Americas and Oceania Group - International Plant Nutrition Institute

652 Ca, 7 Mg, 7 Zn, and 0.2 Se was increased by 8.2 t/ha and profit by 12% over the NPK treatment. Also,
this yield was 131, 43, and 42% higher than the yields in minus N, P and K treatments, respectively. Zinc
and Se contents of Italian ryegrass increased by 7 and 50% respectively. There was some effect of different
treatments on goose meat quality. Additional application of Zn and Se enhanced their contents in meat by
11 and 60%, and increased P, Mg, and amino acid contents by 8, 9, and 16, respectively. Straw from Italian
ryegrass when returned to the farmland at 6,413 kg/ha increased the yield of early rice by 1,067 kg/ha than
with no straw returned. Jiangxi-27
Efficient Nutrient Management Strategy for Modern Rice Planting in China
Project Leader: Prof. Li Zhuzhang, Jiangxi Academy of Agricultural Sciences Soil and Fertilizer Institute, Nanchang,
Jiangxi. E-mail: lgrtfs@sina.com
Project Cooperators: Fusheng Yuan, Qixiang Luo, Gang Sun, Changxu Xu, Duogen Xiong, and Wenxue Zhang
Rice is the most important grain crop in China. Large amounts of commercial fertilizers are used annually
for higher rice production, but with low use efficiency. To establish better nutrient management strategies for
rice in different regions of China, the IPNI China program in collaboration with Soil and Fertilizer Institute
of Jiangxi Academy of Agricultural Science, a nationwide cooperative research project was carried out in 11
main rice production provinces (Jiangxi, Hunan, Guangxi, Fujian, Zhejiang, Jiangsu, Anhui, Hubei, Sichuan,
and Yunnan). A total of 37 on-farm rice fertilization trials were conducted in the 11 provinces in 2011 with
different cropping rotations and soil fertility levels.
Results indicated that, in all regions, optimal fertilizer treatment (OPT; NPKZn) obtained higher rice
yields compared with the no fertilizer (CK) treatment (22% to 70%) and common farmer practices (12%).
Nitrogen was the most important nutrient limiting factor for rice, followed by P, K, and Zn. The optimum N
fertilization rates for late rice and mid-season rice were 180 and 240 kg/ha, respectively. Based on the results,
an optimum N application strategy was suggested that included the application of 40% of N fertilizer as basal,
and then top dressing 20% of N fertilizer each at tillering, panicle initiation, and spike growth stages of rice.
Jiangxi-30
Transformation, Interaction and Bioavailability of Nutrients in the Fertisphere
Project Leader: Zhou Jian-min, Chinese Academy of Science Nanjing Institute of Soil Science, Nanjing, Jiangsu.
E-mail: jmzhou@issas.ac.cn
Project Cooperator: Xiaoqin Chen, xqchen@issas.ac.cn
In the interface of soil and fertilizer, the concentration of nutrients is several times that in bulk soil,
resulting in strong and special reactions between nutrients or nutrients and soil fractions. It’s important to
study the transformation, transference, and reactions of nutrients in this micro-zone to better understand
their effect on the enhancement of fertilizer use efficiency and in designing new fertilizer products. Study on
the effects of interactions of N and K, or N and P, and the application sites on K or P use efficiency, could
help design better fertilization strategies and enhance K and P use efficiencies. The effects of ammonium
and K interaction on the transformation and transference of K in the paddy soil-fertilizer interface were
studied in 2011 by the Nanjing Institute of Soil Science, CAS. In addition, the effects of N and P interaction
on the transformation and transference of P, and the influence of N and P fertilization on the uptake and
bioavailability of N and P on wheat in the alluvial soil were also explored.
The use efficiency of K fertilizers could be increased by reducing the fixation of K in soil fertisphere. When
potash was applied together with ammonium, the contents of soil water soluble and exchangeable K were
increased in the paddy soil fertisphere, while the non-exchangeable K content was decreased. The increase
of water soluble P and Ca 2 -P contents and the decrease of Ca 8 -P content was found in the co-application
of Ca(H 2PO 4 ) 2 and (NH 4 ) 2 SO 4 treatment. But when Ca(H 2 PO 4 ) 2 was co-applied with urea, these effects of
N fertilizers on the P availability of co-applied P fertilizer were not expressed in the wheat pot experiment.
Maximum N use efficiency was observed when N was applied 5 cm below wheat roots in the soil. When P
fertilizer was mixed thoroughly with soil near roots, the best P use efficiency was obtained. Nanjing-11
IPNI Interpretive Summaries 75