The effect of harvest date on yield loss of long and short-grain rice cultivars (Oryza sativa L.) in Northeast China

2021 ◽  
Vol 131 ◽  
pp. 126382
Author(s):  
Jinwu Wang ◽  
Xiaobo Sun ◽  
Yanan Xu ◽  
Qi Wang ◽  
Han Tang ◽  
...  
2018 ◽  
Vol 3 (1) ◽  
pp. 69
Author(s):  
Jorge Serrano ◽  
José Fábrega ◽  
Evelyn Quirós ◽  
Javier Sánchez- Galán ◽  
José Ulises Jiménez

The objective of this work is to perform a prospective analysis of the wavelengths that can be used to recognize a rice crop due to its phenological status and variety. For this purpose, field measurements of spectral signature in the 350 nm -1049 nm range were employed. The rice cultivars FCA 616FL and IDIAP 54-05 were used. The study site was located in the Juan Hombrón area in the Coclé province, Panama. A principal component analysis (PCA) was carried out, which resulted in the lengths 728.16, 677.89 and 785.48 nm let phenological differentiation within the cultivar FCA 616FL and IDIAP 54-05, the lengths 729.72, 814.58 and 666.81 nm let distinguish between crop varieties FCA 616FL and IDIAP 54-05 in vegetative phase.Keywords: Rice, reflectance, hyperspectral signature, phonological state.


2020 ◽  
Vol 7 (3) ◽  
Author(s):  
Debarati Das ◽  
Paulin Seal ◽  
Sabarni Biswas ◽  
Asok K Biswas

The trace element Selenium (Se) has a dual role in the growth and metabolism of plants. Low concentration of selenium (2 ?M selenate) promotes growth and counteracts the detrimental effects of abiotic stress as opposed to higher levels (?10 ?M) where it acts as a pro-oxidant. We focused on both individual and interactive influence of selenate and sulphate on thiol metabolism in seedlings of rice cultivars, satabdi and khitish. Inhibition of ascorbate contents by about 17% on an average, in the test seedlings treated with Se correlated with increased activities of ascorbate peroxidase and ascorbate oxidase in the cultivars. The glutathione levels also increased significantly, on an average by about 102% in roots and 74% in shoots of cv. satabdi compared to a rise, by about 49% in roots and 56% in shoots of cv. khitish. The elevated level of glutathione coincided with the stimulatory influence of Se on its regulatory enzymes. Concomitantly the levels of ?-tocopherol and phytochelatins were also induced in both the test cultivars. Increase in ?-tocopherol activity reached a maximum by about 47% in roots and 80% in shoots of cv. satabdi whereas it increased by about 36% in roots and about 64% in shoots of cv. khitish. Substantive increase in the levels of PC4 followed by PC2 and PC3 was also noted. The effects were found to be less conspicuous in shoots than in roots. Rice seedlings exposed to combined Se and 10mM sulphate treatments showed improved growth and development as a result of better thiol metabolism due to amelioration of the adverse effects caused by selenium alone on all the parameters tested.


2015 ◽  
Vol 20 (2) ◽  
pp. 264-277
Author(s):  
Fathy Radwan ◽  
Mahmoud Gomaa ◽  
Ahmed El- Hissewy ◽  
Germeen Abou El- Soud

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1674
Author(s):  
Ponraj Arumugam ◽  
Abel Chemura ◽  
Bernhard Schauberger ◽  
Christoph Gornott

Immediate yield loss information is required to trigger crop insurance payouts, which are important to secure agricultural income stability for millions of smallholder farmers. Techniques for monitoring crop growth in real-time and at 5 km spatial resolution may also aid in designing price interventions or storage strategies for domestic production. In India, the current government-backed PMFBY (Pradhan Mantri Fasal Bima Yojana) insurance scheme is seeking such technologies to enable cost-efficient insurance premiums for Indian farmers. In this study, we used the Decision Support System for Agrotechnology Transfer (DSSAT) to estimate yield and yield anomalies at 5 km spatial resolution for Kharif rice (Oryza sativa L.) over India between 2001 and 2017. We calibrated the model using publicly available data: namely, gridded weather data, nutrient applications, sowing dates, crop mask, irrigation information, and genetic coefficients of staple varieties. The model performance over the model calibration years (2001–2015) was exceptionally good, with 13 of 15 years achieving more than 0.7 correlation coefficient (r), and more than half of the years with above 0.75 correlation with observed yields. Around 52% (67%) of the districts obtained a relative Root Mean Square Error (rRMSE) of less than 20% (25%) after calibration in the major rice-growing districts (>25% area under cultivation). An out-of-sample validation of the calibrated model in Kharif seasons 2016 and 2017 resulted in differences between state-wise observed and simulated yield anomalies from –16% to 20%. Overall, the good ability of the model in the simulations of rice yield indicates that the model is applicable in selected states of India, and its outputs are useful as a yield loss assessment index for the crop insurance scheme PMFBY.


2019 ◽  
Vol 42 (9) ◽  
pp. 1001-1015 ◽  
Author(s):  
Willy Irakoze ◽  
Brigitte Vanpee ◽  
Gervais Rufyikiri ◽  
Hélène Dailly ◽  
Séverin Nijimbere ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document