Adaptability Analysis of Walnut in Zigui County

A Brief Analysis of the Adaptability of Walnut in Zigui County

Since 2004, Zigui County has firmly seized the opportunities of the Grain for Green Program, modernagriculture, and follow-up projects of the Three Gorges, and has cumulatively established walnutbases of 14,900 hm2, which has become the second largest forest and fruit industry in Zigui Countyand also the number one walnut county in Yichang City. At present, due to various reasons,walnuts suffer from many pests and diseases and cannot hold their fruit, resulting in poor benefits from walnuts, and manycadres and masses doubt the adaptability of walnuts in Zigui County, leading tothe phenomenon of letting walnuts grow unchecked or cutting down trees to grow grain occurring from time to time. If thiscontinues, it will seriously affect the development of the walnut industry in Zigui. This article conducts a scientificanalysis of the adaptability of cultivated walnuts in Zigui in order to strengthen the confidence of the broadcadres and masses.

1 Analysis of the adaptability of walnuts in Zigui from conditions such as climate and soilAdaptability

1.1 Comparative analysis of climatic conditions

1.1.1 Comparative analysis of temperature conditions

Comparing the adaptability of walnuts to temperature with the annual temperature situation of Zigui County(see Table 1) yields: Zigui County has a relatively high average annual temperature and a relatively long frost-free period;the meteorological observation point is at a low altitude of 295.5 m, while walnut cultivationpoints are in the high-altitude area of 600-1,200 m, where the temperature will be somewhat lower,thus it can be asserted that it basically meets the needs of walnut growth and development.

Table 1 Comparison of temperature conditions in Zigui County and the suitable range for walnuts

1.1.2 Comparative analysis of light conditions

After walnuts enter the fruiting stage, they need sufficient light conditions, and the annualsunshine hours are required to be >2,000 h to ensure normalgrowth and development of walnuts; if <1,000 h, both the shell and kernel develop poorly.The annual sunshine hours in Zigui County are 1,567.3 h (data from 1998-2015).The light conditions are slightly insufficient; as long as comprehensive measures such as site selection, planting density,and pruning are taken to compensate, there is no problem in meeting thelight requirements for walnut growth.

1.1.3 Comparative analysis of moisture conditions

Generally, an annual rainfall of 600-800 mm meets theneeds of walnuts;the annual rainfall in cultivation areas of iron walnut is 800-2,000 mm. The annual precipitationin Zigui County is 1,264.0 mm (data from 1998-2015).From the analysis of annual rainfall, Zigui is relatively suitable for cultivating iron walnut, and cultivatingwalnut is prone to serious diseases due to the large rainfall. Many years of cultivation practice in Ziguihave proved that introduced northern walnut varieties such as Liaoning No. 1, Xiangling, and Luguangare seriously susceptible to disease, which is one of the important reasons for the low benefits;while the introduced Yunxin series interspecific hybrid varieties and the budsport variety "Zhilin No. 1" selected from them are less susceptible to disease. Therefore, when cultivating walnutson a large scale in Zigui, disease resistance must be considered as an important indicator. Liu Xianglinproposed that iron walnut or varieties with iron walnut genes should be selectedfor cultivation.

1.2 Comparative analysis of soil conditions

Walnuts require soil with pH 6.2-8.2 (optimal pH 6.5-7.5), preferably slightly acidic soil, neutral soil, and weakly alkaline soil rich in lime,and grow poorly in soil with too high a groundwater level (requiring the groundwater level to be below 2 m) andheavy clay soil. Zigui is a mountainous county with relatively little flat land,good drainage, and basically no problem of high groundwater level. TheZigui County Agriculture Bureau, from 2006 to 2015, respectively in 12 townshipsand 186 villages of the whole county, took 15,928 sampling points for soil testing.Points with pH 6.0-8.5 accounted for more than 50% of the whole county, and organic matter wasabundant, with relatively high contents of major and secondary elements; coupled with reasonable fertilization, they can meet thegrowth needs of walnuts in all periods. However, there are also a few places with insufficient soil fertility,relatively thin soil layers, and heavy clay soil, and walnuts cannot be plantedin these places.

2 From cultivation history, proving the adaptability of walnuts in Zigui

Zigui County has a long history of walnut cultivation, with more than 1,000 existing large treesover 30 years old, among which one ancient walnut tree in Jiulingtou Village, Quyuan Town,is over 150 years old, with a breast circumference of 3.44 m, a tree height of 20m, and can harvest 100 kg of dried walnuts each year. From 2011 to 2012, 7superior plants were selected for asexual progeny testing and regional trial experiments.

Consulting the Hubei Province Statistical Yearbook from 1958 to 1995, there were 11 counties (cities) inHubei Province with historical output exceeding 100 tons (see Table 2), and ZiguiCounty had 147.05 t in 1978.

Table 2 Overview of counties in Hubei Province with historical annual walnut output exceeding 100 tonsUnit: t

From the existing status of walnut resources and the historical walnut output of Zigui,it can be fully proved that Zigui is suitable for the development of the walnut industry.

3 From successful cultivation examples, proving the adaptability of walnuts in ZiguiAdaptability

3.1 Introduction and breeding of walnut varieties suitable for Zigui CountyZigui County has successively introduced varieties such as Liaohe, Zhonglin, Xiangling, Luguang, Qingxiang,and Yunxin for cultivation. The Yunxin series, hybridized by the Yunnan Academy of Forestry with Yunnan bubble walnut xXinjiang early-fruiting walnut, is the most adaptable, among whichYunxin GaoyuanandYunxin Yunlintwo varieties perform best. The walnut bud sport variety "Zhilin No. 1" selected from Yunxin Gaoyuanhas passed theapproval of the Hubei Province Forest Tree Variety Approval Committee, becoming the current bestnew early-fruiting walnut variety in Hubei Province.

3.2 Farmers' cultivation practice proving the adaptability of walnuts in Zigui

Through years of practical exploration, although the benefits of large-scale walnut cultivation in Ziguiare not good, some farmers have basically mastered the key points of cultivation and managementtechniques, and a number of advanced examples of shaking off poverty and becoming rich through developing walnutshave emerged, setting an example for the development of the county's walnut industry. For example: Mei Dasanof Shuitianya Village, Meijiahe Township, Wang Shifeng of Jingzhangping Village, Wan Min, Tan Yuanjing, Zheng Jialiangof Tanjiahe Village, Lianghekou Town, Zhou Yao of Quyuanmiao Village,Zhou Zongcheng of Dayuchi Village, Zhenxi Town, etc., whose perennialdried walnut output per mu is all above 150 kg; in particular, Mei Yungangof Shazhenxi Town has had a per-mu output of more than 300 kg for 6 consecutive years, with an average per-mu income reaching 10,000 yuan.

4 Summary

(1) Through comparing the climate and soil conditions of Zigui County with the conditions requiredby walnuts, the walnut cultivation history of Zigui County, and the successful examples ofwalnut cultivation by some farmers in Zigui, it is fully proved that Zigui County is suitable forlarge-scale walnut cultivation and development.

(2) Compared with major walnut provinces such as Hebei, Shanxi, Henan, Xinjiang,and Yunnan, the climatic conditions of Zigui County mainly differ in large rainfall, longfrost-free period, and less light; during cultivation, corresponding technical countermeasures should be adopted according to these differences,and the techniques of other places should not be mechanically copied.