Effects of Potassium Application and Straw Returning on Potassium Management and Benefit of Banana

HighlightsThe effects of potash fertilizer and straw returning on a banana orchard were studied by field experiment.Fertilizer with straw was more conductive to potassium nutrient balance and improved banana yield and quality.The economic benefits of straw replacing different amounts of potassium fertilizer were compared.Abstract. To explore the effects of potash fertilizer and straw returning in banana production, a field experiment was carried out, and four treatments were set up: NP fertilizer (NP), NP fertilizer and banana straw (NP+St), NPK fertilizer (NPK), and NPK fertilizer and banana straw (NPK+St). Through the soil potassium balance, the effects of potash fertilizer and straw returning on the yield, quality, and economic benefits of bananas were studied. The results showed that the application of potash fertilizer and straw could improve banana yields. Compared with the NP treatment, the banana yields of the NP+St, NPK, and NPK+St treatments increased by 17.5%, 50.5%, and 71.6%, respectively. The order of banana yield, potassium balance coefficient, and nutrient accumulation was NPK+St > NP+St > NPK > NP. The NPK+St treatment also improved the recovery rate and agronomic utilization rate of potash fertilizer, which were higher than that of potassium application without straw (NPK) and straw application without potassium (NP+St). Potassium application with straw improved the banana yield, increased the total accumulation of nitrogen, phosphorus, and potassium, and improved the efficiency of potash fertilizer uptake by the crop. Therefore, this study demonstrates the importance of straw for maintaining the soil potassium balance in banana production. The input cost of potassium fertilizer was reduced, and the resource utilization of banana straw was realized by straw returning, which can be promoted in local agricultural production. Keywords: Banana, Potassium application, Potassium balance, Straw returning, Yield.

POTASSIUM BALANCE IN THE SOIL AND THE EFFECTIVENESS OF POTASSIUM DEFICIENCY SYSTEM OF FERTILIZATION

The influence of long-term application of potassium-deficient fertilizer system in the field crop rotation (winter wheat, corn, spring barley, soybeans) on podzolic heavy loam black earth of the Right-Bank Forest-Steppe of Ukraine on potassium content in plants, its costs for formation of one unit of the harvest was determined; potassium balance was calculated and the effectiveness of different doses of potassium fertilizers was comprehensively assessed. It was found that the potassium content in grains and seeds of agricultural crops under the influence of potassium fertilizers varies by no more than 8%, while in straw and stalks - by 10-24% depending on the variant of the experiment. It is shown that the non-grain part of the crop contains a significant part of potassium - 50-80% of economic removal depending on the crop. It is calculated that if it is left in the field for fertilizer in the variant of the experiment Basis + K80, it compensates for the consumption of potassium by 71%. By applying K40 and K80on the basis of applying N110P60 and leaving the non-commodity part of the crop in the field for fertilizer, the balance of potassium in the soil is formed positive with intensity of 111 and 212%, respectively. According to the index of complex assessment, which takes into account seven indicators: payback of 1 kg of mineral fertilizers; additionally conditionally net profit; net energy profit; humus balance and intensity of nitrogen, phosphorus and potassium balance, the best variant of the experiment is application of N110P60K40 per 1 ha of field crop rotation area. This indicates the possibility of a temporary reduction in the dose of potassium fertilizers in field crop rotation on podzolic heavyloam black earth in the Right-Bank Forest-Steppe of Ukraine

Potassium fractions in soil and simple K balance in long-term fertilising experiments

Experiments were used to determine the potassium release from the non-exchangeable K (Kne) forms that are involved in plant nutrition and which replenish the pool of available K. Long-term stationary field experiments with different fertilisation systems (organic: farmyard manure, sewage sludge, straw; mineral: NPK, N) were carried out to study the potassium balance and the K content changes in the topsoil (0–30 cm) and subsoil (30–60 cm). The trials were located at three sites with different soil-climatic conditions. The following crops were rotated within the trial: potatoes (maize) – winter wheat – spring barley. All three crops were grown each year over 21 years. Positive correlations between the contents of the available K in the topsoil and the potassium balance (K inputs – K outputs) were observed. There were no statistically significant differences among the treatments. Depending on the soil properties, the ratio of non-exchangeable K (Kne) was 12–37% of the values obtained via the aqua regia extraction. Depending on the site, the amount released from the Kne forms to the available K form was 46–69 kg K/ha/ year. The use of K from the farmyard manure varied from 7.4% up to 25%. Due to the low K content in the sewage sludge, the long-term fertilisation with sludge may only lead to the depletion of the available K in the soil, similar to the sole N mineral fertilisation.