RBSE SS Agricultural Chemistry case studies
RBSE SS Agricultural Chemistry · Put your knowledge to work in context.
RBSE Senior Secondary Agricultural Chemistry is a Class 12 elective subject examination under the Rajasthan Board of Secondary Education (RBSE) framework for the agriculture stream. It suits students who intend to move into agriculture, horticulture, agronomy, soil science or rural advisory work, and it also serves candidates preparing for agricultural entrance tests and extension jobs. The RBSE SS Agricultural Chemistry case studies are 5 cases and about 3,751 words.
1Liming an acid sandy loam: rate, timing and the phosphate clash
Ramesh farms 2.0 ha of a sandy loam (clay 12%, organic carbon 0.38%) in a semi-arid block. A composite 0-15 cm sample analysed last month gave pH 5.2 (1:2.5 in water), EC 0.11 dS/m, CEC 9.6 cmol(p+)/kg, exchangeable Al 2.8 cmol(p+)/kg, base saturation 42%, available N 180 kg/ha, Olsen P 9 kg/ha and available K 145 kg/ha.
762 words, about 4 min2Chlorosis in a calcareous wheat field: iron or manganese?
A 1.5 ha wheat crop in a canal command area shows pale interveinal striping on the youngest fully expanded leaves, with irregular brown necrotic speckles and streaks; older leaves remain green. Soil (0-15 cm): pH 8.4 (1:2.5 water), EC 0.28 dS/m, free CaCO3 22%, organic carbon 0.31%, DTPA-Fe 3.6 mg/kg, DTPA-Mn 1.9 mg/kg, DTPA-Zn 0.9 mg/kg.
745 words, about 4 min3Fertiliser arithmetic and ammonia loss on a calcareous zero-till field
A zero-till wheat grower with 1.0 ha has a recommendation of 150 kg N, 60 kg P2O5 and 40 kg K2O per hectare. His stock is urea (46-0-0), DAP (18-46-0) and MOP (0-0-60).
730 words, about 4 min4Is the compost heap fit for a tomato nursery?
A 3.0 t heap of on-farm compost (cattle dung, wheat straw, vegetable waste) has been turned twice and is six weeks old. Analysis: total C 32%, total N 1.23% (C:N 26), NH4-N 1,800 mg/kg, NO3-N 40 mg/kg, EC (1:5) 4.2 dS/m, pH 8.6, moisture 55%, core temperature 34 °C and still above ambient, 40% of the mass coarser than 10 mm, and a faint ammonia smell.
728 words, about 4 min5A tank mix, alkaline borewell water and a three-day harvest
A 0.4 ha tomato crop at peak fruiting has 18% fruit borer damage. The last spray, 8 days ago, was quinalphos 25% EC.
786 words, about 4 min