Abstract

Rice-maize is an emerging cropping system in South Asia that plays significant role in terms of achieving food security in the region. However, achievement of attainable yield in these two crops is often a constrain due to imbalanced and inadequate use of essential plant nutrients. Understanding the contribution of different nutrients (N, P, K, S and Zn) toward yields of hybrid rice—hybrid maize cropping system in calcareous soil is a need for large number of smallholder farming systems. A four seasons study was conducted with an objective to develop further knowledge on crop productivity and nutrient performance indicators in this newly adapted emerging farming system. Replicated nutrient omission trials were conducted at Bihar, India. At the calcareous soil, omission of the nutrients reduced yields, and N was the most limiting nutrient followed by P and K. Omission of Zn impacted crop yields more than S omission, effect was more prominent in hybrid maize. Nutrient uptake in the cropping system was declined by 58%, 37%, 34%, 31% and 25% for N, P, K, S, and Zn, respectively, when these nutrients were systematically removed from fertilization schedule. Sustainable Yield Index (SYI) for cropping system was highest in the ample balanced fertilizer treatment. Post-harvest soil nutrient availability declined in the nutrient omission plots as compared to the initial soil status. We included additional treatments of ample balanced nutrient application and unfertilized check where hybrid cultivars were replaced by inbred varieties of rice and maize. Cropping system productivity highlighted the synergistic effect of seed and nutrients. The unfertilized checks reduced yield by 9 t/ha and 5 t/ha for the hybrid and inbred cropping systems, respectively. Results from present study conclude that adoption of hybrids in rice-maize system and balanced nutrient management are the best management practices for sustainable food production.

摘要

稻－玉米是南亚新兴的种植系统，在实现该地区的粮食安全方面发挥着重要作用。但是，由于必需植物营养素的不平衡使用和不足，这两种作物通常都无法达到可达到的产量。要了解不同养分（N，P，K，S和Zn）对石灰性土壤中杂交水稻－玉米杂交作物的产量的贡献，就需要大量的小农耕作制度。进行了四个季节的研究，目的是在这种新近适应的新兴耕作制度中，进一步了解作物生产力和养分表现指标。在印度比哈尔邦进行了重复的养分去除试验。在钙质土壤上，缺少养分会降低产量，氮是限制最严格的养分，其次是磷和钾。锌的遗失对作物单产的影响大于硫的遗失，杂交玉米的影响更为显着。当从施肥计划中系统去除这些养分后，氮，磷，钾，硫和锌的养分吸收系统的养分吸收分别降低了58％，37％，34％，31％和25％。在充分平衡的肥料处理中，作物系统的可持续产量指数（SYI）最高。与初始土壤状况相比，养分遗失区中收获后土壤养分的有效性下降。我们采用了更多的营养平衡施肥措施和未施肥检查，其中杂交品种被水稻和玉米的自交系替代。种植系统的生产力突出了种子和养分的协同作用。杂种和自交系统的未受精检查分别降低了9吨/公顷和5吨/公顷的产量。本研究的结果得出结论，在玉米-玉米系统中采用杂种和均衡的养分管理是可持续粮食生产的最佳管理方法。