**2. Material and methods**

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 on Experimental Teaching Resort of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. The experiments were located on the northern slope, weak to moderately sloping land, with soil type preluvosol (SRTS, 2003), medium fertile, humus content 3%, texture loam-clay, 42-45% clay. Experience was held between 2004 and 2009 and had more objectives:

#### **2.1 The vegetative cycle and the productivity characters of** *Echinochloa crus-galli*  **depending on the rise period, at Cluj area**

The researches were made between 2004 and 2007, respecting the climatic conditions of the soil appropriate to every year. The researches were made outdoors onto 1 m2 plots, where we sowed 20 caryopsis of *Echinochloa crus-galli* per plot, at the beginning of April, May, June,

by a plant varies between 200 and 10,000. Chirilă (1967) establishes as limits of seeds number/plant from 150 to 10,000. The medium mass of 1,000 bobsleighs is 2.48 g. (Anghel et al., 1972; Berca, 1996). The reserve of *Echinochloa crus-galli* seeds that can be found in the soil can reach impressive values, correlative with the production potential of the species and the vegetative conditions specific to the infestation areas. The number of seeds found by Kott (1953) reported to the surface of one hectare gets to 1-2.5 billion *Echinochloa crus-galli* seeds. Berca (1996) referring to the seeds of this species and their germination, shows that germination happens after one year of seeds forming, by instalment both as structure and life. The germination happens all over the year, especially in the spring time, 1-2 cm depth when the temperature is over 10 ºC. The *Echinochloa crus-galli* seeds have a post maturation period that happens into the soil, especially the upper side of the soil. The length of seminal

The period of germination-rising starts for *Echinochloa crus-galli* in April, depending by the temperature provided by the soil, the minimum germination temperature is 8ºC, and it ends in September. The maximum germination is between May and June, after this period there comes an attenuation of germination proportion and plants rising, so that in October it is

The elongation of the *Echinochloa crus-galli* plants is in a strong connection with the temperature. In the spring time when the temperature is low the elongation is a slow one but in the summer time when the temperature is high the plants grow very fast (Păunescu, 1997; Rusu et al., 2010). At the beginning the plants grow slowly, after 2-3 weeks after their rising starts the tillering period after that the plants start a very fast growing if the conditions of light, humidity and nutritive substances are assured (Berca, 1996). After the floral branches cutting of this weed, or after the first fructification they sprout again during

*Echinochloa crus-galli* belongs to the yearly monocotiledonate weeds class with late spring germination very harmful for the corn cultures. Growing very fast it asphyxiates the corn

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 on Experimental Teaching Resort of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. The experiments were located on the northern slope, weak to moderately sloping land, with soil type preluvosol (SRTS, 2003), medium fertile, humus content 3%, texture loam-clay, 42-45% clay. Experience

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

The researches were made between 2004 and 2007, respecting the climatic conditions of the soil appropriate to every year. The researches were made outdoors onto 1 m2 plots, where we sowed 20 caryopsis of *Echinochloa crus-galli* per plot, at the beginning of April, May, June,

rest depends by a lot of internal and external factors (Berca, 1996).

the same year and fructify for the second time (Staicu, 1969).

was held between 2004 and 2009 and had more objectives:

**depending on the rise period, at Cluj area** 

accomplished to a very low level.

crop and infamies the crop.

**2. Material and methods** 

July and August. The observations were made every 10 days between rising and maturity. We analyzed the rising period according to the sowing date; the leaves appearance, the sprouting and the stem elongation, the panicle appearance and the flourishing beginning, the plants' maturation, the caryopsis' maturation and the dissemination and the productivity's characters variation.

In each lot the plants were rarefied, the observations regarding the productivity elements being done upon a number of 3 plants on surface unit. We chose this density for the reason of the necessary space protection for the *Echinochloa crus-galli* growing in order to touch the maximum values of the productivity parametres according to the biological potential of the plant.

The years of experiment with climatic specific (May 1 – August 31)

2004: 405.7 mm (excessively wet climate) and 17.6 oC (normal temperatures conditions); 2005: 349.6 mm (excessively wet climate) and 18.05 oC (normal temperatures conditions); 2006: 455.4 mm (excessively wet climate) and 18.5 oC (warm temperatures conditions); 2007: 167.5 mm (excessively dry climate) and 18.8 oC (warm temperatures conditions).


Table 1. The climate conditions during the 1st of April and the 30th of September in Cluj.

#### **2.2 Productivity elements variation of** *Echinochloa crus-galli* **in accordance to density**

In order to follow the variations of productivity parameters to *Echinochloa crus-galli*, the experiences were fixed on the field, in 4 random repetitions, after blocks method, on 1m² lot surface. In the last decade of April there were seeded 200 caryopsis of *Echinochloa crus-galli*  on each lot so that the rising of the plants to be assured for the beginning of May.

After the plants rising and the forming of two first leaves, there was done their spacing in order to achieve the density of 50, 20, 10, 5, 3, 2 plants per m². The rating of the plants growing parameters and plants productivity was done in the last decade of July – first decade of August – when the plants were mature enough having as goals: plants height, tillering, panicles length, number of seeds (production).

The results interpretation was done by means, percents, statistical elaboration (variance analyzes). In order to analyze the values that were obtained there were used control data, medium values of the parameters obtained in the variant of density 3 plants/m².

Influence of Degree Infestation

germination temperature.

The rising period/The vegetative

The end of the tillering, the culm

precocious flourishing and ageing.

The intensive tillering, the

The seeds' maturation;

(Table 2).

stem.

rising period).

that rose in August.

with *Echinochloa crus–galli* Species on Crop Production in Corn 457

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

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

1-3 leaves phase 8 – 10 6 - 8 6 – 7 6 5 – 6 Tillering beginning 19 – 23 17 - 20 13 – 17 12 – 15 12 – 14

adventitious roots rising 32 – 38 28 – 34 20 – 21 18 – 20 16 – 19

elongation 50 – 56 48 – 50 30 – 34 28 – 30 26 – 30 The skin stage\* 70 – 80 64 – 68 43 – 46 38 – 43 36 – 41 The panicle apparition, flowering\* 83 – 90 74 – 79 58 – 61 49 – 54 48 – 50 The grains filling \* 94 – 105 80 – 88 64 – 70 60 – 63 59 – 63

dissemination\* 110 - 115 95 – 99 79 - 82 70 - 79 65 - 72 \*This information is specific for the main stem. The shoots pass progressively these stages after the main

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

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

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

At the beginning of September the first plants dry out; they are those that rose in April,

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

while those that rose in August dry out at the end of October.

plants sowed in August, it ends in October.

stage April May June July August

#### **2.3 Influence of degree infestation with** *Echinochloa crus–galli* **species on crop production in corn**

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

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 holings.

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

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 cm.
