**3. Results and discussion**

#### **3.1 The vegetative cycle and the productivity characters of** *Echinochloa crus-galli* **in accordance to rising period**

The biological particularities of weeds make them be superior to the cultivated plants, as they use more effective the vegetation conditions and the afferent inputs of an agricultural area. *Echinochloa crus-galli* is an annual monocotyledonous species, which germinates late in spring. This species is spread onto extensive areas in the world, covering all continents between 500 northern latitude and 40o southern latitude. In Romania there is plenty of it in all regions, prevailing in the south western part of the country (90%) and in the eastern part (75%). In the other areas, the species varies between 9% (Dobrogea) and 57% (Transylvania). It is very harmful for hoed cultures. In the Cluj County, *Echinochloa crus-galli* represents between 36% and 52% of the weedy rate of the hoed cultures. *Echinochloa crus-galli* produces big damages in Romania's agriculture: in maize – over 70%, in rice – 60 – 65%; in sunflower – 30%; in soybean – 15 – 20%, in sugar beet 25%, in wheat – 10%, in flax – 10%.

In autumn or early spring sowed cultures (that cover the soil to a large extent) *Echinochloa crus-galli* hardly forms a small stem, but when the cultures are harvested off the field, the weed heavily sprouts and it produces a large amount of seeds as it has more space, light, nutrition and moisture.

The high ecological plasticity and adaptability of this species, completed by the possibility of flourishing in a wide range of photoperiods are biological particularities of *Echinochloa crusgalli.*

The plants rising takes place monthly in different percentages until September, when the rising is reduced. The rising period is of 8 – 16 days since the sowing depending on the

Experience was held between 2008 and 2009. Biological material was the hybrid Turda 201, recommended for this area of culture. The research was done on two agrofonds: unfertilized

In the unfertilized maize crop were made four variants (I-IV) with different degrees of infestation with *Echinochloa crus-galli*, from about 40 to 100 plants/m2 and witness – 2

In fertilized plots were used the next herbicides for weed control: V1 - dimetenamid 900 g/l – 2 l/ha applied p.p.i. (pre plant incorporated). V2 - acetoclor 860 g/l – 2 l/ha applied preemergent. V3 - isoxaflutol 750 g/l – 0.15 g/ha, applied p.p.i. + (bentazon 320 g/l +

Herbicide application was made with the pomp for experience, applying 300 l solution/ha. The experience was organized after randomized blocks method, in four repetitions and area of a plot is 25 m2. Competition between corn plants and weeds present was studied in natural density infestation, in unfertilized plots and in those fertilized in which the process of herbicides took place. Weed biomass, corn plants and grain production was measured in the ripening stage. Samples of plants and weeds were harvested using metric frame of 50/50

**3.1 The vegetative cycle and the productivity characters of** *Echinochloa crus-galli* **in** 

The biological particularities of weeds make them be superior to the cultivated plants, as they use more effective the vegetation conditions and the afferent inputs of an agricultural area. *Echinochloa crus-galli* is an annual monocotyledonous species, which germinates late in spring. This species is spread onto extensive areas in the world, covering all continents between 500 northern latitude and 40o southern latitude. In Romania there is plenty of it in all regions, prevailing in the south western part of the country (90%) and in the eastern part (75%). In the other areas, the species varies between 9% (Dobrogea) and 57% (Transylvania). It is very harmful for hoed cultures. In the Cluj County, *Echinochloa crus-galli* represents between 36% and 52% of the weedy rate of the hoed cultures. *Echinochloa crus-galli* produces big damages in Romania's agriculture: in maize – over 70%, in rice – 60 – 65%; in sunflower

In autumn or early spring sowed cultures (that cover the soil to a large extent) *Echinochloa crus-galli* hardly forms a small stem, but when the cultures are harvested off the field, the weed heavily sprouts and it produces a large amount of seeds as it has more space, light,

The high ecological plasticity and adaptability of this species, completed by the possibility of flourishing in a wide range of photoperiods are biological particularities of *Echinochloa crus-*

The plants rising takes place monthly in different percentages until September, when the rising is reduced. The rising period is of 8 – 16 days since the sowing depending on the

– 30%; in soybean – 15 – 20%, in sugar beet 25%, in wheat – 10%, in flax – 10%.

**2.3 Influence of degree infestation with** *Echinochloa crus–galli* **species on crop** 

**production in corn** 

holings.

cm.

and mineral fertilized (MF) with NPK 100 kg/ha.

dicamba 90 g/l) – 2 l/ha applied postemergent.

**3. Results and discussion** 

**accordance to rising period** 

nutrition and moisture.

*galli.*

temperatures. The correlations established between the soil temperature conditions and the *Echinochloa crus-galli* plants rising are very significantly positive. From the specific equations for the experiment years result that the percentage of the plants that are rising is increasing by 5.75 – 6.87 per 1 0C of the soil temperature - beginning with 80C, the minimum germination temperature.

The plants' growth varies according to the rising period. So, the plants that rise up during the second half of April pass through each specific vegetative stage for a longer period comparing to the ones that rise up during the next months – when the temperatures increase (Table 2).


\*This information is specific for the main stem. The shoots pass progressively these stages after the main stem.

Table 2. The period in days passed by a *Echinochloa crus-galli* plant from it's rising to each vegetative stage (the average period for the years 2004 – 2007 on Cluj-Napoca conditions).

The daytime influences the flourishing period so that the plants that rise later (July, August) reach the flourishing phase in a much shorter period (48 -54 days), comparing to the plants that rise in April (83 days). The shorter days of late August and early September stimulate precocious flourishing and ageing.

The caryopses are maturating in a 20 – 30 days period, after heading (depending on the rising period).

The first panicle dissemination is taking place during 10 -16 August for the plant that rose in April; 15 – 19 August for those that rose in May (first decade); 28-30 August for those that rose in June; 25 – 28 September for the plants that rose in July and 15 – 18 October for those that rose in August.

At the beginning of September the first plants dry out; they are those that rose in April, while those that rose in August dry out at the end of October.

The vegetative cycle of *Echinochloa crus-galli* plants is taking place in summer (Fig. 1). It begins in April for the plants sowed in April and it ends in August. But the cycle for the plants sowed in August, it ends in October.

Influence of Degree Infestation

seeds comparing to the plants height.

**density** 

LSD 5% 1% 0.1%

for the next cultures.

with *Echinochloa crus–galli* Species on Crop Production in Corn 459

There have been variations of the productivity characters among the 4 experimentation

The climate of 2006 and 2007 significantly influenced the productivity characters of this species. So, during 2006 – the wealthiest in precipitation, the vegetative growth of the *Echinochloa crus-galli* plants was impressive: the maximum height was 218 cm, the shoots number was 49, and the developed panicles number was 45. During 2007 – when it was drought, there were the lowest values for the vegetative growth, but there were a lot of

**3.2 The productivity features variation of** *Echinochloa crus-galli* **in accordance to** 

year when the medium difference of height was significantly negative was 2007.

The productivity features variations of *Echinochloa crus-galli* depend by the plants density to

The height of the plants is strongly influenced by density, increasing significantly to a low density (2 plants/m² than 3 plants/m²) and a high one (50 plants/m² than 3 plants/m²) due to a strong shading and lack of light (Table 4). This feature (height) did not present a constant variation regarding the climatic conditions specific the experiment years, the single

Density / Year 2004 2005 2006 2007 Average 50 plants/m2 172.6\*\*\* 135.6\*\*\* 184.5\* 65.8ooo 139.6\*\*\* 10 plants/m2 159.8\*\*\* 120.1\*\*\* 158.6ooo 76.3oo 128.7ns 5 plants/m2 142.2oo 101.3oo 180.2o 81.4\*\* 126.3ns 2 plants/m2 152.6\*\*\* 118.9\*\*\* 205.6\*\*\* 84.2\*\*\* 140.3\*\*\* Control 3 pl/m2 145.6 103.5 182.4 78.5 127.5

> 1.19 1.70 2.46

The other characters of productivity are strongly influenced by the plants density on the surface unit. Between 3 and 5 plants /m² it is achieved a close tillering, panicles number, panicles length and seeds number, with no significant differences while the density growing is 5 plants bigger on the surface unit all these conditions are decreased to limits between signification negative to very signification negative. The density attenuation under 3 plants

The danger that this plant represents even to a reduced infestation of the cultures comes from the possibility of achievement both a high biomass through the vegetative growing elongation, and a very high production of seeds that will represent the source of weeding

The influence of the nutritional space size and development is very strong upon this species *Echinochloa crus-galli.* The tillering, the panicles number and panicles length are very

1. 58 2.24 3.25

1.41 2.01 2.91 1.75 2.48 3.56

years, according to the temperatures and the pluviometric quantities.

surface unit and climatic conditions specific to experimental years.

1.85 2.63 3.80

Note: ns – not significant, \* signification positives, 0 signification negatives

Table 4. The height of *Echinochloa crus-galli* (cm) in accordance to density.

on square metre has as effect the growing of the species productivity potential.

significantly reduced to densities bigger than 5 plants per surface unit (Table 5).

The length of the vegetation period for a plant and the productivity characters (the height, the shoots number, the panicles number, the panicles' length, the caryopsis number of a plant, the bio weight) are reduced as the plants' rising is late (Table 3).

Fig. 1. The growth cycle of *Echinochloa crus-galli* (L.) P.B. on Cluj-Napoca conditions.

The variation of the vegetation period of this species (85 – 140 days) reflects the extraordinary flexibility and the excellent adaptability of *Echinochloa crus-galli* in different environment conditions.

The plants height decreases from 170 cm (the plants that rose in April) to 55 cm (the plants that rose in August). The vegetative growths are reduced as the vegetative period is decreasing and the daily average temperatures are increasing. The plants that rise in spring (April, May) grow and tiller very intensely, they reach considerable heights as a consequence of late flourishing, as the daytime is longer.

The roots of the early plants grow more intensely.

The whole weight reaches impressive values for the long vegetation period plants; it decreases drastically for the plants that rose late. The seeds production decreases as the vegetative periods diminish. It is notable that *Echinochloa crus-galli* seeds production is important (8435 caryopsis/plant) even for the plants that rose in August.


Table 3. The vegetation period and the productivity features of *Echinochloa crus-galli*  depending on the rising period on Cluj-Napoca conditions.

The length of the vegetation period for a plant and the productivity characters (the height, the shoots number, the panicles number, the panicles' length, the caryopsis number of a

Fig. 1. The growth cycle of *Echinochloa crus-galli* (L.) P.B. on Cluj-Napoca conditions.

consequence of late flourishing, as the daytime is longer.

depending on the rising period on Cluj-Napoca conditions.

important (8435 caryopsis/plant) even for the plants that rose in August.

The roots of the early plants grow more intensely.

environment conditions.

The variation of the vegetation period of this species (85 – 140 days) reflects the extraordinary flexibility and the excellent adaptability of *Echinochloa crus-galli* in different

The plants height decreases from 170 cm (the plants that rose in April) to 55 cm (the plants that rose in August). The vegetative growths are reduced as the vegetative period is decreasing and the daily average temperatures are increasing. The plants that rise in spring (April, May) grow and tiller very intensely, they reach considerable heights as a

The whole weight reaches impressive values for the long vegetation period plants; it decreases drastically for the plants that rose late. The seeds production decreases as the vegetative periods diminish. It is notable that *Echinochloa crus-galli* seeds production is

The rising period/The features April May June July August The vegetative period (days) 135-140 125-130 115-120 95-100 85-90 The plants height (cm) 150-170 140-150 120-130 90-105 55,75 Number of shoots 23-25 19-25 16-18 12-14 13-15 Number of panicles 27-31 20-24 16-18 10-16 12-14 The length of the panicles (cm) 12.5-20.4 11.2-18.5 8.5-10.6 7.5-9.4 5.6-7.2 Number of seeds (average/plant) 15794 13406 10898 8762 8435 The length of the roots (cm) 39-45 35-38 30-34 24-27 13-16 Bioweight (gr./plant – herb weight) 895 794 586 338 212

Table 3. The vegetation period and the productivity features of *Echinochloa crus-galli* 

plant, the bio weight) are reduced as the plants' rising is late (Table 3).

There have been variations of the productivity characters among the 4 experimentation years, according to the temperatures and the pluviometric quantities.

The climate of 2006 and 2007 significantly influenced the productivity characters of this species. So, during 2006 – the wealthiest in precipitation, the vegetative growth of the *Echinochloa crus-galli* plants was impressive: the maximum height was 218 cm, the shoots number was 49, and the developed panicles number was 45. During 2007 – when it was drought, there were the lowest values for the vegetative growth, but there were a lot of seeds comparing to the plants height.

#### **3.2 The productivity features variation of** *Echinochloa crus-galli* **in accordance to density**

The productivity features variations of *Echinochloa crus-galli* depend by the plants density to surface unit and climatic conditions specific to experimental years.

The height of the plants is strongly influenced by density, increasing significantly to a low density (2 plants/m² than 3 plants/m²) and a high one (50 plants/m² than 3 plants/m²) due to a strong shading and lack of light (Table 4). This feature (height) did not present a constant variation regarding the climatic conditions specific the experiment years, the single year when the medium difference of height was significantly negative was 2007.


Note: ns – not significant, \* signification positives, 0 signification negatives

Table 4. The height of *Echinochloa crus-galli* (cm) in accordance to density.

The other characters of productivity are strongly influenced by the plants density on the surface unit. Between 3 and 5 plants /m² it is achieved a close tillering, panicles number, panicles length and seeds number, with no significant differences while the density growing is 5 plants bigger on the surface unit all these conditions are decreased to limits between signification negative to very signification negative. The density attenuation under 3 plants on square metre has as effect the growing of the species productivity potential.

The danger that this plant represents even to a reduced infestation of the cultures comes from the possibility of achievement both a high biomass through the vegetative growing elongation, and a very high production of seeds that will represent the source of weeding for the next cultures.

The influence of the nutritional space size and development is very strong upon this species *Echinochloa crus-galli.* The tillering, the panicles number and panicles length are very significantly reduced to densities bigger than 5 plants per surface unit (Table 5).

Influence of Degree Infestation

LSD 5% 1% 0.1%

LSD 5% 1% 0.1%

plants/m².

**maize crop** 

0.56 0.79 1.15

457.05 649.71 940.74

(Table 8).

with *Echinochloa crus–galli* Species on Crop Production in Corn 461

precipitations, when the productive potential of the species is directed to vegetative features

Density/Year 2004 2005 2006 2007 Average 50 plants/m2 11.4ooo 11.3ooo 12.2ooo 10.3ooo 11.3ooo 10 plants/m2 14.1ooo 13.4o 14.3ooo 12.1ooo 13.5ooo 5 plants/m2 16.1ns 13.6ns 16.2ns 13.4ns 14.8ns 2 plants/m2 16.4ns 15.1\*\*\* 17.1\* 14.9\* 15.9\* Control 3 pl/m2 16.1 13.9 16.4 13.9 14.85

> 0.43 0.61 0.89

Table 7. The length of panicles on *Echinochloa crus-galli* (cm) in accordance to density.

Density/Year 2004 2005 2006 2007 Average 50 plants/m2 1,289ooo 1,216ooo 1,482000 2,105ooo 1,523ooo 10 plants/m2 9,462ooo 8,324ooo 9,874ooo 7,304ooo 8741ooo 5 plants/m2 13,821ooo 10,918ns 12,956ooo 10,021oo 12,179oo 2 plants/m2 15,659ns 12,164\* 16,102ns 11,434\* 13,840ns Control 3 pl/m2 15,208 11,303 16,018 10,795 13,406

> 667.1 948.3 1,373.1

The productivity features of *Echinochloa crus-galli* suffer changes in accordance to the weed density per unit surface, to high densities the increasing in high are very visible while the tillering, panicles number, panicles length and the number of seeds produced by a plant are reduced very significant. Between 2 and 5 plants of *Echinochloa crus-galli* /m2, the productivity parameters vary in more reduced limits, being in the most cases the consequence of the climatic conditions of the experimentation years. The inter specific concurrency is felt even when speaking about the increasing with one plant per surface unit, but this one becomes hypercriticalism in case of density growing with more than 5

Table 8. The number of seeds/plant on *Echinochloa crus-galli* in accordance to density.

**3.3 Influence of degree infestation with** *Echinochloa crus–galli* **species upon the** 

*Echinochloa crus-galli* is known as a weed which germinate in late spring, invades especially weeding crops on wetlands, fattened with manure, grows very quickly, suppress and compromise the culture. Precipitation in April - May 2009 (102 mm in April compared to 47 mm multiannual average and 105 mm in May compared to 76 mm) have delayed corn seeding until the end of the optimal period and promoted the accumulation of moisture in the soil of 30% on average depth from 0 to 50 cm and a reserve of water on the same depth of 977 m3/ha. Under these conditions, sown late, high humidity, fertilization in the last year

0.63 0.83 1.29

669.8 952.1 1,378.7 0.73 1.04 1.52

511.3 731.08 1,058.5 0.65 1.25 1.56

678.6 973.4 1,354.8

The differences that appear among the years represent a consequence of species adaptability for adjustment conditions of the productivity in accordance to climatic conditions. If during the rainy years the tillering is influenced from distinctive significant to very negative significant by plants density growing with 2 samples per surface unit, during the very dry year – 2007 - this condition does not suffer any adjustment having a significant growing by density increasing with 2 plants per surface unit. The explanation of this fact is found into the high capacity of tillering of this species when the height growing is diminuated.


Table 5. The tillering per plant on *Echinochloa crus-galli* in accordance to density.

The number of panicles per plant (table 6) follows, in general, the same tendency of a very significant decreasing to densities bigger than 5 plants per surface unit and increasing or decreasing from insignificant to very significant in the situation of a density increasing with only 2 plants, in accordance to the climatic conditions of the year. The weed density decreasing under 3 plants /m² has as effect in both character situations (tillering and panicles number) increasing from insignificant to very positive significant. The number of panicles is, especially, the most influenced positively character by the density decreasing.


Table 6. The number of panicles on *Echinochloa crus-galli* in accordance to density.

The panicles length is very significant reduced to plants densities of *Echinochloa crus-galli*  bigger than 10 plants /m² while density of 5 plants /m² does not make significant differentiations (Table 7).

The production of caryopsis per plant is very significant reduced to increasing of plants density per surface unit starting with density of 5 plants /m². On this density, where the other productive features are less influenced compared with witness density (3 plants/m²), the seeds production suffers major decreasing especially during the years that are rich in

The differences that appear among the years represent a consequence of species adaptability for adjustment conditions of the productivity in accordance to climatic conditions. If during the rainy years the tillering is influenced from distinctive significant to very negative significant by plants density growing with 2 samples per surface unit, during the very dry year – 2007 - this condition does not suffer any adjustment having a significant growing by density increasing with 2 plants per surface unit. The explanation of this fact is found into

Density/Year 2004 2005 2006 2007 Average 50 plants/m2 3.2ooo 2.9ooo 4.2ooo 2.4ooo 3.2ooo 10 plants/m2 12.9ooo 12.1ooo 14.3ooo 9.3ooo 12.2ooo 5 plants/m2 19.3oo 18.8oo 20.4ooo 16.9\* 18.9ns 2 plants/m2 23.4ns 20.1ns 26.2\* 18.5\*\*\* 22.1\* Control 3 pl/m2 22 20 25 16 20.5

> 0.73 1.04 1.5

The number of panicles per plant (table 6) follows, in general, the same tendency of a very significant decreasing to densities bigger than 5 plants per surface unit and increasing or decreasing from insignificant to very significant in the situation of a density increasing with only 2 plants, in accordance to the climatic conditions of the year. The weed density decreasing under 3 plants /m² has as effect in both character situations (tillering and panicles number) increasing from insignificant to very positive significant. The number of panicles is, especially, the most influenced positively character by the density decreasing.

Density/Year 2004 2005 2006 2007 Average 50 plants/m2 2.4ooo 2.6ooo 3.1ooo 3.9ooo 3.0ooo 10 plants/m2 13.1ooo 14.5ooo 16.6ooo 9.6ooo 13.5ooo 5 plants/m2 20.8ooo 21.2\*\* 26.8ns 18.2ns 21.7ns 2 plants/m2 25.2\*\*\* 26.1\*\*\* 32.4\*\*\* 20.8\*\*\* 26.1\*\*\* Control 3 pl/m2 23 20 27 18 22

> 0.83 1.19 1.72

The panicles length is very significant reduced to plants densities of *Echinochloa crus-galli*  bigger than 10 plants /m² while density of 5 plants /m² does not make significant

The production of caryopsis per plant is very significant reduced to increasing of plants density per surface unit starting with density of 5 plants /m². On this density, where the other productive features are less influenced compared with witness density (3 plants/m²), the seeds production suffers major decreasing especially during the years that are rich in

Table 6. The number of panicles on *Echinochloa crus-galli* in accordance to density.

0.95 1.35 1.95 1.22 1.73 2.50

Table 5. The tillering per plant on *Echinochloa crus-galli* in accordance to density.

0.97 1.38 2.00 0.88 1.25 1.81 1.35 2.13 2.97

> 1.12 1.49 2.38

the high capacity of tillering of this species when the height growing is diminuated.

1.59 2.26 3.27

> 0.96 1.36 1.97

LSD 5% 1% .1%

> LSD 5% 1% 0.1%

differentiations (Table 7).


precipitations, when the productive potential of the species is directed to vegetative features (Table 8).

Table 7. The length of panicles on *Echinochloa crus-galli* (cm) in accordance to density.


Table 8. The number of seeds/plant on *Echinochloa crus-galli* in accordance to density.

The productivity features of *Echinochloa crus-galli* suffer changes in accordance to the weed density per unit surface, to high densities the increasing in high are very visible while the tillering, panicles number, panicles length and the number of seeds produced by a plant are reduced very significant. Between 2 and 5 plants of *Echinochloa crus-galli* /m2, the productivity parameters vary in more reduced limits, being in the most cases the consequence of the climatic conditions of the experimentation years. The inter specific concurrency is felt even when speaking about the increasing with one plant per surface unit, but this one becomes hypercriticalism in case of density growing with more than 5 plants/m².

#### **3.3 Influence of degree infestation with** *Echinochloa crus–galli* **species upon the maize crop**

*Echinochloa crus-galli* is known as a weed which germinate in late spring, invades especially weeding crops on wetlands, fattened with manure, grows very quickly, suppress and compromise the culture. Precipitation in April - May 2009 (102 mm in April compared to 47 mm multiannual average and 105 mm in May compared to 76 mm) have delayed corn seeding until the end of the optimal period and promoted the accumulation of moisture in the soil of 30% on average depth from 0 to 50 cm and a reserve of water on the same depth of 977 m3/ha. Under these conditions, sown late, high humidity, fertilization in the last year

Influence of Degree Infestation

Plot I

Plot II

Plot III

Plot IV

Witness (2 holings)

chemical weed control.

with *Echinochloa crus–galli* Species on Crop Production in Corn 463

many times one impediment to assure the optimal conditions for corn seeding and establish the optimal time for seeding. The repercussions of these deficiencies can be found for the most times in: culture late rising, culture irregularity, a bigger number of weeds, the passing of some phonological phases by corn plants during inappropriate periods, the

m2

104 10

25 4 7

95 8

12 3 7

58 4

22 4 9

47 6

14 2 3

Dico *Galinsoga parviflora* 22,113

Dico *Galinsoga parviflora* 14,587

Dico *Galinsoga parviflora* 10,230

Dico *Galinsoga parviflora* 8,464

Dico *Convolvulus arvensis* 1,950

2 2

Mono *Echinochloa crus – galli* 3 990 990

Table 9. Influence of the density of *Echinochloa crus – galli* species and of other weed species upon the maize crop in the case of unmineral fertilized soil and without any measure of

Mass, kg/ha

4 - - 2,100

4 - - 4,630

4 - - 130,000

4 - - 19,720

4 - - 29,790

18,052 2,312

1,516 72 161

12,633 171

1,341 81 361

8,323 110

1,293 102 402

7,080 203

1,012 90 83

240 720

Species Group Total

20,364

1,749

12,804

1,783

8,433

1,797

7,283

1,185

960

288

1,116

2,526

3,866

5,157

differentiation of productivity organs during dryness periods, reduced productions.

Field Group Species Plants/

*Convolvulus arvensis* 

*Convolvulus arvensis Matricaria,Lapsana, Hibiscus* 

*Convolvulus arvensis Plantago,Matricaria, Lapsana* 

*Convolvulus arvensis Shymphytium, Lapsana*

*Shymphytium officinalis* 

*Matricaria, Lapsana, Hibiscus* 

Mono *Echinochloa crus – galli Setaria glauca* 

Mono *Echinochloa crus – galli Setaria glauca* 

Mono *Echinochloa crus – galli Setaria glauca* 

Mono *Echinochloa crus – galli Setaria glauca*

Corn whole plant grains

Corn whole plant grains

Corn whole plant grains

Corn whole plant grains

Corn whole plant grains

Mono – Monocotyledonous; Dico – Dicotyledonous.

with manure, favoured an excessive infestation of the culture, with species that germinate in late spring and especially *Echinocloa crus-galli*. At the same time, shortcomings on internal drainage of the soil aggravate the maintenance of crops in critical periods. Under these circumstances, competition for factors of vegetation was quickly won by *Echinochloa crusgalli* which influenced the subsequent development of maize and other weeds (Fig. 2).

In the unfertilized variant, corn invaded by weeds grows anemic and has a yellowish green color, develops storied, on the upper *Echinochloa crus-galli* dominate, in the middle floor develops *Setaria glauca* (L.) Beauv. and in the lower floor a number of dicotyledonous: *Galinsoga, Convolvulus, Matricaria, Lapsana, Hibiscus, Plantago* etc. (Table 9). The amount of weeds, obviously influenced production levels of maize grain and green mass (Fig. 3). Thus, it is found that on unfertilized agrofond with 22,113 kg/ha weed, maize green mass production is 2,100 kg/ha and with 200 kg/ha weed, maize green mass production is 29,790 kg/ha. The total amount of green mass (weed + maize/ha) varies in very close limits between 24,213 kg/ha to 31,740 kg/ha. On fertilized variant, the competition between weeds and maize, on the one hand and between monocotyledonous and dicotyledonous on the other hand, is more balanced, as dicotyledonous come from 1,700 kg/ha in unfertelized variants (Table 9), to 4,159 kg/ha in untreated, mineral fertilized variant (Table 10). On fertilized agrofond in untreated plot, the whole plant corn production was 27,600 kg/ha, and the grain production was 1,965 kg/ha, while the total mass of monocotyledonous weeds weighed 19,560 kg/ha and dicotyledonous weeds 4,159 kg/ha. In the variant treated with dimethenamid the whole plant corn production increased to 48,500 kg/ha, and the grain at 5,070 kg/ha, while total weed mass was 9,671 kg/ha. Similar results were obtained in the variant treated with acetochlor.

The highest production of whole plant corn 53,600 kg/ha and 7,020 kg/ha grain were obtained in the variant treated with isoxaflutol + (bentazon + dicamba). In this variant, because of the high efficiency of herbicides, the total amount of weeds was the smallest, only 950 kg/ha. In this experience, on fertilized background, in variant treated with herbicides, the amount of corn (27,600 kg/ha) + weeds (23,719 kg/ha) totals 51,393 kg/ha, which is practically equal to the best variants treated with isoxaflutol + (bentazon + dicamba), where were obtained 53,600 kg/ha maize and 950 kg/ha weeds, thus in total 54,550 kg/ha.

The reserve of *Echinochloa crus-galli* seeds in the 0-10 cm soil layer determinates at maize harvest shows the danger constituted by late infestations of maize crops with weeds, in maintaining the cultural hygiene of exploitation. From a valuable point of view this reserve of seeds is about 22,264 seeds/m² (average on the three years) in the variant of no disproof, 3,512 seeds/m² in the variant of a classical disproof, 5,394 seeds/m² in a chemical disproof variant through a pre emergent treatment, 6,042 seeds/m² in a chemical disproof variant through a post emergent treatment and 3,816 seeds/m² in a chemical disproof variant through two treatments (p.p.i. + postem.). We can state that the *Echinochloa crus-galli* seed reserve accumulated in the superficial soil layer is tightly related to the biomass of the weeds present in the culture before maize harvest.

#### **3.4 The influence of climatic and technological factors upon the weed characteristics**

The variable characteristics of the clime in the hilly area in the spring time, especially in April-May, completed with the particularities of soils workability from this area build for

with manure, favoured an excessive infestation of the culture, with species that germinate in late spring and especially *Echinocloa crus-galli*. At the same time, shortcomings on internal drainage of the soil aggravate the maintenance of crops in critical periods. Under these circumstances, competition for factors of vegetation was quickly won by *Echinochloa crusgalli* which influenced the subsequent development of maize and other weeds (Fig. 2).

In the unfertilized variant, corn invaded by weeds grows anemic and has a yellowish green color, develops storied, on the upper *Echinochloa crus-galli* dominate, in the middle floor develops *Setaria glauca* (L.) Beauv. and in the lower floor a number of dicotyledonous: *Galinsoga, Convolvulus, Matricaria, Lapsana, Hibiscus, Plantago* etc. (Table 9). The amount of weeds, obviously influenced production levels of maize grain and green mass (Fig. 3). Thus, it is found that on unfertilized agrofond with 22,113 kg/ha weed, maize green mass production is 2,100 kg/ha and with 200 kg/ha weed, maize green mass production is 29,790 kg/ha. The total amount of green mass (weed + maize/ha) varies in very close limits between 24,213 kg/ha to 31,740 kg/ha. On fertilized variant, the competition between weeds and maize, on the one hand and between monocotyledonous and dicotyledonous on the other hand, is more balanced, as dicotyledonous come from 1,700 kg/ha in unfertelized variants (Table 9), to 4,159 kg/ha in untreated, mineral fertilized variant (Table 10). On fertilized agrofond in untreated plot, the whole plant corn production was 27,600 kg/ha, and the grain production was 1,965 kg/ha, while the total mass of monocotyledonous weeds weighed 19,560 kg/ha and dicotyledonous weeds 4,159 kg/ha. In the variant treated with dimethenamid the whole plant corn production increased to 48,500 kg/ha, and the grain at 5,070 kg/ha, while total weed mass was 9,671 kg/ha. Similar results were obtained

The highest production of whole plant corn 53,600 kg/ha and 7,020 kg/ha grain were obtained in the variant treated with isoxaflutol + (bentazon + dicamba). In this variant, because of the high efficiency of herbicides, the total amount of weeds was the smallest, only 950 kg/ha. In this experience, on fertilized background, in variant treated with herbicides, the amount of corn (27,600 kg/ha) + weeds (23,719 kg/ha) totals 51,393 kg/ha, which is practically equal to the best variants treated with isoxaflutol + (bentazon + dicamba), where

The reserve of *Echinochloa crus-galli* seeds in the 0-10 cm soil layer determinates at maize harvest shows the danger constituted by late infestations of maize crops with weeds, in maintaining the cultural hygiene of exploitation. From a valuable point of view this reserve of seeds is about 22,264 seeds/m² (average on the three years) in the variant of no disproof, 3,512 seeds/m² in the variant of a classical disproof, 5,394 seeds/m² in a chemical disproof variant through a pre emergent treatment, 6,042 seeds/m² in a chemical disproof variant through a post emergent treatment and 3,816 seeds/m² in a chemical disproof variant through two treatments (p.p.i. + postem.). We can state that the *Echinochloa crus-galli* seed reserve accumulated in the superficial soil layer is tightly related to the biomass of the

**3.4 The influence of climatic and technological factors upon the weed characteristics**  The variable characteristics of the clime in the hilly area in the spring time, especially in April-May, completed with the particularities of soils workability from this area build for

were obtained 53,600 kg/ha maize and 950 kg/ha weeds, thus in total 54,550 kg/ha.

in the variant treated with acetochlor.

weeds present in the culture before maize harvest.

many times one impediment to assure the optimal conditions for corn seeding and establish the optimal time for seeding. The repercussions of these deficiencies can be found for the most times in: culture late rising, culture irregularity, a bigger number of weeds, the passing of some phonological phases by corn plants during inappropriate periods, the differentiation of productivity organs during dryness periods, reduced productions.


Mono – Monocotyledonous; Dico – Dicotyledonous.

Table 9. Influence of the density of *Echinochloa crus – galli* species and of other weed species upon the maize crop in the case of unmineral fertilized soil and without any measure of chemical weed control.

Influence of Degree Infestation

Untrated Corn whole plant

grains

Corn whole plant grains

Corn whole plant grains

Corn whole plant grains

Mono – Monocotyledonous; Dico – Dicotyledonous.

significant variations of this climatic parameter.

weed of the culture (Table 11).

Herbicides kg/ha

V1 -

V2 – acetoclor

V3 -

isoxaflutol + (bentazon + dicamba)

dimetenamid

with *Echinochloa crus–galli* Species on Crop Production in Corn 465

/m2

34 3

9 8 8

14

2 4

Dico *Amarantus retroflexus* 9,671

5 3 7

7 6

Dico *Amaranthus retroflexus* 1 950 950

Dico *Amaranthus, Cirsium* 10 2,202 2,202

Table 10. Influence of density *Echinochloa crus – galli* species upon the maize crop in the case

The determined correlations confirmed a very strong connection between the climatic conditions and weed amount inclusively with *Echinochloa crus-galli.* There are also very significant direct relations between the overtaking of the optimal seeding date (April 15) and

One significant correlation exists between the quantity of precipitations and *Echinochloa crusgalli* (r = 0.875), but this species has a lower dependence to humidity, at least in the first periods of growing comparatively to other weeds, fact that explains the big number of exemplaries, even in the years with a low amount of precipitations and soils with a low reserve of humidity. The air temperature has a lower influence upon the weeding (r=0.571) especially during the first period of corn vegetation in conditions in that there were not

The overtaking of seeding optimal date determinates the increasing range of weed inclusively the amount of *Echinochloa crus-galli* per surface unit. The relation is very significant, the correlation coefficient has values between 0.766 and 0.840 (very significantly)

Mass, kg/ha

19,420 140

891 1,040 1,241

987

2,060 1,040

3,230 940 2,401

3,880 1,010

4 - - 27,600

4 - - 48,500

4 - - 49,120

4 - - 53,600

Species Group Total

19,560

4,159

3,100

6,571

4,890

1,965

23,719

5,070

5,421

7,092

7,020

Group Species Plants

Mono *Echinochloa crus – galli Setaria glauca* 

Mono *Echinochloa crus – galli Setaria glauca* 

*Cirsium arvense* 

Mono *Echinochloa crus – galli Setaria glauca* 

of a mineral fertilized soil and measure of chemical weed control.

*Chenopodium,Gallinsoga* 

*Chenopodium album Polygonum convolvulus Matricaria, Cirsium Euphorbia helioscopia* 

Dico *Galinsoga parviflora* 

Fig. 2. Influence of *Echinochloa crus – galli* species on the development of other weeds and the green mass corn yield (t/ha).

Fig. 3. Correlation between the weeds quantity and the greenery corn (t/ha).

*Echinochloa crus - galli*

Other weeds

Corn

Plot I Plot II Plot III Plot IV Witness MF

Fig. 2. Influence of *Echinochloa crus – galli* species on the development of other weeds and the

1,954 1,907 1,388 <sup>960</sup>

13,000

7,080

19,720

990

19,420

29,790

4,299

27,600

8,323

0

green mass corn yield (t/ha).

5000

10000

15000

20000

18,052

4,061

2,100

12,633

4,630

Fig. 3. Correlation between the weeds quantity and the greenery corn (t/ha).

25000

30000

t/ha


Mono – Monocotyledonous; Dico – Dicotyledonous.

Table 10. Influence of density *Echinochloa crus – galli* species upon the maize crop in the case of a mineral fertilized soil and measure of chemical weed control.

The determined correlations confirmed a very strong connection between the climatic conditions and weed amount inclusively with *Echinochloa crus-galli.* There are also very significant direct relations between the overtaking of the optimal seeding date (April 15) and weed of the culture (Table 11).

One significant correlation exists between the quantity of precipitations and *Echinochloa crusgalli* (r = 0.875), but this species has a lower dependence to humidity, at least in the first periods of growing comparatively to other weeds, fact that explains the big number of exemplaries, even in the years with a low amount of precipitations and soils with a low reserve of humidity. The air temperature has a lower influence upon the weeding (r=0.571) especially during the first period of corn vegetation in conditions in that there were not significant variations of this climatic parameter.

The overtaking of seeding optimal date determinates the increasing range of weed inclusively the amount of *Echinochloa crus-galli* per surface unit. The relation is very significant, the correlation coefficient has values between 0.766 and 0.840 (very significantly)

Influence of Degree Infestation

years.

years.

Medicine Cluj-Napoca, Romania.

with *Echinochloa crus–galli* Species on Crop Production in Corn 467

Fig. 4. The relation between biomass of *Echinochloa crus-galli* and corn yield during the dry

Fig. 5. The relation between biomass of *Echinochloa crus-galli* and corn yield during the rainy

The problem of the influence of different species of weeds on the production of agricultural plants has been studies by many researchers. The damage caused by weeds in maize crop is mostly of 30-70%, and when the infestation is strong culture can be fully compromised. Our researches highlight in terms of Transylvania, the influence of *Echinochloa crus-galli* species (L.) Pal. Beauv. and other weeds on corn production, according to the degree of infestation. Researches have been conducted at the University of Agricultural Sciences and Veterinary

The researches was done on two agrofunds: unfertilized and mineral fertilized with NPK 100 kg s.a./ha. The unfertilized maize crop has been made in four variants with different degrees of infestation of *Echinochloa crus-galli*, from about 40 to 100 plants/m2 and witness – 2 holdings. In fertilized plots were used 4 herbicides for weed control (isoxaflutol 750 g/l; acetoclor 860 g/l; dimetenamid 900 g/l; bentazon 320 g/l + dicamba 90 g/l). Weed biomass,

corn plant and grain production was measured in the ripening stage.

and the regression equation y=2.5148 x + 288.96 shows that every day of seeding delay conduce to weed increase with more than 2 weeds/square metre.

The explanation of the identified correlations is found in the climatic characteristics of the experimental years. The dry periods influence negatively the corn germination and rising taking in consideration the spent period from seeding rising, culture density and its homogeneity. The weeds are also influenced less as frequency and more as rising and development period. During the years that are rich in precipitations the weeds succeeded in germination, rising and assurance of a high infestation of the culture. The plus of humidity and temperature from May and June favoured the weeding both as frequency and phonological development especially between May 30 and June 30. The weeds concurrence to the corn plants in this period it was an acerbic one.

The existent weeds mass in the corn crop before harvesting reflects on one side the climatic specific of the agrarian year, but mostly the effectiveness of each applied method to combat the weeds and not lastly the capacity of weeds concurrence.

The correlations established between the biomass achieved at harvesting moment of *Ecinochloa crus-galli* and yield (Fig. 4, Fig. 5 and Fig. 6) are – very strong, proving once again the fact that this species is a majoritary one both as frequency in corn crops from Cluj area but also as a corn concurrency potential bringing to significant production reductions. The correlation coefficient (r) is very negative significant having values between 0.861 and 0.952.


r / p 5% = 0.497; 1% = 0.623; 0.1% = 0.742

Table 11. The existent correlations between the weed characteristics, climatic and technological conditions from the corn crop.

The assessment of each combating method both under efficiency in corn crop weeds control aspect and achieved productions level after weeds combating (Fig. 7) it is compulsory and objective. The combating range of *Echinochloa crus-galli* accomplishes with the production a strong positive relation r = 0.959\*\*\*. Therefore, in the case of a 10% increasing of combating range, the production rises with 48.65 kg/ha.
