scholarly journals Canopy Hyperspectral Sensing of Paddy Fields at the Booting Stage and PLS Regression can Assess Grain Yield

2018 ◽  
Vol 10 (8) ◽  
pp. 1249 ◽  
Author(s):  
Kensuke Kawamura ◽  
Hiroshi Ikeura ◽  
Sengthong Phongchanmaixay ◽  
Phanthasin Khanthavong

Canopy hyperspectral (HS) sensing is a promising tool for estimating rice (Oryza sativa L.) yield. However, the timing of HS measurements is crucial for assessing grain yield prior to harvest because rice growth stages strongly influence the sensitivity to different wavelengths and the evaluation performance. To clarify the optimum growth stage for HS sensing-based yield assessments, the grain yield of paddy fields during the reproductive phase to the ripening phase was evaluated from field HS data in conjunction with iterative stepwise elimination partial least squares (ISE-PLS) regression. The field experiments involved three different transplanting dates (12 July, 26 July, and 9 August) in 2017 for six cultivars with three replicates (n = 3 × 6 × 3 = 54). Field HS measurements were performed on 2 October 2017, during the panicle initiation, booting, and ripening growth stages. The predictive accuracy of ISE-PLS was compared with that of the standard full-spectrum PLS (FS-PLS) via coefficient of determination (R2) values and root mean squared errors of cross-validation (RMSECV), and the robustness was evaluated by the residual predictive deviation (RPD). Compared with the FS-PLS models, the ISE-PLS models exhibited higher R2 values and lower RMSECV values for all data sets. Overall, the highest R2 values and the lowest RMSECV values were obtained from the ISE-PLS model at the booting stage (R2 = 0.873, RMSECV = 22.903); the RPD was >2.4. Selected HS wavebands in the ISE-PLS model were identified in the red-edge (710–740 nm) and near-infrared (830 nm) regions. Overall, these results suggest that the booting stage might be the best time for in-season rice grain assessment and that rice yield could be evaluated accurately from the HS sensing data via the ISE-PLS model.

Agronomy ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 106 ◽  
Author(s):  
Ke Zhang ◽  
Xiaojun Liu ◽  
Syed Tahir Ata-Ul-Karim ◽  
Jingshan Lu ◽  
Brian Krienke ◽  
...  

Accurate estimation of the nitrogen (N) spatial distribution of rice (Oryza sativa L.) is imperative when it is sought to maintain regional and global carbon balances. We systematically evaluated the normalized differences of the soil and plant analysis development (SPAD) index (the normalized difference SPAD indexes, NDSIs) between the upper (the first and second leaves from the top), and lower (the third and fourth leaves from the top) leaves of Japonica rice. Four multi-location, multi-N rate (0–390 kg ha−1) field experiments were conducted using seven Japonica rice cultivars (9915, 27123, Wuxiangjing14, Wunyunjing19, Wunyunjing24, Liangyou9, and Yongyou8). Growth analyses were performed at different growth stages ranging from tillering (TI) to the ripening period (RP). We measured leaf N concentration (LNC), the N nutrition index (NNI), the NDSI, and rice grain yield at maturity. The relationships among the NDSI, LNC, and NNI at different growth stages showed that the NDSI values of the third and fourth fully expanded leaves more reliably reflected the N nutritional status than those of the first and second fully expanded leaves (LNC: NDSIL3,4, R2 > 0.81; NDSIothers, 0.77 > R2 > 0.06; NNI: NDSIL3,4, R2 > 0.83; NDSIothers, 0.76 > R2 > 0.07; all p < 0.01). Two new diagnostic models based on the NDSIL3,4 (from the tillering to the ripening period) can be used for effective diagnosis of the LNC and NNI, which exhibited reasonable distributions of residuals (LNC: relative root mean square error (RRMSE) = 0.0683; NNI: RRMSE = 0.0688; p < 0.01). The relationship between grain yield, predicted yield, and NDSIL3,4 were established during critical growth stages (from the stem elongation to the heading stages; R2 = 0.53, p < 0.01, RRMSE = 0.106). An NDSIL3,4 high-yield change curve was drawn to describe critical NDSIL3,4 values for a high-yield target (10.28 t ha−1). Furthermore, dynamic-critical curve models based on the NDSIL3,4 allowed a precise description of rice N status, facilitating the timing of fertilization decisions to optimize yields in the intensive rice cropping systems of eastern China.


2005 ◽  
Vol 19 (2) ◽  
pp. 476-480 ◽  
Author(s):  
Luis A. Avila ◽  
Scott A. Senseman ◽  
Garry N. McCauley ◽  
James M. Chandler ◽  
John H. O'Barr

Field experiments were conducted in 2002 and 2003 in Beaumont, TX, to evaluate the effect of flood timing on red rice control with imazethapyr applied at different cultivated rice growth stages. Treatments included flood establishment at 1, 7, 14, and 21 d after postemergence (POST) herbicide treatment (DAT). Imazethapyr was applied preemergence at 70 g ai/ha followed by 70 g/ ha POST when imidazolinone-tolerant rice cultivar ‘CL-161’ had three- to four-leaf stage (EPOST) or five-leaf stage (LPOST). Flood needed to be established within 14 DAT to achieve at least 95% red rice control when imazethapyr was applied EPOST. However, flood needed to be established within 7 DAT to provide at least 95% red rice control when imazethapyr was applied LPOST. Delaying the flood up to 21 DAT reduced rice grain yield for both application timings.


Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 584
Author(s):  
Omnia M. Elshayb ◽  
Khaled Y. Farroh ◽  
Heba E. Amin ◽  
Ayman M. Atta

Applications of metal oxide nanoparticles in the agriculture sector are being extensively included as the materials are considered superior. In the present work, zinc oxide nanoparticle (ZnO NPs), with a developing fertilizer, is applied in the fortification of rice grain yield and nutrient uptake enhancement. To evaluate the role of ZnO NP, two field experiments were conducted during the 2018 and 2019 seasons. ZnO NPs were small, nearly spherical, and their sizes equal to 31.4 nm, as proved via the dynamic light scattering technique. ZnO NPs were applied as a fertilizer in different concentrations, varying between 20 and 60 mg/L as a foliar spray. The mixture of ZnSO4 and ZnO NP40 ameliorated yield component and nutrients (N, K, and Zn) uptake was enhanced compared to traditional ZnSO4 treatment. Nevertheless, the uptake of the phosphorous element (P) was adversely affected by the treatment of ZnO NPs. Thus, treatment via utilizing ZnO NPs as a foliar with a very small amount (40 ppm) with of basal ZnSO4 led to a good improvement in agronomic and physiological features; eventually, higher yield and nutrient-enriched rice grain were obtained.


Weed Science ◽  
1985 ◽  
Vol 33 (5) ◽  
pp. 703-707 ◽  
Author(s):  
Amadou Diarra ◽  
Roy J. Smith ◽  
Ronald E. Talbert

Field experiments were conducted to investigate methods of controlling red rice (Oryza sativaL. ♯ ORYSA) in drill-seeded rice (O. sativa). Treatments included the rice cultivar ‘Mars', coated with calcium peroxide (CaO2) at 40% (w/w) and a crop protectant, R-33865 (O,O-diethyl-O-phenyl phosphorothioate) at 0.5 and 1% (v/w). Molinate (S-ethyl hexahydro-1H-azepine-1-carbothioate) at 6.7 kg ai/ha was applied preplant incorporated (ppi). The land was flooded (2.5 to 5 cm deep) after seeding with rice (100 kg/ha, 2.5 cm deep), and the water was maintained throughout the growing season. CaO2, with or without molinate, increased rice grain yield 50% and increased rice culm density fivefold above untreated rice. Molinate applied ppi controlled 96% of the red rice. Rice seed coated with only CaO2or with CaO2plus R-33865 at 0.5%, each combined with ppi molinate, produced 5690 and 6030 kg/ha of grain, respectively. These high yields were associated with red rice control by molinate and good stands of rice provided by O2supplied by CaO2. R-33865 applied to rice seed at 1% (v/w) injured rice by reducing rice culm densities 41%, compared with rice without protectant.


2020 ◽  
Vol 7 (01) ◽  
pp. 22-27
Author(s):  
Nalwida Rozen ◽  
Gusnidar Gusnidar ◽  
Nurhajati Hakim

A series of on-farm fi eld experiments were conducted in two locations in Padang, Koto Panjang and Koto Tingga, West Sumatera, Indonesia in 2015. The purpose of the experiment was to establish the formula of organic fertilizer derived from Tithonia supplied with micro nutrients, Zn and Mn, on rice. The experiments were conducted using completely-randomized block design with six treatments and three replications. The treatments were P = Tithonia Organic Fertilizer Plus (TOFP) + 3.0 kg Mn.ha-1, Q = TOFP + 3.0 kg Mn.ha-1+ 3.0 kg Zn.ha-1, R = TOFP + 4.5 kg Mn.ha-1 + 6 kg Zn.ha-1, S= TOFP + 4.5 kg Mn.ha-1+ 9 kg Zn.ha-1, T = TOFP only, U = 100% chemical fertilizer only. Treatment with micro nutrients as addition to TOFP (TOFP+ 3.0 kg Mn.ha-1 and TOFP+ 3.0 kg Mn.ha-1+3.0 kg Zn.ha-1) increased rice grain yield by 80 g per clump.


Author(s):  
Megha Vishwakarma ◽  
P. S. Kulhare ◽  
G. S. Tagore

Field experiments were conducted during winter season of 2018-19 and 2019-20 with three sources of nutrient  viz., inorganic, organics (FYM, VC and biofertilizers) and their integration as main treatments and five levels [S1-0 (0-0-0 kg NPK ha-1), S2-100% (120-60-40 kg NPK ha-1), S3-150% (180-90-60 kg NPK ha-1), S4-200% (240-120-80 kg NPK ha-1) and S5-Soil Test based (STV) NPK i.e. 149-176-33 kg ha-1 in split plot design with three replications. The chlorophyll content (‘a’, ‘b’ and total) in leaves and Soil Plant Analyzer Development (SPAD) value were recorded at crown root initiation (CRI), tillering, jointing and milking stage of wheat. The pooled data of findings revealed that the treatment with inorganic sources showed significant increase in the SPAD readings (9.62, 15.54, 23.77 and 29.83), chlorophyll ‘a’ (0.76, 0.83, 1.47 and 0.63 mg g-1 leaf tissue), ‘b’ (0.44, 0.78, 0.87 and 0.57 mg g-1 leaf tissue) and total (1.19, 1.64, 2.25 and 1.14 mg g-1 leaf tissue) chlorophyll content in leaves over organic source at all the growth stages. All the levels of nutrient were significantly increased the chlorophyll content and SPAD value over control at all the stages except chlorophyll ‘a’ at jointing and milking stage. However, amongst the levels 150% and 200% NPK were found significantly superior to 100% NPK for SPAD value (8.32 and 8.71 at CRI and 12.56 and 12.19 at tillering), chlorophyll ‘a’ (0.73 and 0.70 mg g-1 leaf tissue at CRI), chlorophyll ‘b’ (0.46 and 0.45 mg g-1 leaf tissue at CRI, 0.68 and 0.71 mg g-1 leaf tissue at tillering and 0.53 and 0.59 mg g-1 leaf tissue at milking), respectively. The interaction results suggested that the 200% NPK with inorganic and integrated sources significantly superior to 100% NPK for chlorophyll ‘a’ content at jointing and milking stage. The application of 150% and 200% NPK with inorganic source were found significantly higher over the same level of NPK with integrated source of nutrient for total chlorophyll content and SPAD value at all the growth stages except 150% NPK for total chlorophyll at jointing and milking stage and SPAD value at milking stage. The correlation between SPAD value and chlorophyll ’a’, ‘b’, total were found significantly and positively at all growth stages. Coefficient of determination values between SPAD and chlorophyll content showed linear relationship at all the growth stages.


Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6732
Author(s):  
Haixia Qi ◽  
Bingyu Zhu ◽  
Zeyu Wu ◽  
Yu Liang ◽  
Jianwen Li ◽  
...  

Leaf area index (LAI) is used to predict crop yield, and unmanned aerial vehicles (UAVs) provide new ways to monitor LAI. In this study, we used a fixed-wing UAV with multispectral cameras for remote sensing monitoring. We conducted field experiments with two peanut varieties at different planting densities to estimate LAI from multispectral images and establish a high-precision LAI prediction model. We used eight vegetation indices (VIs) and developed simple regression and artificial neural network (BPN) models for LAI and spectral VIs. The empirical model was calibrated to estimate peanut LAI, and the best model was selected from the coefficient of determination and root mean square error. The red (660 nm) and near-infrared (790 nm) bands effectively predicted peanut LAI, and LAI increased with planting density. The predictive accuracy of the multiple regression model was higher than that of the single linear regression models, and the correlations between Modified Red-Edge Simple Ratio Index (MSR), Ratio Vegetation Index (RVI), Normalized Difference Vegetation Index (NDVI), and LAI were higher than the other indices. The combined VI BPN model was more accurate than the single VI BPN model, and the BPN model accuracy was higher. Planting density affects peanut LAI, and reflectance-based vegetation indices can help predict LAI.


1994 ◽  
Vol 34 (7) ◽  
pp. 1007 ◽  
Author(s):  
PK Bollich ◽  
CW Lindau ◽  
RJ Norman

Approaches taken in management of fertiliser nitrogen (N) in dry-seeded, delayed-flood rice (Oryza sativa L.) in the United States of America vary considerably. A 2-year study was conducted in Louisiana to evaluate N fertiliser efficiency and accumulation when applied in single or multiple applications. The cultivars Lemont and Tebonnet, representing semi-dwarf and conventional tall plant types, respectively, were grown on a Crowley silt loam (Typic Albaqualfs soil). Urea N was applied using 1 of 3 strategies: in a single (1-way) preflood (PF) application of 134 kg Nlha; in a 2-way split consisting of 100 kg N/ha PF and 34 kg N/ha at panicle initiation (PI); or in a 3-way split consisting of 66 kg N/ha PF, 34 kg N/ha at PI, and 34 kg N/ha at panicle differentiation. Microplots were established within each whole plot and fertilised with 2 atom% 15N urea. Fertiliser N application time had no influence on plant accumulation of 15N urea or biomass production. Plant accumulation of 15N urea was significant across year and cultivar. Tebonnet accumulated more 15N urea than Lemont. Accumulation was also significantly higher in 1992. Method of application of fertiliser N significantly affected grain yields. The highest average grain yield of 7905 kg/ha occurred with a single PF application. Yields were reduced by 378 kg/ha with a 2-way split application and by 1074 kg/ha with a 3-way split application. Method of application of main crop fertiliser N had no effect on ratoon crop yields. Total grain yield (main + ratoon) was significantly reduced with the 3-way split. This study demonstrates the importance of supplying adequate N to the rice plant before permanent flood establishment. It also suggests that midseason N applied at specific growth stages is less efficiently utilised, especially when insufficient N is applied at PF.


2012 ◽  
Vol 37 (3) ◽  
pp. 433-439
Author(s):  
MA Haque

Field experiments were conducted at Patuakhali Science and Technology University research farm during 2009 T. Aman season to investigate the effect of tidal submergence on potassium nutrition and yield of rice. The experiment included two levels of irrigation water source- i) tidal water and ii) ground water, and three levels of fertilizers- i) absolute control (no fertilizer), ii) NP (K omission), and iii) NPK (K addition). The rice varieties were BR23 (HYV) and Lalmota (traditional variety). A general increase in growth, yield and yield contributing parameters were found due to irrigation with tidal water. Tidal water contributed about 19% (BR23) and 11% (Lalmota) higher grain yield in Aman season 2009 compared to that grown with ground water. Potassium contents of rice grain and straw were always higher when plants are irrigated with tidal water. In general, tidal submergence increased K uptake of rice. The K uptake by BR23 under tidal water was about 47, 43 and 8 kg/ha more than those recorded with ground water irrigation under absolute control, K omission and K addition treatments, respectively whereas it was 31, 21, and 68 kg/ha, in Lalmota. The results indicated that whether fertilizers were applied or not plants absorb considerable amount of K from tidal water. Bangladesh J. Agril. Res. 37(3): 433-439, September 2012 DOI: http://dx.doi.org/10.3329/bjar.v37i3.12086


2009 ◽  
Vol 45 (No. 3) ◽  
pp. 113-118 ◽  
Author(s):  
Z. Pacanoski ◽  
G. Glatkova

Field trials were conducted in the Agricultural Research Institute for Rice, at two localities during 2005 and 2006. The objective of the study was to establish an appropriate weed management strategy for the effective control of weed flora in direct wet-seeded rice. Herbicide selectivity and influence on grain yield were also evaluated. The weed population in the trials was composed of 8 and 5 weed species in Kočani and Probi&scaron;tip locality, respectively. The most prevailing weeds in both localities were:Cyperus rotundus, Echinochloa crus-galli and Heteranthea limosa. The average weediness for both years was 456.8 weed stems per m<sup>2</sup> in Kočani locality and 589.0 weed stems per m<sup>2</sup> in Probi&scaron;tip locality. In both localities all herbicides controlled Cyperus rotundus, Echinochloa crus-galli and Heteranthera limosa excellently except Mefenacet 53 WP. All applied herbicides showed high selectivity to rice, no visual injuries were determined at any rates in any year and locality. Herbicidal treatments in both localities significantly increased rice grain yield in comparison with untreated control.


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