scholarly journals Estimation of Beech (Fagus crenata) Seed Crops from Female Inflorescence Scars:

2013 ◽  
Vol 95 (1) ◽  
pp. 71-75 ◽  
Author(s):  
Haruki Nakajima
Author(s):  
R. Horrell ◽  
A.K. Metherell ◽  
S. Ford ◽  
C. Doscher

Over two million tonnes of fertiliser are applied to New Zealand pastures and crops annually and there is an increasing desire by farmers to ensure that the best possible economic return is gained from this investment. Spreading distribution measurements undertaken by Lincoln Ventures Ltd (LVL) have identified large variations in the evenness of fertiliser application by spreading machines which could lead to a failure to achieve optimum potential in some crop yields and to significant associated economic losses. To quantify these losses, a study was undertaken to calculate the effect of uneven fertiliser application on crop yield. From LVL's spreader database, spread patterns from many machines were categorised by spread pattern type and by coefficient of variation (CV). These patterns were then used to calculate yield losses when they were combined with the response data from five representative cropping and pastoral situations. Nitrogen fertiliser on ryegrass seed crops shows significant production losses at a spread pattern CV between 30% and 40%. For P and S on pasture, the cumulative effect of uneven spreading accrues, until there is significant economic loss occurring by year 3 for both the Waikato dairy and Southland sheep and beef systems at CV values between 30% and 40%. For nitrogen on pasture, significant loss in a dairy system occurs at a CV of approximately 40% whereas for a sheep and beef system it is at a CV of 50%, where the financial return from nitrogen application has been calculated at the average gross revenue of the farming system. The conclusion of this study is that the current Spreadmark standards are a satisfactory basis for defining the evenness requirements of fertiliser applications in most circumstances. On the basis of Spreadmark testing to date, more than 50% of the national commercial spreading fleet fails to meet the standard for nitrogenous fertilisers and 40% fails to meet the standard for phosphatic fertilisers.Keywords: aerial spreading, crop response, economic loss, fertiliser, ground spreading, striping, uneven application, uneven spreading, yield loss


1979 ◽  
Vol 71 (4) ◽  
pp. 671-675 ◽  
Author(s):  
M. Philip Rolston ◽  
W. Orvid Lee ◽  
Arnold P. Appleby
Keyword(s):  

Author(s):  
Svein Dale

AbstractIn boreal forests, food supplies typically have cyclic variations, and many species here fluctuate in numbers from year to year. One group of species showing large variations in population size is birds specialized on seeds from masting trees. Here, I analyze spatial patterns of a mass occurrence and habitat selection of the Common Redpoll (Carduelis flammea) during the breeding season in southeastern Norway in 2020 after a year with large seed crops from Norway Spruce (Picea abies) and Downy Birch (Betula pubescens). I found that Common Redpoll numbers increased with elevation and towards the northwest. Numbers were also strongly and positively correlated with snow depth in early April when snow was present mainly above 400 m elevation. Sites with snow cover in early April (30% of all sites) held 96.4% of all individuals recorded. Field observations indicated that Common Redpolls foraged extensively for spruce seeds on the snow until the end of May when young were independent. I suggest that the mass occurrence was due to a unique combination of exceptionally large seed crops of two tree species coinciding in the same year. The masting produced large amounts of food both for overwintering (birch seeds) and for breeding (spruce seeds), and during the breeding season snow cover facilitated access to food resources. Dependency of Common Redpolls on snow cover suggests that climate change may negatively impact some seed-eaters in boreal regions. On the other hand, higher temperatures may induce more frequent masting which may be beneficial for seed-eaters. Thus, climate change is likely to lead to complex ecosystem changes in areas where snow cover may disappear.


Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 934
Author(s):  
Chris O’Brien ◽  
Jayeni Hiti-Bandaralage ◽  
Raquel Folgado ◽  
Alice Hayward ◽  
Sean Lahmeyer ◽  
...  

Recent development and implementation of crop cryopreservation protocols has increased the capacity to maintain recalcitrant seeded germplasm collections via cryopreserved in vitro material. To preserve the greatest possible plant genetic resources globally for future food security and breeding programs, it is essential to integrate in situ and ex situ conservation methods into a cohesive conservation plan. In vitro storage using tissue culture and cryopreservation techniques offers promising complementary tools that can be used to promote this approach. These techniques can be employed for crops difficult or impossible to maintain in seed banks for long-term conservation. This includes woody perennial plants, recalcitrant seed crops or crops with no seeds at all and vegetatively or clonally propagated crops where seeds are not true-to-type. Many of the world’s most important crops for food, nutrition and livelihoods, are vegetatively propagated or have recalcitrant seeds. This review will look at ex situ conservation, namely field repositories and in vitro storage for some of these economically important crops, focusing on conservation strategies for avocado. To date, cultivar-specific multiplication protocols have been established for maintaining multiple avocado cultivars in tissue culture. Cryopreservation of avocado somatic embryos and somatic embryogenesis have been successful. In addition, a shoot-tip cryopreservation protocol has been developed for cryo-storage and regeneration of true-to-type clonal avocado plants.


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