THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF PAPAYA (CARICA PAPAYA L.): A REVIEW

2013 ◽  
Vol 50 (2) ◽  
pp. 270-283 ◽  
Author(s):  
M. K. V. CARR
Keyword(s):  
Water Relations ◽  
Time Lag ◽  
Crop Coefficient ◽  
Juvenile Period ◽  
Abaxial Leaf Surface ◽  
Tropical America ◽  
In The Wild ◽  
High Yields ◽  
The Tropics ◽  
Changing Light

SUMMARYPapaya has never been found in the wild, but is believed to have originated in tropical America from where it has spread throughout the tropics and subtropics. This fruit crop is particularly important in India and Brazil. Most research on the water relations of papaya has been undertaken in Brazil and on the island of Guam (United States of America). Papaya is a short-lived large herb, growing to a height of up to 10 m. Leaves emerge from the upper part of the unbranched stem. After a juvenile period, lasting for about two months, flowers begin to develop in leaf axils. Flowering continues throughout the year as new leaves emerge. The plants, which are dioecious, begin to bear fruit within a year after planting, sustaining high yields for two years before yields decline. The ‘effective’ root depth varies with the method of irrigation, but can reach 0.55 m. The seedlings and the trees are susceptible to wind damage, a topic that has been well researched. Stomata are only found on the abaxial leaf surface. They are sensitive to changes in the saturation deficit of the air. Stomata also respond quickly to changing light conditions. On clear days, midday suppression of photosynthesis occurs as a result of partial closure of the stomata. In the morning, there is a time lag between water loss by transpiration and sap flow, as water is taken from storage in the hollow stem. Few attempts have been made to measure the actual water use of papaya, and there are no reliable published values for the crop coefficient. Limitations to the design of the papaya irrigation experiments reported so far make it difficult to reconcile the results in practical ways. Water productivities equivalent to 1.8 to 2.8 kg (fresh fruit) m−3 (irrigation water) have been obtained. Although papaya is generally considered to be drought sensitive and responsive to irrigation, there is a shortage of good experimental evidence to support this view. There is a need to establish practical irrigation schedules for this remarkable crop. A uniformity of approach to irrigation experimentation and a common, universally agreed nomenclature would facilitate this process.

THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF MANGO (Mangifera indica L.): A REVIEW

2013 ◽  
Vol 50 (1) ◽  
pp. 1-23 ◽  
Author(s):  
M. K. V. CARR
Keyword(s):  
Water Relations ◽  
Potential Evapotranspiration ◽  
Mangifera Indica ◽  
Water Productivity ◽  
Crop Coefficient ◽  
Future Research ◽  
Abaxial Leaf Surface ◽  
Wide Range ◽  
Tropical Areas ◽  
Irrigation Requirements

SUMMARYThe results of research on the water relations and irrigation requirements of the mango fruit tree are collated. The stages of development (including roots) are summarised, followed by reviews of plant water relations, water requirements, water productivity and water management. This long-lived tree is well adapted to a wide range of tropical and subtropical environments. In the low-latitude tropics, flowering is initiated after a period of water stress (at least six weeks duration) and is ended by rain or irrigation. In the high-latitude tropics and subtropics, flower buds are initiated during the cool winter months (<15 °C). Less than 1% of the flowers that set fruit reach maturity. Roots can reach depths of 5 m. Stomata occur mainly on the lower (abaxial) leaf surface. They are sensitive to dry air, closing as the saturation deficit increases (from 0.5 to 4.0 kPa). In humid tropical areas, the mean seasonal potential evapotranspiration rates (ETc) average 4–5 mm d−1, with peak rates of 5–6 mm d−1. The crop coefficient (Kc) varies between 0.65 and 1.05. Water productivities are in the range 3–6 kg (fresh fruit) m−3 (irrigation). Micro-sprinklers and drip irrigation are the preferred methods of irrigation. The trend towards greater intensification of production will impact on the water relations and irrigation needs of mango and provide a focus for future research.

scholarly journals THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF SUGAR CANE (SACCHARUM OFFICINARUM): A REVIEW

2011 ◽  
Vol 47 (1) ◽  
pp. 1-25 ◽  
Author(s):  
M. K. V. CARR ◽  
J. W. KNOX
Keyword(s):  
Water Stress ◽  
Water Relations ◽  
Sugar Cane ◽  
Root Zone ◽  
Water Productivity ◽  
Crop Coefficient ◽  
Saccharum Officinarum ◽  
Irrigation Scheduling ◽  
Background Information ◽  
Technology Choice

SUMMARYThe results of research on the water relations and irrigation needs of sugar cane are collated and summarized in an attempt to link fundamental studies on crop physiology to irrigation practices. Background information on the centres of production of sugar cane is followed by reviews of (1) crop development, including roots; (2) plant water relations; (3) crop water requirements; (4) water productivity; (5) irrigation systems and (6) irrigation scheduling. The majority of the recent research published in the international literature has been conducted in Australia and southern Africa. Leaf/stem extension is a more sensitive indicator of the onset of water stress than stomatal conductance or photosynthesis. Possible mechanisms by which cultivars differ in their responses to drought have been described. Roots extend in depth at rates of 5–18 mm d−1 reaching maximum depths of > 4 m in ca. 300 d providing there are no physical restrictions. The Penman-Monteith equation and the USWB Class A pan both give good estimates of reference crop evapotranspiration (ETo). The corresponding values for the crop coefficient (Kc) are 0.4 (initial stage), 1.25 (peak season) and 0.75 (drying off phase). On an annual basis, the total water-use (ETc) is in the range 1100–1800 mm, with peak daily rates of 6–15 mm d−1. There is a linear relationship between cane/sucrose yields and actual evapotranspiration (ETc) over the season, with slopes of about 100 (cane) and 13 (sugar) kg (ha mm)−1 (but variable). Water stress during tillering need not result in a loss in yield because of compensatory growth on re-watering. Water can be withheld prior to harvest for periods of time up to the equivalent of twice the depth of available water in the root zone. As alternatives to traditional furrow irrigation, drag-line sprinklers and centre pivots have several advantages, such as allowing the application of small quantities of water at frequent intervals. Drip irrigation should only be contemplated when there are well-organized management systems in place. Methods for scheduling irrigation are summarized and the reasons for their limited uptake considered. In conclusion, the ‘drivers for change’, including the need for improved environmental protection, influencing technology choice if irrigated sugar cane production is to be sustainable are summarized.

Bixa orellana (annatto).

2021 ◽  
Author(s):  
Eduardo Ventosa
Keyword(s):  
Main Product ◽  
Organic Dye ◽  
Maximum Diameter ◽  
Agricultural Crops ◽  
Bixa Orellana ◽  
Breast Height ◽  
Tropical America ◽  
Medicinal Properties ◽  
Strong Winds ◽  
The Tropics

Abstract B. orellana is a small, bushy tree 2-8 m tall, with maximum diameter at breast height 10-30 cm (Hensleigh and Holaway, 1988). The main product is a non-toxic organic dye obtained from the fruits, known as annatto or bixin. This dye is used commercially in foods, cosmetics, textiles, polish, wax and stains; locally it is used as an insect repellent and as a body paint. The bark exudes a gum and contains fibres which may be twisted into a cordage; the seeds and leaves have medicinal properties (Lemmens and Wulijarni-Soetjipto, 1991; Anon, 1986). B. orellana originated in tropical America (Hensleigh and Holaway 1988) and is now widely planted and naturalized in the tropics (Quisumbing 1951; Backer and Brink, 1963; Quimbo, 1980; Lemmens and Wulijarni-Soetjipto, 1991). It is a light-demanding species and grows well in warm, humid climates which are free from frost and strong winds (Lemmens and Wulijarni-Soetjipto, 1991). This species requires uniformly distributed rainfall, unless the land is irrigated (Bayot, 1986). B. orellana is often intercropped with agricultural crops, and is also grown as an ornamental bushy tree. B. orellana may be propagated from seeds. The pods are harvested once they begin to show a tinge of red or when they begin to split (Hensleigh and Holaway, 1988). Average annual yields of dry seed have been reported as 4.5-5 kg/tree or about 350-700 kg/ha (Brown, 1957; Hensleigh and Holaway, 1988). Seeds are soaked in water or scarified in order to enhance germination, and may be planted in nursery beds or directly in the field. However, propagation from cuttings is often more favourable, as cuttings from high-yielding cultivars yields may bear fruit within two years (Lemmens and Wulijarni-Soetjipto, 1991). This species can also be propagated by air layering. B. orellana grows well without fertilizers, provided the young plants are weeded.

Complex diversity in a mainly tropical group of ant parasitoids: Revision of the Orasema stramineipes species group (Hymenoptera: Chalcidoidea: Eucharitidae)

Zootaxa ◽  
2018 ◽  
Vol 4401 (1) ◽  
pp. 1 ◽  
Author(s):  
ROGER A. BURKS ◽  
JOHN M. HERATY ◽  
CHRYSALYN DOMINGUEZ ◽  
JASON L. MOTTERN
Keyword(s):  
Biological Control Agent ◽  
Sister Group ◽  
Molecular Data ◽  
Species Group ◽  
Control Agent ◽  
Wasmannia Auropunctata ◽  
Secondary Infections ◽  
Tropical America ◽  
Morphological And Molecular Data ◽  
The Tropics

Twenty-nine species are recognized in the Orasema stramineipes species group, including 22 new species in what is now the most diverse species group of the New World ant-parasitoid genus Orasema Cameron. Orasema aenea Gahan syn. n. is synonymized with O. freychei (Gemignani), the holotype of which has been rediscovered. Orasema smithi Howard syn. n. is synonymized with Orasema minutissima Howard. Orasema violacea Gemignani syn. n. and its replacement name Orasema gemignanii De Santis syn. n. are synonymized with O. worcesteri (Girault). Twenty-two species are described as new: O. arimbome Dominguez, Heraty & Burks n. sp., O. carchi Heraty, Burks & Dominguez n. sp., and the following 20 species by Burks, Heraty & Dominguez: O. chunpi n. sp., O. cozamalotl n. sp., O. evansi n. sp., O. hyarimai n. sp., O. kaspi n. sp., O. kulli n. sp., O. llanthu n. sp., O. llika n. sp., O. mati n. sp., O. nyamo n. sp., O. pirca n. sp., O. pisi n. sp., O. qillu n. sp., O. qincha n. sp., O. rikra n. sp., O. taku n. sp., O. tapi n. sp., O. torrensi n. sp., O. woolleyi n. sp., and O. yaax n. sp. The stramineipes-group has much greater diversity in tropical America than outside the tropics, and is much more diverse than its sister-group, the susanae-group, which is mainly present in temperate regions of Argentina. A hypothesis of phylogenetic relationships is proposed based on an analysis of 28S-D2 rDNA and cytochrome oxidase I (COI) for 14 stramineipes-group species. Species concepts were established using both morphological and molecular data. Most species in the stramineipes-group have a tropical distribution, with only a few species in temperate regions. Ant hosts for the group include Pheidole Westwood, Wasmannia Forel, and possibly Solenopsis Westwood (Formicidae: Myrmicinae). Orasema minutissima is a common parasitoid of Wasmannia auropunctata Roger in the Caribbean and has the potential to be a biological control agent in other areas of the world. Two distinct size morphs are recognized for O. minutissima, which are correlated with attacking either Wasmannia (small morph) or different castes of Pheidole (medium to large size morphs). Some species of Orasema have been regarded as pests due to scarring or secondary infections of leaves or fruit of banana, yerba mate or blueberry, but outbreaks are rare and the threat is usually temporary. 

Ecology of the Atlantic Forest

Ecology ◽  
2021 ◽  
Author(s):  
Elise Damstra ◽  
Cristina Banks-Leite
Keyword(s):  
Atlantic Forest ◽  
Forest Cover ◽  
Time Lag ◽  
Native Forest ◽  
Important Species ◽  
Habitat Transformation ◽  
Golden Lion Tamarin ◽  
Palm Heart ◽  
In The Wild ◽  
Unique Domain

Extending along the southern coast of Brazil, into Argentina and Paraguay, the Atlantic Forest is a domain that once covered 150 Mha and includes many distinct forest subtypes and ecosystems. Its large latitudinal (29˚) and altitudinal (0–2,800 m above sea level) range, as well as complex topography in the region, has created microclimates within forest subtypes, which has led to biodiversity specifically adapted to narrow ecological ranges. The region is incredibly species-rich and is home to charismatic or economically important species such as the black and golden lion tamarin, the red-browned Amazon parrot, and the highly prized palm heart from Euterpe edulis. Through widespread human-driven change dating back to the arrival of European settlers in 1500, this realm has been extensively reduced, fragmented, and modified. Nowadays, this region is home to about 130 million people (60 percent of the Brazilian population) and is responsible for producing 70 percent of Brazil’s GDP, putting a strain on natural resources and providing challenges to conservation. Due to its high levels of endemic species coupled with a high threat of habitat loss and fragmentation, the Atlantic Forest has been identified as a “biodiversity hotspot.” Numerous studies have assessed the effects of habitat transformation on biodiversity and the consensus is that the majority of species are negatively affected. It is puzzling however that few species have actually gone extinct in the wild, even if some extinctions might have gone undetected. Extinctions do not immediately follow habitat change, there is often a time lag of many decades between habitat transformation and extinction. This may suggest that many species in the Atlantic Forest are “living deads,” as despite their presence the available habitat no longer supports their requirements. It also suggests that there is a window of opportunity to restoring the domain to avert extinctions before they are realized. Current research and policy actions are geared toward optimizing restoration and increasing the extent of native forest cover, bringing hope to the conservation of this unique domain.

A Trypanosome and Haemogregarine of a Tropical American Snake

Parasitology ◽  
1908 ◽  
Vol 1 (4) ◽  
pp. 314-317 ◽  
Author(s):  
C. M. Wenyon
Keyword(s):  
Accurate Description ◽  
Tropical America ◽  
The Tropics

The trypanosome to be described in this paper was discovered in blood films taken from the snake Erythrolamprus aesculapii (Duméril and Bibron) of tropical America. For these films I am indebted to Dr Leiper. In addition to the trypanosome there was present in the blood a haemogregarine. Though haemogregarines are very common in snakes, especially in the Tropics, where nearly every snake examined is found to harbour these parasites, the reverse is the case with trypanosomes. Several observers have recorded the presence of trypanosomes in snakes but hitherto no one has given an accurate description of one of trypanosomes of the whole group of reptiles is very limited when campared with other groups of vertebrata. On this account it seems of interest to place on record the characters of this trypanosome as it appears in the blood films mentioned above.

scholarly journals Variability in the speed of the Brewer–Dobson circulation as observed by Aura/MLS

2013 ◽  
Vol 13 (9) ◽  
pp. 4563-4575 ◽  
Author(s):  
T. Flury ◽  
D. L. Wu ◽  
W. G. Read
Keyword(s):  
Time Series ◽  
Interannual Variability ◽  
Lower Stratosphere ◽  
Meridional Circulation ◽  
Time Lag ◽  
Quasi Biennial Oscillation ◽  
One Year ◽  
The Tropics ◽  
Biennial Oscillation ◽  
Stratospheric Water Vapour

Abstract. We use Aura/MLS stratospheric water vapour (H2O) measurements as tracer for dynamics and infer interannual variations in the speed of the Brewer–Dobson circulation (BDC) from 2004 to 2011. We correlate one-year time series of H2O in the lower stratosphere at two subsequent pressure levels (68 hPa, ~18.8 km and 56 hPa, ~19.9 km at the Equator) and determine the time lag for best correlation. The same calculation is made on the horizontal on the 100 hPa (~16.6 km) level by correlating the H2O time series at the Equator with the ones at 40° N and 40° S. From these lag coefficients we derive the vertical and horizontal speeds of the BDC in the tropics and extra-tropics, respectively. We observe a clear interannual variability of the vertical and horizontal branch. The variability reflects signatures of the Quasi Biennial Oscillation (QBO). Our measurements confirm the QBO meridional circulation anomalies and show that the speed variations in the two branches of the BDC are out of phase and fairly well anti-correlated. Maximum ascent rates are found during the QBO easterly phase. We also find that transport of H2O towards the Northern Hemisphere (NH) is on the average two times faster than to the Southern Hemisphere (SH) with a mean speed of 1.15 m s−1 at 100 hPa. Furthermore, the speed towards the NH shows much more interannual variability with an amplitude of about 21% whilst the speed towards the SH varies by only 10%. An amplitude of 21% is also observed in the variability of the ascent rate at the Equator which is on the average 0.2 mm s−1.

Effects of Time of Nitrogen Application on Yield of Maize in the Tropics

1966 ◽  
Vol 2 (2) ◽  
pp. 101-105 ◽  
Author(s):  
Adeboyejo A. Fayemi
Keyword(s):  
Nitrogen Fertilizer ◽  
Crude Protein ◽  
Crude Protein Content ◽  
Nitrogen Application ◽  
Time Of Application ◽  
Cropping Season ◽  
Maize Grain ◽  
High Yields ◽  
The Tropics ◽  
Maize Ear

SummaryA four-year study from 1958 to 1962 showed that time of application of fertilizer nitrogen greatly influenced the yield of grain, the percentage of nitrogen and the crude protein of the grain under Nigerian conditions characteristic of the early maize cropping season from March to July. Split applications of nitrogen fertilizer significantly increased maize grain yield by 35 per cent when two equal doses were given one month and two months after planting; and by 31 per cent when four equal doses were supplied at planting and one month, two months and three months after seeding. Yield was significantly reduced when application was delayed two months after planting. High yields of maize were not obtained by supplying the whole of nitrogen fertilizer at one time, eidier at sowing or any time later during the growing season. However, applying all of the nitrogen fertilizer one month after planting significantly increased the percentage of nitrogen and of the crude protein content of the grain. The maize ear weight was favourably influenced by spreading the nitrogen application over the three-month period of the maize growth.

scholarly journals Prospects for Improving Subseasonal Predictions

2011 ◽  
Vol 139 (11) ◽  
pp. 3648-3666 ◽  
Author(s):  
Kathy Pegion ◽  
Prashant D. Sardeshmukh
Keyword(s):  
Time Lag ◽  
Thermal Inertia ◽  
Coupled Model ◽  
Longwave Radiation ◽  
Forecast Skill ◽  
Ensemble Prediction ◽  
Coupled Models ◽  
Ensemble Prediction System ◽  
Predictability Analysis ◽  
The Tropics

Abstract Extending atmospheric prediction skill beyond the predictability limit of about 10 days for daily weather rests on the hope that some time-averaged aspects of anomalous circulations remain predictable at longer forecast lead times, both because of the existence of natural low-frequency modes of atmospheric variability and coupling to the ocean with larger thermal inertia. In this paper the week-2 and week-3 forecast skill of two global coupled atmosphere–ocean models recently developed at NASA and NOAA is compared with that of much simpler linear inverse models (LIMs) based on the observed time-lag correlations of atmospheric circulation anomalies in the Northern Hemisphere and outgoing longwave radiation (OLR) anomalies in the tropics. The coupled models are found to beat the LIMs only slightly, and only if an ensemble prediction methodology is employed. To assess the potential for further skill improvement, a predictability analysis based on the relative magnitudes of forecast signal and forecast noise in the LIM framework is conducted. Estimating potential skill by such a method is argued to be superior to using the ensemble-mean and ensemble-spread information in the coupled model ensemble prediction system. The LIM-based predictability analysis yields relatively conservative estimates of the potential skill, and suggests that outside the tropics the average coupled model skill may already be close to the potential skill, although there may still be room for improvement in the tropical forecast skill.

THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF PASSION FRUIT (PASSIFLORA EDULIS SIMS): A REVIEW

2013 ◽  
Vol 49 (4) ◽  
pp. 585-596 ◽  
Author(s):  
M. K. V. CARR
Keyword(s):  
Water Stress ◽  
Water Relations ◽  
Potential Evapotranspiration ◽  
Crop Coefficient ◽  
Heavy Rain ◽  
Passion Fruit ◽  
Flower Bud ◽  
Leaf Production ◽  
Passiflora Edulis ◽  
Bud Initiation

SUMMARYIt is generally accepted that the two forms of Passiflora edulis, the golden and the purple, originated on the edges of tropical rainforests in Brazil. Extensive hybridisation has since taken place between these two forms and their hybrids. The passion fruit (a vine) is now grown throughout the tropics and subtropics. A limited amount of basic, fundamental research has been published on the water relations of passion fruit. Leaf production and expansion are both sensitive to water deficits, while water stress reduces leaf and floral bud initiation. A single axillary flower bud forms at each leaf node of new growth along with a tendril. Flower bud development and fruit set are less sensitive to water stress than leaf initiation. Heavy rain during pollination prevents fertilization. Unevenness in crop distribution during the year is possibly linked to water stress and temperature variation. Potential evapotranspiration rates in Brazil varied between 3.5 mm d−1 and 5.8 mm d−1. The value for the crop coefficient increases from about 0.6 during apical vegetative growth up to about 1.25 during flowering and fruiting. Water productivities still need to be determined. Micro-sprinklers and drip are the most effective ways of applying irrigation water with precision to passion fruit. Opportunities exist for international cooperation in research projects of mutual interest on passion fruit water relations.

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