Leaf area index determination of wheat indicating heterogeneous soil conditions

2006 ◽  
Author(s):  
K. Huber ◽  
J. Eitzinger ◽  
P. Rischbeck ◽  
W. Schneider ◽  
F. Suppan ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Soil Conditions ◽  
Area Index ◽  
Heterogeneous Soil

Determination of critical nitrogen concentration and dilution curve based on leaf area index for summer maize

2018 ◽  
Vol 228 ◽  
pp. 195-203 ◽  
Author(s):  
Ben Zhao ◽  
Syed Tahir Ata-Ul-Karim ◽  
Aiwang Duan ◽  
Zhandong Liu ◽  
Xiaolong Wang ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Nitrogen Concentration ◽  
Dilution Curve ◽  
Summer Maize ◽  
Area Index ◽  
Critical Nitrogen Concentration

Determination of critical nitrogen dilution curve based on leaf area index in rice

2014 ◽  
Vol 167 ◽  
pp. 76-85 ◽  
Author(s):  
Syed Tahir Ata-Ul-Karim ◽  
Yan Zhu ◽  
Xia Yao ◽  
Weixing Cao
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Dilution Curve ◽  
Area Index ◽  
Nitrogen Dilution

Effects of date of planting on plant emergence, leaf growth, and yield in contrasting potato varieties

1983 ◽  
Vol 101 (1) ◽  
pp. 81-95 ◽  
Author(s):  
J. L. Jones ◽  
E. J. Allen
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Leaf Growth ◽  
Growth And Yield ◽  
Soil Conditions ◽  
Area Index ◽  
Potato Varieties ◽  
Wide Range ◽  
Emerging Treatments ◽  
Soil Temperatures

SUMMARYFive experiments which studied the effects of a wide range of dates of planting on contrasting potato varieties in Pembrokeshire are reported. In three experiments (1976–7) four early varieties (Home Guard, Arran Comet, Irish Peace and Ulster Sceptre) were sprouted from the end of dormancy and compared at four dates of planting, which began as soon as soil conditions allowed (February in 1975 and 1976 and March in 1977). In these experiments all early-emerging treatments were damaged by frost and in 1975 and 1976 date of planting had little effect on leaf area index or yield. In 1977 planting in late April delayed and increased peak leaf area index but reduced yields throughout harvesting. In all experiments the emergence of varieties was affected by date of planting. The varieties with the longest sprouts emerged first only from the earliest plantings; at late plantings all varieties emerged together, which suggests that rate of post-planting sprout elongation decreased in this old seed as planting was delayed despite increasing soil temperatures. The implications for testing of early varieties are discussed.In two further experiments two early varieties (Home Guard in both years and Red Craigs Royal and Arran Comet in 1 year) were compared with three maincrop varieties (Désirée, Maris Piper, Stormont Enterprise) using seed which did not begin to sprout until January at dates of planting beginning in March. Sprout length was again poorly related to earliness of emergence. Delaying planting delayed and increased peak leaf area index in all varieties but only increased yields in the early varieties which had the smallest leaf areas. In maincrop varieties date of planting had little effect on final yields. In these years there were long periods without rain and in 1976 yields were limited by the amount of water available from the soil, for as each treatment exhausted this supply bulking ceased.

Yielding of Asparagus Depending on Harvest Ending Date

2010 ◽  
Vol 73 (1) ◽  
pp. 67-75
Author(s):  
Mikołaj Knaflewski ◽  
Włodzimierz Krzesiński ◽  
Monika Gąsecka ◽  
Jerzy Stachowiak
Keyword(s):  
Field Experiment ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Cross Section ◽  
Significant Influence ◽  
Light Absorption ◽  
Harvest Time ◽  
Storage Roots ◽  
Area Index

Yielding of Asparagus Depending on Harvest Ending DateThe field experiment focused on the determination of yielding of asparagus cv. ‘Thielim’ in relation to harvest duration: traditional (until June 20th), shortened (June 10th) and prolonged (30thJune) harvests. The variation in harvest ending dates did not have a significant influence on the total, marketable and non-marketable yields as well as on the crown weight and the number of storage roots. However, the extension of harvest time until June 30thresulted in an increase in the number of spears in the total and marketable yields, accompanied by a decrease in their diameter. Also prolonging harvest affected negatively the summer stalk size. During harvest until June 10thasparagus plants probably did not use their full yielding potential, because of too short harvest time. It resulted in increased height, weight, light absorption of summer stalks, leaf area index (LAI) and the total of cross-section areas of summer stalks (PPPA) with no significant differences in yield.

On improving the accuracy of digital hemispherical photography measurements of seasonal leaf area index variation in deciduous broadleaf forests

2015 ◽  
Vol 45 (6) ◽  
pp. 721-731 ◽  
Author(s):  
Zhili Liu ◽  
Xingchang Wang ◽  
Jing M. Chen ◽  
Chuankuan Wang ◽  
Guangze Jin
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Seasonal Changes ◽  
Optical Methods ◽  
Hemispherical Photography ◽  
Area Index ◽  
Clumping Index ◽  
Area Variation ◽  
Major Factors

Optical methods have been widely used to estimate seasonal changes of the leaf area index (LAI) in forest stands because they are convenient and effective; however, their accuracy in deciduous broadleaf forests has rarely been evaluated. We estimate the seasonal changes in the LAI by combining periodic observations of leaf area variation with litter collection (LAIdir) in deciduous broadleaf forests and use these estimates to evaluate the accuracy of optical LAI measurements made using digital hemispherical photography (DHP). We also propose a method to correct DHP-derived LAI (LAIDHP) values for seasonal changes in major factors that influence the determination of LAI, including the woody to total area ratio (α), the element clumping index (ΩE, using three different methods), and the photographic exposure setting (E). Before these corrections were made, LAIDHP underestimates LAIdir by 14%–55% from 21 May to 1 October but overestimates it by 78% on 12 May and by 226% on 11 October. Although pronounced differences are observed between LAIdir and LAIDHP, they are significantly correlated (R2 = 0.85, RMSE = 0.32, P < 0.001). After considering seasonal changes in α, ΩE, and E, the accuracy of LAIDHP improves markedly, with a mean difference between the corrected LAIDHP and LAIdir of <17% in all periods. The results suggest that the proposed scheme for correcting LAIDHP is useful and effective for estimating seasonal LAI variation in deciduous broadleaf forests.

scholarly journals Facilitation by Tree Species in Variable Retention Harvesting for the Restoration of Monoculture Plantations in Southern China

2019 ◽  
Vol 12 ◽  
pp. 194008291882483 ◽  
Author(s):  
Jun Jiang ◽  
Yuanchang Lu ◽  
Ling Wang ◽  
Xianzhao Liu ◽  
Daoxiong Cai ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Aboveground Biomass ◽  
Tree Species ◽  
Soil Conditions ◽  
Target Species ◽  
Positive Interaction ◽  
Area Index ◽  
Variable Retention ◽  
Variable Retention Harvesting

Facilitation can drive the successional dynamics and change the restoration trajectory of degraded forests. However, the relative importance of facilitation by tree species after variable retention harvesting is unclear. We used a field experiment to evaluate the effect of two facilitator species, Castanopsis fissa (C. fissa) and Manglietia glauca (M. glauca), managed with variable retention harvesting, on the development of two target species, Castanopsis hystrix (C. hystrix) and Erythrophloeum fordii (E. fordii), in a Masson pine ( Pinus massoniana) monoculture. The following variables were measured for all of the four interplanted tree species: structural growth, regeneration, aboveground biomass accumulation, leaf area index, and soil conditions. The results indicate that the abundance, growth, and aboveground biomass were relatively greater in plots planted with C. fissa compared with M. glauca and that the target species performed best with 50% retention harvesting of C. fissa, with an improved establishment of both target species indicating a positive interaction. In addition, the regeneration, leaf area index and soil conditions differed between the two facilitators in the variable retention harvesting treatments because of the different intrinsic characteristic of the facilitators. In summary, our results imply that managers have considerable flexibility to employ various types of facilitation schemes coupled with different harvesting systems for successful short-term restoration within a monoculture.

scholarly journals Determination of critical nitrogen dilution curve based on leaf area index for winter wheat in the Guanzhong Plain, Northwest China

2019 ◽  
Vol 18 (10) ◽  
pp. 2369-2380
Author(s):  
Sheng-cai QIANG ◽  
Fu-cang ZHANG ◽  
Miles Dyck ◽  
Yan ZHANG ◽  
You-zhen XIANG ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Northwest China ◽  
Dilution Curve ◽  
Area Index ◽  
Nitrogen Dilution
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