Soybean Response to Tillage and Nitrogen, Phosphorus, and Potassium Fertilization¹

Abstract

Consenation tillage is being increasingly recommended as a means of reducing both cost of tillage and soil erosion. A study was conducted for two years with the objective of evaluating the performance of a determinate soybean (Glycine max (L.) Merr.) cultivar, Sprite, planted in narrow rows on a Nicollet (Aquic Hapludolls)-Webster (Typic Haplaquolls) complex, with different tillage systems and different levels of N, P, K fertilization for higher yield. Variables studied included: (i) three tillage systems (disk, chisel plow, and moldboard plow tillage) and (ii) three levels of N, P, and K fertilization (Pat 0, 74 and 111 kg/ha; Kat 0, 186, and 279 kg/ha; and Nat 0, 135, and 270 kg/ha). Plant population was unaffected by the treatments. Phosphorus and K applications increased soil and leaf P and K contents over time and with application levels. Tillage had no significant effect on grain yield. Lodging was significantly increased by P application. Lodging, plant height, and grain yield were significantly increased by K application. Nitrogen application increased lodging and plant height, but not yield. It was concluded that soybean can be successfully grown with reduced tillage in central Iowa without a yield reduction or change in fertility requirement. Soybean responded to K application when the soil test levels were medium to high.

Agri-environmental models using Mehlich-III soil phospho rus saturation index for corn in Quebec

“…Soybean crops did not respond to fertilizer P except in two soils showing (P/Al) M-III ratios of 0.010 and 0.014. In general, soybean does not respond to fertilizer P at high to excessively high STP, but could respond in soils with low or extremely low STP levels (DeMooy et al 1973;Bharati et al 1986;Mallarino et al 1991;Tremblay and Beausoleil 2000). The critical agronomic (P/Al) M-III ratios were thus driven by corn rather than soybean in corn-soybean rotations.…”

Physiological quality of soybean and wheat seeds produced with alternative potassium sources

“…Many authors have found positive effects of K on seed weight and quality (Bharati et al, 1986;Khan et al, 2004). However, this study aimed to compare the effects of alternative sources of K, and KCl was considered as the control because it is the most common source of K supplied to plants.…”

“…However, at some point, as the rates were increased, the difference between the alternative sources and the KCl became significantly higher (Figure 2). Although KCl is an important source of K, Borkert et al (1996) observed that in Paraná state, Brazil, the recommended doses applied in-furrow can harm seedling emergence and studies have shown saline stress symptoms caused by doses higher than 80 kg ha -1 . Conversely, the other K sources supplied for soybean development may have been more appropriate, resulting in the production of high quality seeds.…”

Réponse du soya à la fertilisation minérale en éléments majeurs NPK sur des sols classés de riches à excessivement riches en phosphore ou en potassium des Basses Terres du Saint-Laurent

“…Le soya ne répond donc pas à la fertilisation minérale en éléments majeurs sur de tels types de sols. Cette constatation est similaire à celles de Hanway et al (1962) et Bharati et al (1986) qui ont démontré que les probabilités que le soya réponde à une fertilisation en phosphore ou en potassium sur des sols riches en ces éléments sont très faibles. L'effet de l'azote (N) est généralement non significatif sur le rendement, sauf pour les séries Dujour et SainteRosalie en 1996 (tableau 3).…”

“…D'autre part, plusieurs études démontrent qu'il y a peu ou pas d'augmentation de rendement du maïs-grain ou du soya lorsque la richesse des sols en phosphore et en potassium assimilables par les plantes est supérieure au niveau moyen (Hanway et al 1962;Grove et al 1987). Quelques essais réalisés sur des sols riches en phosphore ou en potassium du Corn Belt révèlent que les probabilités que le soya ou le maïs-grain répondent à une fertilisation en phosphore ou en potassium sont très faibles (Hanway et al 1962;Bharati et al 1986). Mallarino et al (1991a,b) ont d'ailleurs démontré que les producteurs de soya et de maïs-grain pouvaient augmenter la rentabilité économique de leur entreprise en ne fertilisant pas en phosphore ou en potassium les sols classés riches ou excessivement riches en ces éléments.…”