Fertiliser recommendation tables for beet culture have been prepared based on the response to potassium (K) doses in soils with a low nutrient content. However, there is little research that evaluates potassium fertilisation for beet crops in soil with high K content, a condition commonly found, which allows a better understanding of the crop’s response to the nutrient. The objective was to evaluate the response of beet to doses of K in Oxisol with a high K content. The experiment was carried out in the field, with an experimental design in randomised blocks, in a 4 x 2 factor scheme with four replications. The doses of K were 0, 60, 120 and 180 kg ha-1 of K2O, and the cultivars were ‘Early Wonder’ and ‘Kestrel’. At 50 days after transplantation, the levels of nitrogen (N), phosphorus (P), K and boron (B) in the diagnostic leaf were evaluated. Beet yield and accumulation of these four nutrients were analysed at harvest. The doses of K positively influenced the leaf content of K; however, without an effect on beet yield. Therefore, in Oxisol with a high K content available, potassium fertilisation is not recommended. To maintain soil fertility at a high potassium content, fertilisation with 162 and 126 kg ha-1 of K2O is recommended for ‘Early Wonder’ and ‘Kestrel’, respectively; doses equivalent to the quantities exported by the beet root.

Vegetable intercropping has advantages over single cultivation in terms of less environmental impact. However, to convince farmers to adopt this production system, it is necessary to prove greater efficiency in the production of more food per unit area and therefore an increase in productivity. An experiment was carried out aiming to evaluate the effect of the chicory transplant time in intercrops with collard greens on crop yields and land use efficiency index (LUE). The experimental design was a randomized block, with nine treatments in a 2 × 4 + 1 factorial scheme, and four replications. Crop systems (intercrop and monoculture) and chicory transplant time (0, 14, 28 and 42 days after transplant (DAT) of collard greens) were evaluated. The collard greens yield increased as the chicory transplant time was delayed. The total and per harvest yields of chicory were not influenced by its transplant time. Regardless of chicory transplant time, collard greens and chicory intercropping provided greater LUE than their monocultures and reached the maximum value (52% higher) when the chicory was transplanted 42 days after collard greens. Highlights: The collard green yield increased by 11 kg ha-1 for each day of delay in the chicory transplant (0 to 42 days). The total and per harvest chicory yields were not influenced by its transplant time in relation to collard green transplant. The collard green and chicory intercropping provided 52% higher land use efficiency than their monocultures when the chicory was transplanted 42 days after collard green.

The compositional nutrient diagnosis (CND) method considers the multiple relationships among nutrients and has been proposed to evaluate the nutritional status of plants in place of the univariate and bivariate methods. As it is mathematically based and considers the interactions among all nutrients at the same time, it avoids the errors and trends observed in the calculations of other methods estimating nutritional status, enabling a greater relationship with productivity. The objective of this study was to obtain the CND norms for high-yielding populations of potato crops. For this, 587 samples were used from 21 experimental areas in the state of São Paulo, Brazil to correlate the leaf nutrient contents and the yields of potato crops. Crops with yields higher than 48,993.24 kg ha⁻¹ were considered to have high yields, and the Mahalanobis distance separated the balanced samples from the nutritionally unbalanced ones. Thus, the CND-ilr method generated the norms and classified the 587 samples as nutritionally balanced with a high yield (5% of the total), nutritionally unbalanced with a low yield (92%), nutritionally unbalanced with a high yield (0.3%), or nutritionally balanced with a low yield (2.7%), with accuracy, sensitivity, specificity, NPV, and PPV scores of 96.9, 97.1, 93.6, 64.4, and 99.6%, respectively.

An experiment was carried out aiming to evaluate the effect of phosphorus rates on beet, in an Oxisol with high phosphorus (P) content, in Jaboticabal city, São Paulo, Brazil. The treatments were arranged in a factorial scheme, in a randomized block experimental design with four replicates. The factors evaluated were P rates (0, 120, 240, 360 and 480 kg ha-1 P2O5) and cultivar ('Early Wonder' and 'Kestrel'). At 50 days after transplanting the seedlings, foliar nitrogen (N), P, potassium (K) and boron (B) contents were evaluated, and there was no effect of the interaction between factors on foliar nutrient contents. The accumulation of these four nutrients was evaluated at harvest. All evaluated nutrients accumulated to higher levels in ‘Early Wonder’ than in 'Kestrel' both in the shoots and tuberous root. N, P and B accumulated more in the tuberous root whilst K accumulated more in the shoots. P dose did not influence the yield. Therefore, phosphate fertilization is not recommended for beet crop when cultivated in an Oxisol with a high content (88 mg dm-3) of available P.