Can Corn Be Grown in the Hilly Regions of South China? A Detailed Guide to Suitable Sowing Times

South China's hilly region is suitable for growing corn, and the growing areas are widely distributed, including all of Guangdong, Hainan, Fujian, Zhejiang, Jiangxi, Taiwan, China and other provinces, the southern part of Jiangsu and Anhui, and the eastern part of Guangxi, Hunan and Hubei; it is China's main rice-producing region, with a very small corn planting area, accounting for about 3.2% of the national total and 2.2% of production, and corn can be planted all year round.

This region has a subtropical and tropical humid climate, with relatively high temperatures and abundant rainfall; the period suitable for crop growth lasts as long as 220-360 days, and the effective accumulated temperature period suitable for corn growth and development is more than 250 days. Annual rainfall is 1000-1800 mm, evenly distributed, with 1600-2500 hours of sunshine throughout the year, and corn can be planted all year round. However, the climate conditions in this region are more suitable for growing rice, so the corn area is relatively small and not stable enough. But the region has good conditions for developing autumn and winter corn production, with great potential.

1. Cropping systems

This region has traditionally practiced multiple cropping, from two crops a year to three or four crops a year, and corn can be grown all year round, but it is mainly cultivated in autumn and winter. Representative cropping patterns include:

Wheat-corn-cotton (Jiangsu)

Wheat (or rapeseed)-rice-autumn corn (Zhejiang, Hubei)

Spring corn-late rice (Jiangxi)

Early rice-mid-season rice-corn (Hunan)

Spring corn (intercropped with green manure)-late rice (Guangxi)

Double-cropping rice-winter corn (Hainan)

Autumn corn in this region is mainly distributed in Zhejiang, Jiangxi and parts of Hunan and Guangxi, often as the third crop in a three-crop system, and also has the effect of paddy-upland rotation. Winter corn is mainly distributed in Hainan, Guangdong, Guangxi and southern Fujian; after the 1960s it developed into a southern propagation and breeding base for upland crops such as corn and sorghum, and after the 1980s it gradually became China's off-season melon and vegetable production base. Corn has become a fixed crop in multiple cropping systems and is also an important component of paddy-upland rotation.

This region has rich experience in raising seedlings and transplanting corn; for example, in the autumn corn areas of Zhejiang, Jiangxi, Hunan and other provinces, nutrient pot seedling raising is generally used, and corn is transplanted in time after the mid-season rice harvest, which can significantly increase corn yield.

2. Main corn varieties grown

The corn area in the hilly region of South China is relatively small, and some subtropical corn varieties can be grown, but varieties planted in winter require low-temperature tolerance and relatively early maturity, and also need resistance to multiple diseases and pests, such as stalk rot, rust and sheath blight. The main varieties grown in this region include: Guideng No. 1, Yedan 13, Yayu No. 2, Yedan 12, Yundan No. 1, etc.

3. Analysis of production conditions and measures to further increase yield

The hilly corn region of South China has a large population and little land, abundant water and heat resources, and a relatively high level of production technology; it is an important production base for commercial grain and various economic crops in China. However, the soil texture is poor, the fertility of red and yellow soils is relatively low, and soil erosion is severe. In land use, paddy fields are valued more than dryland. On hilly dryland, farmland water conservancy facilities are relatively poor, corn cultivation and management are extensive, and yields are relatively low. Local farmers and technicians lack corn-growing experience and adapted varieties, which also limits the improvement of corn yield levels.

The southern provinces are the main consuming areas for commercial corn, and large amounts of corn are transported from the north or imported from abroad every year. Many farmers have to use rice to feed livestock and poultry, which is very uneconomical. Developing autumn and winter corn production in the south will alleviate part of the supply-demand contradiction and help establish a sustainably growing agricultural production structure. At the same time, with the development of farmland water conservancy construction, increased fertilizer application, expanded green manure planting and improved soil fertility, it will be conducive to expanding the development of autumn and winter corn production. Developing autumn and winter corn production in the south requires solving the following problems:

(1) Develop winter fallow fields. In the rice-producing areas of South China, 180 million mu of dryland are still not fully utilized, of which about 100 million mu are suitable for planting corn. By reforming the farming system, increasing the multiple cropping index, and developing intercropping and relay intercropping, southern corn production can be effectively promoted. At the same time, advanced cultivation techniques should be promoted, such as rational close planting, seedling raising and transplanting, and using corn stalks to feed cattle, then increasing fertilizer application, and improving dryland and barren slopes and beaches.

(2) Expand paddy-upland rotation. Hunan and Hubei provinces have reformed their cropping systems and promoted spring corn-late rice or early rice-summer corn paddy-upland rotation multiple cropping; corn yield per mu can reach 400-500 kg, rice yield per mu can reach 500-600 kg, and the two seasons together can exceed one ton of grain per mu. Guangdong, Jiangxi and Fujian are also demonstrating this yield-increasing technique.

Promote corn-based intercropping and relay intercropping techniques on hilly dryland. For example, intercropping or relay intercropping corn with sweet potato, peanut, beans, etc., can increase income by 200-250 kg of corn per mu on top of the original crops.

Promote plastic film mulching techniques in high-cold mountainous areas. Corn can increase yield by 30-50%.

Select and breed improved varieties. The south lacks adapted hybrids; varieties introduced from other regions usually cannot fully adapt to the ecological requirements and natural conditions of multiple cropping in the hilly region of South China, and their disease resistance is also not fully suitable, so the yield potential of these varieties cannot be brought into full play. Breeding adapted hybrids is an important measure for developing autumn and winter corn production in the south.

Increase fertilizer application, and research and promote local high-yield corn cultivation techniques.