Rice (Oryza sativa L.) is the major wet season crop in the eastern part of India (comprising the states of Bihar, Odisha, Jharkhand, and West Bengal and the union territory of the Andaman and Nicobar Islands), covering 49 percent of the gross cropped area and 62 percent of the area under food grains [1]. During the winter and summer seasons, non-rice crops (maize, pulses, oilseeds, and vegetables) are grown due to the scarcity of irrigation water. The short winters allow for the growth of only select oilseed crops, such as toria (Brassica campestris var. toria). After the winter season, maize (Zea mays) is a desirable crop for the summer due to the presence of husks on the cobs, which shield the crop from the impacts of adverse weather, particularly hailstorm damage. Additionally, due to their increased stomatal resistance, maize plants, which have the C₄ pathway, withstand higher temperatures and insolation [2] and achieve higher production efficiency under moisture stress [3]. Furthermore, in recent years, the demand for sweet corn among the various types of maize has been rising in the vicinity of this region’s urban and peri-urban districts; therefore, rice–toria–sweet corn is one of the most suitable cropping sequences for the irrigated coastal plains of Eastern India. Rice benefits from the monsoon rains, while toria, a short-duration crop, utilizes the residual moisture when sown early, and sweet corn takes advantage of the carryover effects of the soil left by the previous crops. This diversified cropping system can stabilize productivity under environmental stress.

Crop/cropping system performance is a reflection of the integrated effects of the weather, soil, crops, and management practices. Of these, weather elements are beyond the control of the farmer. However, the timing of post-rice crop planting is crucial to the rice–toria–sweet corn system’s performance. Crop establishment can be modified to align the cropping system’s life cycle with a favorable weather window. Furthermore, the sowing time of post-rice crops is greatly dependent on the growth duration of the rice cultivar used in rice-based cropping systems. Very often, toria sowing is delayed due to the late harvesting of long-duration rice varieties; therefore, it is essential to find a rice cultivar that will provide the optimum sowing window for the succeeding non-rice crops to avoid heat stress due to adverse weather. Heat stress reduces mustard yields by decreasing the crop growth duration [4] and maize yields by affecting pollen viability [5]. It has been observed that dry-season crops planted after short-duration rice varieties perform better in terms of productivity and profitability in the winter [6].

Nutrient management, particularly N, is crucial in improving the soil quality and achieving the sustainable productivity of exhaustive rice–toria–sweet corn systems. The base crop (rice) in the system requires about 20 kg N t⁻¹ of economic product. The N recovery efficiency of applied fertilizers is only 20–40% in the crop due to losses of the element through various channels, such as nitrate leaching, surface run-off, denitrification, and ammonium volatilization [7]. The nitrous oxide released into the atmosphere is also a major greenhouse gas (GHG), with a global warming potential (GWP) that is 265 times higher than that of CO₂ [8]. Biologically fixed N is environmentally friendly and less subject to losses. Nitrogen in organic sources is biologically fixed. Organic sources, such as animal manure, crop residues, and green manure, provide available nutrients to crops, enhance the soil porosity, increase the crop-accessible water content, and increase the soil organic matter content. They have positive effects on the crop yield and quality. Using maize crop residues and green leaf manure as mulch between rows of pigeon peas after harvesting maize in maize + pigeon pea intercropping systems increased the system’s productivity and profitability and improved the soil fertility [9]. Animal manures produced a 20% higher grain yield of rice compared to crop residues [10]. The application of 30% nitrogen as poultry or cattle manure, combined with 70% N from chemical fertilizers, increased the post-anthesis N uptake, improved the soil quality, and increased the grain yield of rice [11]. Manure amendment could modulate the adverse effects of extreme temperatures on the rice yield, improve the soil fertility, and decrease the global losses in rice productivity due to global warming from 33.6 to 25.1% [12]. The replacement of 30% of the recommended dose of fertilizer with sheep manure, poultry manure, rice husk biochar, or sugarcane press mud improved the nutrient balance, soil quality, and yield of the rice–wheat system in North India [13]. The application of cattle manure resulted in higher sugar beet root yields than a chemical fertilizer [14]. Hence, the integration of organic sources with mineral fertilizers can enhance the productivity of rice-based cropping systems and restore the soil quality [15]. When all three crops of the system are non-legumes and exhaustive, the inclusion of pre-rice green manuring crops will contribute to improvements in soil quality and sustain system productivity. Sesbania green manuring (GM) helps in symbiotic nitrogen fixation and increases the soil organic matter (SOM) and available nutrient status. Positive effects of the substitution of chemical nitrogen with Sesbania GM on the soil quality of the rice–green gram cropping system [16] and the N recovery efficiency and soil carbon in the rice–rice system [17] have been reported. However, the effect of the substitution on the system yield, nutrient uptake, and soil quality under rice-based intensive cropping systems is still unclear.

Transplanted rice is a tillage-intensive crop, and the subsequent crops, such as rapeseed and maize, respond differently to the different tillage practices of rice [18]. In general, the early establishment of toria in winter and maize in summer increases the system yield. Apart from the rice maturity duration, the timing of winter- and summer-season crop establishment is also governed by the tillage practices followed, which strongly affect the soil properties as well. Conventional tillage (CT), comprising repeated tillage operations, damages the soil structure. Zero tillage (ZT) advances the planting time by 7–10 days and helps in the better utilization of soil moisture [19]. Furrow-irrigated raised bed planting in post-rice crops improves the water economy and soil quality. ZT has been found to be the most appealing and economical alternative to CT for toria and sweet corn in other parts of India [20,21].

Sufficient food production to support life depends on soil quality improvement. It is a reflection of the integrated effects of the soil’s physical, chemical, and biological parameters, which influence each other and determine the land productivity. The soil quality is degraded by the loss of organic matter, the inadequate and imbalanced supply of plant nutrients, soil erosion, and excessive tillage. The introduction of rice crops in rotation has a negative impact on the soil quality due to a decrease in organic matter [22]. The sustained productivity of intensive rice-based systems requires the monitoring of key soil parameters to assess periodic changes, as well as adopting management practices to restore the soil quality. There is also a need to identify management-sensitive key indicators that can be used to monitor and predict periodic changes in soil quality [23]. Soil parameters have variable effects on the soil quality and yields of crops. Soil properties with a positive and greater influence on productivity should be identified through correlation, regression, and principal component analysis (PCA). Good-quality soils maintain adequate available nutrients for uptake by crops, produce good yields, maintain the environmental quality, and consequently enhance animal and human health [24]. Nutrient uptake and crop yields are functionally related. A positive relationship between nutrient requirements and grain yields in rice has been reported previously [25].

The global challenges in agricultural sustainability encompass climate change, environmental degradation, biodiversity declines, persistent poverty, and related injustices [26]. The present investigation addresses these challenges through the substitution of chemical nitrogen with green manuring and a decrease in the carbon footprint [27], the avoidance of excess tillage, the maintenance of the soil structure, and crop intensification and pre-rice green manuring to enhance the biodiversity and farm income among limited landholdings.

Considering the above, an experiment was designed with the hypothesis that green manure-based nitrogen management practices for rice cultivars and appropriate tillage methods for post-rice crops would avoid climatic stresses to crops, ensure suitable weather conditions for crop growth, enhance the energy use efficiency, decrease the carbon footprint and water use, improve the soil quality, enhance the nutrient uptake by crops, and sustain the productivity and profitability of an intensive and exhaustive rice–toria–sweet corn system in the irrigated coastal plains of Eastern India. Therefore, the present article focuses on the comparative efficacy of the studied treatments in enhancing system nutrient uptake, increasing the biological yield, and improving the soil quality. Earlier, the authors reported research findings regarding the energy–carbon–water use efficiency, base crop equivalent yield, and system net return, which were based on distinct objectives [27].