ABSTRACT
A field experiment was conducted for two seasons to evaluate the application effects of a decision support system named Nutrient Expert on radish based on yield response and agronomic efficiency, to provide theoretical and technical support for convenient and quick recommendation on fertilization management. There were seven treatments: farmer's practice treatment (FP), recommended fertilization treatment based on Nutrient Expert (TE), recommended fertilization treatment based on soil testing (TS), treatment of replacing 30% nitrogen fertilizer with organic fertilizer based on TE (TE+OM), and corresponding nitrogen omission treatment (TE-N), phosphorus omission treatment (TE-P), and potassium omission treatment (TE-K). We measured and compared the effects of different fertilization managements on radish yield, nutrient uptake, fertilizer utilization and fertilization benefit. The results showed that the N, P2O5 and K2O fertilizer applications based on Nutrient Expert were 200, 132 and 215 kg·hm-2 in the first half of the year, and 171, 204 and 251 kg·hm-2 in the second half of the year, respectively. The Nutrient Expert recommended fertilization adjusted the application amount of nitrogen, phosphorus, and potassium fertilizer. Compared with FP treatment, the economic yield of radish in the two-season experiments increased by 14.8% and 18.4%, and the profit of fertilization increased by 20115 and 14905 yuan·hm-2, respectively. Compared with the TS treatment, the economic yield of radish over the two seasons increased by 9.8% and 16.8%, and the profit of fertilization increased by 9076 and 9987 yuan·hm-2, respectively. The Nutrient Expert recommended fertilization improved the agronomic efficiency and nutrient recovery efficiency of radish, and promoted the efficient utilization of nutrients. The reasonable proportion of organic fertilizer in radish production could promote the transfer of plant nutrients to roots to a certain extent. In general, the application of Nutrient Expert on radish was feasible. This method could make full use of the indigenous nutrients of soil, consider the balance and sustainable supply, and reasonably regulate the supply of nitrogen, phosphorus and potassium, and finally result in high yield, high efficiency and sustainable development of radish production.
Subject(s)
Fertilizers , Raphanus , Expert Systems , Nutrients , SoilABSTRACT
In order to make clear the recent status and trend of wheat (Triticum aestivum L.) production in China, datasets from multiple field experiments and published literature were collected to study the agronomic characteristics related to grain yield, fertilizer application and nutrient use efficiency from the year 2000 to 2011. The results showed that the mean grain yield of wheat in 2000-2011 was 5950 kg/ha, while the N, P2O5 and K2O application rates were 172, 102 and 91 kg/ha on average, respectively. The decrease in N and P2O5 and increase in K2O balanced the nutrient supply and was the main reason for yield increase. The partial factor productivity (PFP, kg grain yield produced per unit of N, P2O5 or K2O applied) values of N (PFP-N), P (PFP-P) and K (PFP-K) were in the ranges of 29.5~39.6, 43.4~74.9 and 44.1~76.5 kg/kg, respectively. While PFP-N showed no significant changes from 2000 to 2010, both PFP-P and PFP-K showed an increased trend over this period. The mean agronomic efficiency (AE, kg grain yield increased per unit of N, P2O5 or K2O applied) values of N (AEN), P (AEP) and K (AEK) were 9.4, 10.2 and 6.5 kg/kg, respectively. The AE values demonstrated marked inter-annual fluctuations, with the amplitude of fluctuation for AEN greater than those for AEP and AEK. The mean fertilizer recovery efficiency (RE, the fraction of nutrient uptake in aboveground plant dry matter to the nutrient of fertilizer application) values of N, P and K in the aboveground biomass were 33.1%, 24.3% and 28.4%, respectively. It was also revealed that different wheat ecological regions differ greatly in wheat productivity, fertilizer application and nutrient use efficiency. In summary, it was suggested that best nutrient management practices, i.e. fertilizer recommendation applied based on soil testing or yield response, with strategies to match the nutrient input with realistic yield and demand, or provided with the 4R's nutrient management (right time, right rate, right site and right fertilizer) should be adopted widely to improve the yield production and nutrient use efficiency.
Subject(s)
Soil , Triticum/growth & development , China , FertilizersABSTRACT
In this study, the input and output parameters of N for wheat production were collected from published literatures and International Plant Nutrition Institute in the period of 2000 to 2011 to evaluate N cycling and balances in North China, the middle and lower reaches of Yangtze River and Northwest China. The results showed that the N fertilizer application rates for each region were 170, 183 and 150 kg N . hm-2, the amounts of N from the previous crop were 74.6, 15.2 and 8.1 kg N . hm-2, and from seeds were 4.9, 4.2 and 3.5 kg N . hm-2, respectively. The N inputs from symbiotic fixation, atmospheric deposition and irrigation water in North China were 15, 12.9 and 9.9 kg N . hm-2, and in the middle and lower reaches of Yangtze River were 15, 14.5 and 5.8 kg N . hm-2, and in Northwest China were 15, 9.4 and 7.7 kg N . hm-2, respectively. The amounts of N uptake by aboveground plant at harvest time in North China, the middle and lower reaches of Yangtze River and Northwest China were 174.3, 144.4 and 122.3 kg N . hm-2, respectively, and the rates of ammonia volatilization, N20 emission and N leaching in North China were 19.9, 2.6 and 11.8 kg N . hm-2, in the middle and lower reaches of Yangtze River were 9.4, 2.4 and 15.5 kg N . hm-2, and in Northwest China were 3.4, 0.7 and 0 kg N . hm-2, respectively. As a result, the N balances in these three regions were all showing surpluses by 78.7, 66.0 and 67.3 kg N . hm-2. It is therefore necessary to adjust the N fertilizer application rates in these three regions to avoid the negative impacts on the environment.
