Americas and Oceania Group - International Plant Nutrition Institute

Asia and Africa Group
China
Southwest Region: Dr. Shihua Tu
Cucumber Yield, Nutrient Use Efficiency, Economic Returns and Soil Phosphorus Forms as Affected by Fertilization and
Irrigation Systems in Yunnan
Project Leader: Hong Lifang, Yunnan Academy of Agricultural Sciences Soil and Fertilizer Institute, Kunming, Yunnan.
E-mail: gredbean@163.com
Project Cooperator: Fu Libo
This ongoing study initiated in 2010 continued to investigate the effects of different fertilizer practices on
yield, economic return, and nutrient use efficiency of cucumber, one of the most commonly grown vegetables
in Yunnan. The goal was to determine optimal fertilizer rates for cucumber production in the region. The
experiment consisted of 26 fertilizer treatments involving different rates of N, P, and K, each receiving two
types of irrigation (drip and traditional) and replicated three times. In addition, there were two forms of K
(KCl and K 2 SO 4 ) used in the study to evaluate source differences. Based on the results obtained in 2010,
fertilizer rates in 2011 were adjusted to 0, 120, 240, and 360 kg of N, 0, 60, 120, and 180 kg of P 2 O 5 , and
0, 195, 390, and 585 kg of K 2 O per hectare, of which rates of N and P were lowered and K was raised, and
applied several times in a 10-day interval starting from seeding.
Results showed that 2011 cucumber yields were higher than those in 2010, especially for drip irrigation.
Drip irrigation increased cucumber yield by 7,960 to 11,380 kg/ha (20 to 30%) and saved water by 563 m 3 /
ha (40%) compared to the traditional irrigation. The optimal (OPT) fertilizer treatment tested was 240-120-
390 kg N-P 2 O 5 -K 2 O/ha under both irrigation systems in 2011, a reduction of 60 kg N/ha and 30 kg P 2 O 5 /ha,
but an increase of 30 kg K 2 O/ha compared to rates used in 2010. The net income of OPT was USD 14,787 for
drip irrigation and USD 11,774 for traditional irrigation. The agronomic efficiencies of N, P, and K fertilizers
were 45, 53, and 36 kg cucumber/kg nutrient under drip irrigation and 36, 46, and 31 under the traditional
irrigation, respectively. Potassium chloride produced higher cucumber yield than K 2 SO 4 at all K rates in 2010,
but this was reversed in 2011, possibly due to continued omission of S over for two years. This study revealed
that in addition to meeting the proper 4R management of the crop, other agronomic practices such as proper
irrigation method were crucial to improving crop yield and fertilizer use efficiency. Yunnan-BFDP-08
Effect of Balanced Fertilizers on Papaya Yield and Quality in Guangxi
Project Leader: Tan Hongwei, Guangxi Academy of Agricultural Sciences Soil and Fertilizer, Nanning, Guangxi.
E-mail: hwtan@public.nn.gx.cn
Project Cooperator: Zhou Liuqiang
This study, initiated in 2010, continued to evaluate the effects of different fertilizer treatments on fruit yield
and quality of papaya grown in Nanning City, Guangxi. There were seven treatments including: an optimal
treatment (OPT) and treatments individually omitting N, P, K, Mg, B, and Zn within the OPT. Since papaya
response to Mo was insignificant in the previous year, it was omitted from this year’s design. The OPT
treatment remained the same as set in 2010 at 900-190-960 kg N-P 2 O 5 -K 2 O/ha, plus 130 kg MgO/ha, 4.0 kg
borax/ha, and 4.0 kg zinc sulfate/ha.
Papaya yields significantly responded to N, P, and K application at two sites in spite of the considerable
difference in their productivity. Yields were reduced by 18.6 t/ha (-41.6%), 8.6 t/ha (-19.1%), and 5.7 t/ha
(-12.6%) with omission of N, P, or K, respectively. Omission of Mg or Zn reduced papaya yield by 3.4%
and to 4.5%, respectively, while omission of B had little effect on yield, implying that the critical value for
B needs to be adjusted as soil testing did indicate existing deficiencies. Agronomic efficiencies for different
fertilizer application were 20.7 kg fruit/kg N; 44.8 kg fruit/kg P 2 O 5 ; 5.9 kg fruit/kg K 2 O; 12 kg fruit/kg MgO;
2,200 kg fruit/kg Zn, and 1,300 kg fruit/kg B, respectively.
Based on the two-year results of OPT treatments, 1,000 kg of papaya fruit requires 3.3 to 4.2 kg of N, 1.3 to
1.8 kg of P 2 O 5 , 9.0 to 11.1 kg of K 2 O, 1.4 to 1.8 kg of MgO, 7.4 to 9.8 g of Zn, 2.7 to 3.6 g of B, respectively.
Guangxi-BFDP-08
IPNI Interpretive Summaries 63