scholarly journals Studies on the Relationship between the Change of Growing Season and Irrigation in Upland Crops. : II. The relationships among planting time, plant population and irrigation in soybean culture.

1965 ◽  
Vol 34 (2) ◽  
pp. 127-132
Author(s):  
Yoshimichi NAGASE ◽  
Shohei TAKEMURA
Author(s):  
O. A. Zadorozhna ◽  
T. P. Shyianova ◽  
M.Yu. Skorokhodov

Seed longevity of 76 spring barley gene pool samples (Hordeum vulgare L. subsp. distichon, convar. distichon: 56 nutans Schubl., two deficience (Steud.) Koern., two erectum Rode ex Shuebl., two medicum Koern.; convar. nudum (L.) A.Trof.: one nudum L. та subsp. vulgare: convar. vulgare: nine pallidum Ser., three rikotense Regel.; convar. coeleste (L.) A.Trof.: one coeleste (L.) A.Trof.) from 26 countries, 11 years and four places of reproduction was analyzed. Seeds with 5–8% moisture content were stored in chamber with unregulated and 4oC temperature. The possibility of seed storage under these conditions for at least 10 years without significant changes in germination has been established. The importance of meteorological conditions in the formation and ripening of seeds for their longevity is confirmed. The relationship between the decrease of barley seeds longevity and storage conditions, amount of rainfall, temperature regime during the growing season of plants is discussed.


2000 ◽  
Vol 43 (4) ◽  
pp. 387-391 ◽  
Author(s):  
Jonez Fidalski ◽  
Pedro Antonio Martins Auler ◽  
Valdomiro Tormem

The Valencia orange orchards established on soils of low fertility in the Northwest region of Paraná State, Brazil, have showed symptoms of Mg deficiency and reduced fruit yields. The objective of this study was to verify the relationship between yield with soil and leaf nutrients during 1996/97 growing season. Two sites of low and high productivity were selected in seven orchards. Leaf and soil samples (fertilized rows and interrows) were collected in 1996. The results showed that the citrus yields were negatively related with soil Mg/K and Ca+Mg/K ratios in the fertilized rows, and fruit weight positively correlated with leaf Zn in the low productivity orchards. The fruit weight was positively related with leaf Ca and soil Ca in the fertilized rows of the high productivity orchards. The results suggested an adequate lime and K fertilization managements in the fertilized rows, as well as an adequate Zn supply.


2018 ◽  
Vol 115 (47) ◽  
pp. 11935-11940 ◽  
Author(s):  
Ethan E. Butler ◽  
Nathaniel D. Mueller ◽  
Peter Huybers

Continuation of historical trends in crop yield are critical to meeting the demands of a growing and more affluent world population. Climate change may compromise our ability to meet these demands, but estimates vary widely, highlighting the importance of understanding historical interactions between yield and climate trends. The relationship between temperature and yield is nuanced, involving differential yield outcomes to warm (9−29 °C) and hot (>29 °C) temperatures and differing sensitivity across growth phases. Here, we use a crop model that resolves temperature responses according to magnitude and growth phase to show that US maize has benefited from weather shifts since 1981. Improvements are related to lengthening of the growing season and cooling of the hottest temperatures. Furthermore, current farmer cropping schedules are more beneficial in the climate of the last decade than they would have been in earlier decades, indicating statistically significant adaptation to a changing climate of 13 kg·ha−1· decade−1. All together, the better weather experienced by US maize accounts for 28% of the yield trends since 1981. Sustaining positive trends in yield depends on whether improvements in agricultural climate continue and the degree to which farmers adapt to future climates.


1984 ◽  
Vol 14 (6) ◽  
pp. 950-952 ◽  
Author(s):  
K. T. Smith ◽  
R. O. Blanchard ◽  
W. C. Shortle

Cambial electrical resistance (CER) was related to the number of cells per radial file of vascular cambium in dominant and codominant balsam fir (Abiesbalsamea (L.) Mill.) trees sampled during the growing season. Scanning electron microscopy (SEM) was used to examine the vascular cambial zone (VCZ) of balsam fir during the growing and dormant seasons. Trees selected for SEM were categorized as having growing season CER < 10 kΩ or CER > 12 kΩ. The two growing trees with CER < 10 kΩ had a mean of seven cells per radial file of VCZ in contrast with four cells per radial file in the two trees of CER > 12 kΩ. Trees of either growing season category had dormant season CER > 12 kΩ and four cells per radial file of VCZ. The relationship between CER and the number of cells per radial file of VCZ supports the hypothesis relating CER to periodic growth rate in balsam fir.


Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2108 ◽  
Author(s):  
Ari Guna ◽  
Jiquan Zhang ◽  
Siqin Tong ◽  
Yongbin Bao ◽  
Aru Han ◽  
...  

Based on the 1965–2017 climate data of 18 meteorological stations in the Songliao Plain maize belt, the Coupled Model Intercomparision Project (CMIP5) data, and the 1998–2017 maize yield data, the drought change characteristics in the study area were analyzed by using the standardized precipitation evapotranspiration index (SPEI) and the Mann–Kendall mutation test; furthermore, the relationship between meteorological factors, drought index, and maize climate yield was determined. Finally, the maize climate yields under 1.5 °C and 2.0 °C global warming scenarios were predicted. The results revealed that: (1) from 1965 to 2017, the study area experienced increasing temperature, decreasing precipitation, and intensifying drought trends; (2) the yield of the study area showed a downward trend from 1998 to 2017. Furthermore, the climate yield was negatively correlated with temperature, positively correlated with precipitation, and positively correlated with SPEI-1 and SPEI-3; and (3) under the 1.5 °C and the 2.0 °C global warming scenarios, the temperature and the precipitation increased in the maize growing season. Furthermore, under the studied global warming scenarios, the yield changes predicted by multiple regression were −7.7% and −15.9%, respectively, and the yield changes predicted by one-variable regression were −12.2% and −21.8%, respectively.


1991 ◽  
Vol 15 (3) ◽  
pp. 261-289 ◽  
Author(s):  
Glen M. MacDonald ◽  
Kevin J. Edwards

The latter half of the past decade witnessed important progress in elucidating the principles of fossil pollen analysis and in the application of palynology to the study of palaeoecology and palaeoclimatology. Areas with particularly notable efforts include: 1) the theoretical consideration of the spatial representation of fossil pollen records and the relationships of pollen proportions to the abundance of contributing plant populations; 2) the quest for palynological data with increasingly fine temporal and spatial resolution; 3) the development of large databases of modern and fossil pollen data for macroscale palaeoecological and palaeoclimatic studies; 4) the application of palynology to questions of plant population biology, most notably the study of plant invasion and implications for invading and pre-existing plant populations; 5) the demonstration of the relatively ephemeral nature of major vegetation types; 6) the refinement and development of techniques for providing quantitative estimates of past climate and testing climate reconstructions. Despite this progress important uncertainties remain regarding the relationship between plant abundance and pollen representation and the nature of climate-vegetation relationships, particularly at the meso- and microscales. Resolution of these questions is particularly important for plant population and climatic studies based on fossil pollen data.


Plant Disease ◽  
2007 ◽  
Vol 91 (9) ◽  
pp. 1131-1136 ◽  
Author(s):  
M. Berbegal ◽  
A. Ortega ◽  
J. García-Jiménez ◽  
J. Armengol

The relationship between inoculum density of Verticillium dahliae in soil and disease development was studied in 10 commercial artichoke fields. Inoculum density of V. dahliae varied between 2.2 and 34.2 microsclerotia (ms) g–1 of soil near planting. Artichoke plants were monitored for disease at the beginning and the end of each growing season. There was a significant correlation, which was best described by negative exponential models, between inoculum density and disease incidence, symptom severity, and recovery of the pathogen from the plants. Inoculum densities ranging from 5 to 9 ms g–1 of soil were associated with a mean percentage of infected plants of about 50%. Additionally, three fields were monitored in two consecutive growing seasons to evaluate the population dynamics of V. dahliae microsclerotia in soil and disease development. Numbers of microsclerotia per gram of soil decreased significantly by the end of the first growing season but slightly increased at the end of the second growing season. In these fields, symptom severity was greatest during the second growing season when high percentages of infected plants also were recorded.


1986 ◽  
Vol 37 (3) ◽  
pp. 219 ◽  
Author(s):  
WK Anderson

Eight spring bread wheat cultivars (Triticum aestivum L.), differing widely in their nominal yield component characteristics, were tested under rain-fed conditions for three years at sowing densities ranging from 50 to 800 seeds m-2. The objectives of the experiments were to estimate the relationship between grain yield and particular yield components, the expression of plant type (yield components) in relation to plant density, and the plant population x cultivar interaction for grain yield over a range of seasons in a given environment. The 'optimum' plant population (at maximum grain yield) varied over 30-220 plants m-2, depending on season and cultivar. In general, variation in the 'optimum' population was greater between seasons for a given cultivar than between cultivars within seasons. The relationship between grain yield and yield components was examined at the 'optimum' population rather than at an arbitrary population at which grain yield may have been suboptimal for some cultivars or seasons. Grain yields at the optimum populations for the various cultivar x season combinations were positively related to culms m-2, spikes m-2 and seeds m-2. They were not clearly related to culm mortality (%). When averaged across seasons, cultivar grain yields were positively related to harvest index, but the general relationship was not so clear when seasons and cultivars were examined individually. Spike size (seeds spike-I or spike weight) and seed size were also not clearly related to grain yield at the 'optimum' population, and it was thus postulated that the production and survival of large numbers of culms, which in turn led to large numbers of seeds per unit area, were the source of large grain yields. Some interactions were found between yield components and plant population for some cultivars that could have implications for plant breeders selecting at low plant densities. The implications for crop ideotypes of the individual plant characters at the 'optimum' population are also discussed. Interactions between cultivars and plant populations implied that some cultivars required different populations to achieve maximum yields in some seasons. There was a tendency for larger yields to be achieved from cultivar x season combinations where the optimum population was larger, which suggested that commercial seed rates should be re-examined when changes to plant types or yield levels are made.


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