Proximal Sensing of Nitrogen Needs by Spring Wheat

Canopy nitrogen (N) status relates strongly to canopy chlorophyll content and the strength of green color. Proximal photograph by RGB camera was used to select green features that has the potential to assess N content at leaf of plant as a function of its the greenness. We proposed the development of it as a tool for sensing nitrogen content in spring wheat (Triticum aestivum). Image processing algorithm was programed calibrated and validated wheat %N%N. Nitrogen uptake =%N × canopy dry matter was harvested and calculated using simulated dry matter by DSSAT model. The data replicated laboratory measurements. A linear Lab vs Camera model displayed a unit slope with r2 = 0.93. Increase of dry matter was successfully surrogated by days after emergence and used as abscissa for inverse logistic model of critical nitrogen level. It decreased gradually from about 6% to 2% as days after emergence increased from 0 to 110 days. Maximum N uptake calculated from photo and laboratory was 324 Kg ha−1 and 318 Kg ha−1 respectively suggesting insignificant difference. Physiological N-use efficiency (i.e., canopy weight/N weight) was 52 and 78 kg canopy dry weight per 1 kg N for early and late-ripening cultivars, respectively. The determination of N application based on the smartphone photograph proved to be useful by saving on time and expenses for growers who have access to smartphones and can use them for N application and management

Proximal Sensing of Nitrogen Needs by Spring Wheat

Canopy nitrogen (N) status relates strongly to canopy chlorophyll content and the strength of green color. Proximal photograph by RGB camera was used to select green features that has the potential to assess N content at leaf of plant as a function of its the greenness. We proposed the development of it as a tool for sensing nitrogen content in spring wheat (Triticum aestivum). Image processing algorithm was programed calibrated and validated wheat %N%N. Nitrogen uptake =%N × canopy dry matter was harvested and calculated using simulated dry matter by DSSAT model. The data replicated laboratory measurements. A linear Lab vs Camera model displayed a unit slope with r2 = 0.93. Increase of dry matter was successfully surrogated by days after emergence and used as abscissa for inverse logistic model of critical nitrogen level. It decreased gradually from about 6% to 2% as days after emergence increased from 0 to 110 days. Maximum N uptake calculated from photo and laboratory was 324 Kg ha−1 and 318 Kg ha−1 respectively suggesting insignificant difference. Physiological N-use efficiency (i.e., canopy weight/N weight) was 52 and 78 kg canopy dry weight per 1 kg N for early and late-ripening cultivars, respectively. The determination of N application based on the smartphone photograph proved to be useful by saving on time and expenses for growers who have access to smartphones and can use them for N application and management

Tomatoes

IPM has been developed and successfully applied in greenhouse tomatoes in several regions of the world since the 1970s. As an alternative to the exclusive application of pesticides, the cornerstone of this strategy is to use Natural Enemies (NE) to control some of the crop’s key pests (whiteflies, tomato leafminer) and other pests (spider mites, dipteran leafminers, thrips, aphids and noctuid moths). Along with the development of varieties with reduced susceptibility to viral diseases transmitted by insects, such as TYLCV, TICV, ToCV and ToTV (by whiteflies), TSWV (by thrips) and PVY (by aphids), management of these problems in many affected areas has been enhanced by the use of screens in greenhouses and the use of NE to reduce vector populations region-wide (both inside and outside greenhouses). Until recently, fungicides were the only available solution for control of airborne diseases (Botrytis, Oidium, Phytophtora and Alternaria) and soilborne diseases (Verticillium, Fusarium, Rhizoctonia). A number of biological products and biostimulants now available offer a more sustainable solution, but there is yet no effective solution to some pest problems, such as russet mites, and their presence limits wider application of the programme