WEED INFESTATION OF WINTER TRITICALE, DEPENDING ON AGRICULTURAL PRACTICES OF CULTIVATION

2016 ◽  
Vol 11 (3) ◽  
pp. 16-19
Author(s):  
Шашкаров ◽  
Leonid Shashkarov ◽  
Кузнецов ◽  
Leonid Kuznetsov
Keyword(s):  
Humus Content ◽  
Agricultural Practices ◽  
Growing Season ◽  
Soil Tillage ◽  
Winter Triticale ◽  
Perennial Weeds ◽  
Mobile Phosphorus ◽  
Significant Difference ◽  
Weed Infestation ◽  
Salt Extract

The investigations were carried out in 2014-2015, on a light gray forest heavy loamy soil. The humus content in the arable layer was 5.9%. The mobile phosphorus was 162 and exchangeable potassium was 172 mg per kilogram, respectively, pH of salt extract was 5.6. The total area of the plot was 200 m2, the discount area - 150 m2. Replication - fourfold, placing of plots was successive. Experience scheme: Factor A - preplant soil tillage: 1. Cultivation - 10-12 cm. 2. Milling – 10-12 cm. Factor B – fertilizers: 1. Without fertilizers (control). 2. Fertilizers, aimed to 4.0 tons per hectare (N120P75K90). The following varieties were used as the object of the study: Kornet, Kristal and Nemchinovskaya 56. The norms of fertilizers is calculated by the balance method, based on their removal from the crop and in the soil. The options, treated with a cultivator, were the most clogged. There are no significant difference among tested varieties of Kornet, Nemchinovskaya 56 and Kristal, but Nemchinovskaya 56 was the most clogged - 36 units per square meter, and less weedy was Cornet. When milling , the most clogged was Nemchinovskaya 56 variety - 30 units per square meter. In the way of without fertilization (control), Kristal variety was the most clogged - 21 units per square meter. The weed infestation of winter triticale at the beginning of growing season of Kristal variety was more to 21.3%, Nemchinovskaya 56 variety to 17% and Kristal to 21.6% more, than in milling. At the end of the growing season of winter triticale during cultivation the weeds increased by 71% and 74%. The same pattern was preserved debris perennial weeds early in the growing season 2.4-4.2 units per square meter, at the end of the growing season 4.6-4.7 units per square meter. The most clogged varieties were Nemchinovskaya 56 – 2.8-4.6 units per square meter and Kristal 2.7-4.7 units per square meter.

Dynamics of CO2 emission from chernozems under agricultural use

2017 ◽  
Vol 4 (3) ◽  
pp. 43-49
Author(s):  
M. Miroshnychenko ◽  
O. Siabruk
Keyword(s):  
Carbon Dioxide ◽  
Agricultural Practices ◽  
Growing Season ◽  
Warm Period ◽  
Direct Seeding ◽  
Soil Tillage ◽  
Plant Residues ◽  
Hydrothermal Conditions ◽  
Organic Mineral ◽  
Mineral System

Aim. The comparison of the effect of hydrothermal conditions and various agricultural practices on the emission of CO 2 from chernozems in the Left-Bank Forest-Steppe of Ukraine. Methods. The dynamics of the intensity of carbon dioxide emissions from chernozem calcic (typical chernozem – in Ukrainian classifi cation) was studied during the growing season of 2011–2012. The observations were based on two fi eld experiments with various methods of soil till- age (6–7 years from the beginning of the experiment) and fertilization systems (21–22 years from the beginning of the experiment). Particularly, plowing at 20–22 cm, disking at 10–12 cm, cultivation at 6–8 cm and direct seeding using Great Plains drill were studied among the soil tillage methods. Mineral system (N 45 P 50 K 45 ), organic system (manure 8 t/ha) and combined organic-mineral system (manure 8 t/ha + N 45 P 50 K 45 ) were studied among fertilization systems. The intensity of CO 2 fl ux was determined using the non-stationary respiratory chambers by the alkaline absorption method, with averaging of the results during the day and the frequency of once a month. Results. During the warm period, the emission of carbon dioxide from the soil changes dynamically depending on temperature and humidity. The maximum of emission coincides with the periods of warm summer showers in June-July, the minimum values are characteristic for the late autumn period. The total emission losses of carbon in chernozems over the vegetation period ranged from 480 to 910 kg/ha and varied depending on the methods of tillage ± (4.0–6.0) % and fertilization systems ± (3.8–7.1) %. The changes in the intensity of CO 2 emission from the soil under different methods of soil tillage are associated with hydrothermal regime and the depth of crop residues location. The biggest difference is observed im- mediately after tillage, but in the spring period the differences are only 12–25 %, and after drying of the top layer of soil become even less. Direct seeding technology provides the greatest emission of CO 2 from chernozem, which is fa- cilitated by better water regime and more complete mineralization of plant residues on the soil surface. Annual losses of carbon are the least under disking of soil at 10–12 cm. The changes in the intensity of CO 2 emission from the soil under different fertilization systems are associated with the involvement of the additional organic matter from plant residues and manure to the microbiological decomposition. The greatest emission was observed under the organic- mineral fertilization system, which increased the loss of carbon by 7–8 % in comparison with the mineral system in the unfavorable hydrothermal year and by 11–15 % in the more favorable year. These differences are observed mainly during the fi rst half of the growing season when there is a clear tendency to increase the intensity of soil respiration. Conclusions. The hydrothermal conditions of the warm period of the year are decisive in the formation of the CO 2 emission fl ow from chernozems. Due to the improvement of agricultural practices, emissions might be reduced but not more that by 15 % of natural factor contribution.

scholarly journals Influence of basic soil tillage methods on fresh yield and quality of winter rape cultivars

2020 ◽  
Vol 15 (4) ◽  
pp. 335-342
Author(s):  
Anvar Sh. Gadzhikurbanov
Keyword(s):  
Crop Yields ◽  
Maximum Yield ◽  
Soil Tillage ◽  
Flowering Stage ◽  
Winter Rape ◽  
Yield And Quality ◽  
Significant Difference ◽  
Weed Infestation ◽  
The Republic

The development of rational system of basic soil tillage results in formation of sufficiently high crop yields. A two-factor field experiment was carried out to address these issues when cultivating winter rape cultivars on light chestnut soils of the Primorsko-Caspian sub-province of the Republic of Dagestan. VEM (standard), Elvis and Meteor winter rape cultivars were studied in the experiment. The following methods of soil tillage were studied: real tillage (control), subsoil tillage. The research revealed that there was no significant difference in agrophysical indicators between the soil cultivation variants. Data on weed infestation of winter rape fields showed that the number of weeds and their weight increased significantly after subsoil tillage. At the budding stage, the number of weeds increased 2.1-fold compared to the control (real tillage), and the weight of weeds increased 1.88-fold. During flowering stage, these indicators were 2.2 times higher. The maximum yield in all variants of the experiment was formed by Elvis cultivar - 44.9 and 41.4 t/ha, respectively, which is more than VEM (standard) and Meteor cultivars by 20.4 t/ha (7.9 %) and 20.0 t/ha (8.7 %), respectively. The yield of Meteor cultivar in these variants was also high and amounted to 41.6 and 38.1 t/ha, respectively, which was higher by 11.5 and 10.4 % compared with the standard. The greatest increase in the fresh yield was provided by real tillage. On average, the yield increased by 8.7 % for varieties in comparison with subsoil cultivation. Elvis cultivar formed the best quality indicators, followed by Meteor cultivar.

scholarly journals Influence of winter wheat varieties and precursors on soil fertility, grain yield and quality in Stavropol territory

2020 ◽  
pp. 32-37
Author(s):  
Elena Vyacheslavovna Pismennaya ◽  
Margarita Yuryevna Azarova ◽  
Lyudmila Gennadievna Kurasova
Keyword(s):  
Winter Wheat ◽  
Soil Fertility ◽  
Humus Content ◽  
Wheat Yield ◽  
Chestnut Soil ◽  
Growing Season ◽  
Soil Density ◽  
Wheat Varieties ◽  
Mobile Phosphorus ◽  
Average Annual Temperature

Research was conducted on the basis of JSC "Agrohleboprodukt" branch "Agrokevsalinsky" Ipatovsky district of Stavropol territory in 2017-2019 to determine the feasibility of sowing varieties of soft winter wheat (Triticum aestivum L.) on sunflower and chickpeas with No-till technology. The production experience was carried out on an area of 3000 m2. The scheme of the experiment is 2-factors: varieties (factor A) – Zustrich (St.), Bagira, Bagrat; precursors (factor B) – sunflower and chickpeas. The climate of the zone is arid. The average annual temperature is 10.3°С. The average annual precipitation is 36.1 mm. The soil of the farm is dark chestnut carbonate heavy loam. Indicators of water resistance (for sunflower and chickpeas was 49.5 – 49.9 % and 66.7 – 68.2 % respectively) and the coefficient of structure (1.9 – 2.1 and 2.1 – 2.3 respectively) of dark chestnut soil before sowing varieties of winter wheat had optimal values for all predecessors. On average, the soil density for the growing season for sunflower is 1.28 g/cm3, chickpeas – 1.20 g/cm3. For varieties from sowing to the full ripeness phase, the soil density increases by 4.8 % and 2.5 % respectively. On average, the reserve of productive moisture for the growing season for sunflower is 64.7 g/cm3, chickpeas – 76.2 g/cm3. The greatest moisture availability is observed when sowing sunflower and chickpeas in the Bagrat variety – 66.2 mm and 78.8 mm respectively. The content of humus in the soils of the farm is 2.62 – 2.69 %, exchange potassium – 362.5 – 400.5 mg/kg; mobile phosphorus – 32.7 – 37.0 mg/kg; nitrogen – 13.4 – 13.9 mg/kg. In terms of humus content during the growing period, Bagrat varieties have the highest indicators for sunflower and legume precursors (2.62 % and 2.70 %), as well as for exchange potassium, mobile phosphorus and nitrogen (365.7 – 403.0 mg/kg; 33.2 – 37.4 mg/kg; 14.4 – 14.9 mg/kg). The average yield for sunflower and chickpea varieties is 4.44 t/ha and 4.67 t/ha respectively. Bagrat variety proved to be the most productive for both predecessors (for sunflower – 4.72 t/ha, for chickpeas – 5.00 t/ha) with high grain quality indicators (the amount of raw gluten – 27.1 %, nature – 726.4 g/l, vitreous – 86.3 %). The constructed trend models reflected a very high relationship between the predecessors, soil fertility indicators and winter wheat yield (r=1.0).

EFFICIENCY OF HERBICIDES APPLICATION AFTER SPROUTS OF THE MAIZE CORN SOWING

1970 ◽  
pp. 55-58
Author(s):  
V. Z. Venevtsev ◽  
M. N. Zaharova ◽  
L. V. Rozhkova
Keyword(s):  
Field Tests ◽  
Agricultural Practices ◽  
Vegetation Period ◽  
Control Plot ◽  
Soil Tillage ◽  
Corn Yield ◽  
Leached Chernozem ◽  
Weed Infestation ◽  
Average Loss ◽  
Stable Yield

In Ryazan region edaphoclimatic conditions allow to obtain stable yield of corn more than 19841,6 pounds of grain per hectare. Investigators consider that increasing of corn yield by 50% depends on availability of plant food compounds and pest, disease and weeds protection, by 25% from soil tillage quality and by 25% from varietal features of cultivated crop and hybrids. Weeds in the wide-row planting during the active vegetation period compete with crop for nutrients and moisture reserve in the soil. As a result of the institute multi-year research the average loss of corn yield from weeds without protection measurements is 30-50 %. The results of two-year field tests on the study of the herbicide usage effectiveness after corn germination are presented, to reduce the weed infestation of sowing and increase yields. The researches were carried out in the OOO “Svet”, Ryazhskiy district, Ryazan region. The soil is leached chernozem, the content of the humus is 5.2%, potassium and phosphorus- average, pH-6.0. The area of cultivated plot is 10.0 ha, control plot –0.2 ha, record plot – 107.64 sq. ft, number of replication – 4. The corn variety is Klarissa, sowing rate is 55.12 pounds per hectare, forecrop is winter wheat. Agricultural practices in the experience is application of 220.46 nitrophoska pound per hectare, 440.93 pounds per hectare of the ammonia nitrate, harrowing of the autumn plowing, cultivation, seeding with precision seeder. For weed protection of the corn seedlings in 2016 was applied herbicides tank mixture; Egida-48%, VDG (AVG – 0193)– 0.55 pound/ha + Dublon – 4%, SK – 0.26 gal/ha and  factory product Elyumis – 10.5%, MD – 1.32 hal/hа, in 2017 – Egida tank mixture, VDG – 0.44 pound/ha + Dublon, SK – 0.26hal/ha and Elyumis, MD – 0.26 hal/ha. It was found that the studied herbicides effectively reduced the weed infestation of crops and increased the yield of grain maize by 7936.64-12786.8 pound / ha.

scholarly journals Efficiency of herbicides application on barley depending on the soil tillage

2020 ◽  
Vol 50 (5) ◽  
pp. 19-27
Author(s):  
V. N. Timofeev ◽  
O. A. Vyushina
Keyword(s):  
Gray Forest Soil ◽  
Spring Barley ◽  
Growing Season ◽  
Soil Tillage ◽  
High Increase ◽  
Yield Level ◽  
Perennial Weeds ◽  
Tillage System ◽  
Herbicide Mixtures ◽  
Biological Effectiveness

The effect of the use of herbicide mixtures on the reduction of weeds and preservation of barley yield was studied. The experiment (2018–2019) was carried out on dark gray forest soil in the foreststeppe conditions ofTyumenregion. The experiment included two types of basic tillage: moldboard (plowing with a Lemken rotary plow at 20–22 cm) and non-moldboard (tillage with a Smaragd unit at 12–14 cm). The object of research was spring barley, Abalak variety. Biological effectiveness of herbicides, regardless of the soil tillage system, was 94–97% against dicotyledonous weeds, and 80–100% – against cereal and perennial weeds. Efficiency against the entire weed component reached 95–97.5% in 1 month after the application of herbicides, and 96–99% at the end of the growing season. The effectiveness of the use of preparations against cereal weeds was 80–90%, and the effectiveness of herbicides against dicotyledonous weeds – 97–99%. The reduction in the mass of weeds was 90–99%, mostly due to non-moldboard soil tillage. The yield level in the years of research largely depended on the soil tillage with a difference of 0.3–0.4 t in favor of moldboard system and the complex of herbicides applied. A high increase in the yield was provided by a mixture of herbicides Esteron, Speaker + Avantix Extra, Primadonna + Granat + Ovsyugen Super, which amounted to 1.16–1.22 t/ha. The application of comprehensive protection means increased the grain harvest by 1.7 t/ha.

scholarly journals The influence of different herbicide doses on weed infestation of winter triticale cultivated in monoculture

2012 ◽  
Vol 61 (2) ◽  
pp. 229-238
Author(s):  
Piotr Kraska
Keyword(s):  
Chenopodium Album ◽  
Humus Content ◽  
Dry Weight ◽  
Dry Mass ◽  
Infestation Level ◽  
Weighting Method ◽  
Mean Values ◽  
Winter Triticale ◽  
Loamy Sand Soil ◽  
Weed Infestation

The study was carried out in 2003-2005 in the Bezek Experimental Farm (University of Life Sciences in Lublin). The experimental field was situated on light loamy sand soil. The phosphorus content in soil was high, in potassium medium, in magnesium low. The humus content was 1.2%. The experiment was carried out in randomized blocks in three replications. The aim of the investigation was to compare three doses of herbicides in winter triticale canopy (Janko cv., Woltario cv., Krakowiak cv.) cultivated in monoculture. The herbicides Atlantis 04 WG and Factor 365 EC were applied at full recommended doses (200 g×ha<sup>-1</sup>), at doses reduced to 75% and 50%. The control was not treated with the herbicides. The weed infestation level was determined by means of the quantitative-weighting method at two dates: the first one at the 6th week after herbicide application and the second one before harvest. The density of weed individuals was counted; the species composition and air- dry biomass of above-ground parts were estimated from the randomly selected areas of 1 m x 0.25 m at four sites of each plot. The density of weeds and weed air dry weight were statistically analysed by means of variance analysis, and the mean values were estimated with Tukey's confidence intervals (p=0.05). It was found that the number of weeds and air dry mass of weeds in the control were significantly higher in comparison with the herbicide treated objects. The application of different doses of herbicides did not differentiate significantly the weed infestation level in the winter triticale canopy. <i>Viola arvensis</i>, <i>Matricaria maritima</i>, <i>Chenopodium album</i> and <i>Apera spicaventi</i> were dominant species of weeds in the winter triticale canopy. The selection of cultivars did not influence the canopy weed infestation level.

scholarly journals EFFECT OF CROP ROTATION WITH LUPINE AND BASIC SOIL CULTIVATION METHODS ON WEED INFESTATION OF SOWING IN BRYANSK REGION

2020 ◽  
Vol 2020 (3) ◽  
pp. 6-11
Author(s):  
Elena Isaeva ◽  
German YaGOVENKO ◽  
Olga Pedosich
Keyword(s):  
Winter Wheat ◽  
Crop Rotation ◽  
Gray Forest Soil ◽  
Surface Soil ◽  
White Lupin ◽  
Soil Cultivation ◽  
Winter Triticale ◽  
Perennial Weeds ◽  
South West ◽  
Weed Infestation

Tests have been done on gray forest soil in the South-West of the Non-Chernozem zone of Bryansk re-gion in the stationary experiment in the All-Russian Lupin Research Institute in 2015–2018. The aim of the test was to evaluate the effect of the intensity of the basic soil cultivation on crop weed infestation in lupin crop rotation. The experiment has been done during a rotation of the field crop rotation (winter wheat – bare oats – winter triticale – lupin) turned in time and space in the fields of white lupin and win-ter wheat where lupin has been cultivated as a predecessor. During the test years 7 weeds species have been fixed at tillering phase of winter wheat, its number made 9.4–15.4 units/m2. The number of the main weeds decreased to 11 species at the end of the vegetation season (at ripeness stage) and made 9.7–15.9 units/m2. There have been noticed 8 weeds species in white lupin crops, the number made 33.6–55.8 units/m2. The deep non-moldboard soil cultivation decreased weeds number in crop rotation. At dif-ferent basic soil cultivation 8 weeds species occurred in crops. The others were either in the deep non-moldboard soil cultivation or in the surface one. The number and ratio of weeds species changed when the grass component increased to the final field of crop rotation. The annual dicotyledonous species made 45.0–60.5% decreasing at the surface cultivation. Perennial weeds made 38.5–55.0% of the total weeds coenosis. Their number decreased in the case of deep cultivation. Crop infestation degree and as a result the weeds twice during the rotation at the surface soil cultivation.

scholarly journals Effects of disk tillage on soil condition, crop yield and weed infestation

2011 ◽  
Vol 48 (No. 1) ◽  
pp. 20-26
Author(s):  
M. Birkás ◽  
T. Szalai ◽  
C. Gyuricza ◽  
M. Gecse ◽  
K. Bordás
Keyword(s):  
Winter Wheat ◽  
Crop Yield ◽  
Field Experiments ◽  
Soil Layer ◽  
Soil Condition ◽  
Perennial Weeds ◽  
Weed Infestation ◽  
Set Up ◽  
Different Levels

This research was instigated by the fact that during the last decade annually repeated shallow disk tillage on the same field became frequent practice in Hungary. In order to study the changes of soil condition associated with disk tillage and to assess it is consequences, long-term tillage field experiments with different levels of nutrients were set up in 1991 (A) and in 1994 (B) on Chromic Luvisol at G&ouml;d&ouml;ll&ouml;. The effects of disk tillage (D) and disk tillage combined with loosening (LD) on soil condition, on yield of maize and winter wheat, and on weed infestation were examined. The evaluation of soil condition measured by cone index and bulk density indicated that use of disking annually resulted in a dense soil layer below the disking depth (diskpan-compaction). It was found, that soil condition deteriorated by diskpan-compaction decreased the yield of maize significantly by 20 and 42% (w/w), and that of wheat by 13 and 15% (w/w) when compared to soils with no diskpan-compaction. Averaged over seven years, and three fertilizer levels, the cover % of the total, grass and perennial weeds on loosened soils were 73, 69 and 65% of soils contained diskpan-compaction.

Selection of drought-resistant crops for South Steppe of Ukraine

2021 ◽  
Vol 5 (1) ◽  
pp. 13-22
Author(s):  
V. V. Gamayunova ◽  
L. H. Khonenko ◽  
M. I. Fedorchuk ◽  
O. A. Kovalenko
Keyword(s):  
Humus Content ◽  
Soil Layer ◽  
Weather Conditions ◽  
Growing Season ◽  
Grain Sorghum ◽  
Climatic Conditions ◽  
Mineral Fertilizers ◽  
Chemical Application ◽  
Sowing Dates ◽  
Drought Resistant

The cultivation expediency of more drought-resistant crops, in particular sorghum, millet, false flax, safflower and others, instead of sunflower in the area of the Southern Steppe of Ukraine is substantiated. This is, first of all, required by climate change both in Ukraine and in the world. Since 2004, researches of field crops were carried out in the conditions of the Educational and Scientific Practical Center of the Mykolaiv National Agrarian University. Soil phase is the southern chernozem with humus content in the 0–30 cm soil layer which consist of 2.96–3.21 %, with medium and high level of availability of mobile phosphorus and potassium and low – mobile nitrogen. Experiments with soriz (Oksamyt hybrid) were conducted during 2004–2006, millet (Tavriiske, Kostantynivske, Skhidnevarieties) in 2008–2010, grain sorghum (Stepovyi 5 hybrid) in 2014–2016, safflower dye (Lahidnyi variety) in 2017–2019. The years of research differed significantly in temperature and even more in the amount of precipitation before sowing and during the growing season of crops. However, the weather conditions were typical of the Southern Steppe zone of Ukraine. It is established that all studied drought-resistant crops respond positively to nutrition optimization – the level of yield and quality of grain or seeds increases. It was found that the soriz productivity depending on the application of fertilizers and sowing dates increased by 37.6–39.2 %, millet –by 33.3–41.6 %, grain sorghum depending on the background of nutrition and growing conditions – by 8.2–33.2 %, dye safflower – by 11.1–64.6 %. It was determined that the optimization of nutrition of cultivated crops allows to increase their resistance to adverse conditions and productivity in the case of application of low doses of the mineral fertilizers before sowing, pre-sowing treatment of seeds, and growth-regulating chemical application of plants on the main stages of the growing season. Key words: drought-resistant plants, climatic conditions, nutrition optimization, yield, crop quality, varieties, sowing dates.

Developing an Empirical Yield-Prediction Model Based on Wheat and Wild Oat (Avena fatua) Density, Nitrogen and Herbicide Rate, and Growing-Season Precipitation

Weed Science ◽  
2007 ◽  
Vol 55 (6) ◽  
pp. 652-664 ◽  
Author(s):  
N. C. Wagner ◽  
B. D. Maxwell ◽  
M. L. Taper ◽  
L. J. Rew
Keyword(s):  
Field Data ◽  
Wheat Yield ◽  
Growing Season ◽  
Predictor Variables ◽  
Data Sets ◽  
Wild Oat ◽  
Best Fitting ◽  
Weed Infestation ◽  
Growing Season Precipitation ◽  
Better Than

To develop a more complete understanding of the ecological factors that regulate crop productivity, we tested the relative predictive power of yield models driven by five predictor variables: wheat and wild oat density, nitrogen and herbicide rate, and growing-season precipitation. Existing data sets were collected and used in a meta-analysis of the ability of at least two predictor variables to explain variations in wheat yield. Yield responses were asymptotic with increasing crop and weed density; however, asymptotic trends were lacking as herbicide and fertilizer levels were increased. Based on the independent field data, the three best-fitting models (in order) from the candidate set of models were a multiple regression equation that included all five predictor variables (R2= 0.71), a double-hyperbolic equation including three input predictor variables (R2= 0.63), and a nonlinear model including all five predictor variables (R2= 0.56). The double-hyperbolic, three-predictor model, which did not include herbicide and fertilizer influence on yield, performed slightly better than the five-variable nonlinear model including these predictors, illustrating the large amount of variation in wheat yield and the lack of concrete knowledge upon which farmers base their fertilizer and herbicide management decisions, especially when weed infestation causes competition for limited nitrogen and water. It was difficult to elucidate the ecological first principles in the noisy field data and to build effective models based on disjointed data sets, where none of the studies measured all five variables. To address this disparity, we conducted a five-variable full-factorial greenhouse experiment. Based on our five-variable greenhouse experiment, the best-fitting model was a new nonlinear equation including all five predictor variables and was shown to fit the greenhouse data better than four previously developed agronomic models with anR2of 0.66. Development of this mathematical model, through model selection and parameterization with field and greenhouse data, represents the initial step in building a decision support system for site-specific and variable-rate management of herbicide, fertilizer, and crop seeding rate that considers varying levels of available water and weed infestation.

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