Study and Demonstration of Soil Nutrient Management and Balanced Fertilizer Technology for Cotton in Anhui

Anhui province is one of the major cotton producing provinces in China with annual cotton planting area of 400,000 ha. Thus, the study of nutrient limiting factors and scientific fertilization technology for cotton is of great significance in Anhui.

A field experiment was conducted in 2011 in Wuwei county by Anhui Agricultural University. Five treatments: a) OPT (N-P₂O₅-K₂O = 225-150-225 kg/ha + FeSO₄ 22.5 kg/ha + MnSO₄ + ZnSO₄ 7.5 kg/ha), b) OPT-N, c) OPT-P, d) OPT-K, and e) CK (no fertilization) were used in the experiment with three replications. The plot area was 20 m², and planting density was 18,000 plants/ha. The seedlings were planted on April 20, and the crop was transplanted on May 15 in 2011.

The results indicated N as the most important nutrient limiting factor for cotton in this region followed by K. The number of bolls, height, fruit branches, and boll weight of OPT-N treatment decreased by 42.2%, 17.8%, 16.7%, and 10.6%, respectively, when compared with the OPT treatment. Similarly, the number of bolls, height, and fruit branches of OPT-K treatment decreased 25.3%, 6.4%, and 11.1%, respectively, compared with the OPT treatment. The seed yield of the OPT (4,075 kg/ha) was 36.6% higher than OPT-N. Potash application increased cotton bolls, boll weight, and lint yield significantly. Based on applied N at 225 kg/ha and P₂O₅ at 150 kg/ha, the best K₂O application rate was 337.5 kg/ha with seed yield of 4,195 kg/ha and better cotton quality (fiber length was 29.7 mm, increased 14% than that of OPT-K treatment). Anhui-19