Phosphorus Over-Fertilization and Nutrient Misbalance of Irrigated Tomato Crops in Brazil

Abstract

Over the past 20 years, the use of center-pivot irrigation has increased tomato (Solanum lycopersicum L.) yields in Brazil from 42 Mg ha−1 to more than 80 Mg ha−1. In the absence of field trials to support fertilizer recommendations, substantial amounts of phosphorus (P) have been applied to crops. Additional P dosing has been based on an equilibrated nutrient P budget adjusted for low-P fertilizer-use efficiency in high-P fixing tropical soils. To document nutrient requirements and prevent over-fertilization, tissue samples and crop yield data can be acquired through crop surveys and fertilizer trials. Nevertheless, most tissue diagnostic methods pose numerical difficulties that can be avoided by using the nutrient balance concept. The objectives of this study were to model the response of irrigated tomato crops to P fertilization in low- and high-P soils and to provide tissue diagnostic models for high crop yield. Three P trials, arranged in a randomized block design with six P treatments (0–437 kg P ha−1) and three or four replications, were established on a low-P soil in 2013 and high-P soils in 2013 and 2014, totaling 66 plots in all. Together with crop yield data, 65 tissue samples were collected from tomato farms. We found no significant yield response to P fertilization, despite large differences in soil-test P (coefficient of variation, 24%). High- and low-yield classes (cutoff: 91 Mg fruits ha−1) were classified by balance models with 78–81% accuracy using logit and Cate–Nelson partitioning models. The critical Mahalanobis distance for the partition was 5.31. Tomato yields were apparently not limited by P but were limited by calcium. There was no evidence that P fertilization should differ between center-pivot-irrigated and rain-fed crops. Use of the P budget method to arrive at the P requirement for tomato crops proved to be fallacious, as several nutrients should be rebalanced in Brazilian tomato cropping systems.

Adjustment of phosphorus concentration to increase growth and yield of cherry tomato using hydroponic drip system

“…The results showed that increasing the concentration of P until 175 ppm or 200 ppm starting at 12 and 13 WAT have a number of flowers was formed. This data in line with Nowaki et al (2017) who found that the optimum P can increase some of the reproductive properties of the plants in the form of total mass of flowers, fruit production, and number of seed production of pollen per plant. Phosphorus plays a role in increasing the photosynthetic reaction in plants (Gad & Kandil, 2010).…”

“…Application of phosphorus starting from 175 ppm significantly increased Harvest Index and the concentration of phosphorus 200 ppm showed the highest Harvest Index (Table 4). According to Nowaki et al (2017) that the lower the concentration of P applied on tomato plants lead to a decrease on plants dry weight in general so that the lower plants dry weight produced mainly fruit, resulting lower harvest index values.…”

Agronomic yield and quality of industrial tomatoes under NPK doses

“…This result suggests that the hybrid Heinz has greater efficiency in the use of NPK fertilizers. However, Nowaki et al (2017) found no difference between the yields of tomato plants working with P in areas of high and low fertility in São Paulo state, Brazil, and these authors point out the need for balanced management of nutrients during tomato cultivation.…”

“…The nitrogen is cited as one of the main nutrients for tomato, because it constitutes organic compounds that are vital to plants and contributes to fruiting, productivity and economic profitability, but can decrease fruit firmness (Marschner, 2012). Despite being absorbed in smaller quantity and having lower concentrations in plant tissue, the phosphorus is extremely important in root formation and growth, besides increasing the commercial quality of the fruit (Mueller et al, 2013;Nowaki et al, 2017). The potassium is the most required nutrient by tomato (Prado et al, 2011) and contributes to the processes of photosynthesis, enzymatic activation and protein synthesis (Rebouças Neto et al, 2016).…”

Conditioning Machine Learning Models to Adjust Lowbush Blueberry Crop Management to the Local Agroecosystem

“…The P fixation by oxy-hydroxides of Fe and Al at low pH values reduces P fertilizer-use efficiency in the acidic P-fixing podzolic soils used for lowbush blueberry production [ 76 ]. However, making P fertilizer application based on soil P fixing capacity alone can result in wrong decisions [ 77 ]. Soil pH values exceeding 5.2 can decrease the yield of lowbush blueberry [ 73 ].…”