The presence of animal grazing at different intensities in integrated crop livestock systems (ICLS) may affect the forms and the balance of K in the soil, especially after many years. The objective of this study was to evaluate different K forms and their balance for 17 years with ICLS. ICLS experimental area used no-till practices with different grazing intensities of cattle in winter pasture (black oat + annual ryegrass) and soybean production in the summer season. The experiment started in May 2001 at a location with a Rhodic Hapludox (Oxisol). The treatments consisted of varied grazing intensities: intensive grazing (IG) at 10 cm of pasture height, moderate grazing (MG) at 20 cm of pasture height, and a no grazing (NG) treatment. The experimental design was a randomized block design with three replicates. Soil samples were collected in 2001, 2007, 2012 and 2017 in 0−5, 5−10, 10−15 and 15−20 cm of soil layers. Desorption of K was measured using the Mehlich-1 method and the results were fitted to first-order kinetic equations to obtain readily and potentially available K content. Total K was determined by X-ray fluorescence, and the unavailable K by the difference between the total K and potentially available K. Long-term no-till ICLS resulted in an increase in more readily available K forms in the soil surface. The increase was especially prominent in the no-grazing treatment due to the greater amount of K left in the plant residues. Regardless of grazing intensity, soybean cultivation was the controlling component of the soil nutrient budget, representing 98.6 % of the total amount of K exported. Animal outputs represent only 1.4 % of total K exported and are therefore the recycling component of the system. Although meat production in ICLS represents only a very small fraction of the amount of K exported from the system, K tends to become less available in the grazed treatments in the long-term.

综合耕种牲畜系统（ICLS）中不同强度放牧的动物的存在可能会影响土壤中钾的形态和平衡，尤其是在多年之后。这项研究的目的是使用ICLS评估17年中不同的K形式及其平衡。ICLS试验区采用免耕措施，冬季牧场（黑燕麦+年生黑麦草）的牛放牧强度不同，夏季则种植大豆。该实验于2001年5月在Rhodic Hapludox（Oxisol）的位置开始。处理方法包括不同的放牧强度：在牧场高度10 cm时进行密集放牧（IG），在牧场高度20 cm处进行中度放牧（MG），以及不放牧（NG）。实验设计是具有三个重复的随机区组设计。2001年收集了土壤样本，2007、2012和2017年在0-5、5-10、10-15和15-20厘米的土层中。使用Mehlich-1方法测量K的解吸量，并将结果拟合至一阶动力学方程式，以获取容易和潜在可用的K含量。总钾由X射线荧光测定，而无效钾则由总钾与潜在有效钾之间的差值确定。长期免耕ICLS导致土壤表面更易于利用的钾形态增加。由于植物残渣中残留的钾含量更高，因此在非放牧处理中这种增加尤为明显。无论放牧强度如何，大豆种植都是土壤养分预算的控制部分，占钾素出口总量的98.6％。动物输出仅代表1。出口的K总量的4％，因此是系统的回收组件。尽管ICLS中的肉类生产仅占系统输出的K量的很小一部分，但从长期来看，放牧处理中K的可用性往往会下降。