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With the objective of studying the effect of two nutrient solutions and two crop systems (greenhouse and openfield) on nitrate accumulation, incidence of tipburn and chlorophyll content, endive (cv. Cuartana) was planted in 8 L pots, filled with a mixture of coconut coir:perlite (1:1) in three different cycles C1 (winter), C2 (spring) and C3 (summer). Plants were irrigated with two nutrient solutions of different nitrate content: S1, low ([NO−3] = 7.91 mmol L−1) and S2 moderate nitrate content ([NO−3] = 16.91 mmol L−1). Nitrate content was determined by reflectometry, tipburn was evaluated using a qualitative scale and chlorophyll content by soil plant analysis development(SPAD) values. Plants irrigated with S2 showed higher nitrate accumulation in leaves in all cycles, however, no influence of the nutrient solution was observed on the incidence of tipburn. Greenhouse-cultivated plants accumulated more nitrates than those cultivated in open field and also showed a higher incidence of tipburn and SPAD values. [ABSTRACT FROM PUBLISHER]

Cape gooseberry (Physalis peruvianaL.) is a solanaceous plant. The growth and time-course of nutrient accumulation of the plant and its partitioning between roots, stems, leaves, and fruits were examined. The study was conducted analyzing two nutrient solutions in soilless culture under greenhouse conditions during two consecutive seasons. The macronutrient contents were analyzed. On average, the yield was 8.9 t·ha−1. Growth of the plant until 90 d after transplanting obeys an exponential function of time and the relative growth rate for this period was determined. Nitrogen (N) was the element that showed the highest concentration, corresponding to leaves (4.67%), followed by potassium (K) in stems (4.46%). The highest accumulations of N, phosphorous (P), calcium (Ca), and magnesium (Mg) were found in leaves and of K in the stems. Potassium showed the highest nutrient accumulation (29 g·plant−1) and the highest specific uptake rate. [ABSTRACT FROM PUBLISHER]

The plug plant technique for the commercial propagation of strawberries is increasing in importance. Several factors, including the properties of the substrate, can affect plug plant quality. Tests on nine substrates containing different proportions of perlite [from 0-75%, (v/v)], and dark and light peat [both from 0- 80% (v/v)], were performed using a simplex-lattice design in order to establish a model for strawberry plug plant production based not only on the single component composition of the substrate, but also on the influences of the chemical and physical properties of the substrate on plug plant quality. Notable differences in physical and chemical properties were found among the nine different substrates tested, as a consequence of the broad range of their component compositions. Substrate mixes containing medium-to-high proportions [from 60 - 70% (v/v)] of light peat and low proportions of dark peat and perlite are recommended, as these resulted in a low nutrient content, a high organic matter content, a low pH, and a low "coarseness" index, which led to high-grade plug plants with greater root and crown dry weights. [ABSTRACT FROM AUTHOR]

To determine their influence on leaf tipburn incidence and yields six nutrient solutions with different proportions of potassium (K), calcium (Ca), and magnesium (Mg) were tested in 'Camarosa' strawberry plants. Response models were made to predict tipburn incidence, yields and fruit weight. A high Ca proportion in the nutrient solution was determinant for high yields in the first season, while a high Mg content was fundamental for high marketable yields during the two last seasons. In 2001 and 2002, the average fruit weight was higher with high Mg levels, and in 2000 the lowest fruit weights coincided with low levels of Ca in the nutrient solution. The models for tipburn incidence in 2000 and 2002 indicated that solutions with intermediate to high levels of Mg and intermediate to low levels of Ca resulted in a more frequent incidence of tipburn. Conversely, in 2001, the highest tipburn incidence appeared with high K contents. [ABSTRACT FROM AUTHOR]

The efficiency of fertilisation in agriculture is often low and, provided one knows the nutrient uptake rate, the efficiency can be improved by synchronising nutrient supply with nutrient demand. Growth, the time-course of nutrient accumulation and its partitioning between different organs in chufa (Cyperus esculentus L. var. sativus Boeck.), an under-exploited cultivated plant, were examined. The study was conducted in soilless, open-field conditions, at a planting density equivalent to 55,500 plants ha1 in three consecutive seasons. Plants were sampled, fractionated into leaves, roots, and tubers, then dried and weighed. Their macronutrient contents were analysed each fortnight, On average, the yield was 5.0 kg fresh weight of tuber m-2. Growth of whole plants, until 90 d after planting, obeyed an exponential function of time. The relative growth rate (RGR) for this period was therefore determined. The highest N and K concentrations were recorded in leaves, and the highest P, Ca, and Mg concentrations were found in roots. The highest accumulations of N and P were found in tubers, and of K and Ca in leaves. Nitrogen had the highest nutrient accumulation (58.3 g m-2) as well as the highest specific uptake rate. [ABSTRACT FROM AUTHOR]

The effect on fruit quality of grafting and fruit set treatments, was determined in the triploid watermelon (Citrullus lanatus (Thun.) Matsum. and Nakai) cultivar 'Reina de Corazones' grown in a heated greenhouse. Grafting the scion onto 'Shintoza' (Cucurbita maxima × Cucurbita moschata) rootstock and setting fruit through application of the synthetic cytokinin CPPU [1-(2-chloro-4-pyridyl)-3-phenylurea] retarded the accumulation of sugar and development of the flesh colour of the fruit, compared to fruit from non-grafted, pollinated plants. The effects of grafting and of CPPU application on sugar accumulation were additive. At commercial maturity, the fruit of grafted and/or CPPU-treated plants had lower total soluble solids and sugar concentrations, and lower sucrose to hexose ratios, than fruit from control plants. Fruit from CPPU-treated plants also had a weaker red colour than fruit set by pollination. Despite this loss of quality, fruit from grafted plants, set with CPPU and grown in a heated greenhouse, had a total soluble solids concentration similar to fruit from pollinated, non-grafted plants, grown outdoors. [ABSTRACT FROM AUTHOR]

A two-year study was conducted to analyze the yield and irrigation water-use efficiency of chufa crop in response to planting configuration and drip irrigation scheduling as a function of the volumetric soil water content. The planting configurations were: beds with three plant rows and three driplines (B3), beds with three plant rows and two driplines (B2), beds with two plant rows and two driplines ( b ), and ridges ( R ). The yield was affected by the planting configuration; greater yields were obtained in beds (on average 2.36 kg m −2 ) than in R (2.14 kg m −2 ). Considerably less irrigation water was applied in R and in B2 than in beds B3 and b . The irrigation water-use efficiency was affected by the planting configuration in the same line that the irrigation water was applied, with greater values being obtained in B2 (7.58 kg m −3 ) than in the R (6.63 kg m −3 ), which in turn was higher than B3 (5.92 kg m −3 ) and b (5.69 kg m −3 ). These values of the irrigation water-use efficiency were considerably higher than those obtained in previous experiments (based on the volumetric soil water content in the ridges). Neither the yield nor the average tuber weight were affected by the position of the different planting rows in the bed. [ABSTRACT FROM AUTHOR]