THE YIELD ABILITY OF MAIZE UNDER VARIOUS WAYS OF TREATMENT

výnosová schopnost kukuŘice pŘi různém způsobu ošetŘení

P. Fuksa, M. Veselá, J. Vrzal

Czech University of Agriculture, Faculty of Agronomy, Department of Forage Crops Production, Kamýcká 957, 165 21 Prague 6, Czech Republic

Summary

The influence of weed occurrence on yields ability was observed during the years 1998 and 1999. There were 3 variants: variant 1 - maize grew with weeds during vegetative period (control variant), variant 2 - mechanical weeds removal during vegetative period, variant 3 - chemical protection. The total yields of dry mass ranged from 7,1 to 9,1 t.ha-1 in the year 1998 and from 12,2 t.ha-1 to 15,5 t.ha-1 of dry mass in 1999. The DM yield on the variant 2 was higher by 28,2 % in comparison with the control variant, so as the yield of the variant 3 (by 23,9 %) in the year 1998. The same tendency was found in the year 1999 (the yield from variant 2 by 27,0 % and the yield from variant 3 by 10,7 % higher in comparison with the control variant).

maize; weeds; yield ability; chemical protection

Souhrn

V letech 1998 a 1999 byl sledován vliv zaplevelení na výnos kukuřice. Pokus byl zaměřen následujícím způsobem: varianta 1 - zaplevelení porostu po celou dobu vegetace (kontrolní varianta), varianta 2 - porost odplevelován mechanicky po celou dobu vegetace, varianta 3 - porost ošetřen proti plevelům chemicky. V roce 1998 se celkový výnos sušiny pohyboval od 7,1 do 9,1 t.ha-1 a v roce 1999 od 12,2 do 15,5 t.ha-1. Nejnižší výnos v roce 1998 poskytla varianta 1, výnos varianty 2 byl vyšší o 28,2 % a výnos varianty 3 byl vyšší o 23,9 % oproti kontrolní variantě. V roce 1999 byl nejnižší výnos u varianty 1, výnos varianty 2 byl vyšší o 27,0 % a výnos varianty 3 byl vyšší o 10,7 % ve srovnání s kontrolní variantou.

kukuřice; plevele; výnosová schopnost; chemická ochrana

introduction and literal survey

The level of yield and nutrient value of growing maize is influenced with a lot of important factors. There is not the main aim of growing maize just only to reach maximum yield, but also to reach maximum amount of digestible nutrients from unit of area (Dufková et al., 1999).

Effective weed control can be well organized only with excellent biological knowledge of weeds, first of all of especially dangerous species occurred in definite area and in definite crops (Kohout, 1997). Ill-effects of weeds in maize is quite high as a result of low competitive ability in initial period (Janda et al., 1982). Hruška et al. (1962) present yield losses according to various authors 13,0 - 43,8 %. The causes of decreasing yields are various. The weeds are not only hosts of diseases and pests, but they decrease fertility of soil too, shadow cultural crop, repress their growth, take up water and nutrients and they are competitors in space and light.

Material and methods

In the years 1998 and 1999 the experiments with maize were established on lands of Research Station in Červený Újezd, 405 m above the sea level. The experimental area belongs to the beat producing type. The average annual temperature is 7,6 °C, the average annual precipitation sum is 549 mm. The average temperature of vegetation period is 13,9 °C and the average precipitation sum of vegetation period is 361 mm. The duration of the vegetation period is 150 - 160 days.

The experiment is located on stationary stand, where maize has been grown for 8 years. The experiment was established by the method of randomized blocks in four replications. The area of each plot was 15 m2.

The effects of weed occurrence and various methods of treatment on yields ability of maize during the vegetation period were researched.

There were 3 variants:

variant 1 - maize grew with weeds during all vegetative period - control variant,

variant 2 - mechanical weeds removal during all the vegetative period,

variant 3 - chemical control.

The weeds from mechanically cultivated plots were removed in 14 days period.

Results and discussion

The total yields of dry mass ranged from 7,1 to 9,1 t.ha-1 (25,9 - 32,9 t.ha-1 of green mass) in the year 1998 and from 12,2 t.ha-1 to 15,5 t.ha-1 of dry mass (29,5- 37,2 t.ha-1 of green mass) in the year 1999.

The most spread weeds wereas follows: Chenopodium album L., Cirsium arvense L., Amaranthus retroflexus L. and Sonchus oleraceus L.; lower occurrence: Echinochloa crus-galli L. Beauv., Elytrigia repens L. Desv. and Artemisia vulgaris L.

In the year 1998 dry mass yield from variant 1 (maize grew with weeds in all duration vegetative period - control variant) 7,1 t.ha-1 was harvested (table 1). Yield of this variant was the lowest of all observed ones. There was harvested 9,1 t.ha-1 of dry mass from variant 2 (mechanically cultivated during the vegetative period), it was by 2,0 t.ha-1 (28,2 %) more than on the variant 1. The yield from the chemically protected variant was 8,8 t.ha-1 of dry mass (by 23,9 %) higher than on the control variant.

In the year 1999 the DM yield of control variant was 12,2 t.ha-1 (table 2). The DM yield of the variant 2 (mechanical weed control) was higher by 27,0 % (3,3 t.ha-1) and the yield of chemically protected variant by 10,7 % (1,3 t.ha-1) in comparison with the control variant.

The yields on the variant with weeds were markedly lower than on the mechanically cultivated ones in both of observed years. Mechanical cultivation supported favourable conditions for growing maize and therefore also for reaching the highest yield of all observed variants. In both years it was observed mild DM yield decrease on the chemically protected variant in comparison with the mechanically cultivated ones.

Tab. 1 The maize yield ability in various ways of treatment in the year 1998

Tab. 2 The maize yield ability in various ways of treatment in the year 1999

conclusion

In the experiment the influence of weed occurrence on yields ability of maize was observed. Lower DM yields were reached in the variant with weeds in comparison with mechanically or chemically treated variants (tables 1, 2). The knowledge of mutual competitive relationships between maize and weeds and term of cultivation should be used for weed control. Finally it is possible to state that reducing of cost per unit and also improving of ecological conditions can be obtained under high level of weed control.

REFERENCES

Dufková,L. - Jambor, V. - Vosynková, B., 1999: Vliv hustoty porostu a genotypu kukuřice na podíl palic z celé rostliny a stravitelnost organické hmoty. 9. medzinárodné sympózium Konzervovanie objemových krmív, Nitra, s. 170-171.

Hruška, J. et al., 1962: Monografie o kukuřici. SZN Praha, 916 s.

Janda, J. et al., 1982: Kukurica. Príroda Bratislava, 408 s.

Kohout, V., 1997: Plevele polí a zahrad. Agrospoj Praha, 235 s.

Kontaktní adresa: Ing. Pavel Fuksa; ČZU Praha, katedra pícninářství; 165 21 Praha 6 - Suchdol