Late-planted short-season cotton without plastic mulching is an alternative to early-planted mulched full-season cotton

Abstract

The early planting of full-season cotton (Gossypium hirsutum L.) at a moderate plant density under plastic mulching is a traditional means of growing cotton in the Yellow River valley of China. However, it is labor intensive, consumes a large amount of materials, and also results in residual plastic pollution in the soil. While our previous studies indicated that late planted short-season cotton under plastic mulching greatly reduces labor and material inputs and increases net revenue, the residual plastic pollution remains an issue. It is unclear if short-season cotton can be managed without yield loss in the absence of plastic mulching. A field experiment was therefore conducted using a random complete block design with four treatments, including the early planting of full-season cotton with (FCM) and without plastic mulching (FC), and the late planting of short-season cotton with (SCM) and without plastic mulching (SC), in the Yellow River valley from 2017 to 2019. The yield, yield components, input and output values, earliness, dynamics of flowering and boll setting, and late-season leaf senescence in cotton were examined. The results showed that early planted full-season cotton under mulching (FCM) produced a 21.1 and 20.4 % higher seedcotton yield and boll density, respectively, and improved earliness over the non-mulched treatment, while the boll weight did not differ significantly. Short-season cotton without plastic mulching produced comparable seedcotton yields to that with mulching (SCM), and there was no significant difference in average boll weight, boll density, or earliness between the mulching and non-mulching treatments. However, SC had a 7.0 and 12.1 % smaller boll density and boll weight, respectively, than FCM and thus produced a 17.9 % lower seedcotton yield. Therefore, SC produced 14.9 and 14.4 % greater net returns than SCM and FCM, respectively, because it consumed less labor and material inputs. Short-season cotton without plastic mulching delayed leaf senescence due to reduced boll load and thus increased boll weight in the late season compared with SCM. In addition, SC exhibited improved earliness as a result of a higher flowering rate, faster fruiting, and more concentrated boll opening than FCM. Short-season cotton without plastic mulching also avoided the residual film pollution in the soil. The overall results demonstrated that the late planting of short-season cotton without mulching is a promising alternative for sustainable cotton production in the Yellow River valley region of China as well as other cotton growing areas with similar ecology.