Context or problem

Application of recycling organic wastes is a possible way forward in overcoming increasing costs for mineral fertilizers. However, the result of its side effect can be the unbalanced plant nutrition.

Objective or research question

This study was carried out to investigate the side effects of phosphorus (P) applied by organic fertilization on biomass yield, agronomic efficiency and P utilization, P balance and soil P transformation in a long-term 27-year (1993–2019) field experiment with maize monoculture.

Methods

Six treatments including unfertilized control (C), urea ammonium nitrate (UAN), urea ammonium nitrate + wheat straw (UAN+St), sewage sludge (SS), farmyard manure (FYM), and cattle slurry (CS) were applied based on the unified dose of 120 kg N ha⁻¹ year⁻¹ (except C). Following groups of parameters were investigated during the experiment: i) yield characteristics, ii) content of different soil P fractions and iii) soil P sorption characteristics.

Results

UAN+St and FYM treatments showed higher average biomass yield as compared to the positive control (UAN) treatment. Positive phosphorus balance was found only in FYM and SS treatments, where the high amount of P applied by SS represents a higher risk of P over-accumulation. On the other hand, the degree of phosphorus saturation of FYM was 8% higher (in 2019) than for SS. Lower mobility of SS phosphorus was confirmed even with lower readily available soil P contents as compared to FYM and CS. The C, UAN, UAN+St, and CS showed a negative P balance during the experiment. However, CS significantly increased the degree of P saturation. The ratio of P-balance from pseudototal P content in soil exceeded + 10% at SS treatment and was lower than − 10% at UAN and UAN+St treatments, respectively. Unfertilized control resulted in the value of 9.23%.

Conclusion

FYM represents higher risk of P losses as compared to SS at same dose of applied nitrogen. Long-term application of FYM, SS and CS strongly increased the soil available P pool and degree of phosphorus saturation.

Implication or significance

When the ratio of P-balance from pseudototal P content in soil exceeds + or − 10% (UAN, UAN+St, and SS), the depletion of P_AR reserves (UAN, UAN+St) or P over-accumulation (SS) are starting to be statistically significant and changes of agricultural practices according to P fertilizing have to be considered.

中文翻译：

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有机施肥对玉米单作27年磷素转化平衡的副作用

上下文或问题

回收有机废物的应用是克服矿物肥料成本增加的一种可能方式。然而，其副作用的结果可能是植物营养失衡。

目标或研究问题

本研究旨在通过为期 27 年（1993 年至 2019 年）的长期田间试验，研究有机肥施用磷 (P) 对生物量产量、农艺效率和磷利用、磷平衡和土壤磷转化的副作用与玉米单一栽培。

方法

施以不施肥对照（C）、尿素硝酸铵（UAN）、尿素硝酸铵+麦秸（UAN+St）、污水污泥（SS）、农家肥（FYM）、牛粪（CS）6个处理。统一剂量为 120 kg N ha ⁻¹ year ⁻¹（C 除外）。实验期间研究了以下几组参数：i) 产量特性，ii) 不同土壤磷组分的含量和 iii) 土壤磷吸附特性。

结果

与阳性对照 (UAN) 处理相比，UAN+St 和 FYM 处理显示出更高的平均生物量产量。正磷平衡仅在 FYM 和 SS 处理中发现，其中 SS 施用的大量 P 表示 P 过度积累的风险较高。另一方面，FYM 的磷饱和度（2019 年）比 SS 高 8%。与 FYM 和 CS 相比，SS 磷的流动性较低，即使土壤中现成可用的磷含量较低。C、UAN、UAN+St 和 CS 在实验过程中显示负 P 平衡。然而，CS 显着增加了 P 饱和度。SS 处理时土壤假全磷含量的 P 平衡比率超过 + 10%，UAN 和 UAN+St 处理分别低于-10%。未施肥对照的值为 9.23%。

结论

与相同施氮剂量的 SS 相比，FYM 代表更高的磷损失风险。长期施用 FYM、SS 和 CS 显着增加了土壤有效磷库和磷饱和度。

含义或意义

当 P 平衡与土壤中假全 P 含量的比率超过 + 或 - 10%（UAN、UAN+St 和 SS）时，P _AR储备（UAN、UAN+St）或 P 过度积累（SS ) 开始具有统计显着性，必须考虑根据磷肥施肥改变农业实践。