Agronomical Performances of Sequential Planting Pak Choi (Brassica rapa subsp. chinensis L.) as Responses to Weed-based Liquid Organic Fertilizer

The use of weed-based liquid organic fertilizers (LOFs) in organic Pak Choi production was expected to improve the effectiveness of solid organic fertilizers. Sequential vegetable planting has been practiced to improve the viability of the organic vegetable business. This research aimed to determine the effects of weed-based LOF on the yields of sequentially cropped organically grown Pak Choi.  Field experiments were conducted in Rejang Lebong Highland, Indonesia, using complete randomized block design with three replicates, The first planting was in May 2021, and the second planting was in June 2021. Treatments were 0, 25, 50, 75, and 100 ppm of weed-based LOF. The results indicated that in each growing season the use of weed-based LOF had no effect on leaf number, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, and leaf greenness, as well as the N, P, K uptakes of Pak Choi.  Nutrient (N, P and K) uptakes of Pak Choi in the second planting were 27.8%, 91.6% and 51.4% lower than those of the first planting, respectively.  In addition, shoot fresh weight in the first planting was 56.2% higher than that found in the second planting. Nevertheless, the fresh weight of Pak Choi in both planting seasons was higher than in many studies and that of the Indonesian market standard for Pak Choi.