YIELDING OF MAIZE GROWN FOR SILAGE (CCM) IN RELATION TO STAND DENSITY

Výnosy kukuřice pěstované na siláž (CCM) ve vztahu k hustotě porostu

Edward Wróbel, Maciej Pietkiewicz

Warmia and Mazury University in Olsztyn, Faculty of Environmental Management and Agriculture, Poland

Souhrn, klíčová slova

V roce 2000 jsme v přesném polním pokusu sledovali vliv hustoty porostu (8, 12, 16 rostlin na m-2) na výnos dvou polských odrůd kukuřice (Wilga FAO - 180, Bzura FAO - 230) pěstované na CCM siláž. V našich pokusných podmínkách měly sledované odrůdy stejnou hladinu výnosu. Nepříznivý vliv zvyšující se hustoty porostu neovlivnil výnos sušiny palic. Zvýšení hustoty z 8 na 16 rostlin na m2 vedlo k významnému snížení obsahu sušiny palic.

Klíčová slova: kukuřice, CCM, výnos

Summary, keywords

In the season 2000 in strict field trial the effects of increasing crop density (8, 12, 16 plants per m-2) on yield of two Polish maize cultivars (Wilga FAO - 180, Bzura FAO - 230) grown for silage from cobs (CCM). On the soil classified to good wheat complex according to Polish Society of Soil Sciences studied maize cultivars gave the same level of yield. Adverse effects of increasing plant density in the stand did not affect yield of cob dry matter and structure of cob size remain unmodified. Increase of plant density from 8 to 16 plants per m-2 resulted in significant decrease of content of cob dry matter.

Keywords: maize, CCM, yield

Introduction

Maize is considered and a crop of high yielding potential [5, 7, 8,9]. In Poland growing maize for silage produced from cobs (CCM) and whole plants is known agricultural practise in whole area of our country but growing maize for grain is possible only in south or south-western region of Poland.

Recently maize has become the basic fodder crop in diary farms. Growth of farmers interest in maize production results from the development in breeding of more productive cultivars especially in Polish breeding centres.

Selection of the best-suited stand density of maize is one of most important components of maize growing but it is rather difficult to give univocal recommendation. It depends on several factors and among them conditions on given field, genotypes and purpose of maize growing [3, 4, 8].

Too high plants density results in cobs yield reduction, their share in total yield and in yield of dry matter also decreases whereas stems and leaves increases [5,6,7].

From results of the preliminary studies performed by Plant Breeding Station in Smolice it may be concluded that new cultivars are recommended for growing in north part of Poland for silage prepared from whole plants as for CCM. Because of that in this region farmers are interested in growing maize more thoroughly studies should be undertaken to investigate the usability of new maize genotypes for growing in more severe weather conditions.

The aim of our studies was to determine the optimal stand density for maize cultivars of different time of maturing for obtaining high yield of good technological parameters for production of cob silage (CCM).

Materials and methods

Studies were performed in season 2000 in Experimental Centre Ltd. in Bałcyny which location is classified to 3rd class region for maize production. Experiment was established in randomised sub-plots design in 4 replications in the crop rotation after winter wheat. Soil was classified to good wheat complex according to Polish Society of Soil Sciences. Contents of available P, K and Mg were high and value of soil pH in 1 M KCl was 6,7.

First factor was genotype of maize of two classes of maturity and two Polish genotyopes were studied:

1. early (FAO - 180) Wilga

2. medium early (FAO - 230) Bzura.

Second factor was stand density: 8, 12 or 16 plants per 1 m-2.

Maize was sown on 10 May in row apart 60 cm and the following rates of nutrients were applied (kg.ha-1): N - 140, P - 48, K - 125. Weeds were controlled by spraying of two herbicides sulkotrione (Mikado 300 SC) + nikosulphurone (Milagro 040 SC). Area of plot amounted to 18 m2.

Harvesting was performed at the phase of seed wax maturity. The following parameters were registered: number of plants per plot, total yield of dry matter, yield of dry matter of cobs with and without cover and share of core in cob yield. Yield of cob dry matter was subjected to ANOVA by t-Student test.

Results

Maize as a crop of warm climate responds in a very special way to weather conditions pattern. Temperature in growth period seems to be a critical factor for achieving high yield of that crop. Precipitation as the second basic weather parameter also affects development and yielding of maize. In the period of last week of April and first days of May water content in soil determines plant emergence. The highest water demands maize shows in June and June so high rainfalls favour high yields. Low rainfalls in September also positively affect maize yield. Weather data for the season 2000 are given in the Table 1.

Table 1. Meteorological conditions from 01.04.2000 to 31.10.2000

Spring 2000 was exceptionally warm and dry. Mean temperatures of April and May were higher than for many years period. Rainfall in April was by 42 per cent lower than usually. Despite of that plant emerged relatively well and plant losses for treatments with 12 and 16 plants per 1 m-2 were not higher than 6 %. Temperatures of June and August were typical for this region whereas July and September were colder than mean in many years period. Precipitation in June was very low and did not gave appropriate level of water in the soil. July and August were very wet (104,2 and 140,9 mm, respectively). High precipitation sums positively affected maize growth and development. September was colder and drier than appropriate means for many years period. Cultivar Wilga reached wax maturity on 26th September and Bzura on 5th October.

Studied cultivars when harvested at the phase of wax maturity gave similar cob yield (without cover leaves) (Fig.1). The tendency of cv. Bzura to higher yielding was observed. Studied crop density did not significantly affect cob dry matter yield. The significant higher yield of cob (with cover leaves) dry matter was found for cv. Bzura (Fig.1).

Fig. 1. Dry matter cob yield (t/ha)

Cultivar Wilga of shorter growing period accumulated 8 per cent less dry matter compaing to Bzura harvested 9 days later. The relation between length of growing period and accumulation of dry matter was not confirmed what was reported by others[1,2]. Increasing of stand density from 8 to 16 plants per 1 m2 resulted in significant decrease of dry matter from 53.3 to 49.5 per cent (Table 2). Our findings are in line of reports of Machula i Małysiak (1993). The higher content of grain in cob was found for earlier cv. Wilga whereas effects of plants density (8, 12 or 16 plants per m-2) on cob structure was not found (Table 2).

Table 2. Some elements of yield components of dry matter ears of maize grown for CCM as dependent on varieties and plant density

Conclusions

Studied maize cultivars of different time of maturity (FAO - 180, FAO - 230) grown for CCM made of cob without leaves cover gave similar yield.

Increasing plant density from 8 to 16 plants per m-2 did not modify dry matter yield but significant decrease of dry matter content was noted.

Increasing plant density from 8 to 16 plants per m-2 did not affect structure of cob size.

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