Mixed - Brush Canopy Cover - Rainfall Interrelationships with Native Grass Production

Annual production of native grasses on the Texas Coastal Prairie was decreased by 90, 66, and 67 kg/ha in 1978, 1979, and 1981, respectively, for each 1% increase in mixed-brush canopy cover in the range, from 12 to 57%. Differences in regression coefficients among years were not significant (P$0.05), although rainfall varied from 84% of the 26-yr average (91.5 cm) in 1978 to 150% of the annual average in 1981. Grass production during the growing season (May through October) only was decreased by 58, 113, and 78 kg/ha in 1978, 1979, and 1981, respectively, for each unit percentage increase in brush canopy cover. A greater proportion of the annual rainfall occurred during the growing season of 1979 than during the drier spring and summer of 1978. Native grasses typical of brush-free Coastal Prairie occupy the interstitial areas among the mixed-brush mottes, but bunch cutgrass (Leersia monandraSwartz) is the only grass that persists from the canopy edge to 1.5 m inward from the brush driplines. Little or no herbaceous vegetation grows in the centers of the mottes.

Download Full-text

Improved forage production following western snowberry (Symphoricarpos occidentalis Hook.) control with metsulfuron methyl

Canadian Journal of Plant Science ◽

10.4141/cjps95-157 ◽

1995 ◽

Vol 75 (4) ◽

pp. 935-940 ◽

Cited By ~ 4

Author(s):

G. G. Bowes ◽

D. T. Spurr

Keyword(s):

Key Words ◽

Canopy Cover ◽

Native Grasses ◽

Physical Barrier ◽

Forage Production ◽

Metsulfuron Methyl ◽

Grass Production ◽

Low Levels ◽

Better Than

Two 6-yr studies were conducted in southeastern Saskatchewan to evaluate 2,4-D, Metsulfuron methyl (Metsulfuron) and a mixture of 2,4-D + Metsulfuron for the long-term control of western snowberry. Western snowberry is a small shrub that grows in dense stands in rangelands and pastures and acts as a physical barrier to grazing. At the study site, the shrub was growing with native grasses and forbs. Metsulfuron applied at 15 g a.i. ha−1 effectively controlled western snowberry for 6 yr. Control with Metsulfuron was better than with 2,4-D because Metsulfuron killed the crown of the shrub. Control was not improved when 2,4-D was added to Metsulfuron, and at low levels of Metsulfuron the presence of 2,4-D in the mixture rendered Metsulfuron less effective, resulting in a higher canopy cover. Grass production averaged over years and experiments was 788 kg ha−1 for the check and increased to 1328 kg ha−1 after Metsulfuron was applied at 15 g ha−1. Forb production was not affected by the treatments. Key words: Western snowberry, Symphoricarpos occidentalis, metsulfuron methyl, 2,4-D

Download Full-text

Effect of Heat Resource Effectiveness Change on Rice Potential Yield in Southern China

Processes ◽

10.3390/pr9050896 ◽

2021 ◽

Vol 9 (5) ◽

pp. 896

Author(s):

Qing Ye ◽

Xiaoguang Yang ◽

Wenjuan Xie ◽

Junmeng Yao ◽

Zhe Cai

Keyword(s):

Southern China ◽

Cropping Systems ◽

Reduction Rate ◽

Growing Season ◽

Scientific Basis ◽

Yield Reduction ◽

Percentage Increase ◽

Potential Yield ◽

Effective Heat ◽

Rice Growing Season

During the rice growing season, farmers’ decisions about cropping systems and seed varieties directly affect the utilization of heat resource, and eventually affect the potential yield. In this study, we used the hourly accumulated temperature model to calculate the available heat resource as well as the effective heat resource in southern China. We conducted a spatiotemporal analysis of the heat resource effectiveness during rice growing season and an impact assessment of heat resource effectiveness on rice potential yield and cereal yield reduction. The results showed that, during the period of 1951–2015, heat resource effectiveness generally declined in the rice cropping area of southern China. And this decrease worsened during the most recent three decades compared with the period of 1951–1980. A strong correlation was detected between heat resource effectiveness and rice potential yield in the study area. When the effective heat resource during the growing season increased by 1 °C·d, rice potential yield would increase by 14 kg ha−1. For each percentage increase in heat resource effectiveness, the rice potential yield reduction rate would go down by 0.65%. This agro-climatological study aims to offer a scientific basis for rice production decisions in southern China, such as when to plant, which varieties to choose and so on.

Download Full-text

ECOLOGICAL-GEOGRAPHIC APPROACHES TO THE STUDY OF GENETIC DIVERSITY OF BARLEY AND OAT FROM THE VIR COLLECTION

Ecological genetics ◽

10.17816/ecogen16128 ◽

2020 ◽

Cited By ~ 1

Author(s):

Igor Loskutov ◽

Lubov Novikova ◽

Olga Kovaleva ◽

Nadezhda Ivanova ◽

Elena Blinova ◽

...

Keyword(s):

Environmental Conditions ◽

Growing Season ◽

Regression Coefficients ◽

Cultivation Conditions ◽

High Productivity ◽

Sum Of Effective Temperatures ◽

Economically Valuable Traits ◽

Effective Temperatures ◽

The Stability ◽

Selection Of

Under conditions of climate change, the assessment of the stability of genotypes is of particular importance. To conduct directed selection of genotypes with a narrow or broad reaction rate, it is necessary to assess their stability already in the early stages of breeding. The aim of the study was to study the stability of breeding significant traits of oat and barley samples in contrasting ecological and geographical conditions. 25 oat samples and 25 barley samples were studied over 3 years under contrasting conditions in St. Petersburg and the Tambov region. Varieties are characterized by average values of economically valuable traits and genotype regression coefficients on the influence of the bi environment according to Eberhart and Russell. The most sensitive to a change in the ecological and geographical situation were the durations of the germination-heading, germination-harvest periods and grain yield. These characters varied to a greater extent depending on the cultivation conditions than on the genotype. According to regression coefficients for environmental conditions, significant differences in genotypes were only in yield. Contrasting groups of varieties were distinguished by regression coefficients on environmental conditions, genotypes with high productivity. The durations of germination-heading, germination-harvest, the plant height reacted to the change in the environment the same in different varieties. The duration of the growing season was determined by the sum of effective temperatures above 15C. The reduction of the growing season in both crops was 3 days with an increase in the sum of effective temperatures above 15C by 100C.

Download Full-text

PENENTUAN MUSIM TANAM, JENIS VARIETAS, DAN TEKNIK BUDIDAYA TANAMAN PADI TERKAIT MITIGASI EMISI METANA (CH4) (Determination of Early Planting Season, Type Varieties, and Cultivation Techniques of Rice as Mitigation to Methane Emission)

Jurnal Manusia dan Lingkungan ◽

10.22146/jml.23077 ◽

2018 ◽

Vol 24 (1) ◽

pp. 1

Author(s):

Lilik Slamet Supriatin

Keyword(s):

Rainy Season ◽

Growing Season ◽

Dry Season ◽

Wetland Mitigation ◽

Annual Rainfall ◽

Ch4 Emission ◽

Ch4 Emissions ◽

Cultivation Techniques ◽

Planting Season

ABSTRAKEmisi metana (CH4) dari pertanian padi lahan sawah dapat dipengaruhi oleh faktor-faktor seperti cara pemberian air, pengolahan tanah, varietas padi, dan iklim. Pada penelitian ini dikaji tahap penentuan musim tanam, pemilihan varietas padi, dan tahap terakhir adalah teknik budidaya pertanian padi lahan sawah yang terkait mitigasi emisi CH4. Hasil kajian menunjukkan bahwa musim tanam padi pada musim kemarau menghasilkan emisi CH4 lebih kecil daripada di musim hujan dengan pengurangan emisi CH4 sebesar 18,13%. Indonesia yang memiliki tiga tipe pola curah hujan tahunan (monsunal, equatorial, lokal) mengakibatkan periode musim tanam rendah emisi CH4 berbeda antara tipe curah hujan yang satu dengan lainnya. Varietas padi Way apo buru adalah varietas yang menghasilkan emisi CH4 terendah tetapi tetap optimum dalam produksi gabah sehingga dapat dipilih menjadi prioritas pertama untuk ditanam. Teknik budidaya pertanian padi lahan sawah yang menghasilkan rendah emisi CH4 dapat dilakukan dengan membuat genangan air yang dangkal saja, dengan cara pemberian air berselang, dan kombinasi antara pemeliharaan padi, ganggang, tanaman paku air, ikan air tawar, dan bakteri metanotrof dalam satu petak lahan sawah (mina padi plus). Pemberian air dengan cara berselang menurunkan emisi CH4 pada musim kemarau sebesar 59,36% dan pada musim hujan sebesar 51,68% jika dibandingkan dengan pemberian air secara terus-menerus (kontinyu). Teknik budidaya mina padi plus mengurangi emisi CH4 sebesar 21,5 kg/ha/musim tanam dan bakteri metanotrof mengurangi emisi CH4 ke atmosfer sebesar 20-60 Tg. Sawah dapat dijadikan sebagai instalasi terbuka pengolahan udara berlimbah CH4. ABSTRACTMethane (CH4) emissions from rice cultivation can be influenced by several factors i.e. the provision of water, soil cultivation, varieties of rice, and the climate. This study will examine the determination of the growing season, the selection of rice varieties and cultivation techniques of rice agriculture-related wetland mitigation of the CH4 emission. The results showed that the rice planting season in the dry season produces CH4 emissions is smaller than in the rainy season with CH4 emission reduction of 18.13%. Indonesia, which has three types of annual rainfall patterns resulting in periods of low growing season CH4 emissions differ between types of rainfall each other. Way apo buru rice species are varieties that produce low emissions of CH4 but remains optimum in grain production. Cultivation techniques of rice farming rice fields that produce low emissions of CH4 can be done by creating a pool of shallow water only, by way of provision of water intermittent, and the combination of maintenance of rice, algae, plants salviniales, freshwater fish, and bacteria metanotrof in a wetland. The provision of water by intermittent lowering emissions of CH4 in the dry season by 59.36% and in the rainy season amounted to 51.68% when compared to the provision of water continuously (continuous). Mina padi plus cultivation techniques reduce CH4 emissions by 21.5 kg/ha/planting and metanotrof bacteria can reduce CH4 emissions to the atmosphere by 20-60 Tg.

Download Full-text

Using Canopy Measurements to Predict Soybean Seed Yield

Remote Sensing ◽

10.3390/rs13163260 ◽

2021 ◽

Vol 13 (16) ◽

pp. 3260

Author(s):

Peder K. Schmitz ◽

Hans J. Kandel

Keyword(s):

Seed Yield ◽

Prediction Models ◽

Plant Density ◽

Soybean Seed ◽

Canopy Cover ◽

Growing Season ◽

Practical Method ◽

Coefficient Of Determination ◽

Planting Dates ◽

The Individual

Predicting soybean [Glycine max (L.) Merr.] seed yield is of interest for crop producers to make important agronomic and economic decisions. Evaluating the soybean canopy across a range of common agronomic practices, using canopy measurements, provides a large inference for soybean producers. The individual and synergistic relationships between fractional green canopy cover (FGCC), photosynthetically active radiation (PAR) interception, and a normalized difference vegetative index (NDVI) measurements taken throughout the growing season to predict soybean seed yield in North Dakota, USA, were investigated in 12 environments. Canopy measurements were evaluated across early and late planting dates, 407,000 and 457,000 seeds ha−1 seeding rates, 0.5 and 0.8 relative maturities, and 30.5 and 61 cm row spacings. The single best yield predictor was an NDVI measurement at R5 (beginning of seed development) with a coefficient of determination of 0.65 followed by an FGCC measurement at R5 (R2 = 0.52). Stepwise and Lasso multiple regression methods were used to select the best prediction models using the canopy measurements explaining 69% and 67% of the variation in yield, respectively. Including plant density, which can be easily measured by a producer, with an individual canopy measurement did not improve the explanation in yield. Using FGCC to estimate yield across the growing season explained a range of 49% to 56% of yield variation, and a single FGCC measurement at R5 (R2 = 0.52) being the most efficient and practical method for a soybean producer to estimate yield.

Download Full-text

Experimentation of grapevine cultivation in organic system, on five different Romanian vineyards

Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca Horticulture ◽

10.15835/buasvmcn-hort:12206 ◽

2016 ◽

Vol 73 (2) ◽

pp. 175

Author(s):

Aurora Maria Ranca ◽

Victoria Artem ◽

Ionica Dina ◽

Liliana Parcalabu ◽

Maria Iliescu ◽

...

Keyword(s):

Cynodon Dactylon ◽

Climatic Factors ◽

Growing Season ◽

Lobesia Botrana ◽

Amaranthus Retroflexus ◽

Mean Annual Temperature ◽

Stellaria Media ◽

Annual Average ◽

Organic System ◽

Polygonum Aviculare

In five Romanian vineyards, in 2013-2014 period was experimented organic system growing on grape varieties for wine representative for each area, here are applied organic growing technology in parallel with the conventional (control). White varieties studied are: Chardonnay (Murfatlar and Valea Calugareasca), Sauvignon blanc and Muscat Ottonel(Tarnave), Feteasca regala (Tarnave, Bujoru and Copou-Iasi). Red varieties are Cabernet Sauvignon (Murfatlar and Valea Calugareasca) and Merlot (Bujoru).Concerning evolution of main climatic factors for the years 2013-2014 it is show that the annual average air temperature increase compared with the average of the years 1991-2010; is observed an increasing in mean annual temperature, mean temperature during the growing season and the value of sum of sunshine hours. The water regime was kept constant, registering values close to the annual average, both during the growing season and at entire year. The weeds spectrum is represented both by dicotyledonous as knotweed (Polygonum aviculare), Veronica (Stellaria media), news (Amaranthus retroflexus), bindweed (Convolvurus arvensis) and monocotyledonous as grass thick (Cynodon dactylon).Concerning the phytosanitary status, at Murfatlar were registered problems with oidium attack, with all main disease at Dealu Mare and with downy mildew at Bujoru. In all areas the pest has been found are: grape mouth (Lobesia botrana) and spiders (Tetranichus sp.). Schemes of treatments focused generally on substances bassed on copper and sulfur to combat diseases and for pests have been used pheromonal traps or other certified organic products.The grapes harvest was lower in organic plots with till 25%; their quality being close at both growing variants.

Download Full-text

Modeling the irrigation requirements for an experimental site in Northern Alberta, Canada

10.7287/peerj.preprints.696 ◽

2014 ◽

Author(s):

Michel Rahbeh ◽

David Chanasyk ◽

Shane Patterson

Keyword(s):

Water Table ◽

Root Zone ◽

Winter Season ◽

Growing Season ◽

Annual Rainfall ◽

Quality Model ◽

Experimental Site ◽

Supplementary Irrigation ◽

Northern Alberta ◽

Irrigation Requirements

A combined methodology of the Root Zone Water Quality Model (RZWQM), the generation of stochastic rainfall realizations, and an historical meteorological record were used to determine the supplementary irrigation requirement for an experimental site located in northern Alberta. The site receives an annual rainfall of approximately 500 mm yr -1, and contains a fluctuating water table. The simulated results showed maximum irrigation requirements of 270 mm, however, half that amount can be required during an average or wet growing season of mean rainfall of 350 and 500 mm, respectively. The irrigation requirements were influenced by rainfall amount and distribution, downward flux and the subsequent fluctuation of the water table and the depth of water table at the beginning of the growing season, which was influenced by the winter season precipitation. The simulated results suggested that a water table less than 2 m deep from the ground surface can significantly reduce the irrigation requirements. Therefore, the winter precipitation and initial depth of the water table are suitable indicators of the likely requirement of irrigation during the growing season.

Download Full-text

Net ecosystem exchange of carbon dioxide and water of far eastern Siberian Larch (<I>Larix cajanderii</I>) on permafrost

Biogeosciences ◽

10.5194/bg-1-133-2004 ◽

2004 ◽

Vol 1 (2) ◽

pp. 133-146 ◽

Cited By ~ 64

Author(s):

A. J. Dolman ◽

T. C. Maximov ◽

E. J. Moors ◽

A. P. Maximov ◽

J. A. Elbers ◽

...

Keyword(s):

Far East ◽

Siberian Larch ◽

Net Ecosystem Exchange ◽

Growing Season ◽

Eddy Correlation ◽

Annual Rainfall ◽

Surface Conductance ◽

Co2 Uptake ◽

Atmospheric Humidity ◽

Far Eastern

Abstract. Observations of the net ecosystem exchange of water and CO2 were made during two seasons in 2000 and 2001 above a Larch forest in Far East Siberia (Yakutsk). The measurements were obtained by eddy correlation. There is a very sharply pronounced growing season of 100 days when the forest is leaved. Maximum half hourly uptake rates are 18 µmol m-2 s-1; maximum respiration rates are 5 µmol m-2 s-1. Net annual sequestration of carbon was estimated at 160 gCm-2 in 2001. Applying no correction for low friction velocities added 60 g C m-2. The net carbon exchange of the forest was extremely sensitive to small changes in weather that may switch the forest easily from a sink to a source, even in summer. June was the month with highest uptake in 2001. The average evaporation rate of the forest approached 1.46 mm day-1 during the growing season, with peak values of 3 mm day-1 with an estimated annual evaporation of 213 mm, closely approaching the average annual rainfall amount. 2001 was a drier year than 2000 and this is reflected in lower evaporation rates in 2001 than in 2000. The surface conductance of the forest shows a marked response to increasing atmospheric humidity deficits. This affects the CO2 uptake and evaporation in a different manner, with the CO2 uptake being more affected. There appears to be no change in the relation between surface conductance and net ecosystem uptake normalized by the atmospheric humidity deficit at the monthly time scale. The response to atmospheric humidity deficit is an efficient mechanism to prevent severe water loss during the short intense growing season. The associated cost to the sequestration of carbon may be another explanation for the slow growth of these forests in this environment.

Download Full-text

Smoke affects the Germination of Native Grasses of New South Wales

Australian Journal of Botany ◽

10.1071/bt97124 ◽

1999 ◽

Vol 47 (4) ◽

pp. 563 ◽

Cited By ~ 32

Author(s):

Tamara R. Read ◽

Sean M. Bellairs

Keyword(s):

New South ◽

Germination Rate ◽

New South Wales ◽

Germination Percentage ◽

Grass Species ◽

Native Grasses ◽

Environmental Stimulus ◽

Native Grass ◽

South Wales ◽

Stimulation Of

The germination responses to plant-derived smoke of seeds of 20 native grass species from New South Wales, Australia, were tested under laboratory conditions. The species belonged to 14 genera including Bothriochloa, Chloris, Cymbopogon, Danthonia, Dichanthium, Digitaria, Eragrostis, Eriochloa, Microlaena, Panicum, Paspalidium, Poa, Stipa and Themeda. The interaction between smoke and husk-imposed dormancy was examined by removing the floral structures surrounding the seeds, when sufficient seeds were available. Smoke was shown to be an important environmental stimulus for breaking the dormancy of native grasses; however, the response differed considerably between different genera and between species of the same genus. For almost half of the species, smoke significantly increased the germination percentage. Panicum decompositum showed the greatest response, with germination increasing from 7.7 to 63.1% when smoke was applied. Panicum effusum had no germination in the absence of smoke, but 16.7% germination when smoke was applied. Stipa scabra subsp. scabra had germination significantly reduced by smoke from 30.2 to 19.9%. Five species had their germination rate, but not the final germination percentage, affected by smoke, and a third of the species were unaffected by smoke. For five of the species, Chloris ventricosa, Dichanthium sericeum, Panicum decompositum, Poa labillardieri and Stipa scabra subsp. falcata, this is the first report of a smoke-stimulated germination response. For those species with germination promoted by smoke, retention of the covering structures did not prevent smoke stimulation of germination. Sowing smoke-treated husked seeds is likely to be preferable as it would still promote greater germination, whereas dehusking seeds can result in the seeds being more susceptible to desiccation and fungal attack in the field. It is suggested that other grassland communities that respond to pyric conditions may also contain species that respond to smoke.

Download Full-text