Research Article: How do cotton light interception and carbohydrate partitioning respond to cropping systems including monoculture, intercropping with wheat, and direct-seeding after wheat?

Date Published: May 20, 2019

Publisher: Public Library of Science

Author(s): Xiaoyu Zhi, Yingchun Han, Fangfang Xing, Yaping Lei, Guoping Wang, Lu Feng, Beifang Yang, Zhanbiao Wang, Xiaofei Li, Shiwu Xiong, Zhengyi Fan, Yabing Li, Wujun Ma.


Different cotton (Gossypium hirsutum L.)-wheat (Triticum aestivum) planting patterns are widely applied in the Yellow River Valley of China, and crop yield mainly depends on light interception. However, little information is available on how cotton canopy light capturing and yield distribution are affected by planting patterns. Hence, field experiments were conducted in 2016 and 2017 to study the response of cotton canopy light interception, square and boll distribution, the leaf area index (LAI) and biomass accumulation to three planting patterns: a cotton monoculture (CM, planted on 15 May) system, a cotton/wheat relay intercropping (CWI, planted on 15 May) system, in which three rows of wheat rows were intercropped with one row of cotton, and a system in which cotton was directly seeded after wheat (CWD, planted on 15 June). The following results were obtained: 1) greater light capture capacity was observed for cotton plants in the CM and CWI compared with the CWD, and the light interception of the CM was 22.4% and 51.4% greater than that of the CWI and CWD, respectively, at 30 days after sowing (DAS) in 2016; 2) more bolls occurred at the first sympodial position (SP) than at other SPs for plants in the CM; 3) based on the LAI and biomass accumulation, the cotton growth rate was the greatest in CWD, followed by CM and CWI; and 4) the CM produced significantly greater yields than did the other two treatments because it yielded more bolls and greater boll weight. Information on the characteristics of cotton growth and development in response to different planting patterns would be helpful for understanding the response of cotton yields to planting patterns and would facilitate the improvement of cotton productivity.

Partial Text

Cotton (Gossypium hirsutum L.) is grown worldwide as a major source of natural fiber [1]. In China, cotton is grown on 5.2 million hectares, and the annual production is 6.67 million tons [2]. Different cotton-wheat (Triticum aestivum L.) double cropping systems are commonly implemented in various countries worldwide, especially in the Yellow River Valley of China [3]. Double cropping systems are the collective planting of two or more crops within the same field, and compared with monoculture cropping systems, double cropping systems greatly contribute to crop production via the effective use of resources. Moreover, double cropping systems present several other beneficial attributes, such as high light interception [4], high productivity per unit area of land [5], efficient use of both water and nutrients, sequestration of organic carbon and nitrogen in the soil, and suppression of pests and diseases. Additionally, double cropping systems produce substantial increases in multiple crop indexes and reduce competition between grain and cotton for land in China. Further, cotton sown into mature wheat fields prior to or after wheat harvest improves the distribution of labor over time.

In modern agricultural systems, management concerning planting patterns is one method to increase cotton yields, especially given the sharp reduction in cotton planting area in the Yellow River Valley of China. This study found the greatest light capture ability in cotton monoculture system from 80 to 120 DAS. While for the other two intercropping systems, cotton directly sown after wheat system exhibited higher light interception than cotton/wheat relay intercropping system. Comparing with cotton/wheat relay intercropping system and cotton seeded directly after wheat system, the greatest fraction of bolls on the first positions was produced in the cotton monoculture plots, which strongly explained the greater seed cotton yield obtained in the monocultured system. Even though the early development of cotton plants in cotton seeded directly after wheat cropping system was much better improved than plants in the other two cropping systems, but challenged with shortening boll developing duration, therefore the lint yield decreased.