Interseeding silage corn into an alfalfa stand following its spring harvests to produce mixed silage would feasibly break the restriction of alfalfa production during a hot-rainy summer. In this 2-yr experiment, the alfalfa–silage corn intercropping system (AC) with nitrogen (N) fertilization rates of 0, 60, 120, and 180 kg N ha⁻¹ and corn plant densities of 30,000, 45,000, and 60,000 plants ha⁻¹ was compared with the monocultured corn (CK) managed using the local farmers’ practice. Intercropping with alfalfa significantly decreased the dry matter (DM) yield of the corn by 31.5% on average, while increasing the N application rate and corn plant density promoted DM yield and crude protein (CP) accumulation of the intercropped corn, and the intercropping system could achieve the same CP yield as CK—it did in most cases. Although the DM contents, pH values, and NH₃-N concentrations were decreased in the mixed silage, its fermentation quality was not reduced and the CP, water soluble carbohydrates, and lactic acid contents were dramatically increased by 16.3%, 17.8%, and 72.9% compared with those of CK, respectively. For the opposite effects of N fertilization and corn density on silage quality, the treatment combination with a medium corn density (45,000 plants ha⁻¹) fertilized at a medium N rate (120 kg N ha⁻¹) was evaluated as the optimum for more balanced system productivity, silage nutritive values and fermentative characteristics during the coexisting period.

Integrating a forage crop into the fallow (F) of the peanut (Arachis hypogaea L.) (P) mono-cropping system is a practical approach to provide forage yield and increase the resource use efficiency. However, little information about the comprehensive assessment of water utilization and economic benefits in the crop–livestock system exists for the North China Plain (NCP). This study aims to identify the crop rotation for optimizing water management and enhance economic benefit. The field experiment was performed over three years (2011–2014) to assess production, water utilization, and economic benefits when inserting forage triticale (X Triticosecale Wittmack) (T) into the peanut mono-cropping system. Results showed that replacing the fallow F-P cropping system with forage triticale provided a substantial amount of forage (the average of 9.8 t ha⁻¹ per year) and enhanced the average system productivity by 85.1%. Cultivation of forage triticale during the fallow period decreased the subsequent peanut pod yield by 8.3% due to a 19.3% decline in soil water storage capacity during the sowing stage of peanut. Replacing fallow with forage triticale increased the system net income by 1016.2 US$ ha⁻¹ and the water use efficiency (WUE) by 30.0%, while not affecting the economic efficiency of water use (EEWU), and thus can be recommended as a better option for maintaining relatively high system production, economic benefit, and WUE in NCP.

Nitrogen (N) can enhance the biomass and feeding quality of forage crops and advance the growth of the herbivorous livestock industry. Investigating the N fertilizer dynamics in the soil–crop–livestock system is important for resource-use efficiency and environmental safety. By using the ¹⁵N-labeled technology and the in vitro incubation technique, an experiment was conducted in the North China Plain (NCP) in 2015–2016 to quantify the migration and distribution of N fertilizer in the soil–forage triticale (X Triticosecale Wittmack)–dairy cow system. The results showed that 34.1–37.3% of the applied N fertilizer was absorbed by forage triticale, in which 35.9–39.6% N accumulated in the stems and 60.4–64.1% accumulated in the leaves. In addition, 36.3–39.1% of the applied N fertilizer remained in the 0–100 cm soil layer, in which 81.8–91.3% was distributed in the 0–40 cm soil layer. The remaining 24.6–26.8% of the applied N fertilizer was lost in various ways and 28.1–31.3% of the N fertilizer could be utilized by dairy cows. When N fertilizer was applied between 0–225 kg N ha⁻¹, the increased application of N fertilizer improved the biomass yield from 14.0 to 17.5 t ha⁻¹ and enhanced the N content of the forage triticale from 1.3% to 1.4%; however, it did not significantly affect the distribution rate of N fertilizer in the soil–forage triticale–dairy cow system. The optimum N fertilizer application rate for forage triticale is less than 225 kg N ha^–1 to maintain high-efficient N use in the soil–crop–livestock system and reduce the environmental risks in the NCP. Our results quantified the N fertilizer dynamics in the soil–forage triticale–dairy cow system and provided a significant reference for guiding rational strategies of forage triticale cultivation.