Resposta de cultivares de trigo irrigado a diferentes doses e fontes de nitrogênio

High wheat yields require good N fertilization management. The objective of this study was to evaluate the effects of different N applications at sowing using Entec (N source with nitrification inhibitor) and urea (traditional N source) at covering, on four wheat cultivars. The experiment was conducted in a randomized block design in a factorial scheme, with four replications, at the Experimental Station of the Faculdade de Engenharia de Ilha Solteira - UNESP, on a dystrophic, epi-eutrophic alic Red Latosol with loamy texture, formerly under savannah vegetation. Four N rates (0, 60, 120, and 180 kg ha-1) were tested, applied at sowing in the case of Entec and top-dressed 40 days after plant emergence in the case of urea, and the four wheat cultivars E 21, E 22, E 42, and IAC 370. The yield of the wheat cultivars E 21 and E 42 was highest. Plant height and lodging index of cultivar E 22 were greatest, with consequently lowest grain yield. There was no significant difference between Entec (applied at sowing) and urea (top-dressed) in terms of grain yield and yield components. Nevertheless, urea resulted in a higher N leaf content, and Entec in a larger number of undeveloped spikelets. High nitrogen rates influenced the hectoliter mass negatively, affecting wheat grain quality. Grain yield increased under N rates of up to 82 kg ha-1 N, through Entec applied at sowing or top-dressed urea.Altas produtividades de trigo requerem um bom manejo da adubação nitrogenada. O objetivo deste trabalho foi avaliar os efeitos de diferentes doses de nitrogênio na semeadura usando o Entec (fonte de N com inibidor de nitrificação), ou em cobertura, utilizando a ureia, em quatro cultivares de trigo. O experimento foi desenvolvido em área experimental pertencente à Faculdade de Engenharia de Ilha Solteira - UNESP, em um Latossolo Vermelho distrófico epieutrófico álico textura argilosa, o qual foi nativamente ocupado por vegetação de Cerrado. O delineamento estatístico foi o de blocos ao acaso, com quatro doses de N (0, 60, 120 e 180 kg ha-1) na semeadura, usando o Entec, ou em cobertura aos 40 dias (início do alongamento), empregando a ureia e os cultivares E 21, E 22, E 42 e IAC 370, em quatro repetições. Os cultivares de trigo mais produtivos foram o E 21 e o E 42. O cultivar E 22 apresentou maior altura de plantas e altas notas de acamamento, com consequente menor produtividade de grãos. Não houve diferença significativa entre o Entec (aplicado na semeadura) e a ureia (aplicada em cobertura) para produtividade de grãos e para nenhuma das outras avaliações, porém a ureia proporcionou maior teor de N foliar, e o Entec, maior número de espiguetas não desenvolvidas. O incremento das doses de N influenciou negativamente a massa hectolítrica, alterando assim a qualidade dos grãos de trigo. O N aumentou a produtividade de grãos de trigo até a dose de 82 kg ha-1 de N, usando Entec aplicado na semeadura ou ureia aplicada em cobertura

Composted Sewage Sludge Enhances Soybean Production and Agronomic Performance in Naturally Infertile Soils (Cerrado Region, Brazil).

Naturally infertile soils require large amounts of mineral fertilizers to obtain the desired crop yield. In the Cerrado region of Brazil, there is a need to investigate the potential of organic fertilizers to sustainably increase crop productivity and food security. A field study was conducted over two experimental seasons to evaluate the agronomic effectiveness of composted sewage sludge (CSS) as a fertilizer for soybean cultivation in infertile tropical soils. A 4 × 2 + 2 factorial randomized complete block design was applied with the following treatments: (i) CSS: 5.0, 7.5, 10.0, and 12.5 Mg ha−1 on a wet basis applied according to two different methods: whole area (WA) or between rows (BR); (ii) comparison with two alternative treatments: a control with no CSS and mineral fertilizer application, and an area treated with conventional fertilizers only. All the treatments were compared in terms of micronutrient concentrations in surface soil and plant leaves, plant development, crop productivity, and yield. Bi- (ANOVA, correlation matrix, and polynomial regression analysis) and multivariate (PCA, principal factor analysis) statistics were applied to determine statistical differences and relationships/observed variability among the treatments. Results showed that at higher CSS-WA rates: (i) soil and leaf micronutrient concentrations increased; (ii) there was an increase in soybean yield by 12 and 20%, respectively, as compared to control and conventional fertilization; (iii) soybean yield was 67% higher than the mean soybean yields for Brazil. Research outcomes confirm the benefits of CSS application on infertile agricultural soils in the Cerrado region, representing a strong alternative source of micronutrients in the CSS with respect to conventional fertilizers