scholarly journals Autumn and winter application of nitrogen fertilizers on clay soils

1971 ◽  
Vol 43 (2) ◽  
pp. 76-85
Author(s):  
Yrjö Pessi ◽  
Mikko Ylänen ◽  
Auvo Leskelä ◽  
Jorma Syvälahti
Keyword(s):  
Protein Content ◽  
Crop Yield ◽  
Crop Yields ◽  
Early Summer ◽  
Frozen Soil ◽  
Nitrogen Fertilizers ◽  
Clay Soils ◽  
Spring Cereals ◽  
The Difference ◽  
Autumn And Winter

In order to examine the application time of nitrogen given to cereals, several tests have been arranged on the Kotkaniemi Experimental Farm at Vihti ever since 1965. The tests have been carried out on solid clay soils, where the leaching of nitrogen has been expected to be slow. In spring cereals the autumn application of nitrogen in November on frozen soil has given a good crop yield. The protein content of the crop in the plots where nitrogen was given in autumn was lower than in those where the spreading took place in spring. As for winter wheat, application in December has given the best average crop yields but the decline of the protein content is to be considered a disadvantage. In rye, spring fertilization has given the best average crop yield. There has, however, clearly been less lodging in autumn applications than in plots where the nitrogen was spread in the spring. Regarding nitrogen fertilization of autumn sown plants the usual custom in Finland is to give nitrogen in autumn for growth during the autumn and in the spring for the coming growing season. However, as low rainfall is typical ofthe Finnish spring, the effect of nitrogen given by broadcasting in early summer is slow, especially on solid soils like clay. As for spring cereals, the fertilizer placement at a depth of 8 to 10 cms has given distinctly better results than broadcasting and the usual mixing into the soil (Elonen 1967, Larpes 1966 and 1968, Nieminen 1967, Pessi 1970). The difference in the growth intensity has most clearly been evident in the early development of cereals. Simultaneously it has become clear that the placement of nitrogen has been of the greatest importance (Pessi 1970). As during winter in Finland the soil is usually frozen and covered with snow, no noteworthy leaching of nutrients takes place. On the basis of the results and observations mentioned above the question are as to what it would mean in practice in solid soils if the nitrogen was spread already before snowfall or on the snow, when the water from the melting snow would in spring cause the nitrogen to penetrate the soil. For this purpose tests were started on the Kotkaniemi Experimental Farm of Rikkihappo Oy in autumn 1965.

The effects of very deep ploughing and of subsoiling on crop yields

1956 ◽  
Vol 48 (2) ◽  
pp. 129-144 ◽  
Author(s):  
E. W. Russell
Keyword(s):  
Sugar Beet ◽  
Surface Soil ◽  
Crop Yields ◽  
Clay Soils ◽  
Deep Tillage ◽  
Perennial Weeds ◽  
The Difference ◽  
Annual Weeds ◽  
Dry Out ◽  
Complete Inversion

1. Deep tillage, namely, ploughing to a depth exceeding 12 in., or subsoiling to a depth of about 18 in., increased crop yields on about half the fields in which an experiment was made. Unfortunately, it was not possible to recognize what was the difference in soil properties between the 50% of fields that responded appreciably to deep tillage and the remainder whose yields were either unaffected or sometimes reduced by deep tillage, though, as one would expect, sands were normally less responsive to deep tillage than the heavier soils.2. On the clay soils, deep ploughing in autumn tended to give a surface soil that dried out up to several weeks earlier in the spring than land that was shallow ploughed. Subsoiling did not cause the surface soil to dry out in the same way. Only rarely did the subsoil brought up by deep ploughing give difficulty in working down to a seedbed, and probably in as high a proportion of fields the subsoil worked easier than the surface soil.3. On the clays and loams, the response of potatoes to deep tillage was more marked on fields that were heavily manured than on those lightly manured.4. Sugar beet normally gave a higher yield if its potash and phosphate was spread on the land before ploughing, even if this was in the autumn, than if it was applied in the seedbed. The exceptions to this result were for soils heavier than sandy loams if ploughing depths exceeding 12 in. were used, for the yield of beet was, on the average, depressed on these soils if the potash and phosphate was ploughed in compared with it being worked into the seedbed.5. Deep ploughing tended to give better control of many perennial weeds, and often of annual weeds than shallow ploughing. It is suggested that much of this benefit could be obtained when ploughing to 9–10 in. deep if ploughs were used that cut a furrow considerably wider than the conventional 10½–11 in. furrow, so allowing more complete inversion of the furrow slice.

Growth and carcass characteristics of crossbred and straightbred Hereford steers. I. Post-weaning growth

1981 ◽  
Vol 32 (1) ◽  
pp. 161 ◽  
Author(s):  
JM Thompson ◽  
R Barlow ◽  
B Johnston ◽  
PJ Nicholls
Keyword(s):  
Growth Rate ◽  
Slow Growth ◽  
Carcass Characteristics ◽  
Late Summer ◽  
Coastal Environment ◽  
Early Summer ◽  
Significant Difference ◽  
The Mean ◽  
The Difference ◽  
Autumn And Winter

Post-weaning growth characteristics were examined in 28 Hereford, 27 Brahman x Hereford, 23 Simmental x Hereford and 26 Friesian x Hereford steers which were grazed on pasture in a central coastal environment at Paterson, N.S.W. Sixty-seven steers from a 1973 calving were allocated to three groups to be slaughtered when the mean liveweights of the Herefords were approximately 270, 370 and 470 kg. Thirty-seven steers from a 1974 calving were allocated to two groups to be slaughtered when the average liveweights of the Herefords were 470 and 570 kg. Average daily liveweight gains of the crossbred steers were greater (average 19%) than the Hereford steers from weaning to the four slaughter weights (P < 0.05). Of the crossbreds, the Brahman cross steers grew faster than the Simmental cross steers (P < O.05), although the difference was not significant at the highest slaughter weight. The growth advantage of the crossbreds was mainly realized in the periods of slow growth (mean growth rate of 320 g/day) during the late summer, autumn and winter months. During these periods the Brahman cross steers grew faster than the Herefords by an average of 89% (P < 0.05) and the Simmental and Friesian cross steers grew 39% faster than the Herefords (P < 0.05). In the periods of fast growth (mean growth rate of 667 g/day), during the spring and early summer months, there was no significant difference between the sire breeds in growth rate (P > 0.05).

scholarly journals Comparisons between Aquaponic and Conventional Hydroponic Crop Yields: A Meta-Analysis

2019 ◽  
Vol 11 (22) ◽  
pp. 6511
Author(s):  
Emmanuel Ayipio ◽  
Daniel E. Wells ◽  
Alyssa McQuilling ◽  
Alan E. Wilson
Keyword(s):  
Crop Yield ◽  
Effect Size ◽  
Crop Yields ◽  
Meta Analysis ◽  
Information Source ◽  
Aquatic Organism ◽  
Research Attention ◽  
Nutrient Supplementation ◽  
Study Characteristics ◽  
The Difference

Aquaponic is a relatively new system of farming, which has received much research attention due to its potential for sustainability. However, there is no consensus on comparability between crop yields obtained from aquaponics (AP) and conventional hydroponics (cHP). Meta-analysis was used to synthesize the literature on studies that compared crop yields of AP and cHP. Factors responsible for differences were also examined through subgroup analysis. A literature search was conducted in five databases with no time restriction in order to capture any publication on AP and cHP crop yield comparisons. The search was, however, limited to journal and conference articles published in English. Study characteristics and outcome measures of food crops were extracted. A natural log response ratio effect size measure was used to transform study outcomes. An unweighted meta-analysis was conducted through bootstrapping to calculate overall effect size and its confidence interval. Between-study heterogeneity (I2) was estimated using a random effects model. Subgroup and meta-regression were used to assess moderators, in an attempt to explain heterogeneity in the effect size. The results showed that although crop yield in AP was lower than conventional cHP, the difference was not statistically significant. However, drawing conclusions on the overall effect size must be done with caution due to the use of unweighted meta-analysis. There were statistically significant effects of aquatic organism, hydroponic system type, and nutrient supplementation used in the studies on crop yield comparisons. Nutrient supplementation, particularly, led to on average higher crop yield in AP relative to cHP. These findings are a vital information source for choosing factors to include in an AP study. These findings also synthesize the current trends in AP crop yields in comparison with cHP.

Comparative Study of Size, Total Protein, Fibrinogen and 5-HT Content of Human and Canine Platelet Density Subpopulations

1986 ◽  
Vol 56 (03) ◽  
pp. 288-292 ◽  
Author(s):  
Diego Mezzano ◽  
Eduardo Aranda ◽  
Arnaldo Foradori
Keyword(s):  
Comparative Study ◽  
Protein Content ◽  
Cell Density ◽  
Total Protein ◽  
Unit Volume ◽  
Low Density ◽  
Dense Bodies ◽  
Artifactual Changes ◽  
Platelet Release ◽  
The Difference

SummaryThe size, total protein, fibrinogen and 5-HT content were evaluated in density subpopulations of human and canine platelets fractionated in linear arabinogalactan gradients. The methodology was assessed to ascertain that platelet separation was by density and to discard artifactual changes and platelet release during the procedure. EDTA or PGEi increased the size of human PRP-platelets, but not of dog platelets. In humans, high density (HD) platelets were 1.26 times larger and contained 1.88 times more fibrinogen, 2.23 times more 5-HT and 1.37 times more protein than low density (LD) platelets; in dogs, these density cohorts did not differ in protein content, but LD platelets were 1.29 times larger and had 1.33 times more fibrinogen and 5-HT than HD platelets. These findings suggest that cell density is mostly dependent on the protein content per unit volume of platelets (and not on dense bodies). The differences in fibrinogen and 5-HT content between HD and LD cohorts in humans and dogs may be related to platelet age. The difference in volume between HD and LD platelets in dogs is of uncertain interpretation.

Productivity and quality of soybean seeds with different fertilization on podzolized chernozem

2020 ◽  
Vol 1 (97) ◽  
pp. 136-144
Author(s):  
H.M. Hospodarenko ◽  
◽  
I.V. Prokopchuk ◽  
K. P. Leonova ◽  
V.P. Boyko
Keyword(s):  
Crop Rotation ◽  
Crop Yields ◽  
Spring Barley ◽  
Mineral Fertilizer ◽  
Nitrogen Fertilizers ◽  
Mineral Fertilizers ◽  
Forest Steppe ◽  
Soybean Seeds ◽  
Different Doses

The productivity of agricultural crops is the most variable and integral indicator of their vital activity, which accumulates their genetic potential, soil fertility, weather conditions and components of agricultural technology. Soybean under optimal growing conditions (the reaction of the soil is close to neutral, sufficient phosphorus and potassium nutrition, the use of nitraginization) assimilates from the air about 70 % of the total nitrogen requirement. Therefore, it is believed that it is enough to apply only a starting dose of nitrogen fertilizers (20–40 kg/ha a. s.), to get a high yield with good indicators of grain quality. The results of studies of the influence of long-term (8 years) application of different doses and ratios of fertilizers in field crop rotation on podzolized chernozem in the conditions of the Right -Bank Forest-Steppe of Ukraine on the yield and quality of soybean seeds preceded by spring barley were presented. It was found that crop yields could be increased by 18–77 % owing to different doses, ratios and types of fertilizers. The highest indicators of seed yields for three years of the research (3,02 t/ha) were obtained under the application of mineral fertilizers at a dose of N110P60K80 per 1 ha of crop rotation area, including under soybean – N60P60K60. Exclusion of the nitrogen component from the complete fertilizer (N60P60K60) reduced its yield by 26 %, phosphorus – by 17, and potassium by 11 %. There was no significant decrease in soybean yield in the variant of the experiment with a decrease in the proportion of potassium in the composition of complete mineral fertilizer (N60P60K30) for three years of study. The largest mass of 1000 soybean seeds was formed at doses of N60К60 fertilizers, and their protein content — under the application of complete mineral fertilizer in doses of N60P60K60 and N60P60K30.

scholarly journals Assessing the Sensitivity of Main Crop Yields to Climate Change Impacts in China

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 172
Author(s):  
Yuan Xu ◽  
Jieming Chou ◽  
Fan Yang ◽  
Mingyang Sun ◽  
Weixing Zhao ◽  
...  
Keyword(s):  
Climate Change ◽  
Crop Yield ◽  
Food Production ◽  
Crop Yields ◽  
Climatic Factors ◽  
Climatic Data ◽  
The South ◽  
The North ◽  
Output Elasticity ◽  
The Impact

Quantitatively assessing the spatial divergence of the sensitivity of crop yield to climate change is of great significance for reducing the climate change risk to food production. We use socio-economic and climatic data from 1981 to 2015 to examine how climate variability led to variation in yield, as simulated by an economy–climate model (C-D-C). The sensitivity of crop yield to the impact of climate change refers to the change in yield caused by changing climatic factors under the condition of constant non-climatic factors. An ‘output elasticity of comprehensive climate factor (CCF)’ approach determines the sensitivity, using the yields per hectare for grain, rice, wheat and maize in China’s main grain-producing areas as a case study. The results show that the CCF has a negative trend at a rate of −0.84/(10a) in the North region, while a positive trend of 0.79/(10a) is observed for the South region. Climate change promotes the ensemble increase in yields, and the contribution of agricultural labor force and total mechanical power to yields are greater, indicating that the yield in major grain-producing areas mainly depends on labor resources and the level of mechanization. However, the sensitivities to climate change of different crop yields to climate change present obvious regional differences: the sensitivity to climate change of the yield per hectare for maize in the North region was stronger than that in the South region. Therefore, the increase in the yield per hectare for maize in the North region due to the positive impacts of climate change was greater than that in the South region. In contrast, the sensitivity to climate change of the yield per hectare for rice in the South region was stronger than that in the North region. Furthermore, the sensitivity to climate change of maize per hectare yield was stronger than that of rice and wheat in the North region, and that of rice was the highest of the three crop yields in the South region. Finally, the economy–climate sensitivity zones of different crops were determined by the output elasticity of the CCF to help adapt to climate change and prevent food production risks.

scholarly journals The Pitfalls of Relating Weeds, Herbicide Use, and Crop Yield: Don't Fall Into the Trap! A Critical Review

2020 ◽  
Vol 2 ◽  
Author(s):  
Nathalie Colbach ◽  
Sandrine Petit ◽  
Bruno Chauvel ◽  
Violaine Deytieux ◽  
Martin Lechenet ◽  
...  
Keyword(s):  
Crop Yield ◽  
Weed Management ◽  
Crop Production ◽  
Yield Loss ◽  
Crop Yields ◽  
Cropping Systems ◽  
Crop Productivity ◽  
Arable Farming ◽  
Herbicide Use ◽  
The Impact

The growing recognition of the environmental and health issues associated to pesticide use requires to investigate how to manage weeds with less or no herbicides in arable farming while maintaining crop productivity. The questions of weed harmfulness, herbicide efficacy, the effects of herbicide use on crop yields, and the effect of reducing herbicides on crop production have been addressed over the years but results and interpretations often appear contradictory. In this paper, we critically analyze studies that have focused on the herbicide use, weeds and crop yield nexus. We identified many inconsistencies in the published results and demonstrate that these often stem from differences in the methodologies used and in the choice of the conceptual model that links the three items. Our main findings are: (1) although our review confirms that herbicide reduction increases weed infestation if not compensated by other cultural techniques, there are many shortcomings in the different methods used to assess the impact of weeds on crop production; (2) Reducing herbicide use rarely results in increased crop yield loss due to weeds if farmers compensate low herbicide use by other efficient cultural practices; (3) There is a need for comprehensive studies describing the effect of cropping systems on crop production that explicitly include weeds and disentangle the impact of herbicides from the effect of other practices on weeds and on crop production. We propose a framework that presents all the links and feed-backs that must be considered when analyzing the herbicide-weed-crop yield nexus. We then provide a number of methodological recommendations for future studies. We conclude that, since weeds are causing yield loss, reduced herbicide use and maintained crop productivity necessarily requires a redesign of cropping systems. These new systems should include both agronomic and biodiversity-based levers acting in concert to deliver sustainable weed management.

scholarly journals Modeling the Impact of Climate Changes on Crop Yield: Irrigated vs. Non-Irrigated Zones in Mississippi

2021 ◽  
Vol 13 (12) ◽  
pp. 2249
Author(s):  
Sadia Alam Shammi ◽  
Qingmin Meng
Keyword(s):  
Climate Change ◽  
Crop Yield ◽  
Crop Yields ◽  
Negative Impact ◽  
Positive Impact ◽  
Information Criterion ◽  
Growing Season ◽  
Maximum Temperature ◽  
Linear Regression Models ◽  
The Impact

Climate change and its impact on agriculture are challenging issues regarding food production and food security. Many researchers have been trying to show the direct and indirect impacts of climate change on agriculture using different methods. In this study, we used linear regression models to assess the impact of climate on crop yield spatially and temporally by managing irrigated and non-irrigated crop fields. The climate data used in this study are Tmax (maximum temperature), Tmean (mean temperature), Tmin (minimum temperature), precipitation, and soybean annual yields, at county scale for Mississippi, USA, from 1980 to 2019. We fit a series of linear models that were evaluated based on statistical measurements of adjusted R-square, Akaike Information Criterion (AIC), and Bayesian Information Criterion (BIC). According to the statistical model evaluation, the 1980–1992 model Y[Tmax,Tmin,Precipitation]92i (BIC = 120.2) for irrigated zones and the 1993–2002 model Y[Tmax,Tmean,Precipitation]02ni (BIC = 1128.9) for non-irrigated zones showed the best fit for the 10-year period of climatic impacts on crop yields. These models showed about 2 to 7% significant negative impact of Tmax increase on the crop yield for irrigated and non-irrigated regions. Besides, the models for different agricultural districts also explained the changes of Tmax, Tmean, Tmin, and precipitation in the irrigated (adjusted R-square: 13–28%) and non-irrigated zones (adjusted R-square: 8–73%). About 2–10% negative impact of Tmax was estimated across different agricultural districts, whereas about −2 to +17% impacts of precipitation were observed for different districts. The modeling of 40-year periods of the whole state of Mississippi estimated a negative impact of Tmax (about 2.7 to 8.34%) but a positive impact of Tmean (+8.9%) on crop yield during the crop growing season, for both irrigated and non-irrigated regions. Overall, we assessed that crop yields were negatively affected (about 2–8%) by the increase of Tmax during the growing season, for both irrigated and non-irrigated zones. Both positive and negative impacts on crop yields were observed for the increases of Tmean, Tmin, and precipitation, respectively, for irrigated and non-irrigated zones. This study showed the pattern and extent of Tmax, Tmean, Tmin, and precipitation and their impacts on soybean yield at local and regional scales. The methods and the models proposed in this study could be helpful to quantify the climate change impacts on crop yields by considering irrigation conditions for different regions and periods.

A Comparison of Subjective and Historical Crop Yield Probability Distributions

1992 ◽  
Vol 24 (2) ◽  
pp. 23-32 ◽  
Author(s):  
James W. Pease
Keyword(s):  
Crop Yield ◽  
Subjective Probability ◽  
Crop Yields ◽  
Probability Distributions ◽  
Geographical Location ◽  
Subjective Expectations ◽  
Grain Farms ◽  
Western Kentucky ◽  
Relative Variability

AbstractForecast distributions based on historical yields and subjective expectations for 1987 expected crop yields were compared for 90 Western Kentucky grain farms. Different subjective probability elicitation techniques were also compared. In many individual cases, results indicate large differences between subjective and empirical moments. Overall, farmer expectations for 1987 corn yields were below those predicted from their past yields, while soybean expectations were above the historical forecast. Geographical location plays a larger role than crop in comparisons of relative variability of yield. Neither elicitation technique nor manager characteristics have significant effects on the comparisons of the forecasts.

scholarly journals Effects of Environmental Temperature onCapnodis tenebrionisAdult Phenology

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Carmelo Peter Bonsignore
Keyword(s):  
Late Summer ◽  
Early Summer ◽  
Adult Density ◽  
Degree Days ◽  
Continuous Increase ◽  
Climate Conditions ◽  
Average Annual Temperature ◽  
Activity Temperature ◽  
The Difference ◽  
New Generation

The phenology ofCapnodis tenebrionisadults was presented with reference to two different climate conditions. In a temperate moderate-warm climate, adult density showed two separate peaks during the year: one in early summer of the overwintering generation and one with beetles emerging in the late summer. In a warmer semiarid climate, the overwintering adults and the new generation overlapped during summer with a continuous increase of adult density. The difference in the average annual temperature between areas during the study period was almost3∘C, and, in the warmer area, the new generation ofC. tenebrionisemerged at least one month earlier. To make a prediction of adult presence, a model utilizing degree-days was developed from data collected over a five-year period. Models obtained from equations (Logistic 4-parameter,y(x)=yo+a/(1+(x/xo)b)) of each year were developed to describe the relationship between degree-day accumulation (with a minimal threshold activity temperature of14.21∘Ccalculated in the laboratory) and the cumulative percentage of adult presence. According to the overall model, the 50% of overwintering beetles occurred at 726 degree-days (Biofix: 1st March) and the emerging beetles occurred at 801 degree-days (Biofix: 1st July). The results show that a change in temperature is an important aspect that highlights the adaptability of this species.

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