Equal K Amounts to N Achieved Optimal Biomass and Better Fiber Quality of Late Sown Cotton in Yangtze River Valley
MOA Key Laboratory of Crop Eco-physiology and Farming system in the Middle Reaches of Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430000, China
Author to whom correspondence should be addressed.
Agronomy 2020, 10(1), 112; https://doi.org/10.3390/agronomy10010112
Received: 24 November 2019 / Revised: 3 January 2020 / Accepted: 8 January 2020 / Published: 13 January 2020
(This article belongs to the Special Issue Herbaceous Field Crops Cultivation)
Potassium (K) fertilizer plays a crucial role in the formation of the biological and economic yield of cotton (Gossypium hirsutum L.). Here we investigated the effects of the amount of K on biomass accumulation and cotton fiber quality with lowered N amounts (210 kg ha−1) under late sowing, high density and fertilization once at 2 weeks after squaring. A 2-year field experiment was performed with three K fertilizer amounts (168 kg ha−1 (K1), 210 kg ha−1 (K2), and 252 kg ha−1 (K3)) using a randomized complete block design in 2016 and 2017. The results showed correspondingly, K3 accumulated cotton plant biomass of 7913.0 kg ha−1, next to K2 (7384.9 kg ha−1) but followed by K1 (6985.1 kg ha−1) averaged across two growing seasons. Higher K amounts (K2, K3) increased biomass primarily due to a higher accumulation rate (32.68%–74.02% higher than K1) during the fast accumulation period (FAP). Cotton fiber length, micronaire, and fiber strength in K2 were as well as K3 and significantly better than K1. These results suggest that K fertilizer of 210 kg ha−1 should be optimal to obtain a promising benefit both in cotton biomass and fiber quality and profit for the new cotton planting model in the Yangtze River Valley, China and similar climate regions.