Comprehensive climate factor characteristics and quantitative analysis of their impacts on grain yields in China's grain-producing areas

An ensemble deep learning approach for predicting cocoa yield

One important aspect of agriculture is crop yield prediction. This aspect allows decision-makers and farmers to make adequate planning and policies. Before now, various statistical models have been used for crop yield prediction but this approach experienced some hiccups such as time wastage, inaccurate prediction, and difficulties in model usage. Recently, a new trend of deep learning and machine learning are now adopted for crop yield prediction. Deep learning can extract patterns from a large volume of the dataset, thus, they are suitable for prediction. The research work aims to propose an efficient deep-learning technique in the field of cocoa yield prediction. This research presents a deep learning approach for cocoa yield prediction using a Convolutional Neural Network and Recurrent Neural Network (CNN-RNN) with Long Short Term Memory (LSTM). The ensemble approach was adopted because of the nature of the dataset used. Two different sets of the dataset were used, namely; the climatic dataset and the cocoa yield dataset. CNN-RNN with LSTM has some salient features, where CNN was used to handle the climatic dataset, and RNN was employed to handle the cocoa yield prediction in southwest Nigeria. Two major problems generated by the CNN-RNN model are vanishing and exploding gradients and this was handled by LSTM. The proposed model was benchmarked with other machine learning algorithms based on Mean Absolute Error (MAE), Mean Square Error (MSE), Root Mean Square Error (RMSE), and Mean Absolute Percentage Error (MAPE). CNN-RNN with LSTM gave the least mean of absolute error as compared to the other machine learning algorithms which shows the efficiency of the model.

Assessing the Sensitivity of Main Crop Yields to Climate Change Impacts in China

Quantitatively assessing the spatial divergence of the sensitivity of crop yield to climate change is of great significance for reducing the climate change risk to food production. We use socio-economic and climatic data from 1981 to 2015 to examine how climate variability led to variation in yield, as simulated by an economy–climate model (C-D-C). The sensitivity of crop yield to the impact of climate change refers to the change in yield caused by changing climatic factors under the condition of constant non-climatic factors. An ‘output elasticity of comprehensive climate factor (CCF)’ approach determines the sensitivity, using the yields per hectare for grain, rice, wheat and maize in China’s main grain-producing areas as a case study. The results show that the CCF has a negative trend at a rate of −0.84/(10a) in the North region, while a positive trend of 0.79/(10a) is observed for the South region. Climate change promotes the ensemble increase in yields, and the contribution of agricultural labor force and total mechanical power to yields are greater, indicating that the yield in major grain-producing areas mainly depends on labor resources and the level of mechanization. However, the sensitivities to climate change of different crop yields to climate change present obvious regional differences: the sensitivity to climate change of the yield per hectare for maize in the North region was stronger than that in the South region. Therefore, the increase in the yield per hectare for maize in the North region due to the positive impacts of climate change was greater than that in the South region. In contrast, the sensitivity to climate change of the yield per hectare for rice in the South region was stronger than that in the North region. Furthermore, the sensitivity to climate change of maize per hectare yield was stronger than that of rice and wheat in the North region, and that of rice was the highest of the three crop yields in the South region. Finally, the economy–climate sensitivity zones of different crops were determined by the output elasticity of the CCF to help adapt to climate change and prevent food production risks.