scholarly journals Long-term drainage, subirrigation, and tile spacing effects on maize production

2021 ◽  
Vol 262 ◽  
pp. 108032
Author(s):  
Gubir Singh ◽  
Kelly A. Nelson
Keyword(s):  
Maize Production ◽  
Spacing Effects

A long-term nitrogen fertilizer gradient has little effect on soil organic matter in a high-intensity maize production system

2014 ◽  
Vol 20 (4) ◽  
pp. 1339-1350 ◽  
Author(s):  
Kimberly H. Brown ◽  
Elizabeth M. Bach ◽  
Rhae A. Drijber ◽  
Kirsten S. Hofmockel ◽  
Elizabeth S. Jeske ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Nitrogen Fertilizer ◽  
Production System ◽  
High Intensity ◽  
Maize Production

ADDING VALUE TO FIELD-BASED AGRONOMIC RESEARCH THROUGH CLIMATE RISK ASSESSMENT: A CASE STUDY OF MAIZE PRODUCTION IN KITALE, KENYA

2011 ◽  
Vol 47 (2) ◽  
pp. 317-338 ◽  
Author(s):  
P. N. DIXIT ◽  
P. J. M. COOPER ◽  
J. DIMES ◽  
K. P. RAO
Keyword(s):  
Weed Control ◽  
N Fertilizer ◽  
Sub Saharan Africa ◽  
Climate Risk ◽  
Weather Data ◽  
Rates Of Return ◽  
Maize Production ◽  
Fertilizer Use ◽  
N Fertilizer Use

SUMMARYIn sub-Saharan Africa (SSA), rainfed agriculture is the dominant source of food production. Over the past 50 years much agronomic crop research has been undertaken, and the results of such work are used in formulating recommendations for farmers. However, since rainfall is highly variable across seasons the outcomes of such research will depend upon the rainfall characteristics of the seasons during which the work was undertaken. A major constraint that is faced by such research is the length of time for which studies could be continued, typically ranging between three and five years. This begs the question as to what extent the research was able to ‘sample’ the natural longer-term season-to-season rainfall variability. Without knowledge of the full implications of weather variability on the performance of innovations being recommended, farmers cannot be properly advised about the possible weather-induced risks that they may face over time. To overcome this constraint, crop growth simulation models such as the Agricultural Production Systems Simulator (APSIM) can be used as an integral part of field-based agronomic studies. When driven by long-term daily weather data (30+ years), such models can provide weather-induced risk estimates for a wide range of crop, soil and water management innovations for the major rainfed crops of SSA. Where access to long-term weather data is not possible, weather generators such as MarkSim can be used. This study demonstrates the value of such tools in climate risk analyses and assesses the value of the outputs in the context of a high potential maize production area in Kenya. MarkSim generated weather data is shown to provide a satisfactory approximation of recorded weather data at hand, and the output of 50 years of APSIM simulations demonstrate maize yield responses to plant population, weed control and nitrogen (N) fertilizer use that correspond well with results reported in the literature. Weather-induced risk is shown to have important effects on the rates of return ($ per $ invested) to N-fertilizer use which, across seasons and rates of N-application, ranged from 1.1 to 6.2. Similarly, rates of return to weed control and to planting at contrasting populations were also affected by seasonal variations in weather, but were always so high as to not constitute a risk for small-scale farmers. An analysis investigating the relative importance of temperature, radiation and water availability in contributing to weather-induced risk at different maize growth stages corresponded well with crop physiological studies reported in the literature.

scholarly journals Board 121: Retrieval Practice and Spacing: Effects on Long-Term Learning among Engineering Precalculus Students

2020 ◽  
Author(s):  
Robin Hopkins ◽  
Keith Lyle ◽  
Patricia Ralston ◽  
Campbell Bego ◽  
Jeffrey Hieb
Keyword(s):  
Retrieval Practice ◽  
Spacing Effects

scholarly journals Analysis of the Effects of Climate Change on Maize Production in Mali

2021 ◽  
pp. 42-52
Author(s):  
Abdoulaye Maïga ◽  
Moussa Bathily ◽  
Amadou Bamba ◽  
Issoufou Soumaïla Mouleye ◽  
Mamadi Sissako Nimaga
Keyword(s):  
Climate Change ◽  
Unit Root ◽  
Correction Term ◽  
Unit Root Test ◽  
Negative Effects ◽  
Maize Production ◽  
Distributed Lag ◽  
Adequate Food ◽  
Augmented Dickey Fuller

The objective of this paper is to analyze the effects of climate change on maize production in Mali during the period 1990-2020. The unit root test (augmented Dickey-Fuller) was used to check the order of integration between the variables in the study. The ARDL (autoregressive distributed lag) approach to cointegration limits is applied to assess the association between the study variables with evidence of a long-term relationship. The unit root test estimates confirm that all variables are stationary at the combination of I(0) and I(1). The results show that precipitation and temperature in June and July have a negative and highly significant effect on maize production in both the short and long term analyses. Among other determinants, the area of land devoted to maize crops and GDP per capita have a positive effect on production. The estimated coefficient on the error correction term is also highly also highly significant As Mali's population grows, in the coming decades the country will face food security challenges. Possible initiatives are needed to configure the Malian government to address the negative effects of climate change on agriculture and ensure adequate food for the growing population.

SUSTAINABLE MAIZE PRODUCTION USING GLIRICIDIA/MAIZE INTERCROPPING IN SOUTHERN MALAWI

2006 ◽  
Vol 42 (4) ◽  
pp. 441-457 ◽  
Author(s):  
F. K. AKINNIFESI ◽  
W. MAKUMBA ◽  
F. R. KWESIGA
Keyword(s):  
Soil Fertility ◽  
Cropping Systems ◽  
Continuous Cultivation ◽  
Maize Yield ◽  
Fertilizer Application ◽  
Maize Production ◽  
Soil Fertility Replenishment ◽  
P Fertilizer ◽  
Maize Yields

Maize production in Malawi is limited by high costs and sub-optimal use of chemical fertilizers under continuous cultivation. A long-term gliricidia/maize trial was undertaken on a Ferric Lixisol from 1991/92 to 2001/02. The purpose of the study was to assess the performance of a gliricidia/maize intercropping system as a low-input soil fertility replenishment option in southern Malawi. The experiment was a 2 × 3 × 3 factorial design with three replications. Treatments included two maize cropping systems (with and without gliricidia trees), and three rates of inorganic N fertilizer (0, 24 and 48 N kg ha−1 representing 0, 25 and 50% of the national recommended N rate), and three rates of P fertilizer application (0, 20 and 40 P ha−1 representing 0, 50 and 100% of the recommended rate). No effect of P was detected on yield early in the trial, and this treatment was discontinued. The gliricidia pruning biomass did not decline after 10 years of intensive pruning, with strong correlation between tree biomass production and years after establishment (r = 0.91, p < 0.001). Application of gliricidia prunings increased maize yields by three times compared to the yield of unfertilized sole maize. Maize yield from the unfertilized gliricidia pruning treatment was superior to the yield from sole maize supplemented with a quarter or half the recommended N rate. The study confirmed that a gliricidia/maize intercropping system is a promising soil fertility replenishment option in southern Malawi and elsewhere in southern Africa.

Priming and trial spacing in extinction: Effects on extinction performance, spontaneous recovery, and reinstatement in appetitive conditioning

2006 ◽  
Vol 59 (5) ◽  
pp. 809-829 ◽  
Author(s):  
Erik W. Moody ◽  
Ceyhun Sunsay ◽  
Mark E. Bouton
Keyword(s):  
Short Term Memory ◽  
Spontaneous Recovery ◽  
Appetitive Conditioning ◽  
Extinction Performance ◽  
Learning Mechanisms ◽  
Short Term ◽  
Spacing Effects ◽  
Trial Spacing ◽  
Short Itis

Previous research in this laboratory suggests that priming of the conditional stimulus (CS) in short-term memory may play a role in the trial-spacing effects in appetitive conditioning. For example, a nonreinforced presentation of a CS 60 s before a reinforced trial with the same CS produced slower acquisition than a CS presentation that occurred 240 s before the reinforced trial. The results were consistent with the self-generated priming mechanism proposed by Wagner (e.g., Wagner 1978, 1981). The present experiments extended the earlier work by examining the effects of trial spacing in extinction rather than acquisition. After conditioning with a mixture of intertrial intervals (ITIs), rats received extinction with ITIs of 60 or 240 s, longer or shorter values, or different ways of “chunking” extinction trials in time. Although trial spacing produced effects on extinction performance that were consistent with our previous research on acquisition, there were few long-term differences in spontaneous recovery or in reinstatement. Short ITIs in extinction appear to affect extinction performance more than they affect extinction learning. Mechanisms of trial spacing in conditioning and extinction are discussed.

scholarly journals Long-term experiments on chernozem soil in the University of Debrecen

2018 ◽  
pp. 357-369
Author(s):  
Péter Pepó
Keyword(s):  
Winter Wheat ◽  
Crop Rotation ◽  
Management Practices ◽  
Crop Protection ◽  
Chernozem Soil ◽  
Wheat Varieties ◽  
Maize Production ◽  
Long Term Experiments ◽  
The Impact

The impact of agrotechnical management practices (nutrient and water supply, crop rotation, crop protection, genotype) on the yields of winter wheat and maize and on the soil water and nutrient cycles was studied in long-term experiments set up in 1983 in Eastern Hungary on chernozem soil. The long-term experiments have shown that nitrogen fertilizer rates exceeding the N-optimum of winter wheat resulted in the accumulation of NO3-N in the soil. Winter wheat varieties can be classified into four groups based on their natural nutrient utilization and their fertilizer response. The fertilizer responses of wheat varieties depended on crop year (6.5–8.9 t ha-1 maximum yields in 2011–2015 years) and the genotypes (in 2012 the difference was ~3 t ha-1 among varieties). The optimum N(+PK) doses varied between 30–150 kg ha-1 in different crop years. In maize production fertilization, irrigation and crop rotation have decision role on the yields. The efficiency of fertilization modified by cropyear (in dry 891–1315 kg ha-1, in average 1927–4042 kg ha-1, in rainy cropyear 2051–4473 kg ha-1 yield surpluses of maize, respectively) and crop rotation (in monoculture 1315–4473 kg ha-1, in biculture 924–2727 kg ha-1 and triculture 891–2291 kg ha-1 yield surpluses of maize, respectively). The optimum fertilization could improve the water use efficiency in maize production. Our long-term experiments gave important ecological and agronomic information to guide regional development of sustainable cropping systems.

scholarly journals Relating farmers’ perceptions to long term dynamics in maize (Zea mays L.) production: The production of improved maize is coming to a standstill in central Malawi

2020 ◽  
Author(s):  
Harrington Nyirenda ◽  
Wantwa Mwangomba ◽  
Ellen M. Nyirenda
Keyword(s):  
Maize Yield ◽  
Climatic Conditions ◽  
Early Maturity ◽  
Maize Production ◽  
Maize Productivity ◽  
Good Taste ◽  
Production Trend ◽  
Production Area ◽  
Hybrid Maize

AbstractMaize production, area and yield dynamics were assessed based on farmer perceptions and production data from 2004/05-2018/19 using 36 000 households in Salima, central Malawi. The results showed that farmers used 16, six and two varieties for hybrid, Open-pollinated varieties (OPV) and local maize respectively. Farmers sourced Hybrid and OPV maize seed from Private Agro dealers while local maize was own-sourced. Farmers preferred local maize for being cheap, good taste, low storage costs, and pest resistance although low yielding. They preferred hybrid and OPV maize for high yielding and early maturity despite demanding high storage costs, pest susceptibility, and low flour. From 2004/05-2018/19, the area under local and OPV maize reduced by 61% and 12% respectively, while that of hybrid maize increased by 49%. However, the consistent decrease in area for hybrid and OPV and significant increase of that of local maize from 2014/15-2018/19 may signal a catastrophic maize production in the region. From 2019/20-2025/26 production of all maize was projected at 44 172 tons by 2025/26, representing a 1.6% increase from the base year 2019/20. This increase will be due to favorable climatic conditions and not increase in area or yield. If maize yield was improved by 30% production would increase to 110 430 tons representing 67% of the food requirement in the study area. The current maize production trend in Salima does not guarantee food security prospects. Therefore, policymakers should consider reviewing the past interventions (input pricing, promotion strategies, sustainable practices, policies) in the maize subsector to enhance maize productivity.

scholarly journals Monitoring of atrazine and its metabolites in groundwaters of the Republic of Serbia

2013 ◽  
Vol 67 (3) ◽  
pp. 513-523
Author(s):  
Sanja Lazic ◽  
Dragana Sunjka ◽  
Mira Pucarevic ◽  
Nada Grahovac ◽  
Slavica Vukovic ◽  
...  
Keyword(s):  
Residue Level ◽  
Gas Chromatography Mass Spectrometry ◽  
Maize Production ◽  
Average Value ◽  
Groundwater Samples ◽  
Intensive Use ◽  
The Republic ◽  
High Level ◽  
Agricultural Regions

The intensive use of atrazine herbicides in the Republic of Serbia during recent decades has led to the accumulation of residues of atrazine and its metabolites in the environment, which endangers groundwater. With the objective to check the presence of atrazine and its metabolites deethylatrazine (DEA) and deisopropylatrazine (DIA) in the groundwater, the monitoring programme was carried out over the period from 2007 to 2009 in the localities where the atrazine-based herbicides were intensively applied for a number of years. Samples were taken from 327 localities, in total there were 1408 samples of groundwater of the first welling-up collected. The atrazine and its metabolites were extracted with methanol by means of ENVI-C18 (47mm) disc, and the residue level of the studied compounds was analyzed with gas chromatography-mass spectrometry (GC-MS). In the most of groundwater samples collected from agricultural regions, average value of all tested analytes was above 0.1 ?g/dm3. The highest values of atrazine and its metabolites were in the localities that is known for intensive maize production and in the areas of this region under orchards and vineyards, where atrazine was used in large quantities. The average values of content of this active substance in analyzed samples are the result of intensive and long-term usage of this group of herbicides, as well as the high level of groundwater in this region.

Plant density and intra-row spacing effects on phenology, dry matter accumulation and leaf area index of maize in second cropping

Biologija ◽  
2016 ◽  
Vol 62 (1) ◽  
Author(s):  
Raouf Seyed Sharifi ◽  
Ali Namvar
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Dry Matter ◽  
Plant Density ◽  
Block Design ◽  
Row Spacing ◽  
Dry Matter Accumulation ◽  
Maize Production ◽  
Area Index ◽  
Spacing Effects

Crop phenology is one of the most important aspects of crop yield determination and it is essential to predicting physiological responses under varying field conditions. In order to evaluate plant density and intra-row spacing effects on phenology, dry matter accumulation, and leaf area index of maize in second cropping, a factorial experiment based on randomized complete block design was conducted at the research farm of the University of Mohaghegh Ardabili. Experimental factors were: plant population at three levels (7, 9, and 11 plants m–2) with three levels of intra-row spacing (45, 60, and 75 cm). The results showed that the maximum plant height (179.07  cm), total dry matter (592  g  m–2) in 83–91 days after sowing, days to 50% anthesis (45 days), days to 50% silking (50 days), LAI (4.07) in 63–70 days after sowing were observed in the plots with 11 plants m–2 and intra-row spacing of 45 cm. Based on the results, it was concluded that application of 11 plants m–2 with row spacing of 45 cm can be recommended for profitable maize production.

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