Pakistan Research Repository


Kumbhar, Abdul Majeed A. (2008) SYMBIOTICALLY FIXED N AND INORGANIC N EFFECTS ON CROP YIELDS IN VARIOUS CROP SEQUENCES. PhD thesis, Sindh Agriculture University, Tando Jam.



A series of experiments were conducted at Research Area of Student’s Farm, Department of Agronomy, Sindh Agriculture University, Tandojam during 1989-1990 and 1990-1991. The experiments were laidout in randomized complete block design (RCBD) with factorial arrangement consisting four replications. The soil of the experimental area was clay loam in texture, non-saline in nature, slightly alkaline in reaction (pH= 8.1-8.3), low in organic matter (0.58-0.54%) and poor in available phosphorus (3.00-3.50 mg kg-1). The experiment included crop sequences (C1 = wheat-soybean-wheat and C2 =cotton-berseem-cotton). Fertilizer levels for cotton and wheat were 50, 100 and 150 N kg ha-1. The P was applied in the form of DAP uniformly to all the treatments. The findings of study revealed that wheat planted after legumes produced taller plants (77.25 cm), more tillers (4.56), longer spikes (8.99 cm), higher spikelets per spike ( 17.80), more grains per spike (44.93), heavier seed index (35.21 g), better biological yield (6470.33 kg ha-1), maximum harvest index (42.14%), rich in grain protein (11.64%), increased leaf area index (4.20m2), accumulated more dry matter (7244 kg ha-1), and satisfactory grain yield (2763.33 kg ha-1) and higher N uptake (119.26 kg ha-1). The increased level of fertilizer at 150 N kg ha-1 progressively increased wheat plant height (72.62 cm), tiller production per plant (4.60), spike length (9.24 cm), spikelets per spike (17.31), number of grains per spike (44.14), seed index (36.98g), biological yield (7235.50kg ha-1), harvest index 44.18%), grain protein content (10.091%), leaf area index (4.80m2) , grain yield (3198.19 kg ha-1) and N uptake (14.01 kg ha-1). Most of the yields contributing parameters were positively correlated with grain yield. The coefficient of determination for tillers per plant (44%), spike length (59%), grain per spike (43%), seed index (63%) and harvest index (76%) signifies that the total variation in grain yield was due to increase in these characters. Cotton, when the crop was sown after legume, it produced tall plants (99.41 cm), higher production of monopodia per plant (2.68), sympodia per plant (14.10), more bolls per plant (24.83), greater picked bolls per plant (21.04), heavier seed index (6.83 g), maximum GOT (34.47%), better staple length (28.83mm), higher oil content ( 22.87% ), higher dry matter (3303.00 kg ha-1) superior seed cotton yield (2428 kg ha-1) and N uptake increased upto 91.17 kg ha-1. The incorporation of NP fertilizer significantly affected crop parameters. Among the tested fertilizer regimes 150 N kg ha-1 recorded maximum plant height (102.63 cm), monopodia per plant (2.61), sympodia per plant (13.70), bolls per plant (26.40), picked bolls per plant (21.73), seed index (6.83g), GOT (34.57%), staple length (28.65mm), oil content (23.10%), dry matter (3955.50 kg ha-1), seed cotton yield (2538.25 kg ha-1) and N uptake (113.43 kg ha-1). The coefficient of determination for sympodial branches (75%), number of bolls (81%), number of picked bolls (70%), seed index (80%) accounted for total variation in seed cotton yield due to these characters. It is concluded that nitrogen fertilizer is essential nutrient for achieving satisfactory crop yield. The increased soil productivity and fertility for crop production could be obtained by the inclusion of leguminous crop at least once in a two year cropping sequence, because leguminous crops enrich soil fertility by fixing environmental nitrogen in their root nodules, which in turn supply residual food nutrients to the succeeding crop. Thus, it is recommended that (i) continuous cropping in the sequence of wheat-cotton be avoided, (ii) the higher yields of cotton and wheat could be achieved in the farming system which includes legumes in crop rotation, (iii) the application of 150 N kg ha-1 gave better results as compared to 50 and 100 kg N ha-1 application and (iv) the use of in-organic nitrogenous fertilizers could be minimized by including legume crops in the crop sequence.

Item Type:Thesis (PhD)
Subjects:Agriculture & Veterinary Sciences(a) > Agriculture(a1)
ID Code:2725
Deposited By:Mr. Javed Memon
Deposited On:01 Oct 2009 16:04
Last Modified:01 Oct 2009 16:04

Repository Staff Only: item control page