Intensive agriculture is based on the use of high-energy inputs and quality planting materials with assured irrigation, but it has failed to assure agricultural sustainability because of creation of ecological imbalance and degradation of natural resources. On the other hand, intercropping systems, also known as mixed cropping or polyculture, a traditional farming practice with diversified crop cultivation, uses comparatively low inputs and improves the quality of the agro-ecosystem. Intensification of crops can be done spatially and temporally by the adoption of the intercropping system targeting future need. Intercropping ensures multiple benefits like enhancement of yield, environmental security, production sustainability and greater ecosystem services. In intercropping, two or more crop species are grown concurrently as they coexist for a significant part of the crop cycle and interact among themselves and agro-ecosystems. Legumes as component crops in the intercropping system play versatile roles like biological N fixation and soil quality improvement, additional yield output including protein yield, and creation of functional diversity. But growing two or more crops together requires additional care and management for the creation of less competition among the crop species and efficient utilization of natural resources. Research evidence showed beneficial impacts of a properly managed intercropping system in terms of resource utilization and combined yield of crops grown with low-input use. The review highlights the principles and management of an intercropping system and its benefits and usefulness as a low-input agriculture for food and environmental security.

Rice is the lifeline for more than half of the world population, and in India, in view of its huge demand in the country, farmers adopt a rice–rice cropping system where the irrigation facility is available. As rice is a nutrient-exhausting crop, sustainable productivity of rice–rice cropping system greatly depends on appropriate nutrient management in accordance with the inherent soil fertility. The application of an ample dose of fertilizer is the key factor for maintaining sustainable rice yields and nutrient balance of the soil. Considering the above facts, an experiment was conducted on nutrient management in a rice–rice cropping system at the university farm of Visva-Bharati, situated in a sub-tropical climate under the red and lateritic belt of the western part of West Bengal, India, during two consecutive years (2014–2016). The experiment was laid out in a Randomized Completely Block Design with 12 treatments and three replications, with different rates of N:P:K:Zn:S application in both of the growing seasons, namely, kharif and Boro. The recommended (ample) dose of nutrients was 80:40:40:25:20 and 120:60:60:25:20 kg ha⁻¹ of N:P₂O₅:K₂O:Zn:S in the Kharif and Boro season, respectively. A high yielding variety, named MTU 7029, and a hybrid, Arize 6444 GOLD, were taken in the Kharif and Boro seasons, respectively. The results clearly indicated that the application of a recommended dose of nutrients showed its superiority over the control (no fertilizer application) in the expression of growth characters, yield attributes, yields, and nutrient uptake of Kharif as well as Boro rice. Out of the all treatments, the best result was found in the treatment where the ample dose of nutrients was applied, resulting in maximum grain yield in both the Kharif (5.6 t ha⁻¹) and Boro (6.6 t ha⁻¹) season. The corresponding yield attributes for the same treatment in the Kharif (panicles m⁻²: 247.9; grains panicle⁻¹: 132.0; spikelets panicle⁻¹: 149.6; test weight: 23.8 g; and panicle length: 30.6 cm) and Boro (panicles m⁻²: 281.6; grains panicle⁻¹: 142.7; spikelets panicle⁻¹: 157.2; test weight: 24.8 g; and panicle length: 32.8 cm) season explained the maximum yield in this treatment. Further, a reduction or omission of individual nutrients adversely impacted on the above traits and resulted in a negative balance of the respective nutrients. The study concluded that the application of a recommended dose of nutrients was essential for proper nutrient balance and sustainable yields in the rice–rice cropping system.

Maize (Zea mays L.), being a heavy nutrient feeder, improper application of nutrients may cause nutrient deficiency in maize, resulting in yield loss. Considering these, the present study was carried out during the Rabi seasons (November-March) of 2021-22 and 2022-23 at P. G. Research Farm of Centurion University of Technology and Management, Odisha, India. The study was designed by adopting a randomized block design with 13 treatments and they were replicated three times. The treatments were: T₁: recommended dose of fertilizer (RDF) (120-60-60 kg/ha), T₂: 125% RDF, T₃: 75% RDF, T₄: 150% RDF, T₅: RDF + nano urea, T₆: 75% RDF + nano Urea, T₇: leaf colour chart (LCC) ≤ 4, T₈: LCC ≤ 5, T₉: chlorophyll content meter (CCM) at sufficiency index less than 90%, T₁₀: CCM sufficiency index less than 95%, T₁₁: Nutrient Expert (NE) targeted yield 7 t/ha, T₁₂: NE targeted yield 9 t/ha and T₁₃: absolute control. Results of the study revealed that the highest grain and biological yield was noted with the CCM-based sufficiency index less than 95%. The highest agronomic nitrogen use efficiency was recorded with CCM sufficiency index less than 90%, NE targeted yield 9 t/ha and 125% RDF. The highest agronomic phosphorus and potassium use efficiencies were observed with the CCM sufficiency index less than 95%, followed by NE targeted yield 9 t/ha and 125% RDF. The CCM sufficiency index less than 95% showed the highest physiological use efficiencies of nitrogen, phosphorus and potassium, with 150% RDF, 125% RDF and CCM sufficiency Index less than 90% remained close behind. Apparent recovery efficiency (ARE) and partial factor productivity (PFP) for all nutrients registered the highest value in the CCM sufficiency index less than 95%, followed by the CCM sufficiency index less than 90%, NE targeted yield 9 t/ha, 150% RDF and 125% RDF. Nutrient harvest index (NHI) for nitrogen and phosphorus exceeded that of potassium, with the highest NHI noted with the absolute control. Among nutrient-applied treatments, 75% RDF showed the highest NHI, followed by 125% RDF and 100% RDF.