Variable rate poultry litter (PL) application can potentially increase cotton yield and reduce environmental degradation risks associated with excess applications. The objective of this study was to determine whether applying PL in an inherently variable cotton field as variable-rate based on soil organic matter (SOM, VRo) or elevation (VRe) maps leads to greater yield and production efficiency than applying by the traditional uniform rate (UR). Poultry litter was applied by varying the rate within ±20 % of the target rates (7.9–11.2 Mg ha) where the highest elevation or lowest SOM regions received the highest rate, and the lowest elevation or highest SOM regions received the lowest rate. A treatment fertilized with conventional synthetic fertilizers served as the standard control (Std). Cotton fertilized with PL, regardless of the application method, provided greater K, S, and P nutrition and increased lint yield by as much as 30 % relative to the Std treatment. Applying the PL by the VRe method increased the production efficiency (yield per unit applied PL) by nearly 13 % over the UR. The VRo treatment resulted in a yield reduction of up to 11.8 % but the production efficiency was 14.2 % greater than the UR treatment. Variable rate application based on SOM was not as effective as that based on elevation. The results overall show that PL was superior to synthetic fertilizers in this soil and this superiority could further be enhanced by applying the PL as variable rate based on elevation maps.

中文翻译：

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基于海拔图的可变比率家禽垫料施用是棉花生产中一种有前途的方法


可变比率的家禽垫料（PL）施用可以潜在地提高棉花产量并减少与过量施用相关的环境退化风险。本研究的目的是确定在固有变化的棉田中，基于土壤有机质（SOM、VRo）或高程（VRe）图，将 PL 作为变量施用，是否会比传统的统一施用带来更高的产量和生产效率。率（UR）。家禽垫料的施用量在目标施用量（7.9-11.2 毫克公顷）的±20% 范围内变化，其中最高海拔或最低 SOM 区域获得最高施用量，最低海拔或最高 SOM 区域获得最低施用量。使用传统合成肥料施肥的处理作为标准对照（Std）。与标准处理相比，使用 PL 施肥的棉花，无论采用何种施用方法，都能提供更多的 K、S 和 P 营养，并将皮棉产量提高 30%。通过 VRe 方法应用 PL，生产效率（应用 PL 的单位产量）比 UR 提高了近 13%。 VRo 处理导致产量降低高达 11.8%，但生产效率比 UR 处理高 14.2%。基于 SOM 的可变利率应用不如基于海拔的可变利率应用有效。总体结果表明，在该土壤中，PL 优于合成肥料，并且通过将 PL 作为基于海拔图的可变比率应用，可以进一步增强这种优势。