CONTEXT

With increasing population growth and land-use competition, pasture production under photovoltaic installations offers an alternative paradigm for crop-livestock integration. The levels of pasture biomass production and potential for livestock grazing under photovoltaic installations depend considerably on the mode of the photovoltaic system.

OBJECTIVE

This study aimed to model pasture production for sub-tropical grass under different photovoltaic installations and assess the effects of different grazing methods on sub-tropical pasture productivity in Australia.

METHODS

Pasture biomass production under a fixed-tilt array, single-axis tracking array, and dual-axis tracking array were measured for the calibration and validation of Agricultural Production Systems sIMulator (APSIM) to simulate four different grazing strategies: (1) without grazing; (2) 21 days grazing interval; (3) 45 days grazing interval; and (4) continuous stocking.

RESULTS AND CONCLUSIONS

The APSIM model showed satisfactory performance in simulating sub-tropical pasture production under different photovoltaic installations, with the best correspondence under the fixed-tilt array (observed value 6073 kg ha⁻¹ and simulated value 6292 kg ha⁻¹). As compared to full sun condition, biomass production was found to be 15.82, 13.53, and 8.03% higher with the fixed-tilt, single-axis tracking, and dual-axis tracking array, respectively. The model was then used in scenario analysis to evaluate pasture biomass production under different grazing strategies. Simulation results depict the grazing effect on pastures under the photovoltaic systems. Without grazing, maximum biomass production occurred under the fixed-tilt array (7798 kg ha⁻¹) compared to under the single-axis tracking array (7671 kg ha⁻¹), dual-axis tracking array (7186 kg ha⁻¹), and full sun (6766 kg ha⁻¹). In the case of 21 days and 45 days of grazing, the 25-year biomass production under the full sun was lower than all other systems. Compared to other treatments, the fixed titled array offers better performing pasture-grazing integration under a photovoltaic system. We found that models predicted that an increase in grazing pressure via continuous grazing had comparatively similar impacts on sub-tropical pasture biomass production irrespective of photovoltaic installations. Therefore, the potential exists to maximise land use efficiency where options are available to grow and graze pasture under photovoltaic installations.

SIGNIFICANCE

This study confirms that the APSIM-Growth model, calibrated for Bambatsi Panic, can simulate pasture growth in different shading phenomena under the agrivoltaic system. Additionally, this simulation of the grazing systems is essential to identify crucial modelling and direct investigations that could expand knowledge of the procedures and relationships required for model development of pasture production under photovoltaic farms.

中文翻译：

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使用不同放牧策略的不同光伏装置下亚热带草的生物量生产

语境

随着人口增长和土地利用竞争的加剧，光伏装置下的牧场生产为作物-牲畜整合提供了另一种模式。光伏装置下的牧场生物量生产水平和牲畜放牧潜力在很大程度上取决于光伏系统的模式。

客观的

本研究旨在模拟不同光伏装置下亚热带牧草的牧草生产，并评估不同放牧方法对澳大利亚亚热带牧草生产力的影响。

方法

测量了固定倾斜阵列、单轴跟踪阵列和双轴跟踪阵列下的牧场生物量产量，用于农业生产系统模拟器 (APSIM) 的校准和验证，以模拟四种不同的放牧策略：(1) 不放牧；(2) 放牧间隔21天；(3) 45天的放牧间隔；(4) 连续放养。

结果和结论

APSIM模型在模拟不同光伏装置下的亚热带牧草生产方面表现出令人满意的性能，固定倾斜阵列下的对应性最好（观测值6073 kg ha -1 和模拟值⁶²⁹² kg ha ^-1）。与全日照条件相比，固定倾斜、单轴跟踪和双轴跟踪阵列的生物量产量分别高出 15.82%、13.53% 和 8.03%。然后将该模型用于情景分析，以评估不同放牧策略下的草地生物量生产。模拟结果描述了光伏系统对牧场的放牧影响。在没有放牧的情况下，最大生物量生产发生在固定倾斜阵列下（7798 kg ha ^-1) 与单轴跟踪阵列 (7671 kg ha ^-1 )、双轴跟踪阵列 (7186 kg ha ^-1 ) 和全日照 (6766 kg ha ^-1 ) 相比。在放牧 21 天和 45 天的情况下，全日照下 25 年的生物量产量低于所有其他系统。与其他处理相比，固定标题阵列在光伏系统下提供了更好的牧场放牧整合。我们发现，模型预测通过连续放牧增加放牧压力对亚热带牧场生物量生产的影响相对相似，与光伏装置无关。因此，存在最大化土地利用效率的潜力，其中可以选择在光伏装置下种植和放牧牧场。

意义

本研究证实，针对 Bambatsi Panic 校准的 APSIM-Growth 模型可以模拟农用光伏系统下不同遮荫现象下的牧草生长。此外，这种放牧系统的模拟对于确定关键的建模和直接调查至关重要，这些调查可以扩展对光伏农场下牧场生产模型开发所需的程序和关系的知识。