Modern High-Yielding Maize, Wheat and Soybean Cultivars in Response to Gypsum and Lime Application on No-Till Oxisol

Abstract

Modern maize, wheat, and soybean cultivars are usually characterized by a short cycle, high shoot-root ratio, and high responsiveness to nutrient input. Continuous no-tillage management (NTS) frequently leads to a steep gradient in soil chemical quality with depth, thus decreasing yield under conditions of acid subsoil and water stress. This study aimed to evaluate the effect of gypsum, applied separately or in combination with lime, on the yield of cultivars used in the state of Rio Grande do Sul, Brazil. The study consisted of four experiments conducted on a typic Hapludox under NTS. The experiment was arranged in a randomized block design with three replications. Experiments I and II were carried out on soils with a satisfactory chemical soil quality and tested treatments of gypsum applications ranging from 0.0 to 6.5 Mg ha -1 . The other experiments were carried out on acid soil (experiment III) and a soil with an abrupt drop in chemical quality (experiment IV). Experiment III was arranged in a split plot design, where plots corresponded to gypsum rates between 0.0 and 5.0 Mg ha -1 , and subplots to two lime rates (0.0 and 2.0 Mg ha -1 ). Experiment IV was conducted in a split plot design, with plots consisting of gypsum rates from 0.0 to 6.0 Mg ha -1 and subplots of lime rates from 0.0 to 4.8 Mg ha -1 . Of a set of 17 harvests investigated during the experimental period, 82 % responded with yield increases to gypsum and lime inputs. The gypsum rate that induced the highest grain yield was high (4.7 Mg ha -1 ) and similarly, the maximum technical efficiency of lime was higher than the currently recommended. Furthermore, the combined application of lime and gypsum increased yield. There was a correlation between grain yield with the chemical quality of the soil layer 0.25-0.40 m in experiment I, 0.00-0.40 m in experiment II, and the 0.00-0.25 m in experiment IV. Only in experiment III, where the surface layer was acidic, the diagnostic layer usually sampled (0.00-0.10 m) was correlated with grain yield. Therefore, the use of the 0.00-0.25 m soil layer with critical base saturation values of 65 % and maximum Al saturation of 5 % could improve the current recommendations for soil correction. To exploit the yield potential of modern grain cultivars on dystrophic Oxisol, the formation of a thicker layer with high chemical quality is an efficient strategy.

Does gypsum increase crop grain yield on no‐tilled acid soils? A meta‐analysis

“…The number of pair observations and the total number of crop harvests (environment × year) included in each category are shown in parenthses. The critical thresholds for Al saturation in the 0.20-to 0.40-m layer for cereals were >5%, and those of soybean were >40 and >10% with and without the occurrence of water deficiency, respectively to gypsum under much less severe acid conditions Dalla Nora et al, 2017b;Tiecher et al, 2018), possibly as a result of gypsum increasing the availability of sulfate and basic cations in the subsoil and also of the potentially lower acidity tolerance and higher yield potential of current cultivars and hybrids (Dalla Nora et al, 2017b).…”

“…One of the phenomena triggering the adverse effects is the binding of exchangeable Al 3+ to various compounds present in root cells to block Ca 2+ channels and binding sites for transport proteins, thereby hindering absorption of exchangeable Ca 2+ and Mg 2+ , respectively (Zoca & Penn, 2017). Thus, some researchers have found the toxicity of exchangeable Al 3+ ions to adversely affect plant root systems Dalla Nora & Amado, 2013;Dalla Nora et al, 2017b;Michalovicz et al, 2014).…”

“…absence of deep liming usually contain high concentrations of exchangeable Al 3+ and low concentrations of exchangeable basic cations in the subsoil (Bortoluzzi et al, 2014). These conditions hinder root development and compromise nutrient and water uptake by plants, thereby reducing crop grain yields (Caires, Zardo Filho, Barth, & Joris, 2016;Dalla Nora & Amado, 2013;Dalla Nora, Amado, Nicoloso, & Gruhn, 2017b;Michalovicz et al, 2014). The effects of subsoil acidity are especially adverse in NT systems, which account for >32 Mha in Brazil and 180 Mha (12.5% of all cropland area) in the world (Kassam, Friedrich, & Derpsch, 2019).…”

“…The response of crops to gypsum is controversial and ranges from substantial to slight increases in grain yield Costa & Crusciol, 2016;Dalla Nora & Amado, 2013;Dalla Nora et al, 2017a;Soratto & Crusciol, 2008a). Some studies have revealed no effect (Dalla Nora et al, 2017b;Fontoura et al, 2019;Marchesan et al, 2017) Core Ideas • Crop response to gypsum is more likely in subsoils with high Al saturation under drought. • Cereals are more responsive to gypsum than is soybean, with the recommended thresholds levels differing between the two.…”

“…and (iii) What is the probability of a positive response and the associated mean increase in grain yield in NT soils? Answering these questions may help farmers and consultants adopt and improve gypsum application in NT soils (Dalla Nora et al, 2017b;Soratto & Crusciol, 2008a). In addition, establishing specific criteria for gypsum management based on experiments conducted mainly in Brazil may help extend its use to other tropical or subtropical regions (e.g., Latin America, Africa) with naturally acid and low-fertility subsoils (Kihara et al, 2017), although some regional research is necessary.…”