Crop rotation, green manure and nitrogen fertilizers in upland rice under no-tillage

Abstract

The Brazilian Savannah region presents a great potential for the expansion of upland rice crops. However, studies are necessary to identify practices that can improve the crop performance, especially in no-tillage systems. This study aimed to assess the effect of cover crops in association with corn on the development and yield of rice cultivated in rotation and cover fertilized with nitrogen doses. The sprinkler irrigation system was used and the experiment was developed in the 2014/2015 and 2016/2017 harvest years, using a randomized block design, in a 5 × 4 factorial scheme. The treatments consisted of the crop remains combinations of single corn crop, corn + Crotalaria spectabilis, corn + pigeon pea, corn + jack bean and corn + Urochloa ruziziensis, as well as cover nitrogen doses (0 kg ha-1, 40 kg ha-1, 80 kg ha-1 and 120 kg ha-1) in the rice. The cultivation of upland rice in rotation with corn + pigeon pea was favored by the greater soil cover and nitrogen supply via cycling, if compared to the rotation with single corn crop. The intercropped corn + pigeon pea cultivation in the previous summer resulted in a 15 % increase in the yield of rice grains seeded in the rotation, when compared to the single corn crop. The cover nitrogen application positively influenced the grain yield with the maximum estimated doses of 46 kg ha-1 and 105 kg ha-1 of nitrogen, respectively in the 2014/2015 and 2016/2017 harvest years.

Do cover crops improve the productivity and industrial quality of upland rice?

“…Arf et al. () reported that an increased NP may promote competition for nutrients, being insufficient for adequate filling of the grains and reducing their mass.…”

“…This result could be attributed to the lower N nutrition of the rice, indicated by the lower foliar content of the nutrient, as well as the lower accumulation of DMRP. Several studies have demonstrated the important role of N in the development, production components, and grain yield of upland rice (Arf et al, 2018;Fageria, Moreira, & Coelho, 2011;Kamara et al, 2010;Lacerda & Nascente, 2016;Reis et al, 2018).…”

“…The combination of reduced NP and NSP results in greater M100 (Nascente et al, 2013), which may have been caused by the smallest NP providing increased nutrient distribution for grain filling. Arf et al (2018) reported that an increased NP may promote competition for nutrients, being insufficient for adequate filling of the grains and reducing their mass.…”

“…Furthermore, the climatic conditions during summer (high humidity and temperature) favor rapid decomposition (Dias, Umburanas, & Sena Junior, 2018). Because it is difficult to produce straw and keep the soil covered under these conditions, the possibility of cultivating cover crops (Arf, Portugal, Buzetti, Rodrigues, & Sá, 2018) in winter or spring, with the use of irrigation, should be determined.…”

Overcoming Competition From Intercropped Forages on Upland Rice With Optimized Nitrogen Input to Food Production in Tropical Region

“…Recommended N fertilizer rates for monocropped upland rice have been established (Cantarella et al, 1997). However, there is no N fertilizer recommendation for intercropping systems, especially in NTS (Nascente et al, 2013;Arf et al, 2018). We can infer that the current recommended N fertilizer rate may be insufficient to optimize grain yield of rice and biomass and CP in intercropped forage grasses.…”