Nutrient management and balanced fertilization in Shaanxi province

IPNI-2006-CHN-SN4

28 Jan 2008

2007 Annual Interpretive Summary

Research and Extension of Balanced Fertilization Technology on Major Crops in Shaanxi, 2007

Apple, kiwi, wheat, corn, and potato are major crops in Shaanxi Province. Imbalanced use of N, P, and K has restricted yield and quality in these crops, thus a group of field experiments were arranged in the counties of Heyang (apple), Zhouzhi (kiwi), Fufeng (wheat and corn), Weinan, and Mizhi (potato). The basic treatments for each study compared an “optimum” (OPT) against treatments omitting N, P, and K, plus farmer practice (FP). In all studies, soil test P was medium to high.

In apple, balanced use of NPK fertilizer significantly increased the nutrient content in apple branches, the growth of apple tree leaves, and leaf area, as well as apple yield and quality. The OPT of 0.3-0.12-0.5 kg N-P2O5-K2O/tree (2,222 trees/ha) increased 100-leaf dry weight by 5.9 g (25%), 4.6 g (18%), 3.2 g (12%), and 5.6 (23%). It increased leaf area by 6.4 cm2 (26%), 5.6 cm2 (22%), 2.9 cm2 (10%), and 2.4 (8%) compared to the - N, - P, - K, and FP treatments, respectively. Apple yield decreased by 10%, 3%, and 6% with the omission of N, P, and K. The OPT increased vitamin C content by 2.5, 2.8, and 2.7 mg/100g; soluble sugar by 1.8%, 1.0%, and 1.2%; and rigidity by 0.13, 0.11, and 0.04 kg/cm2, compared to the - N, - P, and - K, respectively. Average apple weight increased by 31.2, 23.6, and 16.1 g/apple due to N, P, and K application, respectively.

Research on kiwi fruit (1,666 trees/ha) in Zhouzhi found the OPT of 0.28-0.16-0.25 kg/tree to be most effective. Potassium increased kiwi fruit yield by 31.9 t/ha (81%), followed by N and P which increased yield by 27.4 t/ha (63%) and 18.1 t/ha (34%), respectively. These yield increases represented economic benefits of US$7,247, US$4,808, and US$8,493/ha.

Results from the winter wheat trials showed a sharp increase in nutrient accumulation between the spring green-up stage and grain filling stage. Between 40 to 60% of nutrients were taken up during this period, indicating the importance of fertilization soon after spring regrowth. The OPT of 266-137-219 kg/ha increased grain yield by 1,079 kg/ha (16%), 450 kg/ha (6%), 340 kg/ha (5%), and 769 kg/ha (11%) compared to the - N, - P, - K, and FP (application of 300-98-0 kg/ha) treatments, respectively.

Research on summer corn showed that 70 to 80% of nutrients were accumulated between trumpeting stage (V6-V8) and grain filling stage. The OPT of 314-69-150 kg/ha increased grain yield by 870 kg/ha (11%), 70 kg/ha (1%), 500 kg/ha (6%), and 210 kg/ha (2%) compared to the - N, - P, - K, and the FP (application of 360 kg N/ha alone) treatments, respectively.

In the potato studies, application of the OPT of 181-322-225 kg/ha at Weinan produced 5.9 t/ha (12%), 1.4 t/ha (3%), and 5.6 t/ha (12%) more yield compared to the - N, - P, or - K treatments, respectively. Similarily, in Mizhi, yield under the -N, -P, and -K treatments was 5.1 (19%), 1.5 (6%), and 4.9 t/ha (18%) lower than the OPT treatment of 307-322-225 kg/ha. Shaanxi-NMBF