of those cover crops potentially increase the competition with main crop in various means. The primary objective of this study was to investigate kinds of competition raised when cocoa plants cultivated with ground cover crop of A. pintoi. This study consisted of three experiments. The first experiment aimed to study possible allelopatic competition using root exudates solution of A. Pintoi as well as Leucaena leucocephalaand Adenanthera microsperma as check for being used for watering cocoa plants. The second experiment aimed to study the competition between A. pintoiand cocoa plants in field condition with 1) cover crop fully overlay ground surrounding cocoa basal trunk, 2) no cover crop overlay ground surrounding cocoa basal trunk in a distance of 40 cm in diameter, and 3) no cover crop as check. Third experiment aimed to study the competition between A. pintoiand cocoa plants in limited growth medium (pot), using 10 cm stolon shoots each 4, 2 and 0 shoots per pot. Results showed that A. Pintoidid not produce alleopatic exudates to restrict cocoa growth. Population of A. Pintoi had negative effect on cocoa plant growth in the field by reducing fresh trunk weight and dry root weight, even greater negative effect found in cocoa plant grown in limited growth medium by also reducing dry leaf and trunk weight and leaf area. Key words: Theobroma cacao, Arachis pintoi, allelopathy, competition, denantheramicrosperma, Leucaena leucocephala

Intensity of Ground Cover Crop Arachis pintoi, Rhizobium Inoculation and Phosphorus Application and Their Effects on Field Growth and Nutrient Status of Cocoa Plants

Arachis pintoiis potentially as a cover crop for cocoa (Theobroma cacaoL.) farm, however information regarding its effect on the growth of cocoa plants in the field is very limited. The objective of this experiment is to investigate the combined influence of ground cover crop A. pintoi, rhizobial bacterial inoculation and phosphorus (P) fertilizer on the growth of cocoa in the field and nutrient status. This experiment laid out in split-split plot design consisted of three levels of cover crop (without, A. pintoiand Calopogonium caeruleum), two levels of rhizobium inoculation (not inoculated and inoculated) and two levels of phosphorus application (no P added and P added). The results showed that in field condition the presence of A. pintoias cover crop did not affect the growth of cocoa. On the other hand, C. caeruleumas cover crop tended to restrict cocoa growth compared to A. pintoi. Application of P increased leaf number of cocoa plant. Biomass production of A. pintoiwas 40% higher than C. caeruleum. Soil organic carbon and nitrogen contents were not affected by ground cover crops, though higher value (0.235% N and 1.63% organic C) was obtained from combined treatments of inoculation and P addition or neither inoculation nor P addition. In the case of no rhizobium inoculation, soil N content in cocoa farm with A. pintoicover crop was lower than that of without cover crop or with C. caeruleum. Cover crop increased plant N content when there was no inoculation, on the other hand rhizobium inoculation decreased N content of cocoa tissue. Tissue P content of cocoa plant was not influenced by A. Pintoicover crop or by rhizobium inoculation, except that the P tissue content of cocoa was 28% higher when the cover crop was C. caeruleumand inoculated. Key words : Arachis pintoi, Theobroma cacao, Calopogonium caeruleum, rhizobium, nitrogen, phosphorus.

Isolation of allelochemicals from comfrey (Symphytum officinale L.): A candidate for allelopathic ground cover crop

Isolation of allelochemicals from comfrey (Symphytum officinale L.): A candidate for allelopathic ground cover crop

Toxicity of storm‐water runoff after dormant spray application in a French prune orchard, Glenn County, California, USA: Temporal patterns and the effect of ground covers

Organophosphorous (OP) insecticides, especially diazinon, have been detected routinely in surface waters of the Sacramento and San Joaquin River watersheds, coincident with rainfall events following their application to dormant orchards during the winter months. Preventive best management practices (BMP) aim at reducing off-site movement of pesticides into surface waters. Two proposed BMPs are: The use of more hydrophobic pyrethroid insecticides believed to adsorb strongly to organic matter and soil and the use of various types of ground cover vegetation to increase the soil's capacity for water infiltration. To measure the effectiveness of these BMPs, storm water runoff was collected in a California prune orchard (Glenn County, CA, USA) during several rainstorms in the winter of 2001, after the organophosphate diazinon and the pyrethroid esfenvalerate were applied to different orchard sections. We tested and compared acute toxicity of orchard runoff from diazinon- and esfenvalerate-sprayed sections to two species of fish (Pimephales promelas, Onchorhynchus mykiss) and three aquatic invertebrates (Ceriodaphnia dubia, Simocephalus vetelus, Chironomus riparius), and determined the mitigating effect of three ground cover crops on toxicity and insecticide loading in diazinon-sprayed orchard rows. Runoff from the esfenvalerate-sprayed orchard section was less toxic to waterflea than runoff from the diazinon-sprayed section. However, runoff from the orchard section sprayed with esfenvalerate was highly toxic to fish larvae. Samples collected from both sections one month later were not toxic to fish, but remained highly toxic to invertebrates. The ground cover crops reduced total pesticide loading in runoff by approximately 50%. No differences were found between the types of vegetation used as ground covers.

Allelopathic activity of buckwheat: isolation and characterization of phenolics

Laboratory and field experiments were conducted to assess the allelopathic potential of buckwheat. In the field, buckwheat demonstrated strong inhibitory activity by suppressing weeds. In laboratory studies, aqueous and organic solvent extracts of the aerial parts of common buckwheat inhibited the root and shoot growth of lettuce seedlings. The chloroform and ethyl acetate extracts showed maximum activity, and plants grown in the presence of the ethyl acetate extract showed severe root browning. The allelopathic constituents of the ethyl acetate phase were isolated and identified as gallic acid and (+)-catechin by nuclear magnetic resonance spectroscopy. Gallic acid and (+)-catechin were present in the upper part of buckwheat at concentrations of 0.02 and 0.01%, of fresh weight, respectively. Gallic acid was found to be selectively and strongly inhibitory to root and shoot growth of tested plants at 100 and 10 μg ml−1. (+)-Catechin, however, inhibited plant growth to a lesser extent. These results suggest that buckwheat may have allelopathic potential and that when used as a ground cover crop or green manure may produce inhibitors, which could suppress weeds.

Effects of clovers as vegetative ground cover on the growth of red birch in nursery field production

SummaryVarious clover species were evaluated as vegetative ground covers in nursery field production of micropropagated red birch (Betula pubescens Ehrh. f. rubra Ulvinen) in two experiments each of two years’ duration. The clover species and cultivars were Trifoliumpratense L. ‘Bjursele’, T. repens L. ‘Jogeva’, T. repens L. ‘Sonja’, T. hybridum L. ‘Frida’, T. incarnatimi L. ‘Opolska’, T. resupinatum L. and T. subterraneum L. One treatment was grass sod Festuca rubra L. ‘Ensylva’ and as control coverless ground, kept weed free by hand hoeing. Stem diameter, stem height, leaf area and leaf size were all reduced in the perennial clover plots and grass. The annual clovers, T. incarnatum, T. resupinatum and T. subterraneum, proved to be noncompetitive with the trees. Because of its low growing habit, T. subterraneum seems to be the most suitable of the tested clovers as a ground cover crop.

An economic analysis of improved agroforestry practices in the Amazon lowlands of Ecuador

Since 1985, Ecuador's Ministry of Agriculture has undertaken a demonstration project to promote improved agroforestry practices in already cleared lands of Ecuador's Amazon lowlands to promote regeneration of deforested areas. An important expected outcome of this project is to ameliorate growing population pressures on remaining national forests and natural reserves. These practices include managing natural regeneration of marketable timber trees intercropped to Coffea canephora var. robusta and grass-legume associations, using adequate techniques of coffee pruning, and planting Desmodium ovalifolium CIAT 350 as a ground cover crop or a forage legume in paddocks of the genus Brachiaria. This research was conducted to assess the potential economic impact of such a strategy and to feed back information on research and policy issues. Improved agroforestry practices in this region are not only technically practicable but also economically feasible. Proposed technologies enhance long-term productivity of both land and labor while saving on external inputs and hired labor, making on-going systems more adoptable and sustainable. Future land-use policies should consider on-farm primary forest preservation and controlled natural regeneration of high-value timber in secondary forests as socially efficient land-use patterns. Future research must address germplasm of grass and forage legumes both shade tolerant, and less field management-demanding than current ones. To have a lasting effect this technology should probably be incorporated into a Regional Forest Management Plan, for sustainable production at the secondary forests created with agroforestry technology.

Effects of soil types and cultural practices on the fire ant, Solenopsis invicta, in sugarcane

A two-year study (1984, 1985) conducted in South Louisiana sugarcane fields to investigate the effects of selected soil types and cultural practices on the abundance of the fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), showed that the highest S. invicta populations were present in clayey fields. There was a several-fold difference in the number of S. invicta mounds between the early-harvested fields and late-harvested or plant fields. Additionally, S. invicta mounds were more abundant in fields where there was a greater amount of ground cover (weeds and crop residues). During the 1984 study, foraging by S. invicta on clayey soils was somewhat lower in harvested than in planted fields. However, there was a trend for higher foraging in harvested than in planted fields in 1985. Significantly higher amounts of phosphorus, potassium, calcium, magnesium, sodium and percent organic matter were found in clayey than in sandy fields during 1984 and 1985. The significantly higher moisture content and the lower bulk density in clayey than in sandy soils seemed potentially conducive to greater S. invicta abundance through elimination of the risk of colony desiccation, as well as enhancement of subterranean foraging tunnels and deeper colony expansion.

Crop surveys from multiband satellite photography using digital techniques

Multiband and Multibase photography of the Imperial Valley, California, taken during the Apollo 9 mission was analyzed using statistical multispectral pattern recognition techniques. With a scanning microdensitometer, 70-mm frames were converted into digital form and stored on magnetic tape. All analysis was conducted using a digital computer which enabled rapid automatic processing of any of over five million film density measurements. Automatic recognition of fields of barley, sugar beets, and alfalfa was attempted, and the recognition accuracies were 75% for barley, 59% for sugar beets, and 27% for alfalfa. Highly accurate detection of bare soil, salt flats, and water was achieved. Low percentage ground cover crops such as lettuce, onions, carrots, and cabbage were indistinguishable from bare soil. Results using multiband photography are compared with results using color separations of color infrared photography which covered approximately the same bands.

The Influence of Cover Crop Cultivation on Populations of Injurious Insects and Mites in Florida Citrus Groves

Cultural practices involving the natural ground cover or cover crop vary considerably from area to area and grove to grove in Florida. This variation is, in some instances, governed by the level of the water table or the type of soil involved. More frequently, however, cultivation is modified by the opinions of the grower. Some growers maintain weed-free groves by frequent disking, harrowing or chopping. Others permit cover crop development during the summer months but practice clean cultivation in the fall, winter and spring. Still others allow weeds and wild grasses to grow unhampered from one picking season to the next. Horticultural and agronomic reasons cited for such variations in practices include moisture conservation, soil conservation, fire protection, soil protection, tree stimulation and efficient grove management. Furthermore, many growers believe that such practices cause increases or decreases in insect and mite abundance. To date only two studies have been conducted on the influence of cover crop cultivation on insect and mite infestations. The first was an investigation by Osburn and Mathis (1944) concerning the citrus rust mite, Phyllocoptruta oleivora (Ashmead). These workers concluded that there was no difference between rust mite infestations on trees in clean cultivated plots and on trees grown in plots having a cover crop. They did, however, record stimulation of the trees in the clean cultivation plots. Two years later the same workers (Osburn and Mathis, 1946) reported markedly greater infestations of Florida red scale, Chrysomphalus aonidum (L.), on trees growing in cultivated plots than on trees in uncultivated plots. They were unable, however, to demonstrate striking differences in the percentages of parasitized scales or fungi-affected scales and concluded that tree stimulation, a result of cultivation, was the important factor in the development of larger scale infestations. The present study was conducted to obtain preliminary cultivation data on the major injurious insects and mites attacking Florida citrus and to correlate, if possible, any differences recorded with changes in the rates of parasitism or predation.