Imbalanced Soil Chemical Properties and Mineral Nutrition in Relation to Growth and Yield Decline of Sesame on Different Continuously Cropped Upland Fields Converted Paddy

Abstract

Sesame (Sesamum indicum L.) is an important oilseed crop, but is negatively affected by continuous cropping. There is still a lack of information on the effect of continuous cropping on soil chemical properties and mineral nutrition related to sesame growth and yield decline. Therefore, we investigated sesame growth and yield, nutrient concentration and soil chemical properties on five fields with continuous cropping history: non-continuous cropping (Year 0) and durations of two, four, five and six years on an upland field converted paddy in Tottori, Japan. Results show that plant height significantly decreased by 18.76%, 15.22%, and 13.64% in the Year 4, Year 5 and Year 6 fields, respectively, compared to Year 0. The effect of continuous cropping was more pronounced on the 1000-seed weight decline than seed yield. Compared to Year 0, seed yield decreased by 52.86% in Year 2 with no significant differences among the Year 2, Year 4, Year 5 and Year 6 fields, whereas the 1000-seed weight decreased by 6.68% and 12.20% in the Year 2 and Year 5 fields, respectively, compared to Year 0. Plant leaf tissue N concentration significantly decreased in the Year 2, Year 4 and Year 6 fields compared to Year 0, whereas leaf tissue K concentration decreased in the Year 6 field. The increase in duration of continuous cropping years gradually altered soil chemical properties. Soil pH, exchangeable Ca and Mg and cation exchange capacity (CEC) gradually increased in the long duration of continuous cropping, whereas total N and C, exchangeable NH4+-N, urease, dehydrogenase and catalase activities decreased. Our study suggested that the decrease in soil available N and enzyme activities, and decrease in K nutrition due to competitive ion effect as a result of increase in soil Ca and Mg could possibly contribute to the growth and yield decline of continuous sesame on upland field converted paddy.

Fatty Acid Composition of Sesame (Sesamum indicum L.) Seeds in Relation to Yield and Soil Chemical Properties on Continuously Monocropped Upland Fields Converted from Paddy Fields

“…The decrease in 1000-seed weight signifies that yield decline is consistent with Kelly et al [21], who found that yield decline of soybean under continuous monocropping is attributed to low seed weight. The decrease in 1000-seed weight and, consequently, yield of sesame has previously been attributed to decrease in N availability and to decrease in the uptake of K [7]. Our study showed markedly lower TN and exchangeable K in all continuously monocropped fields in 2016 when compared with those in 2015.…”

“…Despite the importance of sesame seeds, the production of sesame in Japan had been on a negligible scale although it is gradually increasing, especially on abandoned paddy fields [5,6]. However, we previously reported yield decline of sesame on upland fields converted from paddy fields under intensive continuous monocropping as a result of changes in soil nutrient availability [7]. We reported decrease in available N and unbalanced exchangeable cations in which high quantities of Ca and Mg affected uptake of K. These changes or imbalances in soil nutrient status under continuous monocropping of sesame could affect sesame seed composition.…”

“…Although sesame yield decline under continuous monocropping on upland fields converted from paddy fields has been reported [7], there is a lack of information on the fatty acid compositions of sesame seeds produced under such conditions. Moreover, one of the key factors that determine the quality of sesame seed is the fatty acid composition.…”

Growth and K Nutrition of Sesame (Sesamum indicum L.) Seedlings as Affected by Balancing Soil Exchangeable Cations Ca, Mg, and K of Continuously Monocropped Soil from Upland Fields Converted Paddy

“…It is reported that the growth and yield of crops decreased in long-term continuous monocropping due to several factors such as diseases, pests, depletion in soil nutrients, and nutrient imbalances [18]. Our previous study indicated that imbalances in soil exchangeable cations Ca, Mg, and K led to poor K nutrition as a result of high Ca and Mg inhibiting the uptake of K by sesame plants which partly limited sesame growth and yield under continuous monocropping on the upland field converted paddy [9]. Therefore, the poor growth of sesame in the un-balanced soil (control) confirmed the occurrence of continuous monocropping obstacle due to a low uptake of K. Apart from imbalances in cations Ca, Mg, and K, the decrease in K availability from continuous monocropping fields could be attributed to the annual removal of crop because sesame requires a high amount of potassium for growth and the seed usually accumulates a high amount of K as part of the mineral nutrient [8].…”

“…Sesame requires high concentration of K in the tissue, between 1.5% to 2.4%, and low K in the soil can cause poor growth [8]. However, our previous study reported that sesame growth is limited by poor K nutrition as a result of an imbalance in soil exchangeable cations that cause a competitive ion effect on continuous monocropping from upland fields converted paddy in Japan [9]. The decrease in the leaf tissue K content, and consequently its uptake, was attributed to an increase in soil exchangeable Ca and Mg in the long duration of continuous monocropping for four to six years, which caused a competitive ionic effect in the soil, thus negatively influencing the growth and yield.…”