Does intercropping have a future in China? Insights from a case study in Gansu Province Yu Hong i Thesis committee Promotor Prof. Dr E.H. Bulte Professor of Development Economics Wageningen University & Research Co-promotors Dr N.B.M. Heerink Associate professor, Development Economics Group Wageningen University & Research Dr W. van der Werf Associate professor, Centre for Crop Systems Analysis Wageningen University & Research Other members Prof. Dr M.K. van Ittersum, Wageningen University & Research Prof. Dr S. Feng, Nanjing Agricultural University, P.R. China Dr X. Zhu, Wageningen University & Research Dr T. Feike, Julius Kühn-Institut, Kleinmachnow, Germany This research was conducted under the auspices of the Wageningen School of Social Sciences (WASS) ii Does intercropping have a future in China? Insights from a case study in Gansu Province Yu Hong Thesis submitted in fulfilment of the requirement for the degree of doctor at Wageningen University by the authority of the Rector Magnificus, Prof. Dr A.P.J Mol, in the presence of the Thesis Committee appointed by the Academic Board to be defended in public on Monday 2 July 2018 at 1.30 p.m. in the Aula. iii Yu Hong Does intercropping have a future in China? Insights from a case study in Gansu Province, 189 pages. PhD thesis, Wageningen University, Wageningen, the Netherlands (2018) With references, with summary in English ISBN: 978-94-6343-779-0 DOI: https://doi.org/10.18174/450672 iv Table of Contents 1. Introduction ................................................................................................................................... 2 1.1 Problem statement ................................................................................................................. 2 1.2 Objectives and research questions ....................................................................................... 6 1.3 Study area and data collection ............................................................................................. 7 1.4 Outline of the thesis ............................................................................................................... 8 References ........................................................................................................................................ 10 2. Intercropping and agroforestry in China – Current state and trends ............................................... 15 2.1 Introduction ......................................................................................................................... 17 2.2 Material and methods ......................................................................................................... 21 2.2.1 Data collection .............................................................................................................. 21 2.2.2 Intercropping and agroforestry land classification .................................................. 24 2.2.3 Methods of data analysis ............................................................................................. 25 2.3 Results ................................................................................................................................... 28 2.3.1 Intercropping: State and trend .................................................................................. 28 2.3.2 Agroforestry: State and trend .................................................................................... 29 2.3.3 Mixed cultivation systems: State, trend and crop combinations ............................. 31 2.3.4 Explorative analysis of occurrence of intercropping ............................................... 36 2.3.5 Explorative analysis of occurrence of mixed cultivation ......................................... 38 2.4 Discussion ............................................................................................................................. 40 2.5 Conclusions .......................................................................................................................... 44 References ........................................................................................................................................ 46 Appendix .......................................................................................................................................... 51 3. The contribution of intercropping to the technical efficiency of smallholder farming: a case study in Gaotai, China ........................................................................................................................ 62 3.1 Introduction ......................................................................................................................... 63 3.2 Technical efficiency and intercropping ............................................................................. 66 3.3 Model specification .............................................................................................................. 68 3.3.1 Technical efficiency and frontier production function ............................................. 68 3.3.2 Empirical model ........................................................................................................... 70 3.3.3 Estimation method ....................................................................................................... 73 3.4 Data set ................................................................................................................................. 73 3.4.1 Data collection and sampling ...................................................................................... 73 3.4.2 Input and output variables ......................................................................................... 76 3.5 Empirical results and interpretation ................................................................................. 79 - vi - 3.5.1 Production frontier ...................................................................................................... 79 3.5.2 Input-output elasticities .............................................................................................. 81 3.5.3 Technical efficiency estimates ..................................................................................... 82 3.5.4 Factors influencing technical efficiency ..................................................................... 83 3.6 Conclusion ............................................................................................................................ 86 References ........................................................................................................................................ 88 4. Socio-economic factors influencing the adoption of intercropping - Evidence from northwest China ..................................................................................................................................................... 95 4.1 Introduction ......................................................................................................................... 96 4.2 Theoretical framework ....................................................................................................... 98 4.2.1 Yield gains .................................................................................................................... 98 4.2.2 Risk reduction .............................................................................................................. 99 4.2.3 Labour costs ............................................................................................................... 100 4.2.4 Human assets ............................................................................................................. 100 4.2.5 An integrated framework ......................................................................................... 101 4.3 Model specification and estimation strategy ................................................................... 104 4.3.1 Model specification .................................................................................................... 104 4.3.2 Estimation strategy .................................................................................................... 108 4.4 Data and descriptive statistics .......................................................................................... 109 4.4.1 Data collection ............................................................................................................ 109 4.4.2 Descriptive statistics .................................................................................................. 111 4.5 Results and discussion ....................................................................................................... 114 4.6 Conclusion .......................................................................................................................... 121 References ...................................................................................................................................... 123 Appendix ........................................................................................................................................ 128 5. The future of intercropping under growing resource scarcity and declining grain prices in China - A model analysis .................................................................................................................. 131 5.1 Introduction ......................................................................................................................