Macronutrient Uptake And Removal By Upland Rice Cultivars With Different Plant Architecture

Modern high-yielding rice cultivars possibly take up and remove greater quantities of macronutrients than traditional and intermediate cultivars. This study was carried out with the aim of evaluating the extraction and removal of macronutrients by upland rice cultivars. These information are of utmost importance for the correct fertilizer management. The treatments consisted of three upland rice cultivars (Caiapó, a traditional type; BRS Primavera, an intermediate type; and Maravilha, a modern type). Macronutrient accumulation by rice cultivars up to the end of tillering (46 DAE) accounted for only 25 % of the total N and P, and between 35-45 % of the total K, Ca, Mg, and S; after that time, accumulation was intensified. In all of the cultivars, the period of greatest nutrient uptake occurred from 45 to 60 DAE for K, Ca, Mg, and S, and after 65 DAE for N. Phosphorus was taken up at greater rates at 70 DAE by the cultivar BRS Primavera and after 90 DAE by the cultivars Caiapó and Maravilha. The cultivars of the traditional (Caiapó) and intermediate (BRS Primavera) groups took up greater amounts of Ca (143 kg ha-1), Mg (46-53 kg ha-1), and S (45-52 kg ha-1), but amounts of N (147-156 kg ha-1) and P (18-19 kg ha-1) were similar to those of the cultivar of the modern group (Maravilha). Caiapó cultivar took up more K (245 kg ha-1) than other cultivars (204-207 kg ha-1). The cultivars Caiapó and Maravilha showed similar grain yield (4,157 and 4,094 kg ha-1); however, this was lower than the grain yield of cultivar BRS Primavera (6,010 kg ha-1). Cultivars with greater yield levels did not necessarily exhibit a greater uptake and removal of nutrients per area, even if they had greater capacity for conversion of the nutrients taken up into the biomass. © 2016, Revista Brasileira de Ciencia do Solo. All rights reserved.4

Efeitos Residuais Da Calagem Superficial Em Solo Tropical Com Plantio Direto

The objective of this work was to evaluate the long-term effects of the surface application of lime on soil fertility and on the mineral nutrition and grain yield of soybean, and of black oat and sorghum in crop succession. The experiment was carried out on a clayey Oxisol, in a randomized complete block design, with four replicates. Treatments consisted of lime the rates of 0, 1,000, 2,000, and 4,000 kg ha-1, applied in October 2002 and November 2004. Soil samples were collected at five soil layers, down to 0.60-m depth. Surface liming was effective in reducing soil acidity and increasing Ca2+ and Mg2+ contents in the subsurface. Moreover, it increased available phosphorus contents and soil organic matter in the long term (48 to 60 months after the last lime application). Surface liming improved plant nutrition, mainly for N, Ca, and Mg, and increased dry matter production and grain yield of the crops, even in years with regular distribution of rainfall. The greatest productivities of soybean, black oat, and sorghum were obtained with the respective estimated lime doses of 4,000, 2,333, and 3,281 kg ha-1, for shoot dry matter, and of 2,550, 3,555, and over 4,000 kg ha-1, for grain yield.5191633164

Influência De Níveis De Potássio No Crescimento Radicular E Na Absorção De Nutrientes Em Cultivares De Arroz De Terras Altas

Potassium (K) is an essential nutrient for upland rice growth, but little information on the effects of K on root growth and nutrient uptake capacity of upland rice is found. Therefore, an experiment was conducted under greenhouse conditions to evaluate the influence of soil K levels on root growth and nutrient uptake of four upland rice cultivars. A completely randomized experimental design, in a 4x4 factorial scheme (4 levels of K: 20, 40, 80, and 160 mg dm-3; 4 cultivars: Caiapó, BRS-Primavera, IAC-202, and Maravilha) was used, with four replications. Based on regression equations, the highest values of root length density would be found with 136 mg dm-3 of K. The root diameter and dry matter, shoot dry matter and shoot K concentration increased linearly with the increasing K rates. The shoot K concentration of the upland rice cultivars did not differ. The increased level of K in the soil reduced the shoot Ca concentration of intermediate and modern cultivars, and the shoot Mg concentration of all cultivars. The potassium fertilization increased the plant growth, but the magnitude of this effect varied according to the cultivar. © 2017, Universidade Federal Rural do Semi-Arid. All Rights Reserved.301324

Silage Production Of Corn Intercropped With Tropical Forages In An Integrated Crop-livestock System With Lambs

The objective of this work was to evaluate the effect of intercropping systems between corn and tropical forages, at different cutting heights, on silage production, light interception, land use efficiency, intercropping competition factors, and pasture production. In the 2010/2011 and 2011/2012 crop seasons, two cultivation modalities were evaluated in the summer/autumn - monocropped corn with residual regrowth of signal grass (Urochloa decumbens) from the soil seed bank and corn intercropped with palisade grass (U. brizantha 'Marandu') -, in a factorial arrangement with two cutting heights for silage production - 0.20 and 0.45 m. After corn silage harvest, the forages were grazed by lambs in a semi-feedlot system, in the winter/spring. Monocropped corn and 0.45-m cutting height both reduced dry matter yield for silage. Corn intercropped with palisade grass improved land use efficiency from 13 to 31% compared with monocropped crop, with land equivalent ratio greater than 1. Palisade grass showed higher light interception than signal grass over the intercrop period with corn and provided greater forage yield for lambs to graze during winter/spring. Corn intercropped with palisade grass, compared with monocropped corn, especially at the cutting height of 0.45 m, is a viable option for improving silage and pasture production, as well as land use efficiency in the integrated crop-livestock system.521546

Yield And Nutritive Value Of The Silage Of Corn Intercropped With Tropical Perennial Grasses

The objective of this work was to compare the yield and nutritive value of the silage of corn intercropped with palisade grass (Urochloa brizantha 'Marandu') or guinea grass (Megathyrsus maximus 'Tanzânia') with those of the silage of monocropped corn, as well as to evaluate the pasture established in the intercropping systems during two growing seasons (2010-2011 and 2011-2012), in low-altitude Brazilian Cerrado. The treatments consisted of three cropping systems: monocropped corn, corn intercropped with palisade grass, and corn intercropped with guinea grass, with four replicates. Intercropping decreased corn forage dry matter yield for silage; however, due to the addition of grass, total dry matter yield (corn + grass) was similar between treatments. Intercropping also did not negatively affect corn production components and morphological characteristics. The cropping systems provided silages with good nutritive values, and the inclusion of tropical forages increased the silage fiber contents. Intercropping corn with tropical perennial grasses is a viable option for producing large quantities of silage with good nutritive value. The forage yield (silage + pasture) of these intercropping systems is similar to that of monocropped corn in tropical regions and has the advantage of providing a pasture in the off-season.521637