Potassium Effects on Partitioning, Yield, and Earliness of Contrasting Cotton Cultivars

Abstract

Potassium nutrition requirements may differ in cotton (Gossypium hirsutum L.) cultivars that contrast in maturity and growth habit. Our objectives were to determine the effects of K fertility on carbohydrate and biomass partitioning, earliness, and lint yields of two contrasting cultivars. Fertilizer rates of 56 and 112 kg K ha 21 yr 21 , representing 13 and 23 recommended K rates, were applied to long-term K fertility plots on a no-tilled Loring silt loam (thermic Oxyaquic Fragiudalf) in Jackson, TN. Plant samples were harvested at early bloom and cutout, to evaluate carbohydrate and dry matter partitioning during boll filling. Earliness was determined as the percentage of total yield at the first of two harvests. The more determinate cultivar, 'Paymaster PM1218 BG/RR', had higher aboveground dry weight, main stem starch concentrations and percentage first harvest, representing earlier maturity than the more indeterminate 'Deltapine DP555 BG/RR'. The 23 K rate delayed maturity relative to the 13 rate, reflected in biomass partitioning and lint yield distribution. Lint yields were lower at the 13 than at the 23 K in the more determinate cultivar, but K did not affect the indeterminate yields. The two cultivars had equivalent lint yields at the 23 K rate, but the indeterminate cultivar produced more vegetative biomass, further delaying its maturity. Results suggest that an earlier, more determinate cultivar may require more K fertilization for optimal yield response with no tillage.

Potassium Uptake and Partitioning Relative to Dry Matter Accumulation in Cotton Cultivars Differing in Maturity

“…Significant growth responses to additional K were thus observed only rarely, but more often in vegetative than reproductive organs. Results are consistent with those of Clement‐Bailey and Gwathmey (2007)…”

“…Yields of FM 960 and DP 555 were equivalent in 2006 and 2007, although yields of the two cultivars tended ( P = 0.068) to respond differently to K in 2007 (Table 1). There were no significant cultivar × K interactions for yield in this study, unlike the earlier study of Clement‐Bailey and Gwathmey (2007) These researchers reported that PM 1218 yielded about 9% less than DP 555 at the 56‐kg K rate, but that the two cultivars produced equivalent yields with 112 kg K ha −1 Like the current study, however, Clement‐Bailey and Gwathmey (2007) reported a delay in harvest maturity of both cultivars with the higher K fertilization rate.…”

“…In light of higher yield potential of newer cultivars, cultivar responses to higher K fertilization rates have been compared in the southern U.S. cotton belt. Comparing eight cultivars ranging in maturity, Tupper et al (1996) found that yields of some earlier maturing varieties increased with K fertilization rates up to 224 kg K ha −1 yr −1 for 6 yr, while yield for the latest maturing variety was maximized with just 112 kg K ha −1 Clement‐Bailey and Gwathmey (2007) found that two cultivars contrasting in earliness differed in yield and biomass partitioning in response to 56 and 112 kg K ha −1 yr −1 In response to the higher K rate, the earlier maturing cultivar partitioned more dry matter to bolls and produced more yield, while a later, more indeterminate cultivar partitioned more dry matter to vegetative growth but produced no more lint. However, the latter investigators did not report K partitioning or uptake rates, nor rates of dry matter accumulation.…”

Fine root production and mortality in irrigated cotton, maize and sorghum sown in vertisols of northern New South Wales, Australia

“…This may cause a greater proportion of photosynthates to be translocated to above-ground organs of Bollgard varieties rather than the roots, thus resulting in lower root densities than in non-Bollgard varieties. Our observation support the reports by some authors (Clement-Bailey and Gwathmey, 2007;Hulugalle et al, 2014) that root density of Bollgard 1 cotton in some depths was less than that in the corresponding non-Bollgard cotton variety. Clement-Bailey and Gwathmey (2007) have suggested that the lower root densities in Bollgard cotton may reduce potassium uptake.…”

Potassium Fertility Effects Yield Components and Seed Potassium Concentration of Determinate and Indeterminate Soybean

“…The indeterminate MG IV soybean cultivars tend to have a slightly shorter growing season and may be more susceptible to yield loss from nutrient deficiency than the determinate MG V cultivars. Although we could find no conclusive information for soybean, short‐season cotton ( Gossypium hirsutum L.) cultivars are reported to be more sensitive to K deficiency than long‐season cultivars (Tupper et al, 1996; Clement‐Bailey and Gwathmey, 2007). The growth differences between determinate and indeterminate soybean cultivars suggest that their response to K deficiency could be different.…”