Aspects of nitrogen use efficiency of cauliflower II. Productivity and nitrogen partitioning as influenced by N supply

Abstract

SU MMARYBased on studies concerning dry matter (DM) partitioning, DM production, root growth, nitrogen (N) contents of cauliflower organs and soil nitrate availability (first part of the paper Kage et al. 2003 b), an integrated simulation model for the cauliflower/soil system is constructed, parameterized and evaluated.Dry matter production of cauliflower is described and predicted using a simple light use efficiency (LUE) based approach assuming a linear decrease of light use efficiency with increasing differences between actual, NCA Prot , and ' optimal ', NCAopt Prot area based leaf protein concentrations. For 2 experimental years the decline of LUE with decreasing nitrogen concentration was at 0 . 82 and 0 . 75 (g DMrm 2 /(MJrg N)). Using the parameters obtained from the first experimental year shoot DM production data of cauliflower from five independent experiments with varied N supply containing intermediate harvests could be predicted with a residual mean square error (RMSE ) of 72 g/m 2 for intermediate harvest DM values ranging from about 50 to 900 g/m 2 . Nitrogen uptake and partitioning of cauliflower was simulated using functions describing an organ size dependent decline of N content. Leaf nitrate was considered explicitly as a radiation intensity dependent pool, mobilized first under N deficiency. The curd was assumed to have a sink priority for nitrogen. The model predicted shoot N uptake including data of intermediate harvest with a RMSE of 2 . 4 g/m 2 for intermediate harvest N values ranging from about 3 to 30 g/m 2 . Nitrogen uptake of cauliflower at final harvest was correlated to final leaf number.A scenario simulation was carried out to quantify seasonal variation in N uptake of cauliflower cultivars under unrestricted N availability. Due to variations in the length of the vernalization phase, simulated shoot N uptake ranged from about 260 kg N/ha for spring planted crops to about 290 kg N/ha for summer planted crops of the cultivar 'Fremont '. The cultivar ' Linday ', which shows a more severe delay of vernalization under high temperatures, shows on average a larger shoot N uptake for summer planted crops of about 320 kg N/ha and a much larger variation of shoot N uptake.

Cauliflower Plant Organ Water Status and Nitrogen Translocation From Leaf–Stem Sources to Head Sinks in Its Three Hybrid Cultivars

“…Head organ water holding was 17%-48% (or 29% ± 12%) of whole plant water holding ( Figure 4E), which was comparable to the percentages of head (sink) N that accounted for about 29%-35% of whole plant total N uptake based on the determined sink/source N ratio (Table 1). Because sink N values were dependent on source N translocation rates (Alt et al, 2000;Kage et al, 2003;Li et al, 2011), increasing the early, temporal storage of N in leaves, stems, and roots could benefit the translocation of N for head development, indicated by the strong correlation between head size, head fresh yield, and head N accumulation ( Figure 5AB). …”

“…It is estimated that more than 50% of N in leaves is in components associated with plant photosynthesis (Alt et al, 2000;Lopez-Berenguera et al, 2007;Rather et al, 2000). Plant N assimilation is a fundamental biological process associated with water dynamics that has marked effects on crop productivity and quality components (CardenasNavarro et al, 1999;Kage et al, 2003;Lawlor, 2002;Li et al, 2003Li et al, , 2004Li et al, , 2006. Nitrogen translocation from leaf-stem sources to head sinks is directly related to vegetable nutritional quality (Alt et al, 2000;Kage et al, 2003;Li et al, 2009Li et al, , 2011.…”

“…Cauliflower production often calls for large inputs of fertilizer N to maximize yields (Kaniszewski and Rumpel, 1998;McGrady, 1997). It is thought that insufficient N inflow could result in cauliflower yield loss and poor crop quality (e.g., heads of undesirable shape), causing marketability downgrading (Gardner and Roth, 1990;Kage et al, 2003). Cauliflower head NO 3 concentrations increase by 33% and the input rates increase by 50% (Lisiewska and Kmiecik, 1996), which shows the importance of high N input to food quality, because high NO 3 concentrations in the edible part can be harmful to human health (Cardenas-Navarro et al, 1999).…”

Thiamin stimulates growth, yield quality and key biochemical processes of cauliflower (Brassica oleracea L. var. Botrytis) under arid conditions

“…In fact, N plays a vital role in the synthesis of a variety of amino acids, vitamins and proteins and thus it determines the yield and quality of the cauliflower crop [ 65 , 67 , 68 ]. Like several other inorganic nutrients, an optimal N translocation from the shoot (source) to the head (sink) is believed to determine nutritional quality of cauliflower [ 65 , 68 , 69 ]. It is now evident that metabolites transport particularly of sugars and carbohydrates between cells, organelles as well as source and sink tissues is well coordinated, and it facilitates to gather information related to resource and its utilization [ 70 ].…”

Assessment of Nutrient Management Technologies for Eggplant Production Under Subtropical Conditions: A Comprehensive Approach

“…Integrated and inorganic sources excelled over organics not only for producing total fruit yield but also for marketable yield, which is preferred both by the customers and farmers. A slow release and limited supply of nutrients, particularly nitrogen – a key element for optimum nutrition to produce high yield and quality fruits of eggplants – from organic sources might be the reasons for the above observations (Kage et al , 2003). Total amount of nitrogen applied through any of the organics or combination of organics varied from 90 to 151 kg ha −1 .…”