Characterizing the crop environment – nature, significance and applications

2015 ◽  
pp. 321-348 ◽  
Author(s):  
Karine Chenu
Keyword(s):  
2018 ◽  
Vol 24 (11) ◽  
pp. 5072-5083 ◽  
Author(s):  
Daniel Wallach ◽  
Pierre Martre ◽  
Bing Liu ◽  
Senthold Asseng ◽  
Frank Ewert ◽  
...  

1990 ◽  
Vol 80 (4) ◽  
pp. 465-472 ◽  
Author(s):  
R.E. Price ◽  
H.D. Brown

AbstractThe reproductive performance of the African migratory locust, Locusta migratoria migratorioides (Reiche & Fairmaire), was assessed in a cereal crop environment on the temperate Highveld of South Africa. Of the two principal crops involved on the Highveld, maize realized the highest reproductive potential during summer, wheat was successfully utilized for breeding in spring. The combined effects of food and temperature were the main factors influencing seasonal variation in clutch size. Green food was essential for continued reproduction, oviposition ceased for three to four months during winter when food resources deteriorated and was resumed in spring. Although locust size was shown to decrease significantly in early winter, this did not influence fecundity. The effects of egg resorption, female age and phase on clutch size are outlined. Despite the more adverse climate of the Highveld, the migratory locust realized higher individual natality in the cereal crop environment than that recorded previously and consequently achieved outstanding reproductive success in this alternative habitat.


MAUSAM ◽  
2021 ◽  
Vol 49 (4) ◽  
pp. 511-520
Author(s):  
A. KASHYAPI ◽  
S. K. SHAHA ◽  
P. M. GULHANE

The Division of Agricultural Meteorology, at Pune of IMD conducted an experiment at Principal Evapotranspiration Observatory, Canning, W.B., during October, 1995 to study the sudden changes in crop environment. The present study revealed that both the crop canopy temperature and observatory temperature at different heights recorded sharp fall of around 2.0°C at 0900 hr (IST) on the eclipse day. The relative humidity (% ) increased sharply at 0900 hr (IST) on the eclipse day within crop canopy as well as within observatory. The soil temperature dropped suddenly at 10 and 20 cm depths of the subsoil and delayed reversal of the soil temperature gradient occurred on the eclipse day; the grass minimum temperature was 21.2°C. Bright sunshine hours reduced by 0.8 on 'the eclipse day as compared to the preceding and succeeding days. The wind during the eclipse period was almost calm between 0900 -0930 hr (IST). The daily total ET recorded on the eclipse day was the minimum. The rate of evapotranspiration was less than half as compared to the other days, as recorded at 0830 hr (IST) (0.2 mm) on the eclipse day, which was closely followed by that observed at 1130 hr (IST) (0.3 mm).


2005 ◽  
Vol 102 (3) ◽  
pp. 547-552 ◽  
Author(s):  
Johanna VILLENAVE ◽  
Dominique THIERRY ◽  
Abdullah AL MAMUN ◽  
Thierry LODE ◽  
Elizabeth RAT-MORRIS

Author(s):  
N.HEMAMALINI

Water is a natural resource that every human being on earth rely to satisfy his or her needs. The earth is now facing many problems such as climate change droughts and water scarcity which is a result from human activity. Life on earth without water cannot be imagined and importance and usage of water has been discussed in Sanggam Literature. In Sanggam Literature water resource has been treated in a very high state and maintained well. Water maintenance has been equipped with skills and expertise of mankind in design the water construction of reservoirs to dams. A safe crop environment also has been developed and practiced to ensure the water in the pond is not contaminated. On the other hand, guards also assigned to guard the water levels throughout the day and night. This system ensures there is enough water to access and awareness of water disaster from beginning. This paper discuss by establishing the danger of water in proper way it is possible to live by hitting the level of self- sufficient.


1999 ◽  
Vol 65 (5) ◽  
pp. 1919-1923 ◽  
Author(s):  
Juliet A. Durant ◽  
Donald E. Corrier ◽  
J. Allen Byrd ◽  
Larry H. Stanker ◽  
Steven C. Ricke

ABSTRACT Leghorn hens over 50 weeks of age were assigned to two treatment groups designated as either unmolted controls or molted. A forced molt was induced by a 9-day feed withdrawal, and each hen was challenged orally with 105 Salmonella enteritidisorganisms on day 4 of feed withdrawal. On days 4 and 9 of molt, the numbers of lactobacilli and the concentrations of lactate, acetate, propionate, and butyrate, and total volatile fatty acids in the crops decreased while crop pH increased significantly (P < 0.05) in the molted hens compared to the controls. S. enteritidis crop and cecal colonization, in addition to spleen and liver invasion, increased significantly (P < 0.05) in the molted hens compared to the controls. The invasive phenotype of Salmonella spp. is complex and requires several virulence genes which are regulated by the transcriptional activator HilA. Samples of the crop contents from the molted and unmolted birds were pooled separately, centrifuged, and filter sterilized. The sterile crop contents were then used to measure the expression of hilA. By using a lacZYtranscriptional fusion to the hilA gene in S. enteritidis, we found that hilA expression was 1.6- to 2.1-fold higher in the crop contents from molted birds than in those from control birds in vitro. The results of the study suggest that the changes in the microenvironment of the crop caused by feed deprivation are important regulators of S. enteritidis survival and influence the susceptibility of molted hens to S. enteritidis infections. Furthermore, our in vitro results on the expression of hilA suggest that the change in crop environment during feed withdrawal has the potential to significantly affect virulence by increasing the expression of genes necessary for intestinal invasion.


Author(s):  
Zadda Kavitha ◽  
C. Vijayaraghavan

Background: Maruca vitrata is an economically important cryptic insect pest in pigeonpea. Caterpillar, the damaging stage hides in the webs thus escapes the contact with insecticides thus making an effective insecticide also ineffective. Hence, the role of some tall statured intercrops in the manipulation of pigeonpea crop environment for reducing the incidence of this webbing caterpillar was studied. Methods: Studies were conducted at NPRC, Vamban, Pudukottai dt., Tamil Nadu to study the effect of different intercrops in reducing the incidence of Maruca vitrata. During kharif 2016-17 and 2017-18, M. vitrata incidence was compared among the intercropping systems (pigeonpea with pearlmillet, sorghum and maize in 1:6 ratio) and sole pigeonpea crop. IPM modules were formulated in which botanical spray (NSKE 5% at bud initiation stage) and spray of recommended insecticide (indoxacarb 15.8 EC-0.7 ml/lt at flowering and 15 days later) were integrated with intercropping practice and tested for efficacy against this borer pest. Result: Intercropping of pigeonpea with pearlmillet was effective in managing the spotted pod borer. Coccinellids and spiders were more in intercropped pigeonpea than the sole pigeonpea crop. Synchronized flowering times of short duration pigeonpea and intercrops would have facilitated the transfer of natural enemies from intercrops to pigeonpea and this may be the one of the reasons for the lower insect population. IPM module I (pigeonpea intercropped with pearlmillet, NSKE and indoxacarb sprays) was effective in reducing the spotted pod borer damage. In IPM module I, yield of 770 kg/ha was obtained as against 550 kg/ha in sole pigeonpea crop. Among the IPM modules, high B:C ratio of 1:1.66 was recorded with IPM module I.


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