| | E. Ciências Agrárias - 1. Agronomia - 4. Fitotecnia | | | GRAIN YIELD OF MAIZE GROWN AFTER COWPEA | | | Paulo Sérgio Lima e Silva 1 (autor) paulosergio@esam.br | | Kathia Maria Barbosa e Silva 2 (colaborador) paulosergio@esam.br | | Paulo Igor Barbosa e Silva 1 (colaborador) paulosergio@esam.br | | Zenaide Barbosa 3 (colaborador) paulosergio@esam.br |
| | 1. Depto. de Fitotecnia, Escola Superior de Agricultura de Mossoró - ESAM | | 2. Depto. de Biologia, Faculdade de Ciências Naturais - FANAT | | 3. Faculdade do Vale do Jaguaribe - FVJ |
| | INTRODUÇÃO:
Maize (Zea mays L) and cowpea (Vigna unguiculata (L) Walp.) are grown in the State of Rio Grande do Norte for green or dry grain yield. Repeated maize cultivations, which are made possible under irrigation and with the intensive use of chemical products, result in physical, chemical, and biological soil degradation in several areas. Physical degradation results in deterioration of soil properties that influence water infiltration and plant growth. Chemical degradation implies a rapid decline in soil quality. Studies have shown that maize rotation or intercropping with legumes provided positive effects on yield, with economic benefits as well. This work aimed to evaluate plant and ear insertion heights, as well as grain yield and its components in three maize cultivars, after cultivation of cowpea incorporated at three different moments. | | METODOLOGIA:
Two sprinkler-irrigated experiments (one involving cowpea and the other with maize) were conducted at Mossoró-RN, Brazil. The following treatments were applied to the cowpea experiment, in a randomized complete-block design with ten replications: no cowpea cultivation; cowpea cultivation and incorporation into the soil at bloom time; or after four green bean harvests; or after three mature bean harvests (dry grains). The cowpea cultivar utilized was Sempre Verde, of indeterminate growth, and incorporation was made with a hoe. Before incorporation, eight plants were cut even with the ground and weighed for fresh and dry matter yield evaluation. Dry matter evaluation was performed by the oven method, utilizing a 500 g sample of crushed material. After evaluation, the material was returned to the experimental area where it had been removed from. A soil sample from each plot cultivated with cowpea was removed one day after the soil had been tilled to be planted with maize. Soil tillage for maize consisted of two harrowings, and was performed one month after incorporation of the cowpea plants that yielded green or dry kernels. Three cultivars (AG 8080, AG 9010 and DKB 333B) were grown in each of the four areas of each block in the cowpea experiment. Therefore, split-plots were used for the maize experiment with treatments arranged as a randomized complete-block design with ten replications. | | RESULTADOS:
The mean cowpea green pod, green kernel and dry grain yields were, respectively: 2632, 1621, and 1262 kg ha-1. The mean dry matter mass yield values for the above-ground part of incorporated cowpea plants at flowering and after green bean, or mature bean harvesting were, respectively, 1,557 kg ha-1, 3,529 kg ha-1 and 3,786 kg ha-1. There were no differences between dry matter mass values after green bean or mature bean harvesting, but both surpassed dry matter mass at flowering. The analysis of a sample from the above-ground part of the cowpea plants at flowering indicated, in percentages: 0.76 P, 2.31 K, 0.06 Na, 3.92 Ca, and 0.37 Mg. The corresponding values for plants after green bean harvesting were: 0.80, 2.41, 0.04, 1.44, and 1.95. In plants harvested after mature bean harvesting, values were 0.76, 2.03, 0.03, 4.08, and 0.34, respectively. In spite of the differences between the amounts of cowpea matter turned under there were no differences between the chemical characteristics of the soil at maize planting. Despite the fact that cowpea incorporation after the mature grain was harvested yielded a higher number of kernels/ear, there were no differences between plant height, ear insertion height, grain yield, number of ears/ha , and 100-grain weight in maize grown without or after cowpea incorporation at different times. | | CONCLUSÕES:
The incorporation of cowpea, regardless of timing, does not have beneficial effects on maize growth or grain yield. Cultivars AG 8080 and DKB 333B do not differ, but are both superior to cultivar AG 9090 with regard to grain yield. | | | Instituição de fomento: CNPq | | | | | Palavras-chave: Zea mays; Vigna unguiculata; Green bean. |
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Anais da 56ª Reunião Anual da SBPC - Cuiabá, MT - Julho/2004 |