Soil water storage under conservation tillage based on LSTM neural network simulation in the Loess Plateau Gully Region of central Gansu

In order to analyze the effects of soil water storage for four different tillage measurestraditional tillage (T), no-tillage with no straw cover (NT), traditional tillage with straw incorporation (TS) and no-tillage with straw cover (NTS), the field research was conducted in the Loess Plateau Gully Region of central Gansu. The objectives of the study were to establish a prediction model for soil water storage based on Long Short-Term Memory (LSTM), and to evaluate the model's effectiveness using the long-term positioning experiment of the rotation sequence for spring wheat/pea (W/P) and pea/spring wheat (P/W) crops. In the experiment, monthly average temperature, monthly precipitation, monthly average radiation, monthly average evaporation and monthly crop water consumption constituted input factors, and value for soil water storage constituted the output factor in the prediction model. The results of the present study showed that:1) The water storage model based on LSTM neural network showed good applicability for predicting soil water storage, particularly in conservation tillage practice, in the Loess Plateau Gully Region of central Gansu. The average root mean square error and mean absolute error of the model simulation were 7.76 mm and 6.95 mm, respectively; moreover, the relative error was controlled between -5% and +5%. 2) In P/W rotation sequence, the soil water storage of various treatments increased by 1.09%-1.43% as compared to W/P. 3) Within different rotation sequences, water storage effect of NTS treatment turned out to be better than those for other three tillage measures. In W/P rotation sequence, the annual average soil water storage of NTS treatment was 2.89%, 1.70% and 2.46% higher than that of T, NT, and TS, respectively. In P/W rotation sequence, the average annual soil water storage of NTS treatment increased by 3.03%, 1.91% and 2.57%, respectively, compared to that of T, NT, and TS. 4) In the years with different precipitation, the soil water storage of NTS treatment was the highest, and this effect was markedly more significant in the dry year. The soil water storage of NTS treatment increased by 2.71%, 1.48% and 2.19%, on average, in the wet year, and it increased by 3.97%, 2.54% and 3.64%, on average, in the dry year as compared to the values recorded for T, NT and TS. 5) The water storage effect for conservation tillage measures varied with the season. There was obvious water storage advantage of conservation tillage measures during the early stages of crop growth (March-May). However, there was not significant between the results of conservation tillage measures and traditional tillage during the full growth stage (May-June). Nevertheless, the soil water storages for conservation tillage increased significantly during the late stage of crop growth (July). Going by the effect on soil water storage based on LSTM neural network, no-tillage mulching remains the best practice as well as the most suitable measure of protective tillage in the Loess Plateau Gully Region of central Gansu.