Some effects of nitrification inhibitor (2-chloro-6(trichloromethyl)pyridine) on the use of fertilizer nitrogen and the growth of two wheat varieties

1977 ◽  
Vol 17 (87) ◽  
pp. 645 ◽  
Author(s):  
GJ Osborne

A glasshouse experiment was done at Wagga Wagga, New South Sales to assess the value of a nitrification inhibitor2-chloro-6-(trichloromethyl)-pyridine ('N-serve' (R)) as a means of slowing down the rate of nitrification of ammonium added to a red earth soil. The effect of this chemical on the growth of a standard height and a semi-dwarf wheat variety was also assessed. The results indicate that a concentration of only 5 p.p.m. of the inhibitor in this soil slowed down the rate of nitrification of ammonium for up to 140 days. Although 'N-serve' was apparently phytotoxic to volunteer ryegrass and clover at the 5 p.p.m. level, the yield of wheat dry-matter after 60 days and grain at harvest were not significantly affected by concentrations of up to 10 p.p.m. in the soil. However, at the 10 p.p.m, level of inhibitor maturity was delayed.

Weed Science ◽  
1996 ◽  
Vol 44 (3) ◽  
pp. 634-639 ◽  
Author(s):  
Deirdre Lemerle ◽  
Birgitte Verbeek ◽  
Neil E. Coombes

The influence of wheat variety on the dose-response of annual ryegrass to diclofop-methyl (POST) was examined in the field in 1992 and 1993 in southern New South Wales, Australia. The aim was to determine if planting a strongly competitive variety of wheat improved control of annual ryegrass at reduced doses of diclofop-methyl. Suppression of ryegrass was dependent on herbicide dose, season, and wheat variety. In the absence of herbicide, dry matter (DM) production of annual ryegrass at 300 plants m−2at anthesis was 500 g ha−1with Dollarbird and Katunga compared to 1000 g ha−1with Rosella or Shrike in 1992. In 1993, DM was approximately 150 g ha−1with Dollarbird or Katunga, and 350 g ha−1with Shrike or Rosella. Ryegrass DM was reduced by diclofop-methyl to a greater extent, relative to the weedy unsprayed controls, with less competitive varieties Rosella and Shrike than with the more competitive Dollarbird or Katunga. Diclofop-methyl at 0.28 kg a.i. ha−1reduced DM of ryegrass growing with Katunga to less than 100 g m−2in 1992, compared to more than 200 g m2with the other varieties. In 1993, diclofop-methyl was more effective on ryegrass, and the same dose reduced ryegrass DM to almost zero in all varieties. Grain yields in unsprayed weedy controls of Dollarbird and Katunga were reduced approximately 20% by annual ryegrass compared with yields achieved with herbicides in both years. Yields of Rosella and Shrike in the unsprayed controls were reduced about 40% in 1992 and 60% in 1993. Only small increases in grain yields of all varieties occurred from diclofop-methyl doses above 0.13 kg a.i. ha−1. Poorly competitive varieties were dependent on herbicides to achieve grain yield potential and had a greater risk of weed survival when herbicide efficacy was reduced. In contrast, strongly competitive varieties, likely to retard build-up of weed seed in the soil, are less dependent on herbicides to achieve grain yield potential, and therefore result in reduced weed control cost.


1990 ◽  
Vol 30 (2) ◽  
pp. 183 ◽  
Author(s):  
G Annison

The polysaccharide compositions of 20 wheat varieties from New South Wales and Western Australia were determined. Mean pentosan and �-glucan contents ranged from 5.7 1 to 8.18% and from 0.61 to 0.87% respectively, on a dry matter basis. Starch contents ranged from 61.5 to 68.9% and the wheat starches were between 21.1 and 31.8% amylose. The starch digestibility of the wheats was found to be independent of the levels or composition of the polysaccharides when assayed using 5-week-old broiler chickens.


1994 ◽  
Vol 34 (8) ◽  
pp. 1137 ◽  
Author(s):  
DP Heenan

Cultivars of lupin and field pea were grown at different times over 4 years on a red earth at Wagga Wagga, New South Wales, to assess the influence of sowing time on growth and production from each crop. The cultivars of field pea (Pisum sativum) included Dinkum, Derrimut, Dunn, and Maitland; lupins used were Lupinus angustifolius cvv. Danja, Gungurru, and Geebung, and either the L. angustifolius line 75A/330 (1989-90) or L. albus cv. Ultra (1991-92). When autumn rain was sufficient to allow sowing, highest yield and dry matter production of lupin were gained by sowing from late April to 19 May. Yields declined with later sowing, though high spring-summer rainfall in 1992 reversed the decline. There was little difference between Danja, Gungurru, and Geebung, but these were usually higher yielding than the semi-dwarf 75Al330 when sown early. However, Ultra produced higher yields than the L. angustifolius cultivars in 1991 and 1992, particularly under high rainfall conditions. Early-sown crops (late April-mid May) of field peas were often severely infected with black spot blight and, in 1 year, with sclerotinia. In 1992 these diseases devastated all cultivars when sown on 1 May. Sowing later markedly reduced disease infection but also reduced grain yields and dry matter when sown after late June. The semi-leafless, semi-dwarf cultivar Dinkum was usually the lowest yielding and displayed the highest incidence of black spot blight.


1991 ◽  
Vol 31 (5) ◽  
pp. 683 ◽  
Author(s):  
KY Chan ◽  
DP Heenan

The effects of lupin, field pea, barley, canola, linseed and lentil crops on the surface (0-0.10 m) aggregation of a red earth at Wagga Wagga, New South Wales, were investigated in the field under identical cultivation and agronomic practices. Soil friability after cropping was in the order lupin > lentil > canola > field pea = linseed > barley. Both lupin and canola cropping produced significantly stronger aggregates (measured as tensile strength of the aggregates) than barley, lentil and field pea. There was no significant difference (P>0.05) in water-stable macro-aggregation after growing the different crops. However, there was a significant (P<0.05) correlation between the tensile strength of the aggregates and amount of dispersed clay released from moist soil (-10 kPa), possibly indicating different abilities of crops to modify soil bondings affecting aggregate strength.


2014 ◽  
Vol 40 (1) ◽  
pp. 134 ◽  
Author(s):  
Yong-Lu TANG ◽  
Chao-Su LI ◽  
Chun WU ◽  
Xiao-Li WU ◽  
Gang HUANG ◽  
...  

2021 ◽  
Vol 3 (1) ◽  
pp. 29-49
Author(s):  
Ghizlane Astaoui ◽  
Jamal Eddine Dadaiss ◽  
Imane Sebari ◽  
Samir Benmansour ◽  
Ettarid Mohamed

Our work aims to monitor wheat crop using a variety-based approach by taking into consideration four different phenological stages of wheat crop development. In addition to highlighting the contribution of Red-Edge vegetation indices in mapping wheat dry matter and nitrogen content dynamics, as well as using Random Forest regressor in the estimation of wheat yield, dry matter and nitrogen uptake relying on UAV (Unmanned Aerial Vehicle) multispectral imagery. The study was conducted on an experimental platform with 12 wheat varieties located in Sidi Slimane (Morocco). Several flight missions were conducted using eBee UAV with MultiSpec4C camera according to phenological growth stages of wheat. The proposed methodology is subdivided into two approaches, the first aims to find the most suitable vegetation index for wheat’s biophysical parameters estimation and the second to establish a global model regardless of the varieties to estimate the biophysical parameters of wheat: Dry matter and nitrogen uptake. The two approaches were conducted according to six main steps: (1) UAV flight missions and in-situ data acquisition during four phenological stages of wheat development, (2) Processing of UAV multispectral images which enabled us to elaborate the vegetation indices maps (RTVI, MTVI2, NDVI, NDRE, GNDVI, GNDRE, SR-RE et SR-NIR), (3) Automatic extraction of plots by Object-based image analysis approach and creating a spatial database combining the spectral information and wheat’s biophysical parameters, (4) Monitoring wheat growth by generating dry biomass and wheat’s nitrogen uptake model using exponential, polynomial and linear regression for each variety this step resumes the varietal approach, (5) Engendering a global model employing both linear regression and Random Forest technique, (6) Wheat yield estimation. The proposed method has allowed to predict from 1 up to 21% difference between actual and estimated yield when using both RTVI index and Random Forest technique as well as mapping wheat’s dry biomass and nitrogen uptake along with the nitrogen nutrition index (NNI) and therefore facilitate a careful monitoring of the health and the growth of wheat crop. Nevertheless, some wheat varieties have shown a significant difference in yield between 2.6 and 3.3 t/ha.


2019 ◽  
Vol 11 (12) ◽  
pp. 3378
Author(s):  
Charity Ruramai Nhemachena ◽  
Johann F. Kirsten ◽  
Binganidzo Muchara

The strengthening of the intellectual property rights (IPRs) for plant varieties provide incentives for breeding companies to invest more resources in plant breeding. The main objective of this paper was to analyze the effects of strengthening the wheat variety intellectual protection on wheat productivity and the release of new varieties. The strength of IPR systems was measured using an intellectual property (IP) protection index, and plant breeders’ rights (PBRs) granted for wheat varieties. The empirical analyses were based on correlation and multiple regression analyses. The results showed that strengthening IPR systems in South Africa contribute to improving wheat productivity and increasing the number of wheat varieties released. Furthermore, although the robust coefficients of the other IPR variables are positive, they are statistically insignificant for all scenarios. There is a need for more incentives beyond granting PBRs and strengthening of IPR systems to be provided in the whole wheat sector to stimulate increased investments and the release of new varieties.


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