Variation in Soybean Response to Early Season Foliar Fertilization among and within Fields

Abstract

Foliar fertilization of crops can complement soil fertilization. Recent research showed that soybean [Glycine max (L.) Merr.] yield response to early season N–P–K foliar fertilization was inconsistent and difficult to predict. This study's objectives were to further evaluate soybean response to early season N–P–K fluid fertilizers with or without S or micronutrients and to assess the within‐field response variation. The mixtures 3–8–15 (N–P–K), 3–8–15–1 (N–P–K–S), 10–4–8, 10–4–8–1, and 10–4–8–1 plus B, Fe, and Zn were evaluated in 18 conventional small‐plot trials. The within‐field variation in response to a 3–8–15 fertilizer mixed with glyphosate [N‐(phosphonomethyl) glycine] herbicide was evaluated in eight strip trials harvested with combines equipped with yield monitors and differential global positioning systems receivers. A fertilizer rate of 28 L ha−1 was sprayed once at the V5 growth stage. There was a yield response to the 3–8–15 and 10–4–8–1 fertilizers in one small‐plot trial (260 kg ha−1) and to 3–8–15 fertilizer in another trial (360 kg ha−1). There was a small response to the 3–8–15 fertilizer across the 18 trials (93 kg ha−1). Soybean responded to 3–8–15 fertilizer only in one strip trial where the yield response was higher in acidic soil areas. No response variation was detected across contrasting soil test values or soil types within other trials. Soybean response to foliar fertilization across all production conditions will seldom offset fertilization costs. The probability of economic yield response could be increased if the fertilizer is mixed with a postemergence herbicide because application costs are reduced.

Effect of in-season application methods of fertilizer nitrogen on grain yield and nitrogen use efficiency in maize

“…It was reported that foliar fertilization for winter wheat did not affect grain yield (Woolfolk et al 2002). Some other studies demonstrated that even if there was a yield increase, the yield response could seldom offset application costs (Haq and Mallarino 2000;Mallarino et al 2001). As for maize, sprays with low concentrations of urea have not increased grain yield compared with the equivalent amount of soil N applications.…”

Mapeamento das formas do relevo para estimativa de custos de fertilização em cana-de-açúcar

“…Esses processos estão muito ligados ao fluxo de água que, por sua vez, são controlados pelo relevo (KRAVCHENKO & BULLOCK, 2002). Neste sentido, a separação das formas do relevo mostra ser eficiente para identificação e mapeamento de áreas com variabilidade controlada, bem como a transferência de informações, podendo servir de base para elaboração e execução de programas de adubação (MALLARINO et al, 2001;SOUZA et al, 2007). Do ponto de vista de aplicação de insumos, as doses recomendadas no mapa de necessidade de fósforo na área total variaram de 75 a 170 kg ha -1 (Figura 3), levando em consideração a aplicação com taxa variada.…”

“…A identificação dessas zonas garante a localização de limites mais precisos entre áreas distintas, permitindo que técnicas agronômicas possam ser transferidas com facilidade e economia para ambientes semelhantes (MALLARINO et al, 2001;BISHOP & MCBRATNEY, 2002, SIQUEIRA et al, 2010a.…”

Fontes De Fósforo Para Adubação Foliar Na Cultura Do Feijoeiro

“…A adubação foliar não tem sido muito estudada nos últimos anos, principalmente em relação aos macronutrientes, elementos exigidos em maiores quantidades, sendo utilizada mais para corrigir deficiências ou complementar a nutrição (Mallarino et al, 2001) em períodos de maior demanda destes em algumas culturas. Segundo Alvarenga et al (2000), a propaganda e a agressividade comercial fizeram com que a prática da adubação foliar se adiantasse à pesquisa.…”