Effect of Cover Crops on Soil Attributes, Plant Nutrition, and Irrigated Tropical Rice Yield

Abstract

-In flood plains, cover crops are able to alter soil properties and significantly affect rice nutrition and yield. The aims of this study were to determine soil properties, plant nutrition, and yield of tropical rice cultivated on flood plains after cover crop cultivation with conventional tillage (CT) and no-tillage system (NTS) at low and high nitrogen (N) fertilization levels. The experimental design was a randomized block in a split-split-plot scheme with four replications. In the main plots were cover crops [sunhemp (Crotalaria juncea and C. spectabilis), velvet bean (Mucuna aterrima), jackbean (Canavalia ensiformis), pigeon pea (Cajanus cajan), Japanese radish (Raphanus sativus), cowpea (Vigna unguiculata)] and a fallow field. In the subplots were the tillage systems (CT or NTS). The nitrogen fertilization levels in the sub-subplots were (10 kg N ha ). All cover crops except Japanese radish significantly increased mineral soil nitrogen and nitrate concentrations. Sunhemp, velvet bean, and cowpea significantly increased soil ammonium content. The NTS provides higher mineral nitrogen and ammonium content than that by CT. Overall, cover crops provided higher levels of nutrients to rice plants in NTS than in CT. Cover crops provide greater yield than fallow treatments. Rice yield was higher in NTS than in CT, and greater at a higher rather than lower nitrogen fertilization level.Keywords: Nitrogen. No-till. Tropical lowland. PLANTAS DE COBERTURA AFETANDO ATRIBUTOS DE SOLO, NUTRIÇÃO E PRODUTIVIDADE DO ARROZ IRRIGADO TROPICALRESUMO -O uso de plantas de cobertura pode alterar atributos do solo e afetar significativamente a nutrição das plantas e produtividade do arroz cultivado em planícies inundáveis. Este trabalho teve como objetivo determinar atributos do solo, nutrição de plantas e produtividade do arroz irrigado tropical em planícies irrigáveis por inundação após o cultivo de plantas de cobertura, no preparo convencional do solo (PC) ou sistema plantio direto (SPD) em baixa e alta adubação com N. O delineamento experimental foi em blocos casualizados, no esquema de parcelas sub-subdivdidas, com quatro repetições. Nas parcelas estavam as coberturas vegetais [Crotalaria juncea, C. spectabilis, mucuna preta (Mucuna aterrina), feijão de porco (Canavalia ensiformis), feijão guandu (Cajanus cajan), nabo forrageiro (Raphanus sativus), feijão caupi (Vigna unguiculata) e pousio], nas subparcelas o sistema de preparo do solo (PC ou SPD) e nas sub-subparcelas a adubação nitrogenada (10 e 45 kg ha -1 N). As plantas de cobertura, com exceção do nabo forrageiro, proporcionam incrementos nos teores de N total e nitrato no solo. C. juncea, C. spectabilis, mucuna preta e feijão caupi proporcionam incrementos nos teores de amônio no solo. O SPD proporciona maiores teores de N total e amônio do que o PC. No âmbito geral, as plantas de cobertura proporcionaram maiores teores de nutrientes nas plantas de arroz no SPD do que no PC. As plantas de cobertura também proporcionaram maior produtividade do arroz em relação ao t...

Cover Crops and Mechanical Scarification in the Yield and Industrial Quality of Upland Rice

“…The highest number of panicles m −2 , number of total grains and number of filled grains panicle −1 of upland rice in 2013/2014 cropping were observed with C. juncea and P. glaucum as cover crops without mechanical soil scarification and in fallow with mechanical soil scarification in NTS (Figure 2). Reis et al (2017) also reported that inclusion of C. juncea as a cover crop in rice cultivation system had increased number of panicles and panicle mass in a no-tillage system without mechanical soil scarification. The incorporation of crop residues by rotary tiller in NTS has improved physical and chemical characterizations of soil, even though resulted in greater grain yield of rice due to greater organic matter retention (Tang et al, 2020).…”

“…This might be due to greater decomposition potential of C. cajan that consequently release nutrients by mineralization for the crop in succession, in this case rice is successive crop. It was reported that P. glaucum straw can reduce nitrogen supply by biological N fixation and mineralization of P. glaucum as crop residue thus contribute to higher grain yield of rice (Reis et al, 2017). In other case it was indicated that U. ruziziensis was the best option of cover crop before rice cultivation however, low grain yield was due to the deficiency of water during pre-flowering stage (Pacheco et al, 2013), different from the experiment in question as it was irrigated with sprinkler irrigation system.…”

Yield of upland rice as affected by nitrogen application and seed inoculation with diazotrophic bacteria

“…So, the increase of N rates increased the availability of this nutrient and contributed to linear increase of plant tissue (Hernandes et al, 2010;Gitti et al, 2012;Lopes et al, 2013). According to Fageria (2014) and Reis et al (2017) the N and P are part of several structures in the plant and usually increasing the levels of one nutrient in rice leaves implies the increase of the other. The increased content of Ca and Mg upon increasing N rates could be due to more N uptake by rice plants.…”

Utilização De Plantas De Cobertura Como Alternativa De Manejo Sustentável

“…O gênero Crotalária exibe diversas espécies com características favoráveis no emprego de rotação de culturas. Além disso, destaca-se na eficiência de simbiose, com bactérias fixadoras de nitrogênio e auxilia no controle dos principais nematoides prejudiciais as culturas de soja e milho (REIS et al, 2017). Contudo, exibe grande importância na otimização da eficiência do uso de fertilizantes, no incremento de matéria orgânica e na diminuição da suscetibilidade e de prejuízos recorrentes as questões fitossanitárias do cultivo (GARCIA E STAUT, 2018).…”