Yield of upland rice varieties grown as monocrop and with legume intercrop at varying rates of nitrogen in Borongan, Eastern Samar [Philippines]

Results showed that the rice monocrop when applied with 90 kg N/ha had taller plants, had more tillers, panicles and spikelets, heavier 1000 grains weight, higher grain yield per hectare, higher leaf area index (LAI) and more N content in the leaf than rice with peanut and soybean intercrops. Similar results were obtained from the intercrops in terms of height, number of pods and seeds, weight of 100 seeds, seed yield per hectare, LAI, and leaf N content. Moreover, rice varieties grown as monocrop or with legume intercrop applied with 90 kg N/ha had increased LAI to 47 percent from vegetative stage up to late reproductive stage promoting better photosynthesis. However, the N content of the leaf decreased by 37 percent in same growth stages. LAI of the intercrops and leaf N content had an increase of 33 and 25 percent, respectively, from vegetative stage to early reproductive stage but decreased to 38 and 14 percent at late reproductive stage with the same N rate. Soils grown with rice-peanut and rice-soybean, received 90 kg N/ha and retained an average of 17 and 12 percent N, respectively compared to rice monocrop soil. Kalinayan with peanut intercrop retained the highest soil N. The highest land equivalent ratio (LER) was produced by C22 with peanut intercrop that received 0 kg N/ha. Furthermore, rice-peanut and rice-soybean applied with 90 kg N/ha produced an average of 3.68 and 3.14 t/ha grain yield, higher than rice monocrop (2.66 t/ha). The same rate made peanut and soybean intercrops produced 1.18 and 0.58 t/ha seed yield. Intercropping was more profitable than monocropping. UPLRi 7 with peanut intercrops when applied with 90 kg N/ha gave the highest net profit of P42,428.18 or 220.96 percent ROI [return on investment]. Thus, upland rice varieties with legume intercrops can greatly improve upland farm productivity and ultimately the income of the farmer