K. N. Sharma

Influence of paddy and corn in different rotations on wheat yield, nutrient removal and soil properties

SummaryIn a 3 year field study, the effect of two rotations, paddy (Oryza sativa L.), wheat (Triticum aestivum L.), mung (Phaseolus aureus L.) and corn (Zea mays L.), wheat (Triticum aestivum L.), mung (Phaseolus aureus L.) on wheat yield and chemical, physical and biological properties of soil was evaluated. Grain yield of the wheat sown after paddy during 1972–73, 1973–74 and 1974–75 was lesser by 0,300 and 390 kg/ha respectively than that of the wheat following corn. The reduction in the yield of wheat was attributed to relatively higher NPK removal by paddy, greater immobilization of N applied to wheat and deterioration of soil physical conditions in the paddy field. Total NPK removal by paddy average 131 kg/ha more than that by corn. Sharp increase in bacterial population of soil during early growth of wheat that followed paddy and the concurrent less available N in soil and low N content in wheat plants suggested that the N applied to wheat was immobilised to organic form. The increase in soil bulk density and particle dispersion ratio and decrease in water storage in deeper soil layers in the paddy field probably restricted the root proliferation and growth of wheat.

Influence of growing various crops in five different fixed rotations on the changes in nitrate and total nitrogen content of soils

The results on the influence of various crops in five different fixed rotations on the ohanges in nitrate and total N content of soils are reported. Groundnut contributed largely to the accumulation of nitrate nitrogen in the soil profile (to a depth of 120 cm). Bajra fodder exhausted the soil nitrogen reserve to a great extent. Wheat and maize, in a rotation, reduced nitrate leaching to deeper soil layers. Summer moong also left a large amount of unabsorbed nitrate in the profile. Total nitrogen content of the soil decreased after the harvest of cereals. Maximum depletion occurred after the harvest of bajra crop. Potato (a crop which received a heavy dressing of N fertilizer) and legumes contributed to the soil N reserve. A balance sheet of N indicated net gains of total soil N in four of the five cropping sequences. A net loss of 75 kg N/ha was observed in bajra fodder-potato-wheat rotation.

Effect of row orientation on growth, yield and yield attributes of wheat sown on three dates

An experiment to study the effect of row direction on the light interception, growth and yield of three wheat cultivars sown at three different dates was conducted at Punjab Agricultural University, Ludhiana during rabi seasons 1982–3 and 1983–4. The results showed that sowing in a north-south direction resulted in 0·20 and 0·22 t/ha higher yield than sowing east-west. Bi-directional sowing gave further increases of 0·30 and 0·18 t/ha over north-south direction during 1982–3 and 1983–4 respectively. Late sowing significantly reduced yield.

The quantity-intensity relations of potassium in soils from plots having nine fixed crop rotations for six years

SummarySoil samples collected 6 years after raising of various cereals, pulses, oil seed and tuber crops in nine fixed rotations were used to study the quantity-intensity relations of potassium. Potassium activity ratio, where the soil neither gains nor looses K, was correlated in a highly significant manner (P = 0.01) with the total amount of K fertilizer applied during 6 years. The K buffering capacity, the slope of the Q/I curve, when the soil neither gains nor looses K, was positively correlated (P = 0.05) with K saturation of the total and inorganic cation exchange capacities to a similar extent. Superimposing Q/I curves showed no appreciable difference between samples from different treatments. Desorption of potassium with increasing soil∶solution (0.01M CaCl2) ratio followed a Langmuir type of equation and supported the conclusions drawn from quantity-intensity curves.