Replacing 30 % chemical fertilizer with organic fertilizer increases the fertilizer efficiency, yield and quality of cabbage in intensive open-field production

ABSTRACT: The combined application of chemical fertilizer and organic fertilizer is an effective way to improve soil fertility, crop yield and quality. In this study, a field experiment was conducted to evaluate the yield, quality and fertilizer use efficiency of cabbage (Brassica oleracea var. capitata L.) grown under different ratios of organic fertilizer replacing chemical fertilizer at a rate of 225 kg N ha-l in 2019 and 2020. The fertilizer treatments included N0 (non nitrogen fertilizer), CK (only compound fertilizer was applied, N:P:K=15.0 %:6.5 %:12.4 %), T1, T2 and T3 (organic fertilizer replaced 15 %, 30 % and 45 % chemical fertilizer, respectively), and T4 (total nutrient input was reduced by 10 % under T2). Results showed that T2 had the highest marketable yield and fertilizer use efficiency, as well as the best quality. The marketable yield, vitamin C content, soluble sugar content, REN (apparent uptake efficiency of fertilizer N) and AEN (agronomic N use efficiency) of T2 increased by 32.2 %, 14,9 %, 5.5 %, 97. % and 55.6 %, respectively, in contrast, the crude fibers decreased by 34.0 %, compared with CK in the two years. In addition, T4 guaranteed the yield and moderately improved the quality of cabbage, compared with CK. Therefore, we can alternatively apply fertilization according to the purpose of capturing the highest yield or properly declining fertilizer to sustain soil texture and productivity.

Plant Availability of Magnesium in Typical Tea Plantation Soils

Background and Aims: Magnesium (Mg) fertilizer has been proved to play an important role in improving the yield and quality of tea. However, plant availability of Mg, including its use, efficiency, and quality improvement effects, were highly affected by plant species, soil characteristics (nutritional status, etc.), and Mg status (chemical-available, etc.).Methods: Tea plants were pot-cultivated in 12 typical tea plantation soils amended with and without Mg fertilizer. Exchangeable Mg (Ex-Mg) concentration in soils was quantitatively extracted using four extraction solutions (Mehlich-3, BaCl2, CaCl2, and NH4OAC). Plant availability of Mg was evaluated by Mg uptake and its use efficiency, as well as its association with quality components in tea plants.Results: Ex-Mg in soils was extracted most efficiently by Mehlich-3, while Mg concentrations in tea plant tissue were higher correlated with Ex-Mg extracted by CaCl2 than other extraction solutions. Mg fertilizer use efficiency in tea plant varied from 6.08 to 29.56 %, and the effect of Mg application on tea quality improvement and the use efficiency of Mg fertilizer both negatively correlated with total Mg concentration (r = −0.94 and −0.63, respectively) and nitrogen (N) level (r = −0.61 and −0.51, respectively) in soils prior to tea plant cultivation.Conclusions: CaCl2 could be recommended for plant-available Mg extraction in tea plantation soil, and Mg fertilizer use efficiency could be affected and predicted by total N and Mg status in soils prior to tea plant cultivation, providing a potential theoretical for the guidance of Mg fertilization for tea yield and quality improvement in tea plantation management.

GRAIN YIELD OF COFFEE PLANTS FERTILIZED WITH DIFFERENT DOSES OF 20-00-20 NPK FORMULATION UNDER RAINFED CONDITIONS

ABSTRACT Little is known about the management of high-yield clonal Coffea canephora in the Amazonian Region, mainly for nutritional aspects and cultivation system efficiency. This study aimed to evaluate the influence of different nitrogen and potassium fertilization rates on coffee grain yield and fertilizer use efficiency of C. canephora trees. An experiment was performed at an experimental field of the Embrapa Rondônia in Porto Velho (RO), Brazil. It was carried out in a split-plot scheme with six doses of 20-00-20 NPK formulation (0; 250; 500; 1,000; 2,000; and 3,000 kg ha-1) and three years of evaluation (2014, 2015, and 2016). An interaction between fertilizer dose and crop year was observed. Fertilizer doses showed an exponential behavior, with maximum yields of 51, 114, and 79 bags ha-1 at 3,000 kg ha-1 in the crop years of 2014, 2015, and 2016, respectively. Such a behavior impacted average and accumulated yields in the three harvest seasons. As for crop year effect within each fertilizer dose, the highest yield was reached in the second harvest after pruning for renewal of orthotropic stems. Moreover, fertilizer use efficiency by plants decreased exponentially, with the highest value at the lowest dose. Increasing doses of 20-00-20 formulation promoted an exponential increase in grain yield but decreased its use efficiency by C. canephora plants. This management also stimulated a strong biannual production.