In order to determine the effects of different water-saving irrigation techniques on physiological growth, farmland microclimate, and yield of cotton (Gossypium Spp.), a two-year field experiment was carried out in an oasis area of Northwest China, and three irrigation methods were tested, including on-film irrigation (T1), under-film drip irrigation (T2), and automatic irrigation (T3). The results showed that the relative humidity, plant height, leaf area, stem thick, and photosynthetic index with the T3 treatment were significantly higher than those with T2 and T1. The air and soil temperature with T3 (except seedling stage) were considerably lower than those with T2 and T1. According to the fitting and statistical analysis of each index and yield, except for air and soil temperature, the other indices were positively correlated with yield. Based on the analysis of each index, the T3 treatment had the most significant regulatory effect on cotton’s physiological growth and farmland microclimate. Compared with T1, the irrigation amounts of T2 and T3 decreased by 16.43% and 25.90%, but the yield increased by 38.96% and 46.28%, respectively. The automatic irrigation strategy showed significant advantages in water saving and yield increase, which could provide some reference for cotton drip irrigation in similarly arid areas.

Xinjiang has a serious wind erosion problem due to its fragile ecological condition and sensitivity to climate change. Wind erosion climatic erosivity is a measure of climatic factors influencing wind erosion; evaluating its spatiotemporal variations and relationship with the large-scale circulation pattern can contribute to the understanding of the climate change effect on wind erosion risk. Thus, this study quantified the wind erosion climatic erosivity and examined the connections between climatic erosivity and climate indices using trend analysis, geo-statistical analysis, and cross-wavelet analysis based on the observed daily meteorological data from 64 weather stations in Xinjiang, China during 1969–2019 (50 years). The results indicated that the climatic erosivity showed a significant downward trend at seasonal and annual scales over the past 50 years. Strong seasonality in the C-factor was found, with its highest values in the spring and summer and its lowest values in the winter. The average climatic erosivity was weaker during El Niño events than during La Niña events. The impact of El Niño events on climatic erosivity in Xinjiang continued from the beginning of the event to two months after the end of the events. The La Niña events had a lag effect on the climatic erosivity in Xinjiang, with a lag period of 4 months. From a statistical perspective, the El Niño-Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), and Arctic Oscillation (AO) indices showed relationships to the climatic erosivity in Xinjiang in terms of their correlation and periodicity. The relationships between the climatic erosivity and ENSO were not clearly positive or negative, with many correlations advanced or delayed in phase. The NAO and AO indices showed a consistent in-phase relationship with climatic erosivity on significant bands, whereas the profound mechanisms involved in this require further study. The results of this study provide a preliminary perspective on the effect of large-scale atmospheric circulation on wind erosion risk in arid and semi-arid regions.

A two-year experiment was established in the northern Xinjiang to investigate the effects of autumn plowing methods on nitrate nitrogen accumulation, spring-sown soil conditions and cotton emergence rate, and to explore the response relationship between soil water, heat and nitrate nitrogen. The experiment included five autumn plowing treatments, namely, plough tillage (FG), no-tillage (MG), ridge and furrow alternation (LG), plough tillage with straw mulch (FJ) and plough tillage with activated charcoal mulch (FH). The results showed that both FH and FJ treatments were beneficial to promote the nitrate-nitrogen accumulation in topsoil, while FG, MG and LG treatments aggravated the nitrate nitrogen leaching in topsoil. During the freezing period, FH and FJ treatments were beneficial to reduce soil heat loss and facilitate the coordinated upward migration of soil water and nitrate nitrogen. In the thawing period, FH and FJ treatments favored suppressing the synergistic downward transport of soil water and nitrate-nitrogen and motivated the synergistic upward migration of heat and nitrate nitrogen in deep soil. Binary regression analysis suggested that the interaction between water, heat and nitrate nitrogen under FH and FJ treatments showed a highly significant correlation. FH and FJ treatments showed obvious advantages in regulating soil conditions and optimizing soil water, heat and nitrate nitrogen co-transport mechanism. During the spring sowing period, the FH and FJ treatments increased the average soil temperature by 0.99°C and 1.29°C, and the average soil moisture content by 6.01% and 8.70%, and the average soil nitrate content by 10.20 mg/kg and 10.47 mg/kg, in the 0-25 cm soil layer, respectively. FH and FJ treatments significantly grew the emergence rate of cotton, which can be used as the main autumn tillage strategies in arid areas of northern Xinjiang. Keywords: autumn plowing, seasonal freeze-thaw, nitrate nitrogen accumulation, water-heat-nitrogen interaction, Xinjiang DOI: 10.25165/j.ijabe.20221506.7269 Citation: Sun K, Wang C X, Liu H G, Liang F, Wang Y Q. Effects of autumn plowing on the movement and correlation of moisture, heat and nitrate nitrogen in seasonal freeze-thaw soil. Int J Agric & Biol Eng, 2022; 15(6): 143–152.