Search

Purpose – Fewer researchers have investigated the climatic and economic drivers of land-use change simultaneously and the interplay between drivers. This paper aims to investigate the nonlinear and interaction effects of price and climate variables on the rice acreage in high-latitude regions of China. Design/methodology/approach – This study applies a multivariate adaptive regression spline to characterize the effects of price and climate expectations on rice acreage in high-latitude regions of China from 1992 to 2017. Then, yield expectation is added into the model to investigate the mechanism of climate effects on rice area allocation. Findings – The results of importance assessment suggest that rice price, climate and total agricultural area play an important role in rice area allocation, and the importance of temperature is always higher than that of precipitation, especially for minimum temperature. Based on the estimated hinge functions and coefficients, it is found that total agricultural area has strong nonlinear and interaction effects with climate and price as forms of third-order interaction. However, the order of interaction terms reduces to second order after absorbing the expected yield. Additionally, the marginal effects of driven factors are calculated at different quantiles. The total area shows a positive and increasing marginal effect with the increase of total area. But the positive impact of price on the rice area can only be observed when price reached 50% or higher quantiles. Climate variables also show strong nonlinear marginal effects, and most climatic effects would disappear or be weakened once absorbing the expected rice yield. Expected yield is an efficient mechanism to explain the correlation between crop area and climate variables, but the impact of minimum temperature cannot be completely modeled by the yield expectation. Originality/value – To the best of the authors’ knowledge, this is the first study to examine the nonlinear response of land-use change to climate and economic in high-latitude regions of China using the machine learning method.

Efforts to increase sweet corn production are carried out by utilizing marginal land equipped with drip irrigation. This effort requires assembling sweet corn hybrid seeds that are suitable for marginal land. Assembling hybrid varieties requires information related to the expected testing of several hybrid lines. The objective of this study is to examine the growth and yield potential of several combinations of F-1 expectation crosses in marginal land use drip irrigation. This study was conducted at the Experimental Garden of Faculty of Agriculture, UPN “Veteran” Yogyakarta. This study used a diallel cross design with three replications. The treatments were 10 numbers of sweet corn consisting of 7/5-1B, KD/1-3, and 50/4-2B as parents, KD/1-3☓7/5-1B, KD/1-3☓50/4-2B, 7/5-1B☓KD/1-3, 7/5-1B☓50/4-2B, 50/4-2B☓KD/1-3, 50/4-2B☓7/5-1B as F1 and the sweet corn variety Talenta for comparison. The observation variable consisted of plant height, number of leaves, stem diameter, ear height, male flowering age, female flowering age, ear length without husk, ear diameter without husk, weight of ear without husk and level of sweetness. Each variable was analyzed using variance with α = 5%. The results showed that the combination of the F-1 hope crosses which has the potential to become a hybrid variety is the combination of 50/4-2BXKD/1-3 crosses.