The Effects of Summer Green Manures on the ammonia and Nitrate Contents of soils Cropped for Winter Wheat. An Examination of the Woburn Green Manure Plots

1931 ◽  
Vol 21 (3) ◽  
pp. 458-468 ◽  
Author(s):  
T. J. Mirchandani
Keyword(s):  
Critical Period ◽  
Field Experiments ◽  
Nitrogen Deficiency ◽  
Wheat Plant ◽  
Ammonia Nitrogen ◽  
Wheat Crop ◽  
Nitrate Content ◽  
Green Manures ◽  
The Mean ◽  
Nitric Nitrogen

1. The Woburn field experiments on wheat after green manures are briefly reviewed. Contrary to the original expectations the wheat was less good after two summer crops of tares than after two mustard crops. This result was obtained many times and in recent years the wheat yields were extremely low after both green manures.2. Regular soil analyses for nitrate and ammonia through 1928 and 1929 showed that the mean nitrate content was extremely low (1·2 parts of nitric nitrogen per million of soil). During the cold dry winter of 1928–9 the ammonia nitrogen was several times greater than the nitrate nitrogen.3. Further evidence of an acute nitrogen deficiency during the critical period for the wheat plant in May and June was afforded by the large responses to top dressings of sodium nitrate both in the 1929 and the 1930 wheat crop.

Fertility investigations on the black earth wheatlands of the Darling Downs, Queensland. III. Mineral nitrogen in the soil and its relation to the wheat crop

1960 ◽  
Vol 11 (1) ◽  
pp. 27 ◽  
Author(s):  
SA Waring ◽  
LJH Teakle
Keyword(s):  
Grain Yield ◽  
Ammonia Nitrogen ◽  
Mean Value ◽  
Mineral Nitrogen ◽  
Wheat Crop ◽  
Nitrogen Accumulation ◽  
A Value ◽  
The Mean ◽  
The One ◽  
Growing Crop

The level of mineral nitrogen in the soil under fallow and crop was measured for the years 1951 to 1953. Relationships of mineral nitrogen at planting to yield and nitrogen content of wheat grain and straw were examined. Values for nitrate nitrogen at the end of the fallow period ranged most commonly from 10 to 20 µg/g in the surface 2 ft and from 0 to 10 µg/g at 2-4 ft. Approximately one-third of the sites showed an increase from the third to the fourth foot. One site showed extremely high values throughout the profile, particularly at 3-4 ft where a value of 127 µg/g was recorded. Values for ammonia nitrogen were most commonly in the range of 0-3 µg/g . Under the growing crop, mineral nitrogen declined for most depths in the period from planting up to September or October, after which there was little further change to harvest. Uptake of mineral nitrogen was normally greatest from the surface 2 ft of soil. Below 3 ft there were two groups of sites. One group showed moderate to high uptake and the second group low uptake. The low uptake in the latter group provides a reason for mineral nitrogen accumulation below 3 ft at some sites. Mineral nitrogen to 4 ft at planting averaged 126 lb/ac, excluding the one site with exceptionally high values. This was double the mean value of 63 lb/ac for nitrogen recovered in grain and straw, for crops planted in May-June. These figures, combined with trends in the soil under crop, suggest that most of the nitrogen used by the crop was derived from that in the soil at planting. Correlations between mineral nitrogen at planting and grain yield were mostly non-significant, suggesting that in general nitrogen was not an important factor limiting yield. Low grain yield and protein percentage were recorded at a number of sites which had been cultivated more than 50 years.

The availability of mineral nitrogen in a wheat soil from southern New South Wales

1962 ◽  
Vol 2 (6) ◽  
pp. 185 ◽  
Author(s):  
RR Storrier
Keyword(s):  
Nitrogen Uptake ◽  
New South ◽  
New South Wales ◽  
Nitrogen Deficiency ◽  
Ammonia Nitrogen ◽  
Mineral Nitrogen ◽  
Wheat Crop ◽  
Wagga Wagga ◽  
Emergence Period ◽  
South Wales

In a red-brown earth soil from Wagga Wagga the fluctuations in the level of mineral nitrogen (ammonia plus nitrate-nitrogen) and its availability to wheat under growing period rainfalls of 6 inches and 16 inches were studied. Ammonia-nitrogen did not exceed 8 lb nitrogen per acre 6 inches but showed statistically significant short term fluctuations. Mineral nitrogen decreased steadily from the 4-5 leaf stage of plant growth, reaching minimum values in the ear-emergence period when a temporary nitrogen deficiency occurred. Following rainfalls of about one inch or more, conditions favoured biological activity and nitrogen was mineralized, absorbed by the crop and/or leached down the profile. In one season a release of mineral nitrogen about two weeks before flowering contributed an estimated 20-30 per cent of the total nitrogen uptake of the crop. Nitrogen uptake by the wheat crop ceased after flowering and subsequent changes in mineral nitrogen level reflect the net result of mineralization and demineralization processes, and nitrogen uptake by weeds, particularly skeleton weed. Absorption of nitrogen from the profile depended upon seasonal conditions, with the surface 18 inches suppling the greater part of the nitrogen absorbed by the crop. This indicates the need to sample regularly to at least a depth of 18 inches, particularly during the period from 4-5 leaf to flowering, when studying the relation between mineral nitrogen and crop growth. The data suggest that the response of wheat, as measured by grain yield and protein content, to the higher levels of mineral nitrogen in the improved soils of southern New South Wales is determined by soil moisture levels, particularly in the post-flowering period.

scholarly journals Development of Perceptual Inhibition in Adolescents—a Critical Period?

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 457
Author(s):  
Isabel María Introzzi ◽  
María Marta Richard’s ◽  
Yesica Aydmune ◽  
Eliana Vanesa Zamora ◽  
Florencia Stelzer ◽  
...  
Keyword(s):  
Response Time ◽  
Executive Functions ◽  
Critical Period ◽  
Search Task ◽  
Probability Distributions ◽  
Linear Trajectory ◽  
Gaussian Functions ◽  
Mean Response Time ◽  
The Mean ◽  
One Year

Recent studies suggest that the developmental curves in adolescence, related to the development of executive functions, could be fitted to a non-linear trajectory of development with progressions and retrogressions. Therefore, the present study proposes to analyze the pattern of development in Perceptual Inhibition (PI), considering all stages of adolescence (early, middle, and late) in intervals of one year. To this aim, we worked with a sample of 275 participants between 10 and 25 years, who performed a joint visual and search task (to measure PI). We have fitted ex-Gaussian functions to the probability distributions of the mean response time across the sample and performed a covariance analysis (ANCOVA). The results showed that the 10- to 13-year-old groups performed similarly in the task and differ from the 14- to 19-year-old participants. We found significant differences between the older group and all the rest of the groups. We discuss the important changes that can be observed in relation to the nonlinear trajectory of development that would show the PI during adolescence.

scholarly journals Combining Process Modelling and LAI Observations to Diagnose Winter Wheat Nitrogen Status and Forecast Yield

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 314
Author(s):  
Andrew Revill ◽  
Vasileios Myrgiotis ◽  
Anna Florence ◽  
Stephen Hoad ◽  
Robert Rees ◽  
...  
Keyword(s):  
Field Experiments ◽  
Process Models ◽  
Agricultural Technologies ◽  
N Application ◽  
Area Index ◽  
Complex Process ◽  
C Cycle ◽  
The Mean ◽  
Leaf N Content ◽  
Leaf N

Climate, nitrogen (N) and leaf area index (LAI) are key determinants of crop yield. N additions can enhance yield but must be managed efficiently to reduce pollution. Complex process models estimate N status by simulating soil-crop N interactions, but such models require extensive inputs that are seldom available. Through model-data fusion (MDF), we combine climate and LAI time-series with an intermediate-complexity model to infer leaf N and yield. The DALEC-Crop model was calibrated for wheat leaf N and yields across field experiments covering N applications ranging from 0 to 200 kg N ha−1 in Scotland, UK. Requiring daily meteorological inputs, this model simulates crop C cycle responses to LAI, N and climate. The model, which includes a leaf N-dilution function, was calibrated across N treatments based on LAI observations, and tested at validation plots. We showed that a single parameterization varying only in leaf N could simulate LAI development and yield across all treatments—the mean normalized root-mean-square-error (NRMSE) for yield was 10%. Leaf N was accurately retrieved by the model (NRMSE = 6%). Yield could also be reasonably estimated (NRMSE = 14%) if LAI data are available for assimilation during periods of typical N application (April and May). Our MDF approach generated robust leaf N content estimates and timely yield predictions that could complement existing agricultural technologies. Moreover, EO-derived LAI products at high spatial and temporal resolutions provides a means to apply our approach regionally. Testing yield predictions from this approach over agricultural fields is a critical next step to determine broader utility.

scholarly journals Modeling the Competitive Effect of Euphorbia dracunculoides and Astragalus sp. in Zero Input Rainfed Chickpea

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
R.M. IKRAM ◽  
A. TANVEER ◽  
R. MAQBOOL ◽  
M.A. NADEEN
Keyword(s):  
Protein Content ◽  
Critical Period ◽  
Field Experiments ◽  
Seed Protein ◽  
Yield Loss ◽  
Seed Protein Content ◽  
Yield Losses ◽  
Competition Period ◽  
Crop Competition ◽  
Weed Removal

ABSTRACT: Brown chickpea (Cicer arietinum L.) is one of the two chickpea types grown in Pakistan and other countries. The critical period for weed removal in a rainfed chickpea system is an important consideration in devising weed management strategies. Field experiments were conducted in the winter season of 2011 and 2012 to determine the extent of yield loss with different periods of weed crop competition. Seven weed crop competition periods (0, 45, 60, 75, 90, 105 and 160 days after sowing - DAS) were used to identify the critical period for weed removal in rainfed chickpea. Experimental plots were naturally infested with Euphorbia dracunculoides and Astragalus sp. in both years. Individual, composite density and dry weights of E. dracunculoides and Astragalussp. increased significantly with an increase in the competition period. However, yield and yield-contributing traits of chickpea significantly decreased with an increase in the competition period. Chickpea seed yield loss was 11-53% in different weed crop competition periods. Euphorbia dracunculoides and Astragalus sp. removed 39.9 and 36.9 kg ha-1 of N, 9.61 and 7.27 kg ha-1 of P and 38.3 and 36.9 kg ha-1 of K, respectively. Season long weed competition (160 days after sowing) resulted in 19.5% seed protein content compared with 24.5% seed protein content in weed-free chickpea. A Logistic equation was fitted to yield data in response to increasing periods of weed crop competition. The critical timing of weed removal at 5 and 10% acceptable yield losses were 26 and 39 DAS, respectively. The observed critical period suggests that in rainfed chickpea, a carefully timed weed removal could prevent grain yield losses.

scholarly journals Effect of duration of weed competition and weed control on the yield of Indian spinach

1970 ◽  
Vol 33 (4) ◽  
pp. 623-629 ◽  
Author(s):  
MSA Khan ◽  
MA Hossain ◽  
M Nurul Islam ◽  
SN Mahfuza ◽  
MK Uddin
Keyword(s):  
Weed Management ◽  
Critical Period ◽  
Field Experiments ◽  
Agricultural Research ◽  
Cyperus Rotundus ◽  
Weed Competition ◽  
Weed Species ◽  
Maximum Benefit ◽  
Hand Weeding ◽  
Crop Weed Competition

Field experiments were conducted at the research farm of Bangladesh Agricultural Research Institute, Joydebpur during kharif-1 (March to July) seasons of 2005 and 2006 to identify the critical period of crop-weed competition for Indian spinach. Major weed species were Paspalurn commersoni, Echinochlaa crusgalli. Lie nv/nc india. Cyanotis axillaris and Cyperus rotundus. The lowest weed dry matter was 76.3 g m-2 in 2005 and l01.60 g m-2 in 2006 from the plots weeded up to 40 days after transplanting (DAT). The highest yields were obtained (74.82 t ha in 2005 and 48.48 t ha in 2006) from the weed free plots. The fresh yield of Indian spinach did not vary among no weeding upto 20, 30 and 40 DAT in 2006. But weeded plot upto 30 and 40 DAT produced identical yield in 2005. Maximum BCR (4.52) was obtained from weeded plots upto 30 DAT in 2005 but BCR (2.60) was same from weeded upto 30 and 40 DA F in 2006. On an average, highest BCR (3.55) was recorded from weeding upto 30 DAT. Results revealed that the critical period of crop weed competition lies between 20 and 30 DAT and two times hand weeding would be necessary within 30 DAT for maximum benefit. Key Words: Crop-weed competitions, critical period, weed management and Indian spinach. doi: 10.3329/bjar.v33i4.2306 Bangladesh J. Agril. Res. 33(4) : 623-629, December 2008

scholarly journals Living mulch strategy for organic cauliflower (Brassica oleracea L.) production in central and southern Italy

2015 ◽  
Vol 10 (2) ◽  
pp. 90 ◽  
Author(s):  
Stefano Canali ◽  
Gabriele Campanelli ◽  
Corrado Ciaccia ◽  
Mariangela Diacono ◽  
Fabrizio Leteo ◽  
...  
Keyword(s):  
Brassica Oleracea ◽  
Field Experiments ◽  
Southern Italy ◽  
Central Italy ◽  
Climatic Conditions ◽  
F1 Hybrid ◽  
Agronomic Practices ◽  
Burr Medic ◽  
The Mean ◽  
Sustainable Agricultural Systems

In sustainable agricultural systems, intercropping using living mulches (LM) provides many beneficial ecosystem services. The objective of these two-year field experiments was to study the suitability of different LM options of burr medic (<em>Medicago polymorpha</em> L. var. <em>anglona</em>) for organic cauliflower (<em>Brassica oleracea</em> L.) cultivation in two sites under Mediterranean conditions. In central Italy (Experiment 1) contemporary and delayed (to crop) sowings of LM were compared with a no-cover crop treatment, contrasting two local cauliflower cultivars and a F1 Hybrid. In southern Italy (Experiment 2) the sustainability of systems combining LM (anticipated and contemporary sowing compared with no-cover) and organic fertilisation strategies was assessed. The aboveground biomasses dry weights of cauliflower crop (heads and residues), burr medic and weeds were separately determined. Results suggested that in Experiment 1 the LM was not able to smother weeds establishment and growth, as a consequence of early sowing, while cauliflower yield was reduced. Moreover, the genotypes behaviour was greatly influenced by the LM sowing times. In Experiment 2, irrespective of the agronomic practices applied, climatic conditions notably influenced cauliflower cultivation and also reduced the mean yield. Therefore, the recorded differences between the two experimental sites highlighted the need to tailor the LM strategies to the different environmental conditions.

scholarly journals Residual Effect of Poultry Manure and Mineral N Application on Maize Production under Wheat-Maize Cropping System

2017 ◽  
Vol 5 (9) ◽  
pp. 1061
Author(s):  
Syed Azam Shah ◽  
Wisal Mohammad ◽  
Haroon Haroon ◽  
Adnan Anwar Khan
Keyword(s):  
Grain Yield ◽  
Field Experiments ◽  
Poultry Manure ◽  
Residual Effect ◽  
Grain Weight ◽  
Organic N ◽  
Wheat Crop ◽  
Silty Clay ◽  
Mineral N ◽  
1000 Grain Weight

The study was designed to asses the residual effect of organic N (Poultry Manure) and mineral N on maize crop in field experiments carried out on silty clay loam soil at NIFA, Tarnab, Peshawar, Khyber Pakhtunkhwa (KP) Pakistan during 2014-15. Combined dose of N from both sources were 120 kg ha-1 applied to wheat crop alone and in different combination making six treatments. Maize variety (Azam) was sown in Randomized complete block (RCB) design with four replications. Agronomic data, grains ear-1, 1000 grain weight, biomass grain yield data, N-uptake in maize grain and straw were recorded. Results showed that maximum grain ear−1, 1000 grain weight, biomass and grain yield was obtained from treatment where 25% N applied from poultry manure + 75% from mineral N source applied to previous wheat crop. Agronomic efficiency and nitrogen use efficiency were also found maximum in treatment where 75% poultry manure + 25% mineral N was applied. It was concluded from the study that residual effect of organic manure with mineral N in different ratios enhances crop productivity and soil fertility.

scholarly journals Pathogenicity of Fusarium species associated with crown and root rot of wheat (Triticum aestivum) under different condition

2019 ◽  
Vol 7 (1) ◽  
pp. 1-9
Author(s):  
Bareen Sidqi Shareef Al-Tovi ◽  
Raed Abduljabbar Haleem
Keyword(s):  
Disease Severity ◽  
Root Rot ◽  
Field Experiments ◽  
Fusarium Species ◽  
Test Tube ◽  
Spore Suspension ◽  
Wheat Crop ◽  
Pathogenicity Test ◽  
Crown And Root Rot

This study was conducted to test the pathogenicity of Fusarium species, the causes of crown and root rot disease of wheat crop, under three different conditions (Laboratory, Greenhouse and Field) and to show the best method for pathogenicity among different conditions. Pathogenicity test of six isolates of Fusarium species (F. graminearum, F. oxysporum, F. avenaceum, F. nivale, F. solani and F. udum) was tested on durum (Simeto) cultivar of wheat by test tube method in the laboratory, the tested fungi had substantial effect on seed germination. F. oxysporum showed the highest germination failure (44.44%) which significantly differed with other species. In the greenhouse, seedlings were inoculated by spore suspension at the base of each plant stem. The most virulent fungus after 35 days of inoculation was F. oxysporum (0.78) followed by F. solani (0.70) and F. graminearum (0.66), while the lowest disease severity was recorded by F. udum (0.16). Also in the field pathogenicity experiments of three Fusarium species (F. graminearum, F. oxysporum and F. solani) were performed on a durum (Simeto) and soft (Cham6) cultivars. Spore suspension was applied at the 2- to 3-leaf Zadoks’s growth stage. Disease severity was calculated at two stages of wheat growth (Booting and Ripening).The most virulent fungus was F. graminearum (0.42) that was significantly different from  other fungi. This work indicated that F. graminearum, F. oxysporum and F. solani showed higher infection than remaining tested species under threeconditions. Pathogenicity test in laboratory by test tube method (In-vitro) appeared more effective than greenhouse and field experiments

scholarly journals PREHARVEST FOLIAGE SPRAYS OF SUGARCANE WITH 2,4-D

1969 ◽  
Vol 36 (3) ◽  
pp. 187-193
Author(s):  
M. A. Lugo-López ◽  
R. Grant
Keyword(s):  
Sodium Salt ◽  
Field Experiments ◽  
Small Deviations ◽  
Acid Basis ◽  
The Mean

Data are presented here on the effect of applications to sugarcane of 10, 20, and 30 pounds to the acre of the sodium salt of 2,4-D, acid basis, at three intervals (10, 20 and 30 days) prior to harvest. Field experiments were conducted at Humacao and Río Piedras following a randomized block layout. Each treatment was replicated six times. The mean available 96° sugar percent cane was 12.2 at both locations with very small deviations above or below it. No significant differences were observed between the mean Brix, polarization, purity, available 96° sugar percent cane, and tons of cane to the acre at either location.

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