Ricardo Cabeza

Universidad de Talca · Department of Agricultural Production (DPA)

Common bean is one of the most important legumes produced and consumed worldwide because it is a highly valuable food for the human diet. However, its production is mainly carried out by small farmers, who obtain average grain yields below the potential yield of the species. In this sense, numerous mapping studies have been conducted to identify qu...

Bitter pit (BP) is one of the most relevant post-harvest disorders for apple industry worldwide, which is often related to calcium (Ca) deficiency at the calyx end of the fruit. Its occurrence takes place along with an imbalance with other minerals, such as potassium (K). Although the K/Ca ratio is considered a valuable indicator of BP, a high vari...

Salinity abiotic stress is increasing day by day due to continuous global warming and climate change. This is also becoming one of the major causes behind the reduction in crop production. Plant–bacteria interaction plays an essential role in improving crop yield without using any chemical fertilizers. The present study aims to characterize the int...

Chickpea is one of the most important pulse crops worldwide, being an excellent source of protein. It is grown under rain-fed conditions averaging yields of 1 t/ha, far from its potential of 6 t/ha under optimum conditions. The combined effects of heat, cold, drought, and salinity affect species productivity. In this regard, several physiological,...

Selliera radicans is a creeping halophyte herb native to Australia, New Zealand and Chile. It is being used on the lawn to replace traditional grass in gardens. It holds up well against foot traffic and does not need to be mown. It is grown in nurseries, but nutritional or fertilizing aspects are unknown. The aims of this study were to assess plant...

Selliera radicans is a creeping halophyte herb native to Australia, New Zealand and Chile. It is being used on the lawn to replace traditional grass in gardens. It holds up well against foot traffic and does not need to be mown. It is grown in nurseries, but nutritional or fertilizing aspects are unknown. The aims of this study were to assess plant...

Iron (Fe) and manganese (Mn) toxicity is a widespread problem in lentil production in the coastal dryland of Chile. Increasing the soil pH by liming with CaCO3 or incrementing grain yields through nitrogen fertilization can help the plants to reduce metal concentration. Thus, the main objective of this work was to evaluate two different fertilizati...

The runner bean is the third most economically important Phaseolus species, which is cultivated on small-scale agriculture for the production of immature pods or to obtain dry seeds. However, despite the economic importance and agronomic potential of this species, the runner bean has been little studied from the genetic standpoint. Therefore, the m...

14 15 16 Common bean (Phaseolus vulgaris L.) is an important grain legume cultivated worldwide as 17 food for humans and livestock (Schwartz et al., 2005). Common beans in central Chile reach 18 up to 3,893 ha from which 1,069 ha are located in the Maule region. Common bean is 19 produced by small farmers who have limited access to fertilization, t...

The main aim of this study is to develop a mechanistic model of fertilization for recommending the application of zinc (Zn) fertiliser for maize based on the mass balance of Zn. The model would consider the critical Zn level for maize (Zn CL), Zn availability in the soil (Zn A) and Zn buffering capacity (Zn b). Soil samples were collected from 78 m...

Symbiotic nitrogen fixation (SNF) has a high energetic cost for legume plants; legumes thus reduce SNF when soil N is available. The present study aimed to increase our understanding regarding the impacts of the two principal forms of available N in soils (ammonium and nitrate) on SNF. We continuously measured the SNF of Medicago truncatula under c...

In most legume nodules, the di-nitrogen (N2)-fixing rhizobia are present as organelle-like structures inside their root host cells. Many processes operate and interact within the symbiotic relationship between plants and nodules, including nitrogen (N)/carbon (C) metabolisms, oxygen flow through nodules, oxidative stress, and phosphorous (P) levels...

Phosphorus (P) will be exhausted, and its recovery and cycling will play a pivotal role in agricultural systems. Different technologies have been developed to recover P from waste materials, such as mono-incineration, acid digestion, and coprecipitation of P from wastewaters. The aim of this study was to assess the plant availability of P from diff...

Grafting has become a common practice among tomato growers to obtain vigorous plants. These plants present a substantial increase in nitrogen (N) uptake from the root zone. However, the mechanisms involved in this higher uptake capacity have not been investigated. To elucidate whether the increase in N uptake in grafted tomato plants under high N d...

Catastrophic events in temperate forest ecosystems, such as wildfires, alter the dynamics of biogeochemical processes. Soil enzymes are critical to soil nutrient cycling function and their potential activities can be sensitive bioindicators of the temperate forest ecosystems resilience after wildfire events. In this context, this is a preliminary s...

The roots are the plant organs responsible for water and nutrient absorption which are needed for adequate plant growth. Therefore, it is important to know both the extent and distribution of the root system into the soil since it determines the ability of the plant for mining soil resources, especially in poor soils or soils with low nutrient or w...

In alkaline soils, where most of the P is acid soluble, we hypothesize that species that acidify the rhizosphere such as oilseed rape, are more efficient to use soil P than for example maize. In field experiments, adult maize plants extracted more P per unit of root than young plants. Here we hypothesize that older plants access P fractions that yo...

Nitrogen fixation of Medicago truncatula is regulated by the nitrogen status of leaves through inducing a repeatedly occurring 24-h nodule activity rhythm that reduces per day nitrogen fixation. The hypotheses of the present study were that (1) long-term moderate whole-plant P deficiency in Medicago truncatula induces an according daily rhythm in n...

Desde suelos derivados de cenizas volcánicas se evaluó la capacidad degradativa de 2 cepas fúngicas seleccionadas:Trichoderma pseudokoningii y Westerdikella multispora y una cepa control (Trametesversicolor ) sobre paja de trigo previamente sometida a pasteurización y con adición de NH4NO3.. Como controles fueron incluidos paja de trigo y paja de t...

Nitrogenase is an oxygen labile enzyme. Microaerobic conditions within the infected zone of nodules are maintained primarily by an oxygen diffusion barrier (ODB) located in the nodule cortex. Flexibility of the ODB is important for the acclimation processes of nodules in response to changes in external oxygen concentration. The hypothesis of the pr...

Symbiotic nitrogen fixation is a process of considerable economic, ecological and scientific interest. The central enzyme nitrogenase reduces H+ alongside N2, and the evolving H2 allows a continuous and non-invasive in vivo measurement of nitrogenase activity. The objective of this study was to show that an elaborated set-up providing such measurem...

The main aim of this study was to carry out an evaluation of soil fertility and fertilisation practices for irrigated maize (Zea mays L.) under Mediterranean conditions in central Chile. Soil samples were collected from 31 maize fields for macro- and micronutrient analysis; additionally a crop management survey was carried out in each field. These...

Legume nodules are plant tissues with an exceptionally high concentration of phosphorus (P), which, when there is scarcity of P, is preferentially maintained there rather than being allocated to other plant organs. The hypothesis of this study was that nodules are affected before the P concentration in the organ declines during whole-plant P deplet...

Legumes match the nodule number to the N demand of the plant. When a mutation in the regulatory mechanism deprives the plant of that ability, an excessive number of nodules are formed. These mutants show low productivity in the fields, mainly due to the high carbon burden caused through the necessity to supply numerous nodules. The objective of thi...

The mechanism through which nitrate reduces the activity of legume nodules is controversial. The objective of the study was to follow Medicago truncatula nodule activity after nitrate provision continuously and to identify molecular mechanisms which down-regulate the activity of the nodules. Nodule H2 evolution started to decline after about 4 h of...

Isotopically exchangeable P (IEP) is usually considered to be completely plant-available and the major source of P for plant uptake. The aim of the present study is to test whether plants can, besides IEP, also use non-IEP and if part of the IEP has an equilibrium concentration in soil solution which is below the minimum concentration, CLmin, and c...

World phosphorus (P) resources are limited and may be exhausted within 70–175 years. Therefore recycling of P from waste materials by chemical or thermal processes is important. This study evaluated the effectiveness of recycled P products from sewage sludge and animal wastes as P fertilizer. Four products were obtained from chemical processes, thr...

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