| Abstract:Large-scale pig farming had developed rapidly with the adjustment of agriculture structure and continual improvement of husbandry techniques. This has resulted in frequent discharge of enormous pig slurry. This pig slurry not only polluted the nearby water body and the surrounding environment, but also seriously hampered the sustainable development of livestock. Lots of large-scale farms had perfected the technology of comprehensive harnessing of solid waste and aquaculture wastewater. The solid waste had been developed commercialized organic fertilizer. But the wastewater can not been used as a result of high moisture content and long transportation bottleneck. How to deal with the wastewater has been a required problem to be solved, especially for the livestock and fowl breeding in large-scale. Large-scale pig farm-crop production complex system was established under farmland resource condition. It could carry out resource utilization of pig slurry and low maintenance of running. But it was difficult to establish the system if cultivated field was decentralized management. The system required a wide space and matching farmland. Jiangsu has a lot of large farms and is qualified for establishing the system. It might be predominance-region for modern agriculture. Wheat-rice region is the primary planting format in Jiangsu. And this study based on the existence of hand planting rice, mechanical transplanted rice and direct seeding rice, their special requirements for using pig slurry and suitable period for using pig slurry of wheat under production conditions of large scale farms. The field experiments were conducted to study the effects of different pig slurry using models on the nutrient uptake and utilization, the dry matter accumulation characteristics, yield, quality and food safety in wheat and rice. The paper makes clear the utilization technology of pig slurry in wheat and different planting of rice based on three goals of yield, pig slurry burden quantity and food safety, which provided a theoretical foundation for the establishment and further demonstration and promotion of the ecological recycle agriculture mode of large-scale pig farm-cropland plantation. The main results are as follows:1. Effects of pig slurry from large-scale pig farm on transplanting rice With the rapid development of China’s large-scale pig farms, increasing pig slurry is causing serious environmental pollution that in turn threatens the sustainable development of large-scale pig farming. The utilization of pig slurry, a kind source of nutrients, combined by pig farming with cropping is one of the best solutions to this problem. This study was conducted to determine the effects of different substitute proportion and application rate of pig slurry on both grain yield and quality of paddy rice. The pig slurry used in the experiment contained1000mg·L-1of total nitrogen,540mg·L-1of available nitrogen and779mg·L-1available phosphorus. Eleven treatments of the field experiment were designed as follows, CK1(No N), CK2(all nitrogen in chemical fertilizer),40%L(40%pig slurry+60%N, L denotes low amount pig slurry,84m3-ha),40%M(40%pig slurry+60%N, M denotes middle amount pig slurry,108m3·hm-2),40%H(40%pig slurry+60%N, H denotes high amount pig slurry132m3·hm"2),70%L(70%pig slurry+30%N, L denotes low amount pig slurry,147m3·hm-2),70%M(70%pig slurry+30%N, M denotes middle amount pig slurry,189m3·hm-2),70%H(70%pig slurry+30%N, H denotes high amount pig slurry198m3·hm-2),100%L(100%pig slurry+0%N, L denotes low amount pig slurry,210m3·hm-2),100%M(100%pig slurry+0%N, M denotes middle amount pig slurry,270m3·hm-2) and100%H(100%pig slurry+0%N, H denotes high amount pig slurry,330m3·hm-2). The results showed that:(1)100%L treatment was highly favourable for improving the NPK content and the NPK accumulation of70%M treatment was the highest. Compared with CK2, increase amplitude of the N content of pig slurry+N fertilizer were respectively:0.2%-8.4%,3.0%-4.1%,2.9%-8.8%,0.7%-1.9%, increase amplitude of the P content of pig slurry+N fertilizer were respectively:6.6%-23.7%,1.0%-21.9%,3.5%-27.7%,2.6%-5.6%, increase amplitude of the K content of pig slurry+N fertilizer were respectively:0.2%-8.0%,1.9%-4.1%,2.4%-10.2%,0.3%-1.6%. Compared with CK2, increase amplitude of the N accumulation of pig slurry+N fertilizer were respectively:3.1%-9.2%,0.2%-11.0%,1.1%-12.7%,3.1%-7.4%, increase amplitude of the P accumulation of pig slurry+N fertilizer were respectively:3.1%-24.9%,0.3%-20.2%,3.1%-43.6%,1.8%-8.8%, increase amplitude of the K accumulation of pig slurry+N fertilizer were respectively:1.4%-10.5%,4.0%-14.1%,2.1%-17.2%,2.4%-7.2%.(2)There were a quadratic regression equation and significant positive correlation between dry matter accumulation and grain in each growing period.(2) Application of pig slurry enhanced rice grain yield and the highest yield was obtained at the rate of9412.6 kg-hm-2with70%M treatment,28.38%to49.13%higher than the control of block and3.1%to6.6%higher than the control of conventional N application rate.(3) Compared with CK2, application of pig slurry could also enhance brown rice, milled rice, head milled rice and the protein content and decrease amylose content of rice grains. Among them, the highest brown rice rate and milled rice rate was obtained with40%H,5.9%higher than the control of conventional N treatment. When the substitute proportion reached40%and70%, the protein content decreased with decreasing of pig slurry’s amount. While when the substitute proportion reached100%, the protein content was obtained at middle amount of pig slurry. The rice grain amylase content increased with decreasing of pig slurry’s amount with each substitute proportion. Compared to convention N treatment, RVA of each pig slurry substitution treatment had no significant difference. Based on yield, income and environment, the proper mode of pig slurry substitute proportion was70%M under this experimental condition.2. Effects of pig slurry from large-scale pig farm on machine transplanted ricePig slurry is a good source of plant nutrients and replacing chemical fertilizers with slurry can not only achieve resource utilization of slurry, but also reduce the amount of fertilizer. In this study, pig slurry was applied in the production of rice, it was attempted to investigate the effects of slurry on nutrition absorption, yield and quality of rice, further more to find the optimum rate of pig slurry. The experiment included12treatments with three repetitions for each treatment, including one unfertilized blank treatment (CK1), one local conventional fertilization treatment (CK2), one pig slurry-only treatment M, and nine treatments receiving the combined application of pig slurry and nitrogen fertilizer (respectively marked as T1, T2, T3, T4, T5, T6, T7, T8, and T9); the randomized block design was employed. For basal application of fertilizer, pig slurry was applied by45m3·hm-2,67.5m3-hm-2, and90m3·hm-2; in the panicle fertilizer stage, pig slurry was applied by60m3·hm-2,90m3·hm-2, and120m3-hm-2, in the tillering stage urea was applied by187.5kg-hm-2. The results showed that:(1) The combined applications of pig slurry and N fertilizer were highly favourable for improving nutrient uptake and dry matter accumulation, especially in the middle and late of rice growth. Compared to conventional fertilization, Application pig slurry can increase the NPK content and NPK accumulation amount. In contrast, CK1had the maximum nitrogen harvest index, nitrogen use efficiency for dry matter production, and nitrogen use efficiency for rice production, all of which were significantly higher than those of most treatments receiving the combined application (except T1and T4) and declined with increasing slurry application amount in the heading stage.(2)Compared to conventional fertilization, the combined application of slurry and nitrogen fertilizer in reduced dose could produce equal or higher yield, with a increase of45-789kg·hm-2.(3)The contents of Pb, As, Ca, Mg and Fe in rice reached the highest at every growth stage, when combined with base fertilizer90m3·hm-2pig slurry,120m3-hm’2and187.5kg-hm-2urea. The levels of Cd, Hg, Cr and Mn reached the highest at every growth stage when using conventional fertilization (CK2).Cu reached the highest value at every growth stage except jointing stage when using pig slurry treatments (M). Zn reached the highest value at every growth stage except jointing stage, when combined with base fertilizer90m3·hm-2pig slurry,120m3·hm-2and187.5kg-hm-2urea. As, Pb, Mg, Zn, Fe, Mn and Cu increased with the increase of pig slurry in heading stage on the basis of identical pig slurry as base fertilizer. Meanwhile, Hg, Cd and Cr reduced with the increase of pig slurry. The contents of Pb, Cd, Cr, As and Hg in grains of every treatments were lower than the maximum levels of contaminants in foods (GB2762-2005). Meanwhile the pig slurry as basal, panicle fertilizer and compound fertilizer could not only enhance the contents of Zn, Fe, Mn, Ca, Na and Mg, but also reduce the contents of Hg, Cd, Cr. It is concluded that the substitute fertilizer of pig slurry could partially improve the beneficial elements contents. Moreover, it could not lead to the elevation of heavy metals, whereas, it could reduce the levels of some heavy metals, such as Hg, Cd and Cr.(4) As for the quality of the grains, compared with the conventional fertilization, all treatments remained basically unchanged in milling quality, but they had better nutritional (protein content, in particular) and eating quality. Under the conditions of this experiment, pig slurry application could reduce up to69%of the nitrogen fertilizer amount without need of either phosphorus or potassium fertilizer.3. Effects of pig slurry from large-scale pig farm on direct seeding riceIn this study, pig slurry was applied in the production of seeding rice, it was attempted to investigate the effects of slurry on nutrition absorption, yield and quality of rice, further more to find the optimum rate of pig slurry. The experiment included11treatments with three repetitions for each treatment, including one unfertilized blank treatment (CK1), one local conventional fertilization treatment (CK2) and nine treatments receiving the combined application of pig slurry and nitrogen fertilizer (respectively marked as T1, T2, T3, T4, T5, T6, T7, T8, and T9); the randomized block design was employed. For basal application of fertilizer, pig slurry was applied by60m3·hm-2,90m·hm-2, and120m3·hm-2; in the panicle fertilizer stage, pig slurry was applied by60m3·hm-2,90m3·hm-2, and120m3·hm-2; in the tillering stage urea was applied by225kg-hm-2. The results showed that:(1) the combined application of pig slurry and N fertilizer was highly favourable for improving nutrient uptake and dry matter accumulation of seeding rice. When the same amount of pig slurry was applied as base fertilizer, the NPK content of seeding rice increased with the pig slurry as panicle fertilizer and the NPK content was positively correlation with the amount of pig slurry.(2) Application of pig slurry enhanced rice grain yield and the highest yield was obtained at the rate of8210.8kg-hm’2with T9treatment,506.3kg-hm-2higher than the control of conventional N application rate.(3) The contents of Pb, Mg, S, Cu, Zn and Fe in seeding rice reached the highest at every growth stage, when combined with base fertilizer120m3-hm-2pig slurry, panicle fertilize120m3·hm-2pig slurry and225kg-hm-2N fertilizer. The levels of Co, Ni, Cr and Mn reached the highest at every growth stage when using conventional fertilization (CK2). When the same amount of pig slurry was applied as base fertilizer, the Pb, Mg, S, Cu, Zn, Fe and Mn of seeding rice increased with the pig slurry as panicle fertilizer, conversely, as the amount of pig slurry increased, Ni, Co and Cr of seeding rice decreased.(4) As for the quality of the grains, compared with the conventional fertilization, milling quality of combined application of pig slurry and N fertilizer was slightly decreased, but protein contents was enhanced and the RVA value was optimized. This explains the fact that combined application of pig slurry and N fertilizer could improve the grain quality of seeding rice. Under the conditions of this experiment, the pig slurry could replace N fertilizer as basal fertilizer and panicle fertilizer, and combined application of90m3·hm-2pig slurry as basal fertilizer,90m3·hm-2pig slurry as panicle fertilizer and225kg·hm-2urea could reach the level of conventional fertilization.4. Effects of pig slurry from large-scale pig farm on wheatTaking Yangmai18, widely cultivated in south of Huaihe River, as experimental material, this study investigated effect of application of30,60,90and120m3·hm-2the pig farm slurry at wintering stage combined with0,30,60,90kg·hm-2N fertilizer at heading stage on nutrition uptake, yield, medium-and micro-element contents and quality of wheat. The results showed that:(1) available effects of pig slurry on nitrogen nutrition in wheat. The winter application of pig slurry of60-120m3·hm-2instead of30-60kg·hm-2nitrogen fertilizer at panicle formation could satisfy the nitrogen nutrition demand of wheat with higher nitrogen accumulation and utilization efficiency.(2)In jointing, the wheat dry matter accumulation rose along with the pig slurry, In heading and maturity stage, there was a quadratic regression equation between yield and dry matter accumulation. Under combination of120m3·hm-2pig slurry with90kg·hm-2, the wheat dry matter accumulation achieved the highest, In yield, the combined application of above60kg·hm-2N fertilizer during heading period and pig slurry could reach conventional fertilization level. The treatment of using120m3·hm-2pig slurry and90kg-hm-2nitrogen during heading period reached the highest yield. Compared to CK2, the yield increase amplitude of the combined applications of pig slurry and N fertilizer were20.26-337.78kg-hm-2.(3)The Ca, Mg and Fe contents of plants firstly decreased then increased with extending of growth period, but the Cu, Zn and Mn contents decreased continuously through the growth period. Ca, Mg, Cu and Zn reached the highest value at every growth stage except jointing stage when applying120m3·hm-2PS with90kg-hm-2urea. Fe and Mn reached the highest value at every growth stage when applying120m3·hm-2PS with90kg-hm-2urea. The contents of Ca, Mg, Cu, Zn, Fe and Mn all increased with increasing PS application across the growth period. For the objective of quality, applying90m·hm-2PS with60kg·hm-2urea was the better fertilization pattern. Combined application of the anaerobic technology, harmless treatment of PS with N fertilizer could increase medium-and micro-element contents and quality of wheat. Generally, it was recommended to apply60-120m3·hm-2PS at wintering stage and90kg-hm-2urea at heading stage under field conditions. Compared with conventional fertilization, combined application of pig slurry and N fertilizer could reduce by more than30%N fertilizer. |
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