Two field experiments were carried out at El-Gemmeiza Agricultural Research Station, El-Gharbia Governorate during two successive seasons of 2012 and 2013. These experiments were conducted to study the probability of using clean agriculture to produce organic cotton and reduce environmental pollution. A randomized complete block design with 4 replicates was used in both seasons, where the following twelve patterns were evaluated with regard to growth and its attributes of the Egyptian cotton (Gossypium barbadense, L.), cultivar Giza 86:- Patterns 1, 2, 3 and 4 included two rates of mineral NPK fertilizers (45 kg N: 22.5kg P2O5 :24 kg K2O /fed (the recommended rate) and 60 kg N :30 kg P2O5 : 36 kg K2O /fed) in combination with chemical or bio- control, respectively. Patterns 5, 6, 7 , 8, 9,10, 11 and 12 included two rates of organic NPK fertilizers (45 kg N: 22.5kg P2O5 :24 kg K2O and 60 kg N :30 kg P2O5 : 36 kg K2O /fed) in the form of pigeon refuse as source of N in Patterns 5, 6, 7 and 8 and in the form of phytocompost in Patterns 9, 10, 11 and 12 + in the form of phosphate ore (20 % P2O5) +Phosphorein as source of P + in the form of potassium ore (8.2 % K2O)as source of K in Patterns 5, 6, 9 and 10, in combination with bio- control. In patterns 7, 8, 11 and 12 the source of P was mixed minerals ore (6.14 % P2O5) +Phosphorein and the source of K was mixed minerals ore (3.37 % K2O) and potassium ore, in combination with bio- control.
The obtained results could be summarized as follow:-
Leaf area index and total dry weight per plant were significantly affected by the tested Patterns at all sampling dates in both seasons, in favor of Pattern 8( high organic NPK rate, where the source of N was pigeon refuse, the source of P was mixed minerals ore +Phosphorein and the source of K was mixed minerals ore and potassium ore in combination with bio-control) and Pattern 6 ( high organic NPK rate, where the source of N was pigeon refuse, the source of P was phosphate ore +Phosphorein and the source of K was potassium ore in combination with bio- control).
Crop growth rate and net assimilation rate were significantly affected by the tested Patterns at the first and second periods in both seasons, in favor of applying Pattern 8 and pattern 6 at the first period in the first season and at the first and second periods in the second season. In addition, these two Patterns gave the tallest plants with the highest number of fruiting branches, while the shortest plants with the lower number of fruiting branches produced from Pattern 9 (low organic NPK rate, where the source of N was phytocompost, the source of P was phosphate ore +Phosphorein and the source of K was potassium ore in combination with bio- control) in both seasons.
The high mineral NPK fertilizers rate when combined with chemical control (Pattern 2) or bio-control (Pattern 4) significantly increased leaf area index at 79 days from sowing in the first season and at 100 and 121 days from sowing in the second season. Also, these two Patterns significantly increased total dry weight per plant at the three sampling dates and crop growth rate at the first and second periods in both seasons and net assimilation rate at the second period in both seasons and produced the tallest plants with the highest number of fruiting branches and highest internodes number per plant as compared with the recommended rate either with chemical control (Pattern 1) or bio-control (Pattern 3).
Insignificant differences in traits under study were found when using the high mineral NPK fertilizers rate either with chemical control (Pattern 2) or bio-control (Pattern 4) or using the recommended rate either with chemical control (Pattern 1) or bio-control (Pattern 3) which indicate that biological control was effective.
The high organic NPK rate significantly increased leaf area index and total dry weight per plant at 79, 100 and 121 days from planting in 2012 and 2013 seasons and crop growth rate and net assimilation rate at the first and second periods in both seasons and gave the tallest plants with the highest number of fruiting branches as compared with the low organic NPK rate especially when the source of N was pigeon refuse, the source of P was mixed minerals ore + Phosphorein and the source of K was mixed minerals ore and potassium ore in combination with bio- control (Pattern 8) or when the source of N was pigeon refuse, the source of P was phosphate ore + Phosphorein and the source of K was potassium ore in combination with bio- control ( Pattern 6).
From the obtained results, it is clear that organic fertilization with 60 kg N: 30 kg P2O5: 36 kg K2O /fed in the form of pigeon refuse as source of N, mixed minerals ore+Phosphorein as source of P and mixed minerals ore and potassium ore as source of K in combination with bio- control (Pattern 8) produced the highest growth of cotton.