The HortSyst model is a new discrete time model for describing the dynamics of photo-thermal time (PTI), total dry matter production (DMP), N uptake (N_up), leaf area index (LAI), and evapotranspiration (ET_c) for greenhouse crops. The first three variables are considered as state variables and the latter two are conceptualized as output variables. This model was developed as a tool for decision support systems in Mexican greenhouses for the application of N and water in tomato (Solanum lycopersicum L.) production. The HortSyst has 13 parameters. It was used to calibrate the model and estimate the correct parameter values for the crop season. An experiment was carried out to test model predictions in a greenhouse during the autumn-winter season in Chapingo, Mexico. Tomato ‘CID F1’ was grown in a hydroponic system and plants were distributed with a density of 3.5 plants m^-2. The tomato crop was transplanted on 21 August 2015. A weather station was installed inside the greenhouse to measure temperature, relative humidity, and global radiation. The HortSyst model provides an excellent predictive quality for DMP, N_up, LAI, and ET_c according to the statistics. Values for bias (BIAS) were DMP (-3.897), N_up (-0.071), LAI (0.026), and ET_c (3.647), values for root mean square error (RMSE) were DMP (14.543), N_up (0.500), LAI (0.100), and ET_c (39.330), and values for modeling efficiency (EF)were DMP (0.996), N_up (0.991), LAI (0.998), and ET_c (0.815). The model proposed and described in this paper can be integrated as a decision support tool for N supply and irrigation management in greenhouse production systems.

Sensitivity analysis is the first step in elucidating how the uncertainties in model parameters affect the uncertainty in model outputs. Calibration of dynamic models is another issue of considerable interest, which is usually carried out by optimizing an objective function. The first aim of this research was to perform a global sensitivity analysis (GSA) with Sobol’s method for the 16 parameters of the new HORTSYST nonlinear model that simulates photo–thermal time $\left(PTI\right)$, daily dry matter production $\left(DMP\right),$ nitrogen uptake $\left(Nup\right)$, leaf area index $\left(LAI\right)$, and crop transpiration $(E{T}_c)$. The second objective was to carry out the calibration of the HORTSYST model by applying a differential evolution (DE) algorithm as the global optimization method. Two tomato (Solanum lycopersicum L.) crops were established during the autumn–winter and spring–summer seasons under greenhouse and soilless culture conditions. Plants were distributed with a density of 3.5 plants m⁻². Air temperature and relative humidity were measured with an S-THB-M008 model sensor. Global solar radiation was measured with an S-LIB-M003 sensor connected to a U-30-NRC datalogger. In the sensitivity analysis run in the two growth stages, it was observed that a greater number of parameters were more important at the beginning of fructification than at the end of crop growth for 10% and 20% of the variation of the parameters. The sensitivity analysis came up with nine parameters ($RUE$, $a$, $b$,$c_{1 }$,$c_2$,$A$, $B_d$, $B_n$, and $PTIini$) as the most important of the HORTSYST model, which were included in the calibration process with the DE algorithm. The best fit, according to $RMSE$, was for $LAI$, followed by $Nup$, $DMP$, and $E{T}_c$ for both crop seasons; the $RMSE$ was close to zero, indicating a good prediction of the model’s performance.

Traditionally, biochar is generally proposed to substitute Canadian Sphagnum peat moss. Sugarcane bagasse, filter press mud and sugarcane bagasse ash were mixed in different ratios and proposed as an alternative to substitute commercial Sphagnum peat moss (SPM) for the soilless cultivation of tomato (S. lycopersicum Linnaeus). The choice of the agroindustrial waste ratio was performed from physical-chemical sample characterization. During vegetable production, an adequate ratio was evaluated based on plant height, substrate pH, number of leaves, yield, and fruit size. The addition of essential macro- and micro-nutrients was performed manually. The results show that as-received materials contain different minerals with a structure that corresponds to the quartz, cristobalite, and feldspar phases. A morphology composed of lamellate structures was observed for sugarcane bagasse, whereas the filter press mud and the sugarcane bagasse ash presented compact agglomerates with a surface area of 1.60, 3.78, and 1.07 m² g⁻¹, respectively. The properties of each component promote the water adsorption, retention and releasing capacity. Important differences were observed as the quantity of filter press mud increased, but also it is required an amount of sugarcane bagasse above of 18 wt% to reach a superior performance. This work demonstrated that, in adequate quantities, agroindustrial wastes can be used as a soilless substrate for growing tomatoes in greenhouse, reducing their disposal problems.

The aphid Melanaphis sacchari/sorghi is considered the most important pest of sorghum cultivation in Mexico. It can cause losses in production of up to 100%. This research was conducted at the Universidad Autonoma Chapingo during 2018 and 2019 with the objective of determining the relationship between chemical fertilization in sorghum and M. sacchari/sorghi (Hemiptera: Aphididae) populations. Different levels of nitrogen (125, 250 and 500 kg ha-1), phosphorus (19.5, 39 and 78 kg ha-1) and potassium (210 and 420 kg ha-1) were supplied to sorghum plants planted in polyethylene pots with a capacity of 6 L under greenhouse conditions. The plants were infested with a total of 15 third-instar nymphs within 60 days of crop emergence. A total of 6 samplings were carried out at 7 day intervals, starting at 7 d after the infestation. Quantifications of total soluble proteins, total soluble sugars, reducing sugars, and levels of nitrogen, phosphorus, potassium and magnesium in leaf tissue were also performed. We observed that higher doses of nitrogen and phosphorus increased the aphid population, while increasing the potassium dose considerably decreased the aphid population. We also found a positive correlation between the aphid population and the total soluble protein concentrations, reducing sugars and nitrogen levels, while the correlation was negative with potassium levels in leaves.

Nutrient solution composition plays an important role in root uptake rate due to interactions among nutrients and internal regulation. Studies to determine the optimum nutrient solution concentration are focused on individual ions, ignoring the adaptation mechanisms triggered by plants when growing in a varying external nutrient concentration. The objective of the present study was to determine the response in growth and tissue ion concentration of lilium cv. ‘Navona’ to nutrient mixtures of varying proportions of nitrogen (N), potassium (K⁺), and calcium (Ca²⁺) in solution using mixture experiments methodology in order to determine the optimum concentration. Bulbs of lilium were transplanted in plastic crates and drip-irrigated with the treatment solutions, which consisted of a mixture of N, K⁺, and Ca²⁺ whose total concentration was 340 mg L⁻¹ and minimum concentrations of each ion was 34 mg L⁻¹. Chlorophyll concentration (SPAD), shoot fresh weight (FW), leaf FW, and leaf area were measured 60 days after transplanting and ion analysis was performed on shoot tissues from selected treatments. Lilium exhibited a moderate demand for N and K⁺ (136–170 mg L⁻¹ N and 116–136 mg L⁻¹ K⁺) and a very low demand for Ca²⁺ (34–88 mg · L⁻¹). This low demand may be due to the remobilization of the nutrients stored in the bulbs. Integrating the predictions of the models estimated to produce >90% of maximum growth, the optimum nutrient solution should contain Ca²⁺ at a concentration between 34 and 126 mg · L⁻¹, K⁺ between 119 and 211 mg · L⁻¹, and N between 92 mg · L⁻¹ and 211 mg · L⁻¹. Increasing external N concentration affected internal N concentration but not internal K⁺ or Ca²⁺ concentrations, despite that the increase in external N was associated with a decrease in external K⁺ and Ca²⁺. Similar trends were observed for external K⁺ and Ca²⁺ concentration. In conclusion, lilium was able to maintain a relatively constant K⁺ and Ca²⁺ concentration regardless of the lower concentration in the nutrient solution when N was increased (similar response was observed for K⁺ and Ca²⁺) and it has a low Ca²⁺ demand and moderate N and K⁺ supply.

Musa spp. is one of the most important fruit crops in the world. Production in Mexico is ranked in the eighth place in the world. Nutrient imbalance is one of the main agronomic problems this species has to deal with. Modern fertilization programs must be designed based on nutrient demand by the cultivated plants, and according to their phenological phase. However, no information is available for ‘Dominico’, one of the most widespread cultivars in Mexico. The objectives of the present study were to evaluate dry mass and macronutrient accumulation and distribution in banana ‘Dominico’ during the fruit development phase. This is to determine the amount and timing of fertilizer application. Adult plants were randomly selected in a banana orchard established in Atzalán, Veracruz, México. Root, corm, pseudostem, leaves with petiole, and the bunch were sampled at 2, 4, 6 and 8 weeks after inflorescence emergence (WAIE) on these plants. Samples were processed, and biomass accumulation and N, P, K, Ca, and Mg concentration were determined. Pseudostem was the plant part with the highest dry mass and nutrient accumulation. Potassium was the most extracted nutrient by the plant and the fruit. The sequence for total nutrient extraction per plant was: K > Ca > N > Mg > P. Fruit extraction sequence was: K > N > Ca ≥ P ≥ Mg. The highest nutrient extraction was detected at 4 WAIE. The quantity of mineral nutrients that would have to be replenished into the soil will be those extracted by the bunches because they are removed from the plantation. It is recommended that fertilizer applications be split up to the 2 WAIE. This is to guarantee nutrient supply by the 4 WAIE so that an optimum fruit and daughter plant development could be achieved.